Brine injection of beef

The effect of moisture enhancement by brine injection on the chemical, microbial and sensory quality of beefGenome-wide genetic marker discovery in South African indigenous cattle breeds using next generation sequencing

Industry Sector: Cattle and Small Stock

Research Focus Area: Animal Products, Quality and Value-adding

Research Institute: Agriculture Research Institute – Animal Production Institute

Researcher:

Dr Phillip Strydom PhD Animal Science

Title Name Surname Highest Qualification
Prof Arnold Hugo PhD
Title Name Surname Highest Qualification
Prof CJ Hugo PhD
Dr C Bothma PhD
Dr C Charimba PhD
Mr M Cluff M.Sc Agric
Ms E Roodt M.Sc Agric
Mr Z Kuhn B.Sc Agric Hons
Mr H Steyn B.Sc Agric Hons
Ms E Moholisa M.Sc Agric
Dr M Hope-Jones PhD
Ms JM Boikhutso MInst. Agrar: Food Production and processing
Ms MM Magoro M.Tech.Food Technology
Mr CA Seomane Grade 8, Meat Technology Research Assistant, 27 years’ experience
Mr WK Seanego Grade 7,Meat Technology Research Assistant 11 years’ experience
Dr SM Van Heerden PhD
Ms OC Sehoole BSc Food management (4 years)
Ms TM Mokhele BInstAgrar Food Processing (4 years)
Ms JH Masilela Grade 9, sensory research assistant 26 years experience

Aims Of The Project

 

3.1 To determine the effect of injection of non-nitrite moisture enhancing injection brines on the nutritional value of beef.
3.2 To determine the effect of injection of non-nitrite moisture enhancing injection brines on the chemical and microbial stability of beef under refrigerated and frozen storage.
3.3  To determine the effect of injection of non-nitrite moisture enhancing injection brines on the textural and sensory properties of beef.

Completion Date: 1 July 2017

Executive Summary

The effect of different injection levels of non-nitrite brines on meat quality characteristics of unaged and aged beef loins was investigated. Beef loin cuts aged for 3 or 10 days were injected with 5, 10, 15 or 20 % brine (weight basis) and compared with non-injected loins with regards to nutritional value, sensory and textural quality, water holding properties, and colour, chemical and microbial stability.

The results illustrated that brine injected in beef loin are retained between 50 to 70 % of injection levels. This resulted in a clear nutrient dilution, best illustrated by the decrease in protein content from 21.1 % in the Control loins to 18.5 % in the loins injected to a target yield of 20 %. The dilution of protein became evident only at an injection level of 10 % and higher but did not increase further with higher levels of injection. Brine injection also increased the levels of phosphate (35 %) and salt (50 %) and the effect was consistent across all injection levels. This is very important since salt and sodium content of especially meat products are currently under the spotlight with new legislation on sodium levels of meat products being implemented on 30 June 2016.

The chemical stability of beef loin as measured by TBARS (measurement of rancidity) was not affected by brine injection. Neither fresh samples, displayed for 6 days, or frozen samples, stored for 180 days, were affected, despite the fact that salt is a pro-oxidant and chemical deterioration was expected with brine injection.

Colour and colour stability were affected by brine injection. Initial colour (just after treatment) measured as chroma (typical colour of fresh meat) was negatively affected only at injection levels above 10%. However, as days on display continued (up to 6 days), all injected samples showed poorer colour stability (lower chroma values) than Control samples. Likewise, injected samples were duller (lower values for lightness, L*).

Brine injected samples tended to show higher initial (day of injection) total aerobic micro-organism counts (0.5 – 0.7 of a log) likely due to the recirculation of the brine during application. However, microbial growth was later (day 6 on the shelf) inhibited, probably by the potassium lactate in the brine mix, eventually leading to the brine injected samples having lower total aerobic bacteria loads (between 0.5 and 0.8 of a log) than Control samples. Also because of recirculation of brine, yeasts and molds were higher in injected samples (0.8 to 1.0 log) after injection, but differences between Controls and injected samples became insignificant after 6 days on the shelf.

Both Warner Bratzler shear force and sensory tenderness showed beneficial effects due to brine injection even at levels as low as 5 %. A slight linear increase (lower shear force and higher tenderness score) was observed with increasing level of injection although the effect was not statistically significant above 10 % injection level. The taste panel also scored injected samples higher for juiciness and although these scores increased slightly with level of injection, no significant effect was observed above 10% levels. As expected, the taste panel also scored injected samples higher for saltiness, but no off-flavours were identified.

Another advantage of brine injection was a reduction in thawing and total cooking losses. The maximum effect was observed at 5 % injection level and cooking loss slightly increased as injection level increased.

In conclusion, it seems that the advantages and disadvantages of brine injection is correctly balanced by the 10% brine injection limit enforced by the Agricultural Product Standards Act, 1990 (ACT No. 119 of 1990; 30 January 2015) for beef. Brine injection levels above 10% showed no additional effect on eating quality. Likewise, the negative effect on colour of freshly displayed meat deteriorated at levels above 10%, while the protein dilution effect also became evident at 10% level. Higher salt irrespective of injection level may be a health concern.

Popular Article

will follow later

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

Heterosis – beef sensory and leather quality traits

Characterization of breed-specific additive and heterosis effects on beef sensory and leather quality traits

Industry Sector: Cattle and Small Stock

Research Focus Area: Research Animal Products, Quality and Value-adding

Research Institute: ARC-Animal Production Institute Northern Cape Department of Agriculture, Land Reform and Rural Development and University of the Free State

Researcher: Prof Michiel M Scholtz D.Sc. Agric

Title Initials Surname Highest Qualification
Mrs. A Theunissen MSc Agric

Dr M D MacNeil Ph.D
Dr J D De Bruyn Ph.D
Prof F W C Neser Ph.D

Completion Date: May 2017

Aims Of The Project

  • To characterize the maternal and paternal heterosis effects on sensory beef traits
  • To characterize the maternal and paternal heterosis effect on leather traits

Executive Summary

The project had two objectives, namely to estimate direct and maternal breed effects and heterosis contributions for Afrikaner (A), Simmentaler (S), Brahman (B), Charolais (C) and Hereford (H) on sensory carcass traits and leather traits.

Sensory carcass traits

Five sensory traits (tenderness, juiciness, aroma and flavor and residual connective tissue) and two physical meat traits viz shear force (N/2.5cm2) and cooking loss (%) were investigated. Data (N=375) arising from 5 straightbred and 24 crossbred combinations were modeled by multiple regression of the phenotypes on expected breed roportions and heterozygosity.

Only direct effects seem important for shear force, tenderness, and residual connective tissue. However, for juiciness and cooking loss maternal effects also seem relevant. This may indicate that effects manifested during the pre-weaning period on components of meat quality were retained through the time of harvest or a predisposition for creating differences in the sensory properties of the meat were established. The indigenous Afrikaner had generally the most favourable sensory profile relative to the imported breeds. This was particularly true for shear force and tenderness.

Sanga cattle, like the Afrikaner, are early maturing breeds. There is clear evidence that the use of exotic germplasm on Sanga breeds can increase feedlot performance and meat yield of cattle reared under South African conditions. Different crossbred genotypes also provide opportunity for more rapid conformation to the changes in market requirements and may offer opportunity for more revenue. However, it appeared based on the sensory data summarized, that crossbreeding with exotic germplasm has little to offer in terms of consumer satisfaction relative to the use of Afrikaner.

Leather quality
It is important to note that hides are normally purchased by weight, but leather is sold by surface area. It is therefore common practice to mechanically stretch the hides during tanning and manufacture. The standard practice is to stretch leather to 20% extension. There is however concern that this stretching may affect important aspects of leather quality and strength.

