Shiga toxin-producing Escherichia coli in beef

Prevalence and risk factors of Shiga toxin-producing Escherichia coli serotypes in beef at abattoirs and retail outlets in Gauteng

Industry Sector: Cattle and Small Stock

Research focus area: Red Meat Safety, Nutritional Value, Consumerism and Consumer Behaviour

Research Institute: Department of Production Animal Studies, University of Pretoria

Researcher: Prof. Peter Thompson Ph.D.

The Research Team

TitleInitialsSurnameQualification
ProfA.A.AdesiyunPh.D
DrE.MadorobaPh.D
DrL.O.OnyekaM.Sc

Year of completion : 2017

Aims of the project

  • To determine the prevalence O157 and non-O157 Shiga-toxin producing Escherichia coli (STEC) in beef abattoirs in Gauteng
  • To determine the prevalence O157 and non-O157 STEC in beef and beef products at retail outlets in Gauteng
  • To identify the important STEC serotypes present in beef and beef products in Gauteng
  • To identify risk factors for STEC contamination of carcasses and beef products in Gauteng

Executive Summary

Shiga toxin-producing Escherichia coli (STEC), particularly the O157 strains, are food-borne zoonotic pathogens of public health importance worldwide. Foods of cattle origin have been implicated in various outbreaks and epidemiological studies have revealed that cattle are major reservoirs of STEC. We conducted cross-sectional surveys from Nov 2015 to Nov 2016, to investigate the prevalence and molecular characteristics of O157 and non-O157 strains of STEC in beef and beef products in the Gauteng province of South Africa.

A total of 265 swab samples of beef carcasses from 12 abattoirs and 399 beef products from 31 retail outlets were screened for STEC using a multiplex PCR. The overall prevalence in abattoir samples was 37% (55/149) in summer and 34% (39/116) in winter. In beef products at retail outlets it was 20% (27/137) in autumn, 14% (18/130) in winter and 17% (22/132) in summer; the highest prevalence was detected in boerewors (35%) followed by mincemeat (21%). The predominant serotypes detected were O113 (19.4%) and O157 (14.9%) in beef products, and O113 (14%) from abattoirs.

Our results demonstrate that STEC is present in South African beef and beef products, and that this may pose a real food-borne disease threat. Further investigation of the epidemiology of the pathogen is required; it is proposed that this take the form of longitudinal studies to investigate the prevalence of shedding of STEC by cattle in the feedlot, following them through to the abattoir to determine factors associated with carcass contamination.

Additional Comments

As this is part of a PhD project, further molecular work is still to be done on the isolates, resulting in further planned publications. The samples also provided material for an MSc student (funded by UP research funds) to work on Salmonella contamination – these results will also be made available to RMRDSA once finalized.

Popular Article

Assessing the prevalence of shiga toxin-producing escherichia coli in beef at abattoirs and retail outlets in gauteng

Dr Lorinda Frylinck, Senior Navorser, LNR-Diere Produksie, Irene.

Introduction

The production of safe and wholesome beef and beef-derived food products is the highest priority for the beef industry in South Africa. There are potential risks associated with the possible presence of harmful pathogens in the food production chain; however, clear guidelines and regulations have been implemented to reduce these risks to a minimum and ensure a safe product for consumers. Nevertheless it remains important to continually assess these risks and to ensure effective implementation of control measures.

Shiga toxin-producing Escherichia coli (STEC) are bacteria associated with food and waterborne diseases and have been recognized as causing public health problems worldwide. The WHO Foodborne Disease Burden Epidemiology Reference Group (FERG) reported that ‘Foodborne STEC’ caused more than 1 million illnesses and 128 deaths in 2010 (8).

Of the over 470 different serotypes of STEC detected in humans, the O157:H7 serotype is the most frequently associated with large food and water-borne outbreaks (7). However, non-O157 STEC have been increasingly isolated from cases of haemorrhagic colitis (severe GIT infection and bloody diarrhoea) and as well as some fatal kidney failure (HUS; haemolytic uraemic syndrome) cases.

Although the first report of the occurrence of HUS in South Africa dated as far back as 1968 (6), the causative agent was poorly understood at that time. The first clinically proven incidence of E. coli O157:H7 in South Africa was later linked with haemorrhagic colitis (3). The importance of the pathogen in South Africa and other southern African countries has, however, been highlighted by subsequent major outbreaks of bloody diarrhoea in which E. coli O157 strains were implicated (4). Of particular interest was a study in Gauteng province in 2011, in which 7.7% of children with diarrhoea were positive for E. coli O157 (5).

Epidemiological investigations have revealed that cattle are a major reservoir of STEC. Many outbreaks of E. coli O157:H7 have been associated with beef, in particular ground beef, and analyses of some cases have identified undercooked beef as a significant risk factor. However, the fact that E. coli-associated conditions in humans, such as HUS, are not as yet notifiable in South Africa may mean that the occurrence of STEC-associated disease in humans is under-reported. In addition, given the weight of evidence from elsewhere in the world, it is possible that contamination of beef products is also a risk factor in South Africa.

Research problem and objectives

There is a dearth of current information on the frequency of occurrence of O157 and non-O157 strains of STEC, and on the risk they pose to consumers of beef products, in South Africa. Hence, the objective of this study was to determine the prevalence and characteristics of O157 and non-O157 STEC strains in beef carcass and beef products sold at retail outlets in the Gauteng province of South Africa.

Materials and Methods

During a one-year period from Nov 2015 to Nov 2016, two independent cross-sectional surveys were carried out to determine the prevalence of STEC at abattoirs as well as at retail outlets where beef-based food products are sold.

Study 1: Twelve abattoirs (six high throughput and six low throughput) were selected and each was visited during summer and winter months for sample collection. Five animals were randomly selected in each abattoir and tagged for sample collection. Firstly, samples were collected by swabbing the skin of the perineal area immediately after slaughter. Thereafter, carcass swab samples were collected from different parts of the carcass at various stages during processing, including pre-evisceration, post-evisceration, post-washing and 24 hours post-chilling.

Beef carcass sampling and processing at the abattoir

Study 2: A total of 31 retail outlets including both large supermarket chains and smaller butcheries were randomly selected. Visits were made to each of these outlets during autumn, winter and summer months of 2016 for sample collection. Sampling of five types of popular beef products (brisket, boerewors, mince, cold meat, and biltong) was done at each outlet during each visit.

Each sample was analyzed for the presence of Shiga toxin-encoding genes (stx1and stx2) using conventional multiplex PCR. All samples positive for stx genes based on PCR were screened for the following O-serotypes: O26, O91, O103, O111, O113, O145 and O157 using a multiplex PCR assay.

Results and Discussion

Overall, the prevalence of STEC in beef carcass swabs collected from 12 red meat abattoirs across Gauteng province during summer and winter months was 35.5% (94/265). The highest prevalence (50%) was detected in perineal samples, which is hardly a surprise because cattle are an established reservoir of STEC; this may therefore reflect the prevalence of the pathogen in cattle arriving at abattoirs. Transportation stress is known to increase the shedding of enteric pathogens and could therefore be a contributing factor to the observed high prevalence in perineal samples. STEC was found in 39% of both pre-evisceration and post-evisceration carcasses, while washed carcasses and 24 hour chilled carcasses had a lower prevalence of 23% and 20% respectively. Therefore, although washing of carcasses at the abattoir removed much of the STEC contamination, the fact that the bacteria were still present on the surface of some chilled carcasses is of potential food safety significance, since cuts from these carcasses end up for sale in various forms at retail outlets.

Boerewors on display in a retail outlet

Of the 399 beef products sampled from 31 retail outlets, 67 (16.8%) were contaminated by STEC strains, an observation that is of food safety significance if such products were to be improperly cooked and consumed by highly susceptible individuals.

The highest prevalence of STEC was detected in boerewors (35%), followed by minced meat (21%). Ground beef ordinarily includes meat from many carcasses; consequently a few infected livestock could potentially contaminate a great quantity of ground beef. Biltong had the lowest prevalence of contamination (5%), while brisket and cold meat had 11% and 6% respectively. These results are in contrast to a previous study in South Africa, in 2009, involving biltong, cold meat and minced meat at retail outlets, which found that 2.8% of the samples were positive for E. coli O157 (1).

The prevalence of STEC in abattoir and retail outlet samples was somewhat higher during the summer months compared to the winter months. While many factors are believed to affect the prevalence of E. coli O157:H7, only season has been consistently shown to impact the shedding of this bacterium by cattle (2), and some previous studies have also observed a higher prevalence of shedding during the warmer months than the winter months.

The serotype analysis showed that O113 was the post prevalent serotype both on beef carcasses (14%) as well as in beef-based products (19%). This observation is of particular interest considering that O113 is an emerging serotype associated with human illness and sometimes with HUS in several countries including Spain, Belgium and Australia. Serotype O113 of STEC may therefore potentially be important in human diseases in South Africa and this requires further studies. Some of the other serotypes detected  have also previously been implicated in human diseases elsewhere in the world.

Unlike in abattoir samples where the prevalence of serotype O157 was very low (1%), a higher prevalence of 15% was detected in retail meat samples. This finding may be explained in part by the fact that the current study was cross-sectional by design (giving a “snapshot” at a particular point in time) and not a longitudinal study. Therefore serotype O157-contaminated beef products may have originated from abattoirs not sampled in the current study, and the prevalence may vary greatly between places and over time. There is also a possibility that it may partially also be a result of contamination from other sources at the retail outlet level.

Mince meat on display in a retail outlet

Conclusion

This study has shown that contamination of beef products with potentially harmful bacteria can occur during different processing stages. The low numbers of reported cases of food-associated disease in South Africa suggest that the risk to consumers is low; however, it is not known whether all cases are reported, or that all cases are correctly diagnosed. Therefore, further research is needed in order better understand the dynamics of foodborne pathogens in South Africa, to accurately assess the risk they pose, and to accurately inform control measures.

It is well known that efficient implementation of control measures during slaughter and processing procedures can greatly reduce meat surface microbial contamination and ensure the safety of the final product. The South African Meat Safety Act (2000) has addressed potential risk factors by adopting several internationally recognized preventive measures such as the Hazard Analysis Critical Control Point (HACCP) system and Good Manufacturing Practices (GMP) in order to promote safe meat for consumers. The application of GMP and HACCP principles during handling and processing of products, as well as the proper cooking of meat products before consumption, will effectively reduce the threat of food borne disease.

Acknowledgments

We thank Red Meat Research and Development South Africa (RMRD SA) for funding this research and the Gauteng Department of Agriculture and Rural Development for granting us access and assistance to carry out the cross-sectional survey at the abattoirs.

References

  1. Abong’o, B.O. and Momba, M.N., 2009. Prevalence and characterization of Escherichia coli O157: H7 isolates from meat and meat products sold in Amathole District, Eastern Cape Province of South Africa. Food Microbiology, 26(2), pp.173-176.
  2. Berry, E.D. and Wells, J.E., 2010. Escherichia coli O157: H7: recent advances in research on occurrence, transmission, and control in cattle and the production environment. Advances in Food and Nutrition Research, 60, pp.67-117.
  3. Browning, N.G., Botha, J.R., Sacho, H. and Moore, P.J., 1990. Escherichia coli O157: H7 haemorrhagic colitis. Report of the first South African case. South African Journal of Surgery, 28(1), pp.28-29.
  4. Effler, E., Isaäcson, M., Arntzen, L., Heenan, R., Canter, P., Barrett, T., Lee, L., Mambo, C., Levine, W., Zaidi, A. and Griffin, P.M., 2001. Factors contributing to the emergence of Escherichia coli O157 in Africa. Emerging Infectious Diseases, 7(5), p.812.
  5. Galane, P.M. and Le Roux, M., 2001. Molecular epidemiology of Escherichia coli isolated from young South African children with diarrhoeal diseases. Journal of Health, Population and Nutrition, 19(1), pp.31-38.
  6. Kiibel, P.J., 1968. The haemolytic-uraemia syndrome: a survey in Southern Africa. South African Medical Journal, 42(27), pp.692-698.
  7. Mora, A., Herrera, A., López, C., Dahbi, G., Mamani, R., Pita, J.M., Alonso, M.P., Llovo, J., Bernárdez, M.I., Blanco, J.E. and Blanco, M., 2011. Characteristics of the Shiga-toxin-producing enteroaggregative Escherichia coli O104: H4 German outbreak strain and of STEC strains isolated in Spain. International Microbiology, 14(3), pp.121-141.
  8. WHO [World Health Organization], 2015. WHO estimates of the global burden of foodborne diseases. Available at http://apps.who.int/iris/bitstream/10665/199350/1/9789241565165_eng.pdf

Please contact the Primary Researcher if you need a copy of the comprehensive report of this project – Peter Thompson onpeter.thompson@up.ac.za