Hide yield (%) and 8 leather characteristics (leather yield (dm2/kg), force 20% extension (Mpa), extension grain crack (%), extension break (%), force break (Mpa), slit tear force (N/mm), distension grain crack (%), and force grain crack (N/mm)) were evaluated. The results indicate breed direct effects and individual heterosis, but not maternal effects, may be important for most of these traits. For all of the exotic breeds, direct effects reduced hide yield and increased leather yield relative to the indigenous Afrikaner. For both of these traits, individual heterosis effects arose primarily from indicus x taurus crossing with the Hereford x Brahman effect being most pronounced. Leather from the exotic breeds appeared to be stronger, as evidenced by greater direct effects for force required to achieve 20% extension and break, than leather from the indigenous Afrikaner. Direct effects on the extension required to crack the grain attributable to Hereford and Simmentaler were less than for the indigenous Afrikaner, Brahman, and Charolais. These results indicate opportunities to improve leather yield and quality through crossbreeding relative to straight bred Afrikaner.

Popular Article

There are 2 scientific articles, please contact the researcher for more information on this.

Please contact the Primary Researcher if you need a copy of the comprehensive report of this project – Michiel Scholtz on GScholtz@arc.agric.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 23 August 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

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 paks’ 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.

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

Discovery of single nucleotide polymorphisms

Genome-wide genetic marker discovery in South African indigenous cattle breeds using next generation sequencing

Industry Sector: Cattle and Small Stock

Research Focus Area: Livestock production with global competitiveness: Animal growth, nutrition and management

Research Institute: Agriculture Research Institute – Animal Production Institute

Researcher: Dr. Avhashoni Zwane

Title Initials Surname Highest Qualification
Prof. Azwihangwisi Maiwashe PhD
Title Name Surname Highest Qualification
Prof Este Van Marle-Koster PhD
Prof Jerry Taylor PhD
Prof Mahlako Makgahlela PhD
Dr Ananyo Choudhury PhD
Dr Farai Muchadeyi PhD

Aims Of The Project

  • To conduct a genome wide search for new SNPs in local cattle breeds
  • To validate newly identified SNPs using Run 5 data from the 1000 Bull Genomes Project and perform functional annotation and enrichment analysis
  • To identify selective sweeps and a panel of SNP markers to discriminate between the three indigenous breeds

Executive Summary

South African (SA) livestock has played an important role in food security country’s sustainability. Due to the important role of indigenous cattle breeds in SA, it is crucial for these breeds to be included in the generation of genotypic and sequence data. Genomic data provide opportunity for various genetic investigations including identification of breed-informative markers, selective sweeps and genome-wide association studies (GWAS). In this study sequence data were generated and used in combination with genotypic data to conduct a SNP discovery in the three indigenous SA breeds (Afrikaner, Drakensberger, and Nguni) and study potential selective sweeps and identify panel of breed-specific markers. Commercial bovine SNP assays, (BovineSNP50 and GGP-80K) were used for identifying the breed-informative markers, while an approach of breed pooled samples were used for sequencing. Sequencing of the three breeds generated approximately 1.8 billion (184 Giga-bp) of high quality paired-end reads which 99 % reads mapped to the bovine reference genome (UMD 3.1), with an average coverage of 21.1-fold. A total of 17.6 million variants were identified across the three breeds with the highest number of variants identified in NGI (12,514,597) than in AFR (11,165,172) and the DRA (7,049,802). In total 89 % of variants were SNPs and 11 % were Indels. On average, 85 % of the total SNPs identified were also shared among the breeds from 1000 Bull Genomes Project data and the remaining 15 % of SNPs were unique to SA indigenous breeds. Novel SNPs were further annotated to identify genes enriched in novel SNPs. In total, 461, 478 and 542 genomic regions identified from the top (5%) windows were enriched for novel variants (p < 0.001). A total of 174 putative breed-specific SNPs were identified across the breeds and showed the overall 100% breed allocation using PCA and GeneClass 2. This study provides the first analysis of sequence data to discover SNPs in indigenous SA cattle breeds and the results provide insight into the genetic composition of the breeds and offer the potential for further applications in their genetic improvement.

Please contact the Primary Researcher if you need a copy of the comprehensive report of this project –  vhashoni Zwane  on Zwanea@arc.agric.za

Crossbreeding Afrikaner, Bonsmara and Nguni cows

Crossbreeding effects with specialized sire lines in Afrikaner, Bonsmara and Nguni beef cattle herds

Industry Sector: Cattle and Small Stock

Research Focus Area: Livestock production with global competitiveness: Breeding, physiology and management

Research Institute: Agriculture Research Institute – Animal Production Institute

Researcher: Dr. M Scholtz

Title Initials Surname Highest Qualification
Mrs. A. Theunissen MSc
Title Name Surname Highest Qualification
Prof F W C Neser Ph.D.
Mr. L De Lange Nat. Dipl.
Mr. T Jonker M.Sc.
Mr. F J Jordaan M.Sc. (Agric)
Dr M D MacNeil Ph.D.
Mr. O Ntwaeagae B.Tech
Mr. W Pieterson Nat. Dipl.
Ms. M C Mokolobate M.Sc. (Agric)
Ms. G M Pyoos B.Sc. (Agric. Sci.)
Ms. M Mokgadi M.Tech

Aims Of The Project

  • 1. To estimate the genetic and phenotypic trends in the dam lines
  • 2. To evaluate crossbreeding systems and quantify the phenotypic progress made in economically important traits in crossbred cattle for beef production
  • 3. To characterize the additive and non-additive genetic effects for production and health traits in progeny of terminal sires and dam line breeding cows
  • 4. To validate an existing simulation model for the development of breeding objectives for specialized sire lines on Landrace breed cows for use in small scale and commercial farming that better meet commercial feedlot requirements
  • 5. To make recommendations with regard to future selection and management of beef herds in warm arid areas
  • 6. To evaluate alternative production systems in anticipation of global warming

Executive Summary

Climate has been changing and these changes are predicted to be highly dynamic. Increasing frequencies of heat stress, drought and flooding events are likely, and these will have adverse effects livestock production. It is therefore important that production systems utilizing local landrace and adapted breeds that are better adapted to warmer climates, be investigated.

In South Africa extensive cattle farming dominate primary cattle production systems, while more than 80% of all beef cattle slaughtered in the formal sector in South Africa originate from commercial feedlots. A total of 67% of feedlot animals are crossbreds, indicating that crossbreeding is playing a significant role in the commercial industry in South Africa. Well-structured crossbreeding systems allows producers to capture benefits from complementarity and heterosis.

The study is being conducted at Vaalharts Research Station. The aim is to use the Afrikaner, Bonsmara and Nguni as dam lines in crosses with specialized sire lines from British (represented by Angus) and European (represented by Simmentaler) breeds. In addition these dam lines were also mated with Afrikaner, Bonsmara and Nguni bulls in all combinations. This is producing 15 different genotypes.

It is anticipated that the information from five breeding seasons will be needed for the a more comprehensive study. Currently the information from three seasons are available and have been summarized. A protocol for Phase 2 of the study has been submitted.

The phenotypic trends in production traits of the three breeds over 25 years revealed an increase in cow productivity in all the breeds varying from 10% in the Bonsmara to 18.3% in the Afrikaner, where cow productivity was defined as kg calf weaned per Large Stock Unit mated. This also resulted in a decrease in the carbon footprint of up to 12%. The bottom line is that cow productivity can be improved if the weaning weight of the calf relative to the weight of the cow can be increased; and the inter-calving period reduced. Well-structured crossbreeding should have a much bigger effect on this and therefore the environmental impact, will be included in the final analyses of this study.

The simulation study indicated that breed, weaner and carcass price have an influence in the gross income from weaner and ox production systems. The simulation model in question can be used to quantify the benefits from the different crosses on completion of the study on condition that it is based on sound assumptions regarding weaner and carcass prices.