Slaughter conditions to optimise chevon meat quality

Determination of slaughter conditions to optimise chevon visual and eating quality

Industry Sector: Cattle and Small Stock

Research focus area: Animal Products, Quality and Value-adding

Research Institute: Agricultural Research Council – Animal Production Institute

Researcher: Dr L Frylinck PhD

Title Initials Surname Highest Qualification
Prof PE Strydom PhD
Prof EC Webb PhD Animal Science
Dr P Pophiwa PhD Animal Science
Prof LC Hoffman PhD Animal Science
Ms GL van Wyk MSce (Registered for PhD)
Ms JD Snyman ND Histologie

Year of completion : 2018

Aims of the project

  • To determine the expression of genomic markers in five South African purebred genotypes – Bos indicus
  • To determine the optimum slaughter procedures (electrical stimulation for 15 – 60 seconds or delayed/step wise chilling – time determined by optimal pH) for carcasses from castrated and intact male goats of two breed types: Boer Goats and Indigenous Veld Goats (IVG, Eastern Cape Xhosa or Northern Cape Speckled Goats
  • To evaluate the tenderness and connective tissue characteristics in six different muscles m. longissimus thoracis et longissimus (LTL), m. semimenbranosus (SM), biceps femoris (BF), supra spinatus (SS), infra spinatus (IS) and semitendanosus (ST) in electrical stimulated carcasses of Boer Goats and IVG from castrated and intact male goats.
  • To evaluate the tenderness and calpain system ageing related characteristics in m. longissimus thoracis et lumborum (LTL) and m. semimembranosus (SM) muscles of electrical stimulated and non-stimulated carcasses of Boer Goats and IVG from castrated and intact male goats.
  • To evaluate sensory attributes and other meat quality characteristics of chevon from the respective post-slaughter treatments in m. longissimus thoracis et lumborum (LTL) and m. semimembranosus (SM) muscles of electrical stimulated and non-stimulated carcasses of the two breed types; Boer Goats and IVG from castrated and intact male goats.

Executive Summary

The demand for goat meat in South Africa is relatively low because of traditional perceptions of off smells, off flavours and expected toughness. Perceptions also exist that Indigenous Veld Goat (IGV) produce tougher meat than Boer Goat (BG) specially bred to be a meat producing breed. The name indigenous goat is perceived as being small and not suitable for meat production. It is now discovered that some Indigenous Eco-types of Southern Africa, compare well with the Boer goat in size, can also produce good meat products if good farming and rearing practices are followed. Except for the advantage to preserve the indigenous breeds for the future generations, these breeds are well adapted to the harsh climate conditions in Southern Africa and are hardy with minimum need for veterinary intervention. Production and slaughter procedures should be adapted to suit the characteristics such as the low glycolytic potential and low carcass fat of goat carcasses. There is therefore a need to optimise the pre- and post-slaughter procedures in order to optimise the chevon (goat meat) visual and eating quality.

The first aim were investigated by applying different pre- and post slaughter procedures such as castration or not, applying electrical stimulation for 20 and 30 seconds or apply stepwise chilling. The monitoring of the muscle pH and temperature, muscle energy, meat colour and tenderness showed that either controlled step wise chilling or electrical stimulation of at least 30 sec will prevent cold toughening and produce ideal conditions for the intra muscular proteolytic enzymes to optimally function. It was found that castrated animals produced more tender meat than intact carcasses, but that more subcutaneous fat were produced, which could be advantageous to its eating experience. Both breed types: Boer Goats and Indigenous Veld Goats (IVG, Eastern Cape Xhosa or Northern Cape Speckled Goats, showed the same advantage in tenderness and colour if slaughter conditions were optimised.

The intrinsic characteristics of the six different muscles m. longissimus (LTL), m. semimenbranosus (SM), biceps femoris (BF), supra spinatus (SS), infra spinatus (IS) and semitendanosus (ST) differed from each other as expected, but castrated muscles had an higher intramuscular fat content – up to 4% than that on intact carcasses – similar in both breed-types tested. Percentage collagen solubility did not differ between the different muscles, but the total collagen measured in each muscle type did differ. Thus is optimal cooking method important.

Evaluating the tenderness and calpain system ageing related characteristics in m. longissimus thoracis et lumborum (LTL) and m. semimembranosus (SM) muscles of electrical stimulated and non-stimulated carcasses of Boer Goats and IVG from castrated and intact male goats confirm that the breed types did not differ in tenderness, but castration do have an advantageous effect on tenderness. It is said for beef that sarcomere length (SL) longer than 1.7 µm does not influence tenderness, but in this project it was obvious that the shorter 1.8 µm sarcomere length compared to that of our first subproject of 2 µm could have influenced meat tenderness. It is said that the calpain system works more effectively when the SL length is longer.

Sensory panel evaluation showed attributes and other meat quality characteristics of chevon from the respective post-slaughter treatments in m. longissimus (LTL) and m. semimembranosus (SM) muscles of electrical stimulated and non-stimulated carcasses of the two breed types; Boer Goats and IVG from castrated and intact male goats. Overall it seems like the sensory panel found the LTL and SM muscles tough, although the shear force measurements was not exactly inline with their findings. As mentioned before, the slaughter conditions could have been chosen better, for instance the ES should have been 30 sec and not 20 sec. Delayed/stepwise chilling could have given better results. I do recommend though that if a future sensory panel study is being done, mutton should be included to remove the possibility of biasness. Although I have no reason to doubt the professionalism of the panel, I do think that there could be a possibility of a negativity towards goat meat.

The evaluation of carcass characteristics and yield of electrical stimulated and non-stimulated carcasses of the two breed types; Boer Goats and IVG from castrated and intact male goats (additional aim) showed more differences between castrated and non-castrated carcasses than between carcasses of the two breed types. The dressing percentages did not differ between the castrated breeds, but was a bit higher that that of the intact carcasses. There was no significant differences in the percentage meat yield between breeds, although the different commercial cuts could differ a bit in sizes, mainly because of different ratios and form of different parts of the carcass that is genotypic-ally expected.

From this project a better understanding is formed on how goat temperament differ from other farm animals, that pre and post slaughter conditions must be adapted to take their unique characteristics into account. A small change in slaughter practice can have a mayor impact on the end product. Information acquired from these and future research should be disseminated to the farmers, producers and specific abattoirs that apply to special slaughter facilities and management for chevon production.

.Development of the market for chevon in South Africa would offer more diversity of species for red meat producers and especially benefit emerging farmers who produce over 90% of the goats in South Africa. There are good indications that goats can yield chevon or kid of acceptable quality to consumers, providing that animals of an appropriate age and sex group are slaughtered, handled and fed well during production and slaughter so as to minimise stress and prevent cold shortening.

Popular Article

Karkaskwaliteit/opbrengs van intakte en gekastreerde Boerbok en groot raam inheemse eco-tiepe veld bokke (sg. Noord-Kaap Spikkel en Oos-Kaap Xhosa (IVB) bokke)

Dr Lorinda Frylinck, Senior Navorser, LNR-Diere Produksie, Irene.

Veertig gespeende Boer en veertig IVB bokkies, waarvan 20 elk gekastreerde en intakte rammetjies was is in die krale van die Landbounavorsingsraad-Diere Produksie, Irene grootgemaak. Hulle is dieselfde dieet gevoer nl. “Ram, Lam en Ooi” pille, lucerne, hooi en natuurlike gras totdat ‘n gemiddelde lewendige massas van ongeveer 35 kg bereik het (lam ouderdom/0 permanente tande). Die gekastreerde IVB bokke was gemiddeld 1 kg ligter as die ander diere.

Hierna is hul geslag en die karkasse is oornag in ‘n koelkas van ongeveer 4°C geplaas. Buiten die warm karkasmassas, is die verdere karkaskwaliteitsmetings die volgende dag geneem. Die koue karkasmassas was tussen 14 to 16 kg en daar was ‘n warm tot koue karkasmassa verskil van ongeveer 3.5%. Die uitslag % vir die gekastreerde diere (BB en IVB)(44.5%) wat ongeveer 2.5% hoër was as die van die intakte rammetjies (42.0%). Ons het die sogenaamde vyfde kwart nie bestudeer nie.

Oogspier omtrekke gemeet in mm2 van die intakte ramme van beide die BB en IVB het nie verskil nie, maar die gekastreerde BB se omtrekke was effens groter end die van die gekastreerde IVB was effens kleiner – te wagte a.g.v. die kleiner karkasse.

Die karkasse is in die volgende kommersiele snitte verdeel en geweeg: nek, dikrib, lies, blad, bors, lende, kruis, boud en skenkel. Elkeen van hierdie snitte is weer gedisekteer om die % been, % sigbare vet en % vleis vir elke snit te bepaal. Verskille wat uitgestaan het tussen die 4 proefgroepe is die hoër nek % en dikrib % van die gekastreerde BB, die groter % lies by die BB oor die algemeen en die hoër % lende en boud van die gekastreerde IVB. Die % kruis van die gekastreerde diere was effens hoër invergelyking met die intakte diere.

Uit bogenoemde massas is die % vleis, % been en % sigbare vet (insluitend onderhuidse vet) per karkas bereken. Verstaanbaar het die intakte ram karkasse ‘n 1 tot 2 % hoër been persentasie van ongeveer 23% gehad teenoor die van 22% van die gekastreerdes. Die gekastreerdes het weer ‘n 2 tot 4% hoër totale vet % gehad van 9 to 10% teenoor die van die intakte ram karkasse van 6% vir die IVB en 8% vir die BB. Teenoorgestelde is weer gevind dat intakte IVB ram karkasse ongeveer 1% meer vleis (71% van die karkasmassa) gehad het invergelyking met die van die BB karkasse (69% van die karkasmassa) en die gekastreerde IVB ‘n karkasvleis % van 67% gehad het. Niere en niervet is ook geweeg. Niervet (kg) in al die gekastreerde karkasse (0.4 kg) was meer as die van die intakte ram karkasse van ongeveer (0.3 kg).

Dit lyk asof IVB nie so goed reageer op kastrasie nie omdat hulle so effens ligter was as die ander toetsgroeps en verdere studies hieromtrent is nodig. Hierdie kan ook dalk toegeskryf word aan kompetisie vir kos en kompeterende diere behoort alpart gehou te word. Tog lyk dit nie of dit die gekastreerde Boerbokke gepla het nie. Die uitslag persentasies het egter nie verskil tussen die gekastreerde rasse nie en was effens hoër as die van die intakte ramme, hoofsaaklik a.g.v. hoër % sigbare vet.Daar was nie noemenswaardige verskille in die % vleis tussen die rasse nie. Die groottes van die verskillende snitte verskil a.g.v. bouvorm en dit is genotipies te wagte, maar oor die algemeen gee die Boerbok en groot raam Inheemse Veld Bokke dieselfde tiepe opbrengs onder dieselfde produksie omstandighede.

Hierdie studie is deel van ‘n groter projek wat deur die Rooi Vleis Navorsings en Ontwikkeling SA (verteenwoordiger van die rooivleisbedryf) en Landbounavorsingsraad befonds word.

Please contact the Primary Researcher if you need a copy of the comprehensive report of this project – Lorinda Frylinck on lorinda@arc.agric.za

Genomic markers in beef tenderness

The effectiveness of genomic markers in predicting the meat tenderness in pure beef genotypes under South African production and slaughter conditions

Industry Sector: Cattle and Small Stock

Research focus area: Livestock production with global competitiveness: Breeding, physiology and management

Research Institute: Agricultural Research Council – Animal Production Institute

Researcher: Dr L Frylinck PhD

Title Initials Surname Highest Qualificaion
Prof PE Strydom PhD Animal Science
Ms A Basson MSc

Year of completion : 2018

Aims of the project

  • To determine the expression of genomic markers in five South African purebred genotypes – Bos indicus (Brahman), Sanga type (Nguni), British Bos taurus (Angus), European Bos taurus (Charolais) and the composite (Bonsmara) for genes associated with beef tenderness in meat.
  • To determine the relationship between the actual physiological tenderness characteristics under South African production and slaughter conditions of the meat from these five main South African genotypes and the known DNA-marker information.
  • To assess the phenotypic variation in meat tenderness within South African selected pure beef genotypes under the same environmental conditions and to build a tenderness prediction model.