The information on 550 weaner calves and 125 feedlot bulls are currently available. The heaviest weaning weights are from Simmentaler sires on Afrikaner (220 kg) and Bonsmara (213 kg) dams, as well as Angus sires on Bonsmara (252 kg) dams. The lightest weaner calves were produced from purebred Ngunis (171 kg) and Angus sires on Nguni dams (173 kg). The severe draught and extreme heat of the 2015/2016 summer season had a big effect on the Angus and Simmentaler sired calves. The Sanga sired calves and Angus/Simmentaler sired calves had the same weaning weight (171 kg) in this season. In contrast, the 2016/2017 summer season was cooler and wetter, resulting in the weaning weight of the Angus/Simmentaler sired calves being 27 kg heavier than the Sanga sired calves (210 kg versus 183 kg). This demonstrates the importance of including the effect of climate on the pre- and post-weaning performance in Phase 2 of the experiment.

At the completion of the study all the information will be updated and this baseline information used to evaluate how effective the current crossbreeding systems in South Africa are and to quantify the direct and maternal heterotic effects, the possible/promising advantages of structured crossbreeding, as well as the effect of climate.

The very dry and hot 2015/2016 season also had an effect on the post weaning feed intake and growth. For example, the ADG of the Angus and Simmentaler types decreased by 17%, whereas that of the Sanga and Sanga derived types (Afrikaner, Bonsmara, Nguni) decreased by 9%, as a result of the heat waves experienced.

It is foreseen that indigenous and adapted beef breeds may become more important in South Africa as a consequence of climate change that will result in more challenging environments. The use of specialized sire and dam lines offer an opportunity to increase output by taking advantage of heterosis and complementarity. The effects of weather patterns on beef production in South Africa should also be estimated and thereafter, mitigation strategies developed in the era of climate change to ensure optimal production efficiency.

With the information collect from the GrowSafe system, it will be possible to study feed and water intake patterns as well as behavior of individual animals and different genotypes. This may give valuable information on the effect of climate on animal performance and behavior.

This study produced one M.Sc. thesis, 8 peer reviewed scientific articles, chapters in books and conference proceedings, as well as 8 popular articles.

Popular Article

The principles behind climate smart beef cow efficiency through utilization of structured crossbreeding

Theunissen1, M.C. Mokolobate2 & M.M. Scholtz2,3

1Northern Cape Department of Agricultural, Land Reform and Ruswral Development, Private Bag X9, Jan Kempdorp 8550, South Africa

2ARC-Animal Production Institute, Private Bag X2, Irene, 0062, South Africa

3University of the Free State, Bloemfontein, 9300, South Africa; South Africa

atheunissen@ncpg.gov.za (Corresponding author)

 Background and deliberations

With the ever swelling costs of production, beef cattle producers in South Africa have a sure challenge for sustainability. This is aggravated by the vagaries of climate change. The country’s most recent vulnerability was displayed during the 2015 drought, which was the warmest year ever recorded and was accompanied by extreme heat. The beef industry is one of the agricultural sectors that need to focus on both adaptation and mitigation strategies in response to  greenhouse gas (GHG) emissions and global warming.

The utilization of more hardy breed resources in a changing production environment is one of the alternative strategies to be considered. The most fundamental factor in this strategy will be the emphasis on a high reproductive rate of the selected breeds in the particular environment to increase the overall efficiency of the beef cattle enterprise.

Another alternate is the use of sustainable crossbreeding systems that pool indigenous and exotic breeds, but with retention of the genetic resources, which have shown to be an effective means to reduces GHG, as it has been shown to increase reproduction and production levels in overseas and in local studies. In this regard, a newly developed more sophisticated Large Stock Unit (LSU) calculator by Neser (2012) and Mokolobate (2015) and the measurement of cow efficiency (to calculate kg calf weaned/kg LSU of the dam); initiated an evaluation tool for “cross-bred” selection and breeding to improve cow efficiency; as long as the nutritional needs of animals are fully met.

This expression of cow efficiency is an improved replacement for the biological definition of kg calf weaned/kg mature cow weight that not only has two variables of which anyone or both in the ratio can change to have the same answer, but does not express beef production in terms of an assigned nutrient intake. The advantage of the new biological expression of cow efficiency is that the method increases output and reduces input, which will then support and facilitate the implementation of climate smart production, adaptation and mitigation measures.

Initially Meissner et al. (1983) defined a LSU on the basis of the nutrient requirement of a unit.  However, with differences in frame sizes there are differences in the voluntary feed intake between such animals although they have the same body weight. The LSU equivalents for beef cattle of different frame sizes also vary according to physiological phases, eg. heifers (over 12 months of age) and lactating cows. Table 1 shows examples of the refined estimations of LSU equivalents according to frame sizes of cows that was derived with the calculator.

Table 1: LSU equivalents for beef cattle of different frame sizes and physiological phases

Weight

Kg

Small Frame Medium Frame Large Frame
Heifer (>12 months) Cow &

Calf

Heifer (>12 months) Cow &

Calf

Heifer (>12 months) Cow &

Calf

150 0.37 X X X X X
175 0.42 X X X X X
200 0.47 X 0.50 X X X
225 0.52 0.83 0.56 X X X
250 0.57 0.89 0.61 X 0.67 X
275 0.61 0.95 0.66 X 0.72 X
300 0.66 1.00 0.70 1.05 0.77 X
325 0.70 1.06 0.75 1.11 0.82 X
350 0.73 1.11 0.80 1.17 0.88 X
375 0.77 1.16 0.84 1.23 0.93 1.48
400 0.80 1.22 0.89 1.29 0.98 1.55
425 0.83 1.27 0.93 1.34 1.03 1.61
450 0.85 1.32 0.97 1.40 1.08 1.66
475 X 1.37 1.01 1.45 1.13 1.72
500 X 1.42 1.05 1.50 1.18 1.78
525 X 1.47 1.08 1.55 1.23 1.83
550 X 1.52 1.12 1.60 1.28 1.88
575 X 1.57 X 1.65 1.33 1.93
600 X 1.61 X 1.69 1.38 1.98
625 X X X 1.74 1.43 2.02
650 X X X 1.78 X 2.07
675 X X X X X 2.11
700 X X X X X 2.15

Crossbreeding has proved to increase cow efficiency when it is measured and calculated with the LSU caculator. Table 2 demonstrates the results of a study that was done at Vaalharts Research Station that used mature cows of different breeds. The cow efficiency, estimated by kg calf weaned / cow LSU (KgC/LSU), for the Afrikaner (A), Brahman (B), Charolais (C), Hereford (H) and Simmentaler (S) breed types were calculated according to their different frame sizes and expressed as percentage deviation from the Afrikaner breed in brackets.

Table 2 The estimated cow efficiency (KgC/LSU) for the 29 different breed types and percentage deviation from the Afrikaner breed in brackets

  Sire Breed
 

Dam breed

Afrikaner  (A) Brahman  (B) Charoloais  (C) Hereford  (H) Simmentaler  (S)
A 142.6

(0.0)

144.2

(1.1%)

145.7

(2.1%)

151.2

(6.0%)

143.7

(0.7%)

B 142.0

(-0.4%)

C 124.9

(-12.4%)

H 149.3

(4.6%)

S 139.3

(-2.3%)

BA 148.9

(4.4%)

147.1

(3.1%)

155.6

(9.1%)

162.0

(13.6%)

160.1

(12.3%)

CA 152.3

(6.7%)

155.5

(9.0%)

154.5

(8.3%)

157.1

(10.1%)

158.4

(11.0%)

HA 155.7

(9.2%)

170.1

(19.2%)

175.1

(22.7%)

161.2

(13.0%)

176.8

(23.9%)

SA 155.9

(9.3%)

156.6

(9.8%)

161.1

(12.9%)

163.8

(14.8%)

162.1

(13.6%)

Table 2 shows that with the exception of the Hereford, purebred dams were less efficient than purebred Afrikaner dams under the particular environmental conditions. The purebred Charolais (C) dam was the least efficient dam out of all the genotypes. Crossbreeding the Afrikaner (A) dam line with Brahman (B), Charolais (C), Hereford (H) and Simmentaler (S) as sire lines indicated small effects (between +0.7 to +6.0%) on KgC/LSU above that of the purebred Afrikaner (A). However, the efficiency in the F1 cow increased relative to that of the purebred exotic cows. For example, the cow efficiency of the CA cow, compared to pure C cow increased with +14.5% (from -12.4% to +2.1%).