Executive Summary

Purebred South African bulls of 5 breeds (n=166) were finished on a grain diet at the Animal Production Institute of the Agricultural Research Council (API-ARC), Irene. Breeds included Angus (n=27; representative of British Bos taurus), Brahman (n=35; Zebu type Bos indicus), Bonsmara (n=35; South African composite breed with large Sanga contribution), Charolais (n=34; European Bos taurus) and Nguni (n=35; Sanga type Bos taurus africanus). Animals were sampled over 3 slaughter periods in 2011 (50 animals), 2012 (50 animals) and 2014/2015 (66 animals). Bulls were sourced from breeders that are registered with the appropriate breeders’ associations and were progeny of registered pure breed bulls and cows. Bulls were ≃9 months old when entering the feedlot and reared under feedlot conditions for ≃120 days to ≃12 months old. Bullas were slaughtered to yield A2/3 carcasses (zero permanent incisors, lean to medium fatness). Bulls were penned overnight with access to water before slaughter following captive bolt immobilization at the abattoir of the API-ARC. All treatments and procedures were approved by the Ethics Committee of the Agricultural Research Council (ARC AEC-I 2010 001).

To determine whether the effects of genotype were additive to electrical stimulation, the right half of the carcass was electrical stimulated for 15 seconds at 500V peak, using 5 ms pulses at 15 pulses per second and directly chilled at 4 °C. The left half of the carcass was not electrically stimulated (served as a control), while chilling was delayed for 6 hours (at 10 °C) to allow for the full development of metabolic processes within muscle fibers before chilling at 4 °C.

Animal measurements included weights, recorded during the feedlot growth period to determine body weight gain (total gain and average daily gain) and liver body weight (BW) measured on the day before slaughter as a final weight. Carcass measurements included hot carcass weight (HCW; used to calculate dressing percentage), cold carcass weight (used to determine carcass mass loss), EMA (in the thoracic region at T9/10), pH and temperature (measured at the lumbar end of the LTL). Beef quality estimates measured from samples collected directly from the carcass or from LTL excised from the lumbar region (L6) up to the thoracic region (T9/10) included myofibrillar fragment length (MFL), Warner-Bratzler shear force (WBSF), calpain enzyme system activities, sarcomere length (SL), colour measurements, energy metabolites, collagen (content and solubility) and water-holding capacity (WHC). Colour was determined using the CIE L*A*b* colour convention with measurements of L*, a*, b*, C* and hab over the ageing period. Energy metabolites included the concentrations of glycogen, glucose 6-phosphate, glucose, lactate, creatine phosphate and ATP determined at 1 h, 3 h, 6 h and 20 h post‑mortem.

The genes that are most likely to affect beef quality, specifically tenderness, as those of the calpain enzyme system. Calpain-1, calpain-2, calpain-3 and calpastatin are all found in the sarcoplasm and are known to determine post‑mortem proteolysis. The genes for these proteins can therefore be identified as causative to proteolysis at least, but potentially also for beef tenderness. We therefore used the 114 SNPs located in these causative genes (capn1capn2capn3 and cast respectively) to determine their genotypic distribution, as well as the association of these genotypes with beef quality traits in order to determine the importance of these genes in determining the quality (tenderness) phenotype. These data were used to identify possible markers for genomic selection (GS), once they were validated for tenderness in South African beef breeds.

  • The capn1 gene (on BTA29) was validated for beef tenderness, with a large number of strong associations (relatively high correlations) with estimates of beef tenderness, found in both the ES and the NS treatment groups. It correlated especially with MFL as a measure of physical tenderness (r2= 0.07 to 0.15), with fewer SNPs explaining the phenotypic variation in WBSF (r2 = 0.09 to 0.10). Almost no associations occurred with calpain-1 enzyme activity itself, but the effects of the SNPs in capn1 was rather a change in the responsiveness of the enzyme to calpastatin inhibition, as shown by several relatively strong correlations (r2 = 0.07 – 0.12) to the relative calpastatin inhibition per calpain(-s).
  • The capn2 gene (on BTA16) was validated for beef tenderness, explaining the phenotypic variation in, especially, the activities of calpain-1 and calpain-2 (r2 = 0.07 – 0.11). Although effects on enzyme activities were evident, these changes only resulted in a few significant associations of the genotypes with physical tenderness MFL (r2 = 0.07 – 0.09).
  • The capn3 gene (on BTA10) exhibited very few associations with beef quality. The protein coded by this gene is responsible for background proteolysis and does not cause variation in tenderness. The lack of an effect of these SNPs on tenderness is therefore unsurprising.
  • The cast gene (on BTA7) is quite large (136,434 bp) and contained a large number of SNPs (63), of which only 4 exhibited extensive effects on tenderness. Many of the correlations with MFL ranged between 0.07 – 0.11, although a few SNPs exhibited strong phenotypic correlations with MFL (r2 = 0.12 – 0.16), while associations with WBSF were less common and less pronounced (r2 = 0.07 – 0.11). These differences in physical tenderness were only in part explained by differences in the total and /or relative inhibition of calpastatin of protease enzyme activities (r2 = 0.07 – 0.12).

Using SNPs of the Illumina Bovine HD SNP BeadChip the capn1capn2 and cast genes were verified for tenderness in SA purebred beef cattle. The amount of phenotypic variation in tenderness estimates explained by some of these SNPs were large, making them useful targets for genomic selection in these breeds. Both Nguni and Bonsmara exhibited high allelic frequencies for alleles that were favorable for tenderness, giving them the genetic potential to produce tender beef.

Popular Article

Inheemse rasse soos die Nguni en Bonsmara het die genetiese potensiaal om sagte vleis te produseer

Basson, A

Inleiding

Hierdie proef is onderneem om vleisbeesgenetika in Suid-Afrikaanse (SA) rasse te ondersoek. As deel van die proef is daar getoets of die rasse wat algemeen vir kruisteling in SA gebruik word, verskil in die verspreiding van voordelige gene vir sagtheid (en ander vleiseienskappe), met spesifieke fokus op die inheemse Bonsmara en Nguni. Die karkasse is gehalveer om die een helfte elektries te stimuleer en dadelik te verkoel, terwyl die ander helfte as kontrole gedien het. Hier is verkoeling vir 6 ure uitgestel om die normale perimortem prosesse soos energieverskaffing in metabolisme, genoeg tyd te gee om te ontwikkel, voordat hierdie nie-gestimuleerde karkas-helftes verkoel is.

Daar is verskeie vrae waarvoor ons antwoorde soek met hierdie navorsing. Ons weet dat die Nguni oor die genetiese en biochemiese potensiaal beskik om sagte vleis te produseer (Frylinck et al., 2009), maar hoe vergelyk dit met Bonsmara, Angus, Charolais en Brahman? Kan die Nguni onder die regte slagtoestande, sagte vleis produseer? Kan ons deur middel van genomiese seleksie (GS) die kwaliteit van beesvleis verbeter in die industrie, waar elektriese stimulering dalk die invloed van voordelige gene sou uitkanselleer, of is verbeterde genetika se positiewe invloed op kwaliteit steeds waargeneem na stimulering?

Die Proef

Vyf vleisbeesrasse is in die proef ingesluit; Angus en Charolais as Bos taurus rasse, Brahman as Zebu-tipe Bos indicus, Bonsmara as ‘n inheemse kruisbeesras met ‘n groot Sanga-tipe bydra en Nguni as inheemse Sanga-tipe Bos taurus africanus. Die stoetbulle is afgerond in die voerkraal tot naastenby 12 maande oud voor slagting, of ‘n karkasklassifisering van A2/3. ‘n Groot aantal monsters is versamel van die Longissimus lumborum et thoracis spier (lende) om die toestande rondom slagting te bepaal, asook lendeskywe wat vakuum-verseël is en verouder is vir 3, 9, 14 en 20 dae, om die invloed van veroudering op vleiskwaliteit te bepaal (met of sonder elektriese stimulering).

Vleis se Kwaliteitseienskappe

Vir kwantitatiewe eienskappe is daar ‘n baie groot aantal gene wat ‘n eienskap bepaal en elkeen van hierdie gene dra slegs ‘n klein proporsie by tot die uiteindelike resultaat, byvoorbeeld sagte vleis. Elkeen van hierdie gene kan honderde (selfs duidende) variasies toon op ‘n molekulêre vlak. Enkel-nukleotied polimorfismes (single nucleotide polymorphisms = SNPs) wat die verskil in een enkele DNA molekule is, kan soms ‘n relatiewe groot invloed op die fenotipe hê. Hierdie SNPs (uitgespreek “snips”) is wat ons geïdentifiseer en getoets het binne-in gene wat sagtheid behoort te beïnvloed.

Genetika en Fisiologie

Spier in die lewendige dier het ‘n baie rigiede proteïenstruktuur wat hoogs ge-orden is, terwyl die omskakelings na vleis in die karkas ‘n ontwrigting van hierdie orde behels – hoe meer die speirstrukture ontwrig word, hoe sagter is die vleis. Die kalpaïen ensiem-sisteem (spesifieke proteases) dra grootliks by tot die ontwikkeling van die finale sagtheid van vleis. Alhoewel kalpaïen‑1 en kalpastatien (die inhibeerder van kalpaïen) die grootste bydra lewer tot die degradering van die proteïene in vleis om dit sagter te maak, kan kalpaïen‑2 en kalpaïen‑3 dalk ook hiertoe bydra. Ons het dus diere met die Bovine-HD SNP BeadChip van Illumina genotipeer vir die gene van die ensieme kalpaïen‑1 (capn1 in chromosoom 29), kalpaïen‑2 (capn2 in chromosoom 16), en kalpaïen‑3 (capn3 in chromosoom 10), asook die ensiem-inhibeerder, kalpastatien (cast in chromosoom 7). Ons bepaal dus eerstens watter gene fisiologies belangrik is en analiseer dan al die geen-variante (of SNPs) om die korrelasie tussen hierdie variante en vleiskwaliteit van die diere te bepaal. ‘n Groot voordeel van hierdie navorsing, wat dit onderskei van ander werk, is dat ons ‘n baie gedetaileerde prentjie van die fisiologie van die vleis het, deur meting van verskeie eienskappe (met of sonder behandeling), gekoppel aan redelik indiepte inligting omtrent die genotipes van hierdie funksionele gene.

Resultate

Brahman bulle (rooi in die grafiek) het deurgaans die hoogste vlakke van kalpastatien per kalpaïene getoon, wat bygedra het tot meer intakte spierveselstrukture (langer miofibril fragment lengtes – MFL) asook verhoogde taaiheid (hoë Warner-Bratzler snyweerstande of WBSW gemeet in kg). In teenstelling het die Nguni (turquois in die grafiek) heelwat laer inhibering van ensiemwerking deur kalpastatien getoon, wat in sommige gevalle die laagste van al die rasse was, met ander woorde die Nguni was die ras met die mees voordelige biochemie. In die Bonsmara was die patroon vir biochemiese en strukturele veranderinge baie soortgelyk aan dié van Nguni’s en die sagtheid van die lendeskywe (verlaging in snyweerstande) het vinnig verbeter tussen dag 3 en 9 van veroudering. Teen 14 dae se veroudering het die snyweerstande gestabiliseer en Bonsmara bulle het nie dieselfde sagtheid as die Nguni bereik nie, inteendeel, hulle snyweerstande was soortgelyk aan Brahman en Charolais.

Kalpaïen-1 is die belangrikste protease wat sagtheid bepaal en die kalpaïen‑1 geen (capn1) behoort dus by te dra tot vleiskwaliteit. Die grootste invloed van capn1 was om die proteïenstruktuur te ontwrig, deur middel van laer relatiewe kalpastatien inhibisie per kalpaïen aktiwiteit. Ons het sterk korrelasies vir verskeie SNPs in hierdie geen geïdentifiseer waar veral MFL (maar ook party van die snyweerstande), sowat 15-20% laer was in die “voordelige” genotipe (voordelig vir sagtheid).

Die kalpaïen-2 ensiem is verantwoordelik vir die ontwikkeling van agtergrond-sagtheid en die geen (capn2) was ge-assosieer met sowat 12 – 15% hoër protease ensiemaktiwiteit, wat in sommige SNPs met soveel as 38% hoër ensiem aktiwiteit geassosieer was. Dit was egter tot ‘n kleiner mate met die bevordering van sagtheid en die ontwrigting van vesels geassosieer.

Kalpastatien aksie kan ‘n groot invloed op sagtheid hê. In die lewendige dier funksioneer dit om die kalpaïen protease ensiemaktiwiteit, wat sellulêre proteïene groot skade sou kon aanrig, in beheer te hou. In die prosesse wat spier omskakel na vleis toe, verhoed dit ook die afbraak van spierproteïene, maar in dié geval sal dit dan die ontwikkeling van sagtheid benadeel. In die kalpastatien geen (cast) was daar ‘n relatief klein aantal SNPs wat ‘n redelike groot invloed op die ontwrigting van spiervesel proteïene gehad het. Die MFL was nagenoeg 10 – 15% laer, terwyl sommige van die SNPs se “voordelige” genotipes tot  meer as ‘n 20% verbetering in die MFL gelei het (i.e. korter lengtes). Dit was gedeeltelik verduidelik deur ‘n verlaging in die totale eenhede kalpastatien werking, met soveel as 20% laer inhibisie vanaf kalpastatien, gekoppel aan ‘n redelike verbetering in die sagtheid van die vleis, veral in die vroeë tot intermediêre stadiums van veroudering.

Bespreking

Uit die 4 gene wat hier getoets is, is die kalpaïen‑1 en kalpastatien gene veral geskik vir genomiese seleksie in Suid-Afrikaanse vleisbeesrasse, terwyl ‘n paar van die SNPs in die kalpaïen-2 geen ook potensiaal toon. Rasverskille in sagtheidseienskappe (fisiese en biochemies) word gereflekteer in verskille in die verspreiding van genotipes tussen die verskillende rasse (sien tabel hier onder)..

Totale Aantal Voordelige Allele*
cast capn1 capn2
Angus (n=27) 189 146 220
Bonsmara (n=35) 270 209 174
Brahman (n=35) 237 39 141
Charolais (n=34) 217 147 215
Nguni (n=35) 256 233 241

* Die groen blok dui die ras met die grootste aantal voordelige allele vir sagtheid aan

Nguni’s hét die genetiese potensiaal om sagte vleis te produseer, maar die noemenswaardige ligter karkasse is geneig om te vinnig te verkoel wat beteken die vleis raak te koud vir metaboliese ensieme om energie optimaal te benut, terwyl die struktuur binne miofibrille ook sub-optimaal word vir die proteases se ensiemwerking. In hierdie proef het Nguni’s die “beste genetika” gehad en die allele wat voordelige is vir sagtheid in die gene wat hier getoets is, was volop in Nguni’s.

Please contact the Primary Researcher if you need a copy of the comprehensive report of this project – Lorinda Frylinck on lorinda@arc.agric.za

Marker detection in beef cattle II

Marker detection in beef cattle Phase II

Industry Sector: Cattle and Small Stock

Research focus area: Livestock production with global competitiveness: Breeding, physiology and management

Research Institute: Agricultural Research Council – Animal Production Institute

Researcher: Dr A Maiwashe PhD

Title Initials Surname Highest Qualificaion
Dr B Dube PhD
Prof MM Scholtz DSc
Prof K Dzama PhD
Prof M MacNeil PhD
Dr L Frylinck PhD
Dr NO Mapholi PhD

Year of completion : 2018

Aims of the project

  • To establish a beef cattle genetic marker discovery population
  • To collect phenotypic data on tolerance to ticks, post-weaning growth and feed efficiency and carcass traits
  • To detect Quantitative Trait Loci for tolerance to ticks, post-weaning growth and feed efficiency and carcass traits

Executive Summary

The project aimed to detect genetic markers for traits of economic importance in the Nguni X Angus F2 crossbred population. The specific objectives of the project were to: (1) establish a beef cattle genetic marker discovery population, (2) collect phenotypic data on tolerance to ticks, post-weaning growth and feed efficiency and carcass traits, and (3) detect quantitative trait loci (QTLs) for tolerance to ticks, post-weaning growth and feed efficiency and carcass traits. Accordingly, a number of experiments were conducted to address these objectives.

Briefly, a total of 233 F2 animals were produced since the inception of the project. The following phenotypic data were collected on the 233 F2 crossbred animals: growth rate, feed intake, tick count, skin volatiles compounds, skin thickness and colour, hematology, skin hypersensitivity and carcass traits. Coat color was scored and skin thickness was also done since they are known to be correlated with tolerance to ticks. Artificial tick infestation was conducted using Amblyomma hebraeum. Each animal was infested with 100 larvae obtained from ARC-Onderstepoort Veterinary research.

Tick counts were also conducted on 586 Nguni cattle under natural infestation with the aim of developing a protocol for measuring tolerance to ticks using tick count procedure.

The results indicate extensive variability on ticks counts among the animals, ranging from 0 to 100 per animal. Tick counts were higher in the hot months and Amblyomma hebraeum was the most dominant tick species. Heritability estimates for tick count ranged from 0 to 0.89. High genetic correlations were observed between whole body count and the anatomical location counts, suggesting that it may not be necessary to conduct whole body counts. Counts from the belly and perineum were most suitable surrogate traits for whole body count.

In another experiment, feed intake and growth performance data were collected at the feedlot on 170 animals at the ARC-Animal Production campus in Irene. Average daily feed intake (ADFI), average daily gain (ADG) and feed conversion ratio (FCR) were computed and analyzed using SAS software. The findings showed a significant effect of genotype on ADFI and ADG (P < 0.05), while there were no differences (P >0.05) in FCR among the genotypes. The F2 Nguni-Angus genotype had the best feedlot performance with ADFI, ADG and FCR of 7.9 kg, 1.5 kg and 5.6, respectively. There was also some correlation between ADG and FCR, while ADG and FCR were not correlated with ADFI.

For genomic analyses, hair and blood samples were collected from 233 F2 animals and DNA isolation conducted on 170 animals. Ninety-six (96) F2 samples were genotyped using Bovine SNP150K assay. A genomic analyses was conducted to characterise genetic parameters of tick count and identify genomic regions associated with tick resistance in South African Nguni cattle. A genome-wide association analysis for tick count was performed using GenABEL. Heritability estimates for the tick count traits ranged from 0.04±0.04 to 0.20±0.04. Two genome-wide significant regions on chromosomes 1 and 19 were identified for total tick count on the perineum and for total body count for A. hebraeum ticks. Additional regions significant at the suggestive level were identified on most chromosomes for several other tick count traits.

This research provides the first line of evidence of association between tick count and SNP markers in beef cattle under South African condition. The results are consistent with results from similar studies conducted in Brazil. Further research should consider fine-mapping of the genomic regions identified to be harbouring genes for tolerance to ticks.

Popular Artcile

Nguni cattle are adapted to the harsh conditions of South Africa characterised by, among others, high levels of tick infestation. This adaptation may be due to the natural resistance of the Nguni, which may be attributed to their genetic make-up. On the other hand, the Angus cattle are exotic to South Africa and are susceptible to tick infestations. However, they have excellent growth, feed utilization and meat quality characteristics. Combining the characteristics of these breeds into one breed may be a sustainable of way of improving beef production in the tick-infested production areas of South Africa. The objective of the study was cross the Nguni and Angus cattle to produce a crossbred animal that potentially has characteristics of both breeds.

The project started in 2013 using 84 Nguni cows and five Angus bulls, and has so far produced 233 animals that have been evaluated for several traits related to resistance to ticks, growth performance and meat quality. After weaning the calves were individually fed under feedlot conditions and their performance recorded and analysed. Daily feed intake for each animal was recorded and weekly weights were taken. At the end of the growth test, each animal was artificially infested with ticks so that its level of resistance can be determined by counting the number of ticks that feed and survive on it. Chemicals on the skin produced by the animal that may be responsible for repelling or attracting ticks were collected. In addition, the ability of the animal’s immune system to respond to tick bites was measured by measuring the degree of swelling and the time taken for it to subside. The response of blood parameters responsible for the immune system to tick bites was also evaluated. Also measured was the thickness of the skin, which may also related to the ability of the ticks to attach to the skin. Hair samples were collected to determine the genetic make-up of the animal, which will later be correlated with the level of resistance to ticks, growth performance and meat quality.

After the 120 days in the feedlot, the animals were then slaughtered following the recommended South African Meat Industry Company procedures. Carcass were weighed after dripping free water after 24 hours. Then several meat quality characteristics were evaluated, which included tenderness, water holding capacity, fat content and moisture content.

The results show that there are differences in the level of resistance to ticks in the cross-bred animals. No relationship was observed in the level of resistance to ticks with growth performance and feed utilization. Skin thickness was not found to influence the ability of ticks to attach to the animal. Meat quality results indicate that the crossbred animals produce meat of commendable quality. Male animals produced heavier carcasses than their female counterparts, and were less fat compared to the females. On the other hand, meat from females was more tender than that from males. So far the results show that there is no relationship between meat quality and the level of tick resistance.  Therefore, resistance to ticks can improved by combining the Nguni and Angus breeds without compromising growth, feed utilization and meat quality characteristics. More studies on the genetic make-up will be done to relate it to the other characteristics.

Please contact the Primary Researcher if you need a copy of the comprehensive report of this project – Azwihangwisi Maiwashe on norman@arc.agric.za

Karoo Predator Project

Karoo Predator Project Management Survey

Industry Sector: Cattle and Small Stock

Research focus area: Predation management

Research Institute: University of Cape Town

Researcher: Beatrice Conradie

Title Initials Surname Highest Qualification
Robertson N Nattrass D Phil
Prof J Piesse PhD

Year of completion : 2018

Aims of the project

  • Conduct an extra wave of the panel survey
  • Study the productivity of the sheep performance system
  • Analyse the effectiveness of predator control
  • Work towards integrating the science and the management data

Executive Summary

The Karoo Predator Project was established in November 2011. Farm management data were collected in four waves (Nov 2012, Sept 2014, Oct 2015, Oct 2016). Analysis of this rich dataset is question-driven and is designed to learn as much as possible about the performance of the farming system. This work has been supported by two RMRDSA contracts (signed 12 November 2014 and 30 June 2016, Pretoria). This report covers all work conducted between January 2016 and July 2018. My main collaborators in this period were profs Nicoli Nattrass on human-wildlife conflict and Jenifer Piesse on farm productivity and farmer attitudes. Students and other colleagues were involved in specific papers.

Survey design and analytical approach

Wave 4 of the Karoo Management Survey was collected in November 2016 on the 2015 production season. This wave of the survey produced 55 useable responses which increased the number of observations in the panel dataset to 255. The three-wave dataset consisting of n = 200 observations was released for analysis in early 2016, and has been used since then to:

  • calculate a new estimate for predation losses for the Karoo
  • model culling effectiveness
  • estimate a stochastic frontier with inefficiency model which identifies opportunities for commercialisation
  • investigate the effect of grazing conditions on farm performance
  • model the structure of farmers’ risk perceptions
  • investigate the effect of information searching behaviour on farm performance

This list adds two outcomes to the original list of three analytical aims. Paper 3 is still under review at the South African Journal of Agricultural Extension, but was enthusiastically welcomed at the South African Society for Agricultural Extension’s June conference in East London and has since been shared with various producer and government stakeholder groups. Paper 4 is in the final review stage for special edition on the Karoo of the African Journal of Range and Forage Science.

The four-wave panel, released at the beginning of 2018, is currently being analysed by two honours students who are studying:

  • the stability of Karoo farmers’ risk perceptions, and
  • the effect of the 2016 drought on farm productivity

All papers in this series broadly share the same analytical strategy namely the quantitative analysis of questionnaire survey data. Methods depend on the question at hand and include descriptive statistics, principal component analysis, k-means clustering, OLS modelling, data envelopment analysis, and error components and technical efficiency effects stochastic frontier analysis.

A new estimate of predation losses for the Karoo

This analysis updates Van Niekerk’s estimate for the Karoo, which for the purpose of the study was defined as the Central Karoo, Cacadu, Pixley Ka Seme and Namakwa district municipalities.

According to Van Niekerk (2010) small stock farmers in the Karoo loses 13 thousand adult sheep, 393 thousand weaners and 517 thousand newborn lambs to predators every year. Since the latter figure is largely an impression, this category of potential losses was not considered in the Karoo Management Survey. Its estimates for predation losses in the Karoo is therefore much lower at 6700 adult sheep and 278 thousand weaner lambs. These figures represent a cost of approximately R278 thousand per year in current prices. When the same calculation is applied to both datasets, the predation figures for the Central Karoo converge on 5% (4.85% in 2008 and 4.7% for the period 2012-2014). This suggests that farmers were providing consistent estimates irrespective of the interview period or the timing of the survey.

A model of culling effectiveness

Models were specified to investigate the effect on livestock losses of culling predators. Farmers cull predators in response to livestock losses, and those who depend more on farming tend to cull more. Predator control however is probably counterproductive as culling is associated with greater subsequent livestock losses. This finding is robust to the inclusion of a set of socio-economic variables and farm characteristics. It is also consistent with ecological models which hypothesises that culling can create vacancies for dispersing juveniles to move into resulting in greater livestock losses later. The results of paired t-tests conducted across waves 1 and 3 of the panel revealed a great degree of churn in the use and perceived effectiveness of lethal and non-lethal methods which means that nobody has come up with a lasting solution yet. Given jackals’ ability to adapt to new control methods, a lasting solution probably does not exist even in principle. Much higher rates of poison use were reported in Wave 3, which is a concern because poison use is illegal, although it might simply reflect higher levels of disclosure rather than a change in practices. A model of the likelihood of using poison shows that poison is used by younger farmers and by people who experience large losses.  Lambing in pens close to the homestead did not matter. Another specification showed that farmers who believe that minor carnivores such as African wildcats, black eagles and crows were a problem too, were more likely to resort to poison, than farmers who were willing to accommodate this wildlife. This variable however lost statistical significance when socioeconomic controls were added to the model.