In the case of FI cows the HA was unsurpassed and increased cow efficiency on average by +17.6%, while the BA, CA and SA dam lines increased cow efficiency by +8.5, +9.0 and +12.1% respectively. Continental and Zebu sire lines mated to the most productive HA crossbred dam line in a three-breed system (S x HA, C x HA and B x HA) increased KgC/LSU on average by +22.7, +23.9 and +19.2% respectively, against that of the A x HA backcross with +9.2%.

The improvement demonstrated in the study concurs with that of Schoeman (2010), which indicated that crossbreeding improves calf/cow efficiency when measured as energy requirements or input costs per kg of equivalent steer weight. Although the effect of heterosis on individual traits is normally relatively small, the cumulative effect on composite traits, such as weight of calf weaned per cow exposed are immense which explains the superiority in kgC/LSU as a composite trait. Conversely, researchers cautioned on the attempt to extrapolate research results to all environments other than those similar to where the studies were conducted because of the presence of genotype x environment interactions.

While KgC/LSU as trait on its own can be used to rank productive cows in a contemporary group, it cannot be used to plan breeding strategies. Fertility, or the number of calves weaned in a cow group should certainly also be considered as a complementary factor that influences cow efficiency. In this study the net effect on weaning rate (WR) was that crossbred dams outperformed their purebred contemporaries by 8%.

Cow efficiency can then be estimated as follows: Y = WR x KgC/LSU

where Y = cow efficiency.

Since weaning rate has a low heritability and largely depends on the climatic and managerial (environmental) factors of a particular farm, this trait can contribute to large deviations in the estimated cow efficiencies that were obtained in Table 2. When weaning rate is included in the metioned Vaalharts study, it showed that when compared to the A, only purebred H and S cows have increased cow efficiency potential (+11.4 and 5.3% respectively). Two-breed progeny of the A dam line increased cow efficiency on average by +16.5%. All these increases are ascribed to the increased WR of the breeds compared to that of the A, B and C pure-breeds.

While A sire line backcrosses increased cow efficiency on average by +20.3%, three-breed progeny from B, C, H and S sire lines had average increases of +21.6, +24.4, +30.2 and 34.8% respectively. The S x HA showed the notable increase of 49.7%. Similarly, the BA, CA, HA and SA dam lines respectively had average increases of +24.1, +18.9. +36.6 and +25.2% on cow efficiency. All crossbred dam genotypes increased cow efficiency, the only exceptions being a trivial increase of +0.6% of the B x CA genotype. In this study the Pearson correlation between kgC/LSU (cow efficiency without WR included) and WR x kgC/LSU (cow efficiency with WR included) is 0.88%.

In the current Vaalharts crossbreeding project, the Bonsmara and Nguni are added to the Afrikaner as dam lines. These dam lines are mated to Angus and Simmentaler as specialized sire lines. In addition, the dam lines are also inter-mated in all possible combinations. The result is 15 different genotypes. The data will be analysed similar to that of the previous crossbreeding project.

Conclusions

A sophisticated Large Stock Unit (LSU) calculator can be used for the measurement of cow efficiency (to calculate kg calf weaned/kg LSU of the dam) of different frame sizes and without additional inputs. Cross-breeding has shown to increase cow efficiency; as long as cow frame sizes do not increase up to a point where the nutritional needs of animals are not fully being met. Increases in cow efficiency (weaning rate x kg calf/large stock unit) in two-breed and three-breed cattle was mainly derived from differences in frame size, fitness and relationships between calf weight and cow Large Stock Units.

The fact that there are large differences in cow efficiency in reproductive cows point to genetic differences and holds the potential for cow ranking and improvement through selection in contemporary groups. Optimum crossbreeding strategies may increase cow efficiency up to a notable 49.7%. This will support climate smart beef production, since it will reduce resource use and reduce the carbon footprint per unit of product produced.

Acknowledgement

This work is based on research supported in part by Red Meat Research and Development South Africa and the National Research Foundation of South Africa (NRF), under grants UID 75122, 75123 and 90097. The Grant-holder acknowledges that opinions, findings and conclusions or recommendations expressed in any publication generated by the NRF-supported research are that of the authors and that the NRF accepts no liability whatsoever in this regard.

References

Meissner, H.H., Hofmeyr, H.S., Van Rensburg, W.J.J. & Pienaar, J.P., 1983. Classification of livestock for realistic prediction of substitution values in terms of a biologically defined Large Stock Unit. Tech. Comm. No. 175. Department of Agriculture, Pretoria.

Mokolobate, M.C., 2015.Novelty traits to improve cow-calf efficiency in climate smart beef production systems. MSc. Dissertation. University of the Free State, Bloemfontein, South Africa.

Neser, F.W.C., 2012. http://www.rpo.co.za/documents/pptrpo/proffrikkieneser.pdf

Schoeman, S.J., 2010. Crossbreeding in beef cattle. In: Beef Breeding in South Africa. 2nd Edition. Agricultural Research Council, Pretoria. ISBN-13 978-1-86849-391-3 pp 21-32.

Please contact the Primary Researcher if you need a copy of the comprehensive report of this project – Michiel Scholtz on gscholtz@arc.agric.za

Effects of growth enhancers on residues in lamb

The effects of steroidal growth implants and β- adrenergic agonist, alone, or in combination on feedlot performance and residues in lamb

Industry Sector: Cattle and Small Stock

Research Focus Area: Animal Products, Quality and Value-adding

Research Institute: University of Pretoria

Researcher: Prof Edward Webb

Title Initials Surname Highest Qualification
Dr A.L. Le Riche BVSc, MScAgric
Dr Shaun Morris BVSc(Hons), MScAgric

Final Report Approved: 23 August 2018

Aims Of The Project

  • To investigate the feedlot performance of feedlot lambs treated with different steroidal growth implants, alone or in combination with oral beta-agonist supplementation
  • To investigate the effects of different steroidal growth implants, alone or in combination with oral beta-agonist supplementation on the residues in the meat
  • To investigate the effects of different steroidal growth implants, alone or in combination with oral beta-agonist supplementation on carcass and meat quality

Executive Summary

The objective of this study was to compare four commonly used growth promotants in a commercial sheep feedlot. The steroidal growth promotants chosen for this trial were Ralgro (zeranol), Revalor G (Rev G; TBA/oestrogen- 17β), Revalor H (Rev H; TBA/oestrogen- 17β) and Zilmax® (zilpaterol hydrochloride). The growth promotants were compared with one another and within three sex groups, namely ewe, ram and wether (castrates), to determine which molecule or combination of molecules, if any, had the most benefit and profitability when measured against a control group.  Sheep were stratified based on initial weights and then randomly allocated to treatment groups in a completely randomised control study. All sheep originated from the same farm, and they were of  similar age, breed,  transport method,  processing method, feed ( the only difference being  the groups receiving Zilmax® during the last 18 days of feeding, making provision for 3 days withdrawal), weather conditions, housing and time on feed. A time constant termination date was used in this study, in order to measure the performance of lambs in treatment groups over time.

The experimental groups were compared over a 10 weeks feeding period according to growth and carcass parameters. The parameters that were measured were gain, FI (feed intake), FCR (feed conversion ratio), ADG (average daily gain), WCM (warm carcass mass), DP (dressing percentage), CL (carcass length) and CC (carcass compactness). Data was recorded in an Excel spread sheet and checked for accuracy. The effect of experimental treatments on growth and production parameters were analysed by means of the GLM ANOVA procedure in SAS (2006). Differences between treatment means were tested at the P<0,05 level of significance by means of the Bonferroni multiple range test in order to correct for unbalanced data (missing values). Correlations between variables were analysed by means of the Pearson product moment procedure in SAS.

Data was analysed within weeks, treatment phases and also over the entire experimental period. Effects of sex, steroid treatment and beta-agonist treatment and interaction effects were calculated. In terms of growth and slaughter parameters the use of zilpaterol hydrochloride alone proved most effective. The latter can be explained by the repartitioning effect of the BAR which increased protein accretion as a result. Benefits gained were not always statistically significant, however taking cost of treatment into account, there is a definite financial significance when choosing which combination of growth promotants to use. Muscle and liver samples were collected for residue analyses, which indicated no significant residue’s in any of the treatment groups. The current data indicate that the use of the various combinations of growth enhancing molecules in sheep pose no risk to consumers in terms of the presence of residue’s, provided that the molecules are used according to prescribed procedures and dosages.

Popular Article

In South-Africa, the finishing of cattle in a feedlot, has, over many years, become part of the value chain of marketing beef. Huge amounts of money have been made available for research to find the most cost-effective ways of producing high-quality beef (Le Riche, 2014). Relatively little research in intensive, sheep production for South-African conditions has been done up to now, leaving a number of questions regarding the safe use of certain growth-promoting agents.

Traditionally sheep were finished extensively on the veld as this was thought to be the least expensive option. Alternatively, farmers bought in lambs from others who did not have enough grazing and finished them on harvested corn fields. This is also an inexpensive option as the corn residues are readily available after harvesting. These practises, however, give rise to seasonable availability of lambs with resultant huge fluctuations in lamb meat prices. Furthermore, the national sheep herd has decreased significantly over the last decade. There are various reasons for this. Drought and the resulting reduction in grazing, being one, and the substantial stock losses due to theft and predators, to name but two, being another (Mokolo, 2011).

Whenever a product is in short supply its price escalates. As a result of this, lamb has become an expensive. There, however, remains a HUGE demand for lamb as it constitutes a major source of protein for a significant part of South-Africa’s population. The constant production of lamb, that meets market specifications has thus become more and more important (Buttry & Dawson, 1990).  In an effort to make lamb more readily and constantly available and also more affordable, lamb feedlotting is increasingly being used as a method for increasing the amount of meat being produced. Due to the current high cost of feed and the labour intensive nature of such ventures, the profit margin of a sheep feedlot can be very small.

At the present time it costs about R 326.00 to FINISH a lamb that is market ready within 70 days, (cost of the lamb excluded) (Le Riche, 2014). The total profit made on such a lamb after all production costs have been deducted could be as little as R24 – 00. The profit margin is dependent on the meat: feed price ratio. In an article by Voermol Feeds (2010) it is stated that feed conversion ratio is considered to be the critical aspect of feedlot profitability. Any reduction in feed intake or increase in feed efficiency, without compromising carcass quality, is economically important (Snowder & Van Vleck, 2003)  Thus the lamb that converts feed the best (in other words the lamb that produces the most kilograms of meat, per kilogram of feed consumed), is the most profitable lamb. One could say that , an increase in profits constitutes a decrease in input cost and/or an increase in production output. Cost of feed is an important input cost, whilst growth rate and carcass composition is an important production output (Buttry & Dawson, 1990; Snowder & Van Vleck, 2003).

There is a need to balance more efficient food production, with positive public perception. This has become a great challenge. Professionals in the industry have to determine which products and methods could be optimally used to the benefit of the producers, without gaining negative opinions from the public sector and it  has to go hand in hand with maintaining a high level of consumer safety (Buttry & Dawson, 1990).

Optimal feeding conditions that promote high voluntary intake, added to a high quality, properly balanced ration should promote profitability. The high cost of quality feed is, however, making it even more important to research the responsible, effective use of different types of growth promoting agents, alone or in combination. These products have the potential to:  1) produce animals with a higher meat: fat ratio; 2) to keep the feeding time down to a minimum and to thus reduce the impact on the environment; 3) to increase the ability to supply the protein needs of an ever-growing population.

The use of BAR agonists in ruminant production animals as a growth ENHANCER has been the subject of many heated debates and much media publicity. The reason for this is the very real potential that some of these products, clenbuterol, to name one, can have serious toxic effects in human consumers. (Stachel et al., 2003). BAR agonists used as growth promoting agents, work on the basis that they reduce body fat whilst increasing muscle hypertrophy, without causing significant alterations in organ and bone mass. They are therefore also known as repartitioning agents (Beermann, 2002). Repartitioning literally means the channelling of energy away from storage cells in the liver and adipose tissue towards muscle tissue. The sensitivity of liver and adipose tissue towards insulin is lessened whilst it is increased in muscle tissue (Beermann, 2002).

Their pharmacological action leads to an improved ADG, improved gain efficiency (G: F) and increased hot carcass weight in both feedlot beef and lambs (Reeds, 1991; Beermann, 2002; Estrada-Angulo, et al., 2008). This effect is seen with no SUBSTANTIAL increase in daily DMI.

When age comparison studies were carried out, maturity of muscle tissues proved to be a critical factor with regards to efficacy .It would then make sense that receptor presence and availability would be important in the physiological effect of this drug as mature muscle would have a higher density of receptors available (Beerman, 2002). The lack of response or reduced response in young animals would also act as proof that young muscle fibres lack enough Beta adrenergic receptors, according to Beerman, (2002).

BAR agonists, such as Zilmax® function by stimulating mainly β2- AR. This causes muscle hypertrophy and hyperplasia, lipolysis and reduced lypogenesis as well as the indirect effect of lowered insulin sensitivity. According to Baxa et.al. (2010), it does have beneficial effects to treat animals with anabolic steroid implants first, following with the oral application of ZH. Cattle that received this combination treatment showed additive improvements to lean carcass mass and performance, such as ADG and FCR.

Growth enhancers such as hormonal implants and repartitioning agents such as zilpaterol hydrochloride  are used in intensive production systems to reduce the cost of production by decreasing the feeding time, improving feed conversion and increasing the carcass slaughter weight (Pritchard, 1998; Duckett & Andrae, 2001).This should prove to be true for both cattle and sheep feedlots. According to Casey (1998) the efficacy of β- receptor agonists are determined by the relationship between the chemical structure of the compound, the theoretical number of receptors that need to be stimulated to elicit a response and the resultant effect when the β2 receptors are stimulated.

Conclusions

In sheep the best reaction is obtained when Zilmax® is fed during the last 18 – 25 days (usually 21 days) of finishing, leaving time for a three day withdrawal period before slaughter. Previous studies indicate that a minimum of 48 hours was necessary in cattle, to reach a minimal residual level. It can be expected that sheep would generally react in the same manner. At present, the acceptable dosage for ruminants is 0.15 mg/kg/day which cconstitutesa dosage of 70 g/ ton of feed in sheep.