The key success factors in Karoo agriculture

To investigate the question of effective commercialisation, production data from commercial operations were used to benchmark farming in extensive grazing areas. The inputs in the technical efficiency effects model were stock sheep, labour, feed and animal remedies and fuel. The functional form was Cobb Douglas and the inefficiency model contained management experience, a dummy variable for a Grootfontein diploma and a dummy variable to indicate fulltime or parttime farming. The farm characteristics considered were  size, grazing conditions, a dummy variable to indicate flexibility and breed type.

The exercise revealed that every fifth commercial farmer in the sample is less than 50% efficient and therefore is as much in need of extension as any smallholder might be. Experience is an important determinant of performance and could be developed in the smallholder sector through appropriate vocational training. A commercial farmer needs at least eleven years of managerial experience to move from the bottom to the middle productivity cohort and a Grootfontein diploma adds eight percentage points to mean efficiency compared to any other configuration of education. Introducing a fiber component (wool, mohair) increases productivity by 13 percentage points. Sheep farming is amenable to smallholder production, because it can be done successfully on a part-time basis. The grazing index was significant but carried the incorrect sign. If all six farm and farmer characteristics identified in the model are set at the optimal levels a farm’s predicted level of productivity rises by 50%, which if incorporated in extension programs will substantially enhance the Black Farmers’ Commercialisation Programme’s chances of success.

The drought

The effect of grazing conditions on productivity was pursued further in stochastic frontier error components model. Results show that during the period 2012-2014, which was a good year followed by two normal seasons, the best farmers were able to maintain productivity at around 93%, while the bottom third producers suffered serious productivity declines. Several bottom-third producers dropped out of wool and mutton production even before the drought started, while many more are expected to have failed since due to the drought.

Risk perceptions

Waves 1 and 4 collected Likert scale data on farmers’ risk perceptions. Principal component analysis uncovered the structure of farmers’ risk perceptions. In round 1 the top threats were predators and rising input costs and the main components of farmers risk perceptions were institutional, market-related, rural safety and security and the environment. The environmental risk component combined drought and predators. OLS models explained individual risk scores with profitability, share of income from farming and key demographic variables. Profitability and income diversification lowers risk perceptions. More experience and education were generally risk mitigating too. Farm size and the amount of time spent the veld explained environmental risk perceptions.

A second round of risk  data, collected during a politically more turbulent and drier period, revealed stable risk perceptions. Four new sources of risk were added in round 2, including weather weirding (a technical term to describe perceived departures from typical conditions), politics, fracking and uranium mining and prospecting. On the longer list, farmers bundled together market risk with regulatory and political risk, which show that risk perceptions are rapidly updated as new threats emerge. Predators were dropped from environmental risk which now focusses on drought / climate change.

Productivity and information searching behaviour

Wave 1 productivity scores (Conradie and Piesse, 2015, Agrekon) were correlated to farmers information searching behaviour on the topics of rangeland management, animal husbandry and predator management. For information on rangeland management farmers still turn to the retired FSD extension agent who is a fellow farmer. For animal husbandry information they rely mainly on breeders and buyers and the representatives of input suppliers and for predator management Niel Viljoen in the preferred source. Farmers do not think that the government has any experience in this domain. A preference for private sources of information correspond to higher levels of productivity than the use of public sources.

POPULAR ARTICLE

To follow soon

Please contact the Primary Researcher if you need a copy of the comprehensive report of this project – Beatrice Conradie on beatrice.conradie@uct.ac.za

Dairy ranching for beef and milk

Small scale Dairy ranching for the resource poor sector in South Africa

Industry Sector: Cattle and Small Stock

Research focus area: The economics of red meat consumption and production in South Africa

Research Institute: Agricultural Research Council – Animal Production Institute

Researcher: Dr. Susanna Maria Grobler PhD

Title Initials Surname Highest Qualification
Prof MM Scholtz DSc
Ms V Leesburg MSc (USDA)

Year of completion : 2018

Aims of the project

  • To generate results from a dairy ranching system that can be used by existing and new emerging cattle farmers.
  • To benchmark the system of dairy ranching for the resource poor sector in comparison with a small scale dairy production and an ordinary beef cattle suckler (weaner calf) system.
  • To do on station characterization and benchmarking of different cattle genotypes for suitability to be utilized in systems of dairy ranching.
  • To measure the levels of methane emission between the different genotypes

Executive Summary

Dairy ranching is defined as the practice of keeping cows of relatively low milk yield, who are parted from their calves in the evenings, milked out in the morning, and spend the day with their calves at foot while the cows are usually not milked in the evening.

The objectives of the study was firstly to generate results from a project that imitate Dairy ranching that can be used by existing and new emerging cattle farmers; secondly to benchmark the system of Dairy ranching for the resource poor sector in comparison with small-scale dairy production and an ordinary weaner system; thirdly to do on station characterization and benchmarking of different cattle genotypes for suitability to be utilized in aDairy ranching system; and fourthly to measure the levels of methane emission between the different genotypes.

The project commenced with five purebred heifers each of the Bonsmara, Brahman, Nguni and Red Poll breed. The small-scale dairy at Roodeplaat, was used to produce milk from Jersey cows grazing natural veld under small-scale conditions with limited resources. The weigh-suckle-weigh technique was used to estimate milk production from all breeds except the Jerseys, which was milked daily.

When comparing the different breeds, the Nguni cows followed by the Brahman cows showed the highest potential income from a weaner production system. In the Dairy ranching system, the dual-purpose Red Poll cows had the highest potential income. The Jersey cows milked in a conventional dairy system potential income reduced by 24% when cows were milked once per day instead of twice per day. The Dairy ranching system produced the highest potential income compared to the weaner production system and conventional dairy milking once per day. The conventional dairy produced the highest potential income when milked twice daily.

With funding from rural development, another ARC-API project “Dairy value chain”, established small-scale milk production units in rural areas in Limpopo, KwaZulu-Natal and Eastern Cape by making use of the Dairy ranching project’s principles after the Dairy ranching project’s promising preliminary results. These small-scale farmers are producing milk now successfully for the past three years.

Understanding the differences in enteric methane production from cattle in different production systems is important for the productivity in the different sectors and for developing mitigation strategies in respect of the contribution of agricultural activities to methane emissions.

In the first study methane production was measured from, Bonsmara, Nguni and Jersey heifers, grazing natural sour veld, forage sorghum under irrigation, oats pasture under irrigation and a total mixed ration (TMR) were significant differences were found between breeds and feed sources. It was also found that individual animals emitted higher or lower quantities of methane irrespective of the feed source. The second study evaluated methane production from pregnant Bonsmara-, Brahman-, Jersey-, Nguni- and Red Poll heifers grazing natural veld and forage Sorghum under irrigation. Bonsmara heifers produced the highest amount of methane and the Jerseys produced the lowest amount of methane on both the natural veld and forage Sorghum.

POPULAR ARTICLE

The smallholder milk producers in South Africa have their own constraints ranging from poor access to support services, lower productivity, limited access to market outlets and low capital reserves. These farmers have the opportunity to make use of a dairy ranching system with lowered liabilities in relation to intensive milk production systems. This includes less infrastructure, lower production costs and relative resilience to rising feed prices.

Methane is one of the major anthropogenic greenhouse gasses, second only to carbon dioxide in its impact on climate change. Understanding the differences in enteric methane production from cattle in different production systems is not only important for the productivity in the different sectors, but also for developing mitigation strategies in respect of the contribution of agricultural activities to methane emissions.

Dairy Ranching can be defined as the practice of keeping cows of relatively low milk yield, who are parted from their calves in the evenings, milked out in the morning, and spend the day with their calves at foot while the cows are usually not milked in the evening. Beef cattle can be a viable option for small-scale farmers to complement other farm enterprises, such as milk production. In tropical countries, making use of the calf to stimulate milking is a popular practice and it was reported that this system is adopted by 95% of 289 farms surveyed in the State of Minas Gerais, Brazil. Advantage of this restricted suckling system include a reduction in milk let-down problems and improved milk production under good nutritional regimes, reduce stress in both cows and calves and the efficiency of milk utilization is higher in calves that are suckled than when they take the same amount of milk from a bucket. Other benefits of suckling calves in relation to bucket fed calves are a reduced incidence of diarrhoea and the elimination of naval suckling. Udder health and the incidence of mastitis also decrease with suckling due to small-scale farmers not being able to milk the cows from time to time due to labour and other personal constraints. When compared to a conventional dairy system, Dairy Ranching has lower input costs, labour requirements and limited infrastructure is needed. It is also the perfect opportunity to add value to small-scale beef production enterprises. Dairy Ranching development in the rural-based, small farmer-oriented cattle industry can therefor increase productivity, raise income, promote self-reliance, reduce malnutrition and therefor improve standard of living.

The ARC-API conducted a trial funded by RMRD-SA to firstly generate results from a project that imitate dairy ranching that can be used by existing and new emerging cattle farmers; secondly to benchmark the system of Dairy Ranching for the resource poor sector in comparison with small-scale dairy production and an ordinary beef cattle suckler (weaner calf) system; thirdly to do on station characterization and benchmarking of different cattle genotypes for suitability to be utilized in systems of dairy ranching; and fourthly to measure the levels of methane emission between the different genotypes measured with a Laser Methane Detector. Purebred Bonsmara, Brahman, Nguni and Red Poll heifers were used to represent a weaner production system and dairy ranching system. Jersey cattle was milked from natural veld in a small-scale dairy at the ARC-API Roodeplaat campus, with limited infrastructure and resources to represent a small-scale rural dairy production system. The weigh suckle weigh technique was used to estimate milk production from all breeds except the Jerseys which was milked daily.

When a small-scale farm has the carrying capacity to sustain 25 large stock units (LSU), the amount of animals that can be sustained on the farm will differ between breeds with different frame sizes and different weights. Therefore, results obtained from the project was converted to simulate a farm with the capacity to sustain 25 LSU which included 15 Bonsmara, 16 Brahman, 20 Nguni, 21 Red Poll and 21 Jersey cows.

When comparing these different breeds in different production systems, the Nguni cows followed by the Brahman cows showed the highest potential income from a weaner production system. In the Dairy Ranching system, the dual-purpose Red Poll cows showed the highest potential income. The Jersey cows milked in a conventional dairy system potential income reduced by 24% when cows were milked once per day instead of twice per day. The conventional dairy produced a higher potential income than a weaner production system from 25 large stock units but less than the Dairy Ranching system, even when compared to pure beef breeds being used for milk production.

With funding from the Department of rural development and land reform’s REID project, another ARC-API project “Dairy value chain” established small-scale milk production units within the resource poor sector in rural areas in Limpopo, KwaZulu-Natal and Eastern Cape as one of the project’s objectives. The uncomplicated, economical small-scale Dairy Ranching unit, showed promising results at Roodeplaat, which inspired the coordinator of the “Dairy value chain” project to implement the principles at the newly established small-scale milk production units in the mentioned three provinces. These small-scale farmers received pregnant heifers in 2013/2014. They are producing milk now successfully for the past two/three years with cows already in their second lactation.

The methane production trial evaluated methane production (g/day) from the pregnant Bonsmara-, Brahman-, Jersey-, Nguni- and Red Poll heifers grazing natural veld and forage Sorghum under irrigation.

The methane production was much higher when grazing natural veld (164.8g/day) than grazing forage Sorghum (130.4g/day). The tannin content in Sorghum may have contributed to lower methane production as tannin content reduce enteric methane production. A significant difference was found between different breeds methane concentration (P=0.0692). The large frame Bonsmara and Brahman cows produced the highest amount of methane, 159.6g/day and 170.5g/day respectively. The small frame Red Poll and Jersey cows produced the lowest amount of methane, 139.4g/day and 119.9g/day respectively. Methane production is linked to body weight and from this study, it is clear that small frame animals produce less methane than medium frame animals

From this study, it is clear that Dairy Ranching is a viable strategy to increase income, add value, increase cash flow, competitiveness and long-term survival of rural smallholder cattle farmers.

Please contact the Primary Researcher if you need a copy of the comprehensive report of this project – Dr Grobler on mgrobler@arc.agric.za

Evaluation of methane measuring techniques

Evaluation of different techniques to quantify methane emissions from South African livestock

Industry Sector: Cattle and Small Stock

Research focus area: Sustainable natural resource utilization

Research Institute: University of Pretoria

Researcher: Dr JL Linde du Toit

Title Initials Surname Highest Qualification
Prof WA van Niekerk PhD
Mr J van Wyngaard MSc
Mrs Z Goemans BSc(Agric)

Year of completion : 2018

Aims of the project

  • To measure methane emissions from livestock using the SF6 technique
  • To measure methane emission from livestock using the handheld laser methane detector (LMD) technique
  • To compare the results of the SF6 and the LMD techniques

Executive Summary

The need to verify greenhouse gas inventories demands the development of high throughput, economical yet accurate short-term measurement techniques, such as the laser methane detector (LMD). The aim of this project was to compare methane (CH4) emission rates as measured by the LMD to the sulphur hexafluoride tracer gas (SF6) technique from lactating dairy cows grazing pasture and to evaluate the practicality of the LMD measurement protocol under grazing conditions in the temperate coastal region of South Africa. Methane production was determined from six lactating Jersey cows on pasture using both techniques. The data generated by the LMD had a superior daily repeatability compared to the SF6 technique in the present study. A higher between-cow coefficient of variation (CV) (0.6 vs. 0.4) from the LMD compared to the SF6 technique was observed and this was ascribed to the sensitivity of the LMD to ambient conditions, animal movement while grazing and time of measurement. Methane production as measured by the SF6 technique (348 g/d) was higher (P<0.05) compared with the LMD technique (82.6 g/d).

Results from this study indicated that the LMD yielded approximately a 70% lower average daily CH4 production when compared to the SF6 techniques under the experimental conditions and daily CH4prediction models using the same animals and dry matter intakes. The lack of a third measuring technique and a standardized LMD methodology makes an accurate comparison between techniques and published data difficult. Both the SF6 and the LMD methods are viable methods to evaluate differences between mitigation options, for ranking of animals for selection purposes and to identify differences between dietary treatments. More research is needed before new techniques such as the LMD can be employed to determine absolute CH4 daily emissions which can be up scaled for inventory purposes.

Popular Article

Measuring methane from livestock

Recently, methane has been reported as the most abundant organic trace gas in the atmosphere. The radiative forcing of methane (CH4) is significantly higher than carbon dioxide (CO2) and it is estimated that CH4 has a global warming potential of 28 compared to CO2 with an atmospheric half-life of 12.4 years1. Enteric production of CH4 from ruminant livestock production systems is one of the major sources of agricultural greenhouse gas emissions globally. The relatively short atmospheric half-life of CH4 makes it the main target in livestock greenhouse gas mitigation protocols. Methane is also an important indicator of livestock productivity as it is associated with the conversion of feed into animal product i.e meat, milk or fibre.

Methane is produced in the rumen by methanogenic bacteria as a by-product of the fermentation process. Ruminal fermentation by rumen microbes result in the formation hydrogen (H2). Accumulation of excessive amounts of H2 in the rumen negatively affects the fermentation rate and growth of some microbial consortia which will reduce feed intake and production of animals. Methanogens therefore reduce carbon dioxide (CO2) to methane (CH4) and water (H20) thereby capturing available hydrogen and sustaining a favorable fermentation environment in the rumen2. Methane is exhaled or belched by the animal and accounts for the majority of emissions from ruminants. Methane also is produced in the large intestines of ruminants and is expelled in much smaller volumes compared to ruminal methane.

There are a variety of factors that affect CH4 production in ruminant animals, such as: the physical and chemical characteristics of the feed, the feeding level and schedule, the use of feed additives to promote production efficiency, and the activity and health of the animal1. Reductions in greenhouse gas emissions from livestock can be achieved through a range of CH4 mitigation strategies and more efficient livestock production systems through improved genetics and management.

Regardless of the mitigation strategy imposed, any reduction in enteric methane production must be quantified and for this to be achieved, accurate baseline emissions data are essential1. There are currently many techniques available to researchers to quantify CHemissions from livestock each with specific applications and challenges. These techniques vary from tracer and capsules for individual ruminants to whole farm systems. The development of baseline emission data can also be achieved through modeling, employing specific livestock and environmental activity data to estimate emissions. One of the main challenges of the majority of the measurement techniques is the lack of “real time” emissions from grazing ruminants under natural conditions. There is a need to develop measuring techniques and methods which can be standardized, is relatively low-cost and which can deliver reliable, feasible and repeatable assessments of emissions from grazing livestock.

The Sulphur hexafluoride (SF6) technique and spot sampling lasers are two of the techniques which shows promise to measure CHemission from grazing livestock. Researchers recently compared these two techniques in a pasture dairy production system in the Western Cape province of South Africa. It was found that the spot sampling with the laser could be useful for purposes such as selective animal breeding and comparing between different mitigation strategies, where the requirement is for relative emission data but not necessarily daily methane production. This trial highlighted the need to develop specific operational standards when employing methane quantification techniques under natural conditions in order to minimize variation and environmental interference when recording measurements.

Strategies to reduce greenhouse gas emissions and to increase farm productivity are likely to remain vague, random and possibly inefficient without the development of standardized, accurate and reliable CH4 measurement techniques1.

References

  1. Hill, J., McSweeney, C., Wight, A.G., Bishop-Hurley, G. and Kalantar-zadeh, K., 2016. Measuring methane production from ruminants. Trends in Biotechnology, Vol. 36 (1).
  2. Goopy, J., Chang, C. and Tomkins, N., 2016. A Comparison of Methodologies for Measuring Methane Emissions from Ruminants. In: Methods for Measuring Greenhouse Gas Balances and Evaluating Mitigation Options in Smallholder Agriculture. Editors: Todd S. Rosenstock, Mariana C. Rufi no Klaus Butterbach-Bahl, and Eva Wollenberg Meryl Richards. Springer International Publishing AG Switzerland.
Please contact the Primary Researcher if you need a copy of the comprehensive report of this project – Linde du Toit on linde.dutoit@up.ac.za

Methane and nitrous oxide from beef cattle manure

Direct manure methane and nitrous oxide emissions from a commercial beef feedlot in South Africa.

Industry Sector: Cattle and Small Stock

Research focus area: Sustainable natural resource utilization

Research Institute: University of Pretoria

Researcher: Dr JL Linde du Toit

Title Initials Surname Highest Qualification
Prof WA van Niekerk PhD
Miss K Lynch BSc(Agric)
Dr L Stevens PhD

Year of completion : 2018

Aims of the project

  • To identify the on-farm manure management system employed in a typical commercial beef feedlot in South Africa
  • To determine the methane emissions from manure in a commercial beef feedlot
  • To determine the nitrous oxide emissions from manure in a commercial beef feedlot

Executive Summary

Methane and nitrous oxide emission from pen surfaces in a commercial beef feedlot in South Africa

Global warming has become a worldwide concern in recent years.  The release of Greenhouse gasses (GHGs) have brought about rapidly changing climate conditions the world over, GHGs produced by various industry sectors are being investigated, researched and laws put in place to limit the production of GHGs wherever possible.  This includes the agricultural sector where extensive animal husbandry has increased the global carbon footprint and environmental pollution.

The International Panel of Climate Control (2006) has three Tiers that estimates methane (CH4) values, one of the main GHGs, from the use of default values to the use of more complicated models and experimental data to improve the accuracy of reporting.  This study investigated the contribution of manure GHGs emissions to livestock emissions focussing on intensive beef feedlot manure emissions. At present in South Africa, these values are only roughly estimated and are only available on an IPCC Tier 2 level.  Gaseous emissions from livestock waste, specifically beef cattle waste, are affected by a variety of external factors (atmospheric temperature, humidity, soil conditions, ration consumption and manure management practices) as well as internal factors, (ration digestibility, nutrient absorption and gut health).

The objective of the study was to achieve an understanding of the gaseous emissions, specifically methane (CH4) and nitrous oxide (N2O), from beef cattle feedlot pen surfaces from a commercial beef feedlot in South Africa as influenced by diet and season, using the closed chamber method of gas collection over the three prominent seasons experienced in Mpumalanga, South Africa.  The sampling of these various factors would lead to more accurate reporting, conforming to Tier 3 methodology results.

Random pen surface and emissions samples were taken from three pens per each feedlot ration fed. The results indicated significant differences in soil/manure characteristics, but little effect on ultimate CH4 and N2O emissions from the pen surface were found across treatments. Similar results were observed for the rangeland manure analysed and manure emissions from manure management practices at the feedlot.  Ambient temperature had a tendency (p<0.10) to affect CH4 and N2O emissions with higher temperatures resulting in higher emissions but. Overall soil and manure characteristics were affected by diet treatments and seasonal variation.  It must be noted that the lack of significant differences in gas emissions in the present study could have been due to sampling error. The gas emissions observed did show a trend between treatment levels and manure management practices within the feedlot, with the effluent dams and manure piles recording the highest CH4 emissions over each of the measured seasons.  The CH4 emissions varied between seasons within the feedlot, rangeland and manure management practices, but a level of significance was never observed even though manure characteristics observed significant differences.  The N2O emissions observed no set trend between areas measured on the feedlot.  The varying values, and negative values obtained may indicate sample error, or a general uptake of N by soil or microorganisms (Chantigny et al., 2007; Li et al., 2011).

In conclusion, it was found that manure characteristics are affected by season and diet characteristics which tended to have an effect on the rate of CH4 and N2O emissions from the manure, although not significantly.

Popular Article

Feedlot greenhouse gas study analyses emissions from pen surfaces and manure management

By CJL du Toit

Researchers from the University of Pretoria spend time at a commercial beef feedlot in Mpumalanga, South Africa to gain a better understanding of the greenhouse gas emissions originating from feedlots pen surfaces and manure.

Why are GHG emissions important to agriculture?

In agriculture and livestock production systems the three main greenhouse gases (GHG) include methane (CH4), nitrous oxide (N2O) and carbon dioxide (CO2).  Greenhouse gases impact the environment through their ability to trap heat which depends on their capacity to absorb and re-emit infrared radiation and the atmospheric life time of the different gasses.  Increasing atmospheric concentrations of GHG caused by fossil fuel combustion, industrial activities, land use change and agricultural activities contributes to changes in global temperatures and rainfall patterns which could impact directly on agricultural and livestock production.

Accurate estimation of GHG from anthropogenic sources is an increasing concern given the current and potential future reporting requirements for GHG emissions.  Research measuring GHG emission fluxes from feedlot surfaces and manure management has been very limited and this was the first research project on the topic under South African conditions.

Livestock manure and GHG emissions

Livestock manure is a source of nutrients and can be used for various purposes including soil amendments to improve fertility and productivity and the generation of green energy.  The main GHG emitted by manure are CH4 and N2O. Methane is produced during anaerobic decomposition of organic matter and N2O is emitted during nitrification and de-nitrification processes. Feedlot manure GHG emissions is influenced by a variety of factors including manure management (pile, anaerobic lagoon, rangeland), manure application (fertilization of rangeland, composting, bio-fermentation), temperature, aeration, moisture and the sources of nutrients in the manure which is in part caused feed inefficiencies. Emission is also influenced by animal factors in the feedlot such as stocking density which will influence the amount of manure deposited, feed intake and digestibility, animal type and age.

What did the researchers do?

Following an extensive review of current literature on GHG emission flux quantification from pasture, cropping and livestock enterprises it was decided to adopt closed static chambers as the measurement methodology. The aim of the study was to determine the effect of feedlot ration and season on the GHG emissions from manure at different sites within in a commercial feedlot operation. Chamber bases were randomly installed at each manure management site (rangeland, pen surface, manure piles and water catchment lagoons) during each season. The seasons were classified as wet and hot (WH), dry and cold (DC) and dry and hot (DH).

Gas samples were drawn from the chambers during mid-day at four time intervals within a 40 min measuring period and analysed using a gas chromatograph to determine average CH4 and N2O fluxes.

What did the researchers learn?

The method employed resulted in large variation within results sets mainly due to difficulty in sealing the chambers bases especially in the pen surfaces which were extremely compacted. The random placement of chambers also caused variation in results as some chambers had a higher manure density and factors such as soil and manure moisture varied between different locations within each pen.  The results yielded an average pen surface manure CH4 emission factor of 449 g/head/year which was 50% lower compared to feedlot manure emission factors previously calculated of 870 g/head/year using IPCC (2006) based models.  The N2O emissions measured from pen surfaces (10.95 g/head/year) were much lower than previously calculated or reported emission factors in literature varying from 54.8 to 2555 g N2O/ head/year.  Within the whole manure management system on the feedlot CH4 emissions from the water catchment dams were the highest followed by manure piles, feedlot pen surfaces and manure deposited on rangeland.  Although no statistical differences were found between the different seasons the wet and hot season produced the highest overall CH4 emissions and the dry and cold season produced the highest N2O emission across all manure management sites.