 

Please contact the Primary Researcher if you need a copy of the comprehensive report of this project – Prof Edward Webb on edward.webb@up.ac.za

Animal welfare, stress biomarkers and meat quality

Pre-slaughter stress, animal-related factors, stress biomarkers, nanostructure and technological properties of beef

Industry Sector: Cattle And Small Stock

Research Focus Area: The Economics Of Red Meat Consumption And Production In South Africa

Research Institute: Fort Hare

Researcher: Dr. Voster Muchenje PhD

Title Initials Surname Highest Qualification
Prof A Hugo PhD
Dr A. Y Chulayo PhD

Final Report Approved: 23 August 2018

Aims Of The Project

  • 3.1 To determine the expression of heat shock proteins, cortisol and glucose and the quality of beef in slaughtered bovine species. 3.2 To determine the activities of stress enzymes in relation to carcass and physico-chemical characteristics of beef from cattle slaughtered under practical 3.3 To determine the effects of pre-slaughter stress and inborn characteristics carcass of beef quality

Executive Summary

The main objective of the study was to determine the effects of transportation, distance travelled, lairage duration and animal-related factors on pre-slaughter stress indicators, carcass characteristics, nanostructure and technological properties of beef from six genotypes of cattle. Transportation and handling of slaughter animals is associated with a series of events that expose animals to stressful and unfavourable conditions, compromising their welfare and meat quality. Stress experienced by animals in unfavourable environmental conditions increases the synthesis of stress proteins. In a heat-shocked cell, the proteins begin to unfold and denature, resulting in the production of heat-shock proteins (HSP). HSPs are a subgroup of molecular chaperones, which are classified into five families (HSP100, HSP90, HSP70, HSP60 and small HSPs [sHSPs]) according to thein molecular weights. During this process, HSPs may bind to heat-sensitive proteins and protect them from degradation. Under normal growth, HSPs maintain homeostasis by regulating the folding quality control of proteins. It includes stressed and non-stressed proteins that accompany unfolded polypeptides.

The study showed that exposing cattle to longer hours of transportation with reduced lairage period did not only decrease glucose levels, but also increased the expression of heat shock proteins, cortisol, creatine kinase and lactate dehydrogenase which are good indicators of animal welfare. Furthermore, pre-slaughter stress negatively affected the beef nanostructure and technological properties, and heifers had the best muscle fibres, sarcomere length and visible intercalated discs with improved tenderness, colour and pH.

Popular Article

The main objective of the study was to determine the effects of transportation, distance travelled, lairage duration and animal-related factors on pre-slaughter stress indicators, carcass characteristics, nanostructure and technological properties of beef from six genotypes of cattle. Transportation and handling of slaughter animals is associated with a series of events that expose animals to stressful and unfavourable conditions, compromising their welfare and meat quality. Stress experienced by animals in unfavourable environmental conditions increases the synthesis of stress proteins. In a heat-shocked cell, the proteins begin to unfold and denature, resulting in the production of heat-shock proteins (HSP). HSPs are a subgroup of molecular chaperones, which are classified into five families (HSP100, HSP90, HSP70, HSP60 and small HSPs [sHSPs]) according to thein molecular weights. During this process, HSPs may bind to heat-sensitive proteins and protect them from degradation. Under normal growth, HSPs maintain homeostasis by regulating the folding quality control of proteins. It includes stressed and non-stressed proteins that accompany unfolded polypeptides.

The study showed that exposing cattle to longer hours of transportation with reduced lairage period did not only decrease glucose levels, but also increased the expression of heat shock proteins, cortisol, creatine kinase and lactate dehydrogenase which are good indicators of animal welfare. Furthermore, pre-slaughter stress negatively affected the beef nanostructure and technological properties, and heifers had the best muscle fibres, sarcomere length and visible intercalated discs with improved tenderness, colour and pH.

Please contact the Primary Researcher if you need a copy of the comprehensive report of this project – Dr Voster Muchenje on vmuchenje@ufh.ac.za

Genetic study on wet carcass syndrome

Detection of quantitative trait loci affecting wet carcass syndrome in sheep

Industry Sector: Cattle and Small Stock

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

Research Institute: Agricultural Research Council – Animal Production Institute

Researcher: Lené van der Westhuizen

Title Initials Surname Highest Qualification
Prof MM Scholtz D.Sc.
Prof MD MacNeil Ph.D.
Prof FWC Neser Ph.D.
Prof A Maiwashe Ph.D.
Mrs A Theunissen M.Sc.
Ms M le Roux M.Sc.

Final report approved: 23 August 2018

Aims of the project

  • To map quantitative trait loci affecting wet carcass syndrome.
  • To identify specific loci affecting the predisposition to wet carcass syndrome (detection of a major gene).
  • To develop a diagnostic test for the genetic predisposition to wet carcass syndrome (if a candidate gene can be identified as the cause).
  • If a major gene is not responsible for wet carcass syndrome the second phase of the project will have the aim to develop a polygenic prediction equation for the predisposition of sheep to wet carcass syndrome.

Executive Summary

Wet carcass syndrome (WCS) is a condition predominantly found in sheep, which negatively affects the quality of their carcasses. During the pre-slaughter period, the animal appears to be clinically normal, showing no symptoms of an abnormality. However, after the removal of the skin during the slaughter process the carcass appears to be “wet”. When the description and results of prior research are taken into account, no physiological, environmental or management system was conclusively identified as the causative agent of WCS. Previous research has also not considered a potential genetic basis for WCS or the potential for an interaction of genotype with the environment (stress). Furthermore, the tentative breed-specificity, i.e. Dorper sheep breed, of the condition lends some credence to a potential genetic basis for it. The current study employed the Ovine Infinium® HD SNP BeadChip and a genome-wide association analysis approach to scan the genomes of both afflicted- and unafflicted sheep in search of putative quantitative trait loci associated with the WCS phenotype. This study was not only one of the first in Southern Africa to make use of this specific BeadChip but also the first to investigate the role of genetics as a causative factor of WCS. Muscle samples from sheep carcasses (33 afflicted and 36 unafflicted) were collected from three different abattoirs.

Using a candidate gene approach it was possible to map genetic loci, RYR1 (Chromosome 14) and PRKAG3 (RN¯; Chromosome two) causative of phenotypically similar conditions such as porcine stress syndrome and red, soft and exudative meat to the ovine genome, respectively. The positions of these loci mapped to the ovine genome were not in accordance with the loci showing significant association with the WCS phenotype; and no relationship was found between single nucleotide polymorphisms located within these genes and WCS. Furthermore, along with the latter approach, the test of runs of homozygosity presented similar results as well as providing plausible evidence that WCS is not a recessive inherited condition.

To test for an association between the phenotype (WCS) and a genetic marker(s) i.e. SNPs, a case-control study design was implemented. Given the relatively small sample size of the current study, the results obtained from the GWAS attested strong evidence of at least two loci, oar3_OARX_29903534 and oar3_OARX_113973214 positioned within the non-homologous region of the X chromosome for WCS carcasses. All afflicted animals, both males and females, carried at least one allele for marker oar3_OARX_113973214, which was shown to be related to the WCS phenotype. On the contrary, some of the unafflicted animals also carried this specific allele.  Given the apparent influence of stress on WCS, these unafflicted males and females in all likelihood did not experience adequate levels of stress to manifest the condition post-slaughter. The results of the current study also indicated that WCS may possibly be a rare X-linked inherited condition, provided only female individuals are considered. Finally, two possible major loci involving two major genes, HTR2C and DMD, positioned on the non-homologous region of the X chromosome have been identified as novel positional and functional candidate genes for WCS in sheep.

Please contact the Primary Researcher if you need a copy of the comprehensive report of this project – Lené van der Westhuizen on PienaarL@arc.agric.za

Lamb and Mutton Quality Audit

South African Retail Lamb and Mutton Quality Audit

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 Michelle Hope-Jones

Title Initials Surname Highest Qualification
Dr PE Strydom Ph.D Animal Science
Title Initials Surname Highest Qualification
Dr L Frylinck Ph.D Biochemistry
Dr SM van Heerden Ph.D Home Economics
Prof A Hugo Ph.D Biochemistry
Ms J Anderson N D Analytical Chemistry
Mrs JD Snyman N D Food Technology

Final report approved: 23 August 2018

Aims of the project

  • o measure the instrumental/physical quality (shear force tenderness, water holding capacity/cooking loss, fat and muscle colour, collagen properties, oxidative status (rancidity)), sensory qualities and chemical composition of lamb and mutton rib or loin chops (M. longissimus dorsi) from various retail outlets (including brand names and generic products).
  • To determine the reasons for variation in quality by chemical, histological, physical and biochemical tests.
  • To use the information from 3.1 and 3.2 to arrive at a list of factors needed to be addressed in research and/or technology transfer to improve meat quality in South Africa.

Executive Summary

Twenty three products (lamb loin chops) were identified and collected from the shelves of five major retail outlets and twelve smaller butcheries on 14 different dates over a three month period (n=306, certain products where not always available due to drought conditions). Products varied in type, namely Karoo lamb (lamb valued for it unique flavour attributes due to grazing on herbaceous bushes and shrubs from a particular region of South Africa), free range or feedlot. Products also varied in packaging (Modified atmospheric packaging: MAP, PVC overwrap, to openly displayed on shelves) and retailers and butcheries were spread over various socio-economic areas. Price was recorded and shear force tenderness, sensory evaluation (tenderness and flavour), colour of meat, drip loss, cooking losses and meat/fat/bone ratios were measured as properties valued by consumers at or after purchase. Physical, histological and biochemical measurements (proximate and fatty acid analyses, lipid oxidation and collagen) were performed in an attempt to explain variations in consumer related properties.

  • Both instrumental and sensory evaluations showed tenderness to be at a high level of acceptance across the board. The Karoo samples were the most tender with the free-range samples performing the worst especially with regard to sensory tenderness.
  • Karoo lamb stood out for ‘barnyard’ aroma and flavour while free-range samples stood out for ‘Karoo bossie” aroma and flavours meaning they could be distinguished from the other samples and from each other. In both cases however, the scores were of a low intensity. Karoo and free-range lamb are purchased for their distinctive flavour.
  • Karoo and free-range samples lost less drip during cooking compared to the remaining products. Thawing loss was very low in general for all the products.
  • Karoo and free-range products have more loin muscle and less fat per chop compared to feedlot products.
  • Colour of all products was at an acceptable level with no distinct pattern showing for any particular product.
  • Lipid oxidation was at a good level over all products and fatty acid profile were consistent with free-range vs. grain-fed products. This makes the lack of free-range and Karoo flavours more perplexing.
  • Karoo and free-range products were more expensive. Regarding the remaining products, price correlated more with socio-economic area and butchery vs. retailer.
  • In general lamb is of a good quality except for drip loss which needs to be attended to. This could be due to incorrect abattoir practices. Karoo lamb is sold at a premium and its lack of flavours is of concern. The consumer however is able to consistently buy tender loin chops at any retailer or butchery.

Popular Article

Quality audit of South African lamb

Dr Michelle Hope-Jones, Researcher: Animal Production Institute, Food Science and Technology Department

Meat tenderness and other quality traits are influenced by a combination of pre-harvest, slaughter and post-harvest conditions and interventions. Research addresses these factors in order to ensure maximum satisfaction for the consumer.

However, the success rate of various sectors of the meat industry to use these technologies may vary depending on factors like technical skills, knowledge, market sector, financial viability and others.

While new projects are designed to address quality challenges, very little is known about the quality of red meat offered to the consumer at various outlets. To this end, a lamb audit was recently conducted to determine the variation in quality (tenderness, colour, water properties and others) within and between different types of outlets, and also to attempt to verify the reasons for variation in quality, so that research or technology transfer can address specific problems.

Product auditing process

The fact that meat in general is distributed all over the country from various production and processing plants, and considering that much of those operations are in Gauteng and distribute to Pretoria outlets, the study was limited to proper sampling and testing within the Pretoria metropolis. All the selected outlets receive meat from different operations, assuring a reliable sample of the industry.

Twenty three products (lamb loin chops) were identified and collected (when available) from the shelves of five major retail outlets (R) and twelve smaller butcheries (B) on 14 different dates over three months (n = 306). Products varied in type, namely Karoo lamb (valued for its unique flavour attributed to grazing on herbaceous bushes and shrubs from a particular region of South Africa), as well as free range and feedlot lamb.

Products also varied in packaging, from modified atmospheric packaging (MAP), where high levels of oxygen are pumped into packages in order for the meat to maintain the desirable red colour that consumers prefer, to PVC overwrap, and also open products displayed on shelves.

Retailers and butcheries were spread over various socio-economic areas.

Evaluation of palatability

The palatability of meat is determined by a combination of tenderness, juiciness and meat flavour.

Tenderness and juiciness

Tenderness is the most variable quality characteristic and is also rated by consumers as the most important sensory attribute. Figure 1 shows that purchasing from retailers vs. butcheries had little effect on tenderness, with instrumental test levels (Warner Braztzler Shear Force, WBSF) being at an acceptable level across all outlets. All of the Karoo products however were more tender. This could be attributed to the use of growth promotants in feedlots.

There was a strong correlation between sensory tenderness (rated by a trained panel) and WBSF. Two of the Karoo products, R2K and B6K, stood out as being more tender.

One of the free range products, R5FR, performed poorly on tenderness, but also scored lower for juiciness. This could probably be attributed to abattoir processes. Increased juiciness can give the perception of a more tender product and the relationship between the two attributes can clearly be seen in the figure. Most of the products which scored low for sensory tenderness (tougher), scored low for juiciness too.

Hoewever, the overall good level of tenderness is good news for the industry.

Flavour and aroma

In the case of lamb, flavour and aroma can play as an important role as tenderness. This is especially the case when comparing free range lamb to feedlot lamb (grass-fed vs. grain-fed) and even more so with Karoo lamb, which has a very specific flavour and aroma. As expected, the three Karoo samples scored higher (a more intense aroma) for ‘barnyard’ aroma, although interestingly not for ‘Karoobossie’ aroma, except for one Karoo product. The opposite was found for the two free range products, which had higher ‘Karoobossie’ aroma when compared to the Karoo products, but did not have a strong ‘barnyard’ aroma.

When looking at the flavour profiles, once again the three Karoo samples stood out as having a stronger ‘barnyard’ flavour. The Karoo samples did not really stand out as having a ‘Karoobossie’ flavour. As Karoo lamb is sold at a premium for its very distinct flavour, it would therefore be expected for this flavour to come out strongly. Instead, the taste panel identified the Karoo samples more as grass-fed meat.

Drip loss

All the free range products, as well as two of the Karoo products (R2K and B6K), had much less drip loss (the liquid you would find in the tray) compared to the other products. In fact, they had just over half the drip loss compared to the product with the most drip (R4).

Colour

All products across the board fell into the distinctly brown category. It was expected that packaging, or whether a sample was cut fresh or was on display, would make a difference to the colour of the meat, but not even the MAP packaged samples were of a desirable colour. This is of concern as consumers rely on visual appearance at the point of purchase and meat with a bright cherry red colour is associated with freshness.

Fat and meat (muscle) ratio, price

(Insert Figure 2)

Figure 2 shows the average percentage of fat and the actual muscle for loin chops from the various outlets. All the Karoo (K) and free range (FR) products had more meat (a greater percentage of loin muscle), compared to the other products. It was however slightly unexpected, as feedlot meat production employs beta-adrenergic agonists, which should increase muscle yield and decrease fat percentage.

However, the feedlot lamb still had a higher percentage of fat compared to Karoo and free range samples, which could overshadow the increase in muscle yield of feedlot samples. Fat percentage followed a pattern of decreasing with an increase in loin muscle, with the Karoo and free range samples having less fat.

Price

There was a strong correlation between price and loin muscle, with a larger percentage of loin muscle resulting in an increase in price.