Managing GHG emissions from manure

The mitigation of GHG emissions from manure management in livestock operations is the topic of many research projects globally. Identified mitigation strategies are already being used by producers but new techniques and fine-tuning of existing options will lead to new and improved alternatives which can be tailored to country or regions specific production systems. The mitigation of GHG emissions from livestock production systems can be complicated as a strategy that reduces one emission may increase the other. Manure emissions can be reduced through two main actions namely input (providing of organic matter e.g. feeds) and manure management.  Overfeeding of nutrients such as nitrogen (N) will result in an increase in the amount of N excreted in manure which will lead to increased N2O emissions. To reduce GHG emission from manure producers will have to use feeding regimes that will maximise feed efficiency and reduce nutrient wastage. The management of on-farm manure can also be tailored to reduce GHG emissions and the effect of production systems on the environment.  The time of manure application to soil and rangeland is important to reduce emissions. Producers should avoid spreading manure when soil is are wet as this will increase CH4 emissions and attempt to reduce the storage time of manure on the farm. The use of technologies such as covered lagoons, digesters, aeration of manure and composting has all been employed to reduce CH4 emissions from manure.

On-going research

There is a need to develop standardised research methodology protocols, for both on-farm and laboratory experiments, which will make it possible to compare mitigation strategies and research results between different studies. Researchers are also attempting to understand the interplay of CH4 and N2O as it seems that the processes that produce these GHG are related.

Please contact the Primary Researcher if you need a copy of the comprehensive report of this project – Linde du Toit on linde.dutoit@up.ac.za

Does short duration grazing work in grasslands?

Does short duration grazing improve livestock production, veld condition and climate resilience compared to other grazing systems in a mesic grassland of South Africa?

Industry Sector: Cattle and Small Stock

Research focus area: Sustainable natural resource utilization

Research Institute: Universtity of Cape Town

Researcher: Dr Heidi Hawkins

Research Team

Title Initials Surname Highest Qualification
Prof S Vetter PhD
A/Prof MD Cramer PhD
Prof V Muchenje PhD
Dr C Mapiye PhD
Mr AS Venter MSc
Ms N Mgwali BSc Hons

Year of Completion : 2018

Aims of the project

  • Overall we wish to test the alleged mechanisms by which short duration grazing (or Holistic Planned Grazing, HPG) “works” explicitly by looking at the underlying mechanisms at the fine scale and overall effects at the camp/farm scale and how these vary and interact with rainfall, temperature, time and specific camps. We wish to apply this understanding to inform efforts being undertaken by government and NGOs to generate sustainable and more commercial red meat production from communal rangelands and land redistribution farms in one of South Africa’s biodiversity ‘hot spots’.
  • At the scale of an experimental farm and experimental plots we test claims that high animal densities in HPG reduces selectivity during defoliation of key plant species leading to conservation of species composition (biodiversity), forage quantity and quality throughout the year
  • At the scale of the farm, plots and pot experiments we determine how grazing intensity (recovery periods /defoliation frequency x defoliation intensity) affects plant recovery.
  • At the scale of the farm and plot we test claims that trampling (from intense hoof action during HPG) results in increased incorporation of nutrients (litter, dung, urine) and water, resulting in increased soil organic matter, nutrients including carbon, microbial activity, soil water infiltration, and reduced compaction and erosion.
  • At the farm scale, we test claims that the increased forage quantity and quality HPG increases animal gain ha-1, meat quality and profit of marketable animals; and at the scale of the individual animal, that HPG results in improved average daily gain per animal, including sufficient nutrition for pregnancy, lactation and re-conception.
  • At the farm and animal scale, we test whether high animal densities alter animal behavior (walking, resting, grazing) and energy expenditure.
  • Also on the individual animal scale, we test whether HPG results in a reduced parasite load (specifically ticks) because of, e.g. rapid movement of animals between camps, and whether the stress of movement compromises disease resistance.

Executive Summary

It has been claimed that Holistic Management (HM) and specifically, Holistic Planned Grazing (HPG, hereafter holistic grazing), can reduce desertification and reverse climate change by using livestock as a tool. At the same time, high animal densities and stocking rates associated with holistic grazing are claimed to result in improved plant and animal production but with little evidence or suggested mechanisms for these changes. The project addressed these gaps in knowledge via a three-year trial and corral studies, fence-line contrasts of existing and long-term practitioners of holistic grazing in the grassland biome, and remote sensing over sub-Saharan Africa.

We found nuanced differences in forage utilization, plant selectivity by animals, litter production, as well as small differences in animal behaviour and more marked differences in forage quality and animal parasites between grazing approaches (continuous, season-long, four camp and holistic planned grazing) in the trial. Some of these differences depended on season, but in all cases the scale of these differences were not enough to affect overall plant or animal production. Thus, the season-long and four-camp approaches were more profitable than the holistic approach due to capital outlay ((fences ands water points for multiple camps, or herders to create virtual camps), with the break-even point for holistic grazing being two years after that for other approaches. Provisional results from a national survey of long-term working farms supported results from the three-year trial. The use of a corrals is associated with holistic grazing in communal livestock systems, and our work showed that if the starting condition of the rangeland was poor with bare ground cover above 12% then basal cover increased under corraling, i.e. at very high animal densities of more than 400 livestock units per hectare, but otherwise increased bare ground so that corraling as a tool may be useful but should be applied with caution. In a remote sensing study, we found that woody plant encroachment has increased by 8% over the last three decades over sub-Saharan Africa and that while this is largely driven by climate, fire and herbivory are important drivers so that judicious use of fire and livestock (possibly at high densities) could help reverse this trend, with implications for the global carbon balance and productivity.

Overall, if animal gain is the priority of a land owner, the additional labour and/or infrastructure associated with holistic grazing is not justified. However, holistic grazing may be useful for rangeland restoration or specific goals.

Useful applications of holistic grazing based on our data may be:

  1. Reduction of under-utilized plant standing biomass and/or creation of a litter layer;
  2. Reduction of external and internal parasite loads (from an already low infestation to slightly lower infestation in our data so the practical usefulness would have to be tested at high infestation rates);
  3. Increased forage quality in some seasons (from normal quality to slightly increased quality in our data);
  4. Possibly, to reduce woody plant encroachment (and runaway fires), especially if browsers are included.

Popular Article

Does holistic grazing improve livestock production, veld condition and climate resilience compared to other grazing systems?

by Heidi-Jayne Hawkins

Director of Research at Conservation South Africa and Honorary Research Associate at University of Cape Town; contacts hhawkins@conservation.org and heidi-jane.hawkins@uct.ac.za

Rangelands, a source of biodiversity and agricultural products, are under threat globally. It has been claimed by the Savory Institute that Holistic Management (HM) and specifically, Holistic Planned Grazing, can reduce desertification and reverse climate change by using livestock as a tool. At the same time, high animal densities and stocking rates associated with holistic grazing are claimed to result in improved plant and animal production but with little evidence or suggested mechanisms for these changes. A recent review of the literature found that holistic grazing has no impact on plant and animal production (Hawkins 2017). In general, any management approach that is adaptive can be expected to sustainably manage rangeland resources by considering both ecological processes and livelihoods. Holistic Management or the Holistic Management Framework (Savory and Butterfield, 2016) is such a framework. While the adaptive approach of HM is not contentious, the livestock management part of this framework has been the subject of debate since the 1980s. Holistic Planned Grazing (HPG; hereafter holistic grazing) describes an intensive, rotational, time-controlled approach much like short duration-, cell-, multi-paddock- and mob-grazing. In South Africa, it is commonly called high-density, short-duration stocking.

During holistic grazing, livestock are kept at high densities using fences or herders with the intention of mimicking free-moving herds of herbivores that are migrating or bunched by predators; and grazing rather than fire is generally favoured as a way of recycling soil nutrients. Our recent article (Venter et al 2017) discusses the great numbers, densities and diversity of herbivores that occurred in the past before mass extinctions and hunting associated with humans spreading over the earth, and it is indeed reasonable to think that higher densities or animals would be ecologically appropriate and that the current use of fire to manage rangelands could in part be replaced by herbivores including livestock. However, the claims made by Savory go beyond this and need testing. Considering the renewed debate and existing threats to our rangelands including grassland and savanna, we examined the evidence for claims and tested various possible mechanisms that could underly these claims ((increased production, nutrient cycling, plant utilization and reduced plant selectivity).

The project addressed these gaps in knowledge via a three-year trial and corral studies, fence-line contrasts of existing and long-term practitioners of holistic grazing in the grassland biome, and remote sensing over sub-Saharan Africa. The research was a collaboration between Conservation South Africa and academics including five researchers and five students from the University of Cape Town, Stellenbosch University and the University of Fort Hare.

The controlled study was conducted on sections of a private farm (30.351767°S, 29.043433°E near Cedarville Flats and 30.394363°S, 29.020521°E on slopes near Goedhoop), called Merino Walk within the Matatiele Local Municipality, Eastern Cape in the grassland biome. Each flats and slopes section was divided into holistic grazing, conventional four-camp rotation, and continuous season-long grazing treatments with the same overall HM management and stocking rate but different animal densities. A national survey of working holistic farms and their neighbours allowed us to broaden the scope of the work from the scale of a local trial to the national scale. Also, the survey allowed us to assess holistic farming over longer time periods than the three years farm trial, as well gain insights into real farms. The questionnaire can be found at https://www.surveymonkey.com/r/grazing_research_survey .

We found nuanced differences in forage utilization, plant selectivity by animals, litter production, as well as small differences in animal behaviour and more marked differences in forage quality and animal parasites between grazing approaches (continuous, season-long, four camp and holistic planned grazing) in the trial. Some of these differences depended on season, but in all cases the scale of these differences were not enough to affect overall plant or animal production and in winter animal production in the rotational treatments was relatively low. Provisional results from a national survey of long-term working farms supported results from the three-year trial.

The season-long and four-camp approaches were more profitable than the holistic approach due to capital outlay (fences ands water points for multiple camps, or herders to create virtual camps), with the break-even point for holistic grazing being two years after that for other approaches.

Looking closer at animal behaviour, there was no evidence that holistic grazing increases dung trampling, the number of steps taken or selectivity at the plant or patch scales. An interesting effect of holistic grazing was a reduction in tick infestation that is thought to be associated with the rapid movements of animals between the mobile camps, so that ticks do not have time to complete their life-cycles. Out of the three grazing treatments, tick counts were higher in the continuous herd compared to the holistic grazing and four-camp herd in spring and summer. In general, internal parasites were very low with faecal egg counts being highest in the hot-rainy season. Both tick and faecal egg counts were not at levels of concern for animal health regardless of treatment effects.

The use of a corrals is associated with holistic grazing in communal livestock systems, and our work showed that if the starting condition of the rangeland was poor with bare ground cover above 12% then basal cover increased under corraling, i.e. at very high animal densities of more than 400 livestock units per hectare, but otherwise increased bare ground increased, so corraling should be applied with caution.

In the remote sensing study, we found that woody plant encroachment has increased by 8% over the last three decades over sub-Saharan Africa and that while this is largely driven by climate, fire and herbivory are important drivers so that judicious use of fire and livestock (especially browsers, possibly at high densities) could help reverse this trend.

Implications

From our results in a mesic grassland:

  • Holistic grazing may be useful as a tool for specific purposes such as increasing the litter layer and reducing tick loads but does not increase production;
  • High-density grazing practices are less profitable than conventional season-long grazing or the four-camp approach;
  • Corrals at animal densities over 400 LSU ha-1 may be a useful disturbance regime for restoration of bare ground and increasing phosphorus concentrations for cropping but only on already disturbed ground;
  • Browser/grazer mix and fire may be useful tools managed to reduce woody plant (bush) encroachment (and runaway fires).

Information sources

Hawkins H-J. 2017. African Journal of Range and Forage Science 34: 65-75.

Savory A, Butterfield J. 2016. Holistic Management. A commonsense revolution to restore our environment (3rd edn). USA: Island Press. ISBN 9781610917445 (e-book).

Venter, ZS., H-J Hawkins, MD Cramer 2017.  Ecosphere 8 (10), http://dx.doi.org/10.1002/ecs2.1946

Venter ZS, Cramer MD, Hawkins H-J 2018. Nature Communications 9, 2272 http://dx.doi.org/10.1038/s41467-018-04616-8

Please contact the Primary Researcher if you need a copy of the comprehensive report of this project – Heidi on heidi-jane.hawkins@uct.ac.za

Formal and Informal Red Meat Industry in the Western Cape

Hidden in Plain Sight: A Regional Inquiry into the Size, Scope and Socioeconomic Effects of the Western Cape’s Formal and Informal Red Meat Industries

Industry Sector: Cattle and Small Stock

Research Focus Areas: Animal Health and Welfare; Animal Products, quality and safety, nutritional value and preference; The economics of red meat consumption and production in South Africa

Research Institute: Agriculture Research Institute – Animal Production Institute

Researcher: Dr Nick Vink PhD (Agric)

Title Initials Surname Highest Qualification
Mr. Michael McCullough M

Completion Date : 2018

Aims Of The Project

  • 3.1 To determine and report the size and scope of the informal red meat I industry as well as the informal industry’s effects on food safety, animal health and l welfare and food security with an initial focus on the Western Cape.
  • 3.2 To determine and report the size and scope of the formal red meat industry as well as the formal industry’s effects on food safety, animal welfare and food security with a primary focus on the Western Cape.
  • 3.3 To create and test a combined quantitative and qualitative methodology for determining the size and scope of the red meat industry in South Africa with a primary emphasis on the informal sector, a secondary emphasis on the formal sector as well as recommendations for improving current levels of food safety, animal welfare and food security.

Executive Summary

Hidden in Plain Sight

The genesis of Hidden in Plain Sight was two previous studies of red meat marketing systems: one in a rural Municipality in the Western Cape that discovered an informal shadow industry operating alongside a formal system of abattoirs, supermarkets and independent butcheries; the other in the townships and informal settlements of Cape Town that described an informal marketing system filling a vacuum created by the abdication of the formal system of supermarkets and butcheries. Beyond the scope of both studies was an appreciation of the size and scope of the Province’s informal systems of red meat production, processing and distribution. Hidden in Plain Sight attempts to determine size and scope of the Province’s informal red meat industry, its effects on food security, food safety and animal health and welfare.

Informal livestock farmers pasturing cattle and sheep primarily on Municipal land as well as raising pigs in improvised piggeries furnish livestock for informal processing; i.e. outdoor slaughter and indoor butchery in unlicensed facilities such as home kitchens and food stands. One and two kilo ‘value packs’ are then sold from kitchen butcheries in rural communities. Braai stands located near taxi ranks, train stations and major intersection in the former townships of Khayelitsha, Gugulethu and Nyanga in the Cape Town Metropole receive live animals directly from informal producers located on City land surrounding these communities. The animals are slaughtered on the sidewalk in front the stands or in any other adjacent open space. The muscle meat is sliced into strips and braaied, the heads are skinned, split and charred and the offal is piled on the counter for sale to hawkers or take-home consumers.

The informal system exists in both urban and rural areas to serve the 2.6 million low to very low income households in the Western Cape. In addition to low incomes many urban and rural households live in virtual ‘food deserts’ where, in the absence of transportation either public or private access to food sellers is at best difficult.  Low to very low incomes and lack of access expose over half of the Province’s households to food insecurity and place 29 percent at risk of hunger.

An expectation at the inception of this study was that size and scope of the informal system although unknown would rival the formal red meat system and would be sufficient to serve a significant percentage of the Province’s food insecure households. Such was not the case. Survey data based on inspections of informal production sites throughout the Province, census  and interview data from the Veterinary Service and the Farmer Support and Development programmes of the Western Cape Department of Agriculture and interviews with Municipal Social Development officials yield numbers of informal produced livestock clearly insufficient to serve a fraction of households at risk for hunger. Three recommendations are offered to increase the capacity of the informal industry to serve food insecure households: conduct a comprehensive inventory of public land suitable for informal production; establish an informal production, processing and distribution pilot project in each District Municipality; investigate existing parallel formal – informal marketing systems in Latin America; develop a prototype two tiered regulatory frame work to facilitate food security whilst ensuring food safety.

POPULAR ARTICLE

Magazine Article

Michael McCullough

When South African consumers walk into their local supermarket to shop for beef, lamb or pork they expect a fresh, high quality, attractively packaged, nutritious product and they get it. No need to worry about the safety of the product. South African cattle, sheep and pigs are given a through once over before they set foot in an abattoir. Any animal injured, unfit or suspected of disease is promptly rejected, condemned and disposed of. It’s not a business decision, it’s the law.

What supermarket shoppers are beginning to worry about is the possibility the meat they serve their family and friends could come from terrified, abused or injured animals. They want to know that the slaughter process is humane and animal suffering is minimised. That may sound like a contradiction in terms but it’s not. Here’s why:

  • After arrival at the abattoir animals must be rested for at least an hour. The animals must calm and ready for inspection just before they are taken into the abattoir.
  • After passing single file through a narrow corridor each animal is taken individually into a slaughter room and placed in a narrow box or a harness. This happens out of sight of the other animals to reduce stress on those queued up behind.
  • The actual killing must be painless. Animals are stunned with a strong but not fatal electric shock or with a captive bolt pistol that delivers a sharp blow to the animal’s forehead.
  • While the animal is unconscious both the arteries and veins in the neck must be severed quickly and accurately. Contrary to the movies where the victim drops dead just after his throat is cut; if one or more veins or arteries are missed the animal may take from a minute to five minutes to die. If the stun wears off before enough blood is lost to shut down the brain the animal can experience pain.
  • Stunning and wielding the knife is hard, skilled and dangerous work. Humane slaughter depends on workers who are alert and careful. Tired operators may become careless or insensitive to animals’ welfare therefore abattoirs insure their operators take regular rest periods to maintain their skills.

The animal’s carcase is then moved to a high ceilinged room and hoisted head down to finish the bleeding process. The carcase is now ready for butchery. For consumers preferring kosher or halal meat the procedure is slightly different. For kosher slaughter no stunning is allowed but to minimise suffering the arteries, veins, vagus nerve, trachea and oesophagus are severed in a single quick sweep of a very sharp knife. Halal abattoirs may elect to stun the animal. Properly done the animal is unconscious in three seconds because severing the vagus nerve is like shutting down the body’s neurological switchboard.  Flip the switch and the lights go out.

One thing consumers shopping at their neighbourhood supermarket or butchery don’t want to worry about is whether the chops and steaks they’re buying are safe to eat. Should they? After all nobody wants to have friends and family or even worse, their boss over for a braai and find out later that everyone wound up at the clinic with gastric ‘distress’ or worse. This threat is all but completely short-circuited by post slaughter meat inspections, cold chain management and strict hygiene practices from the abattoir to the wholesaler to your butcher to your shopping cart.  Here’s how it works:

  • After the carcase has bled out, the head and hide are removed taking care to make sure the hair side of the hide doesn’t touch the meat. After all the animal has never seen a shower stall so the hide is pretty grimy. For this reason anything that touches the hide shouldn’t touch the meat such as dirty hands, in in the low income housing areas next to most country towns and in densely populated urban communities like Khayelitsha in Cape Town implements, dirty hands or soiled protective clothing.
  • Organs like the gut and the gall bladder contain seriously infectious bacteria like salmonella so the viscera must come out intact (the viscera is the sack that contains digestive tract). If it splits like a cheap trash bag on the way out everything you don’t want to touch the meat goes everywhere including all over the carcase. Assuming everything comes out as planned it’s time for final butchering and trimming.
  • The carcases are halved, the spines removed, all the other inedible bits and pieces as well as any contaminated meat is cut out and discarded. The carcase is washed and chilled. The slaughter and butchering processes are done.

From here to your grill is just a matter of maintaining the cold chain – keeping the carcase clean and chilled — until it passes through the wholesaler’s cold storage on its way to your neighbourhood supermarket or butchery. The carcase is then cut into meal sized portions, wrapped, marked, priced and put in the display case. Done and dusted.

Just as every coin has two sides so does every industry. The meat industry is no exception. The formal, visible side of the industry serves the middle and upper classes and the informal, mostly invisible side serves everyone else.

When low to very low income consumers shop for beef, lamb or pork do they expect high quality and fancy packaging?  Do their questions about nutrition go much further than Will it satisfy my family’s hunger or not?  Does price matter more to this consumer than where the animal came from, what condition it was in and how did it die? It’s safe to say that putting enough affordable on the table comes first; nothing else really counts.

For these reasons a growing number of South Africans are turning away from supermarkets and butcheries to buy meat produced and processed in their own communities. Why are a growing number of consumers in low income urban communities bypassing abattoirs, supermarkets and butcheries?

Until recently not much was known about the informal red meat industry in the rural Western Cape. It was not completely invisible but rather operated in the shadows just out of sight of most supermarket and butchery shoppers.  Informal stock producers who supply this industry aren’t usually landowners and depend heavily on leased Municipal property adjacent to low income housing areas and shanty towns. Cattle and sheep producers graze their animals where they can find grass and water. However pig producers must confine their animals to keep them from roaming. They build pens from scraps of lumber, sheet metal or other discarded building materials. Pig can’t be kept just anywhere; they need a source of water for mud to wallow in during the warm months (they don’t sweat enough to keep cool). The smell of an informal pig kraal is unforgettable so most are located away from housing. Although neighbours don’t seem to mind cows or sheep wandering through the community they usually draw the line at somebody else’s pig rooting in their garden.

When an informal producer is ready kill a pig, for example he or she spreads the word and takes orders. When it comes time to slaughter the producer recruits several volunteers; puts a barrel or large pot of water to boil on a wood fire and brings the pig forth. The pig is stunned by one or more blows between the eyes with a heavy hammer. A long sharp knife is inserted to the hilt just above the breastbone, twisted vigorously and pulled out. If all goes well (and it sometimes doesn’t) the pig will bleed out rapidly. Unfortunately most informal sites don’t have a convenient tree to hoist the pig so that it bleeds out completely. It’s often left on the ground to ooze blood until the time seems right to dip the carcase into the hot water to loosen the hair and underlying membrane. After the hair is scraped off down to the white skin it’s time to remove the head, the viscera and the rest of the internal organs. The pig should be hung for a day and allowed to cool. In practice this seldom happens. A carcase hanging from a tree overnight is likely to attract unwanted attention from the authorities. So the carcase is immediately butchered into saleable portions, refrigerated or frozen if possible and sold to local consumers. The helpers are usually rewarded with a share of the meat, the head and the offal.

The routine for cattle and sheep is similar except for the extra volunteers needed to handle a 150 kg cow carcase. Cow hides are removed with a knife and sheep skins are pulled off by hand. Unlike a pig no boiling and scraping is necessary.  Contamination from faeces and urine is hard to avoid and accidents often occur when the processing crew is tugging the heavy, slippery viscera out of the gut cavity not to mention the near certainty of hair and dirt on the meat. The carcase is usually rinsed with water carried to the slaughter site in buckets.  Given the rough ad tumble nature of informal slaughter it’s surprising that reported cases of food poisoning from informally sourced red meat are so rare as to be non-existent.

In Khayelitsha, a large densely populated suburb of Cape Town the informal system is not only out of the shadows it’s out loud and proud. Next to every train station, taxi rank and surrounding every major street intersection sidewalk braai stands do a thriving business in grilled beef, pork and mutton. Tens of thousands of commuters stop by these stands every day to pick up a takeaway meal on the way to and from work. Think off these stands as fast food outlets for the black urban working class. Just like the ‘McWhatevers’ in other neighbourhoods      braai stands offer accessible and  affordable (but not necessarily inexpensive) meat to consumers without the means or time to buy meat fresh, take it home, refrigerate it and cook it later. The big difference between fast food outlets in neighbourhoods like Khayelitsha and outlets other less crowded and more affluent neighbourhoods is how the meat gets there and what happens when it arrives.

Live animals are brought in from surrounding communities and slaughtered on sidewalks in front of the stands, alleys behind the stands or any unoccupied space. A source of water to rinse the carcases is strictly optional. The muscle meat is sliced into strips and immediately grilled. The heads are skinned or scraped, split and charred for serving. The offal is piled on tables and sold to customers for home consumption.

To outsiders the scene is a bloody, chaotic and cruel public health disaster. Are there issues with quality? Yes. Nutrition? Absolutely. Packaging? Of course. Safety? Afraid so. Access? No. Affordability? No. To Khayelitsha residents braai stands are a local informal industry that meets their community’s needs because the formal industry is either unwilling or unable to do so.

So which consumer model makes will prevail? The supermarket model that creates expectations of quality, safety and nutrition wrapped up in attractive packaging but comes at a high price? Or the braai stand/informal butchery next door that makes up for little or no packaging, no guarantees of quality, safety or nutrition but delivers affordable prices and accessibility?

For the foreseeable future the answer is both. Consumers who are willing and able to pay a price premium for the value added by abattoirs, wholesalers and supermarkets in exchange for guarantees of quality, safety and nutrition will continue to do so because they can. Consumers who lack the means to pay for those kinds of guarantees and who must take their chances in return for accessible and affordable meat will continue to do so because they must.

Please contact the Primary Researcher if you need a copy of the comprehensive report of this project – Dr Nick Vink  on nv@sun.ac.za