The Karoo and free range products were markedly more expensive, except for R2K (which was sold at a lower level retail store which was more accessible to the bulk of the public). All other Karoo products were sold at butcheries in areas of increased socio-economic status. The area in which the products were bought and the type of retailer/butchery that it was bought from, seem to be more of an indicator of price, than the percentage loin muscle, with stores in higher income areas charging more.

Problems to be addressed

With lamb being an expensive product, it is good to see that the consumer can consistently buy a tender product. There are, however, a few problems which were identified.

  • Karoo lamb, which is sold as a speciality product, does not consistently stand out from other free range products.
  • Colour as a whole is also a problem, with lamb meat not having the cherry red colour that the consumer associates with freshness.
  • Generally only 50% of a loin chop consists of meat and price alone does not seem to be a very accurate indicator of how much meat the consumer will get, except for the more specialised Karoo and free range products, which have a much better meat to fat ratio.

Please contact the Primary Researcher if you need a copy of the comprehensive report of this project – Michelle Hope-Jones on hopejonesm@arc.agric.za

Nutrient content of lamb and mutton offal

The nutritional composition of South African lamb and mutton offal

Industry Sector: Cattle and Small Stock

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

Research Institute: University of Pretoria

Researcher: Dr JL du Toit

Title Initials Surname Highest Qualification
Prof HC Schönfeldt PhD

Ms C Muller MSc
Dr N Hall PhD
Ms M Bester MSc
Ms D Human Matric

Final report approved: 23 August 2018

Aims of the project

  • To determine the nutritional composition of South African lamb and mutton offal products (raw and cooked)
  • To determine yield, retention and physical composition of the different cooked offal products to ultimately determine the edible portion of each product
  • To incorporate the nutritional composition data and physical composition data into the national food composition tables as well as the food quantities manual of the Medical Research Council

Executive Summary

Offal, also called variety meats, or organ meats or the ”fifth quarter”, have been overlooked in the past in dietary guidelines and recommendations, irrespective of their potential contribution to food and nutrition security. This study focussed on understanding the physical and nutrient composition, as well as the potential nutritional contribution of lamb and mutton offal, when used in the correct amounts, to South African diets.

Significant amounts of protein, iron and zinc (three nutrients of concern in South Africa) can be found in selected organ meats which compared favourably with beef and lamb muscle meat cuts. The most significant findings of the study were the high levels of protein (>10g/100g) found in all cooked lamb and sheep offal cuts ranging from 14.26g/g (cooked lamb intestines) to 32.6g/100g (cooked sheep kidneys). High levels of total iron were found in cooked sheep lungs (TFe=10.73mg/100g); cooked sheep spleen (TFe=11.71mg/100g); cooked sheep liver (TFe=7.95mg/100g) cooked lamb lungs (TFe=8.368mg/100g) and lamb spleen (TFe=22.83mg/100g).

Instead of simply focussing on total protein, attention has shifted to the greater importance of protein quality than actual quantity, emphasising the presence of individual amino acids in a food. Protein quality answers two important questions namely, how much protein as well as what kind of protein should be consumed. Dietary proteins are classified as either being complete or incomplete. Foods containing all essential amino acids (indispensable amino acids) are referred to as a complete protein. The sum of the essential amino acids for lamb and mutton offal varies between 4.2 g/100g and 8.1 g/100g for mutton tongue and liver respectively. The study found that South African lamb and mutton offal adheres to the requirements as set out by the Department of Health to be labelled and proclaimed as a complete, quality protein.

Offal products contribute consistently to the diet not only in terms of essential fatty acids such as linoleic acid (C18:2n-6) and arachidonic acid (C20:4 n-6), but also eicosanoic (arachidic) acid (C20) and docosanoic acid (C22) polyunsaturated fatty acids. Ruminant meats and oily fish are the only significant sources of preformed and C22 PUFA in the diet (Enser, et al., 1998; Wyness, et al., 2011). Although human beings have the metabolic capacity to synthesize C20 and C22 fatty acids from the n-6 or n-3 precursors of linoleic and α-linolenic acid respectively, an increase in the consumption of C20 and C22 n-3 polyunsaturated fatty acids could overcome the perceived imbalance in the ratio of n-6:n-3 polyunsaturated fatty acids in modern diets.

Based on the results of this study South African lamb and mutton offal cuts can be considered a good source of protein and also a nutrient dense food source. Due to the current state of nutrition in South Africa such foods are important commodities and the promotion thereof should be prioritised.

Popular Article

Nutrient density lamb and mutton offal

1Pretorius, B., 1,2Schönfeldt, H.C. and 1Bester, M.

1Department of Animal and Wildlife Sciences, Institute of Food, Nutrition and Well-being. University of Pretoria. South Africa

2Professor and Director: ARUA Centre of Excellence: Food Security

Despite economic growth, undernutrition and food insecurity remain today at unacceptably high levels, while at the same time, diet-related non-communicable diseases (cardiovascular diseases, diabetes and hypertension) have exponentially increased to become the leading cause of mortality worldwide. The situation is set to worsen dramatically in the near future as powerful drivers of change such as population growth, climate change and urbanization converge on food systems. Consumption recommendations for high quality nutrient dense foods such as animal source foods (ASFs) are of utmost importance and should be adhered to, to keep up with the specific physiological demands of each life stage. However it was found that the feasibility for nutritionally vulnerable individuals in South Africa to adhere to these recommendations seems unlikely. The dire economic climate which South Africans, particularly those of low socio economic status, currently have to face, is probably the main reason for the problem that nutritionally vulnerable individuals cannot meet the recommendations of the Food-based Dietary Guidelines for South Africans.

Offal has been overlooked in the past in dietary guidelines and recommendations, irrespective of their potential contribution to food and nutrition security in South Africa. Limited information is available on the composition of South African lamb and mutton organ meats as cooked and consumed at home. This study focussed on understanding the physical and nutrient composition, as well as the potential nutritional contribution of lamb and mutton offal, when used in the correct amounts, to South African diets.

Table 1: Moisture, fat and protein content of 100g edible portion cooked lamb & mutton offal

Lamb Mutton
n=3 Moisture Protein Fat Moisture Protein Fat
  g/100g g/100g g/100g g/100g g/100g g/100g
Intestines 55.2cd 14.3d 31.2a 48.2d 15.3d 37.9a
Lungs 74.1a 21.1bc 6.53b 71.1a 23.2bc 3.97d
Hearts 65.1b 19.3cd 13.5b 57.6bc 20.4cd 20.2c
Livers 61.2bc 23.6bc 8.39b 64.5ab 23.1bc 6.27d
Stomachs 49.6d 24.8ab 29.9a 53.1cd 17.8d 27.3bc
Kidneys 65.8b 24.4abc 12.1b 57.2bcd 32.7a 7.77e
Spleen 67.1ab 29.5a 6.62b 66.2ab 27.8ab 5.23e
Tongues 63.7b 19.2cd 16.8b 52.6cd 15.8d 33.2ab
P-value <0.001 <0.001 <0.001 <0.001 <0.001 <0.001

Note: Means with different superscripts in a column differ significantly

Table 2: Mineral content of 100g edible portion cooked lamb offal

Ca P Mg Cu Fe Zn K Na
n=3 mg/100g mg/100g mg/100g mg/100g mg/100g mg/100g mg/100g mg/100g
Intestines 18.6b 124e 21.9a 0.28b 1.40c 2.60c 75.1d 38.4f
Lungs 8.90b 271c 22.2a 0.46b 8.37b 2.59c 298b 160b
Hearts 5.12b 195d 29.0a 0.49b 3.84bc 2.49c 261b 101cd
Livers 5.03b 423a 28.3a 17.9a 6.07bc 4.17a 315b 70.8e
Stomachs 52.7a 170de 25.3a 0.40b 4.85bc 3.90a 155c 79.5de
Kidneys 9.38b 330b 30.6a 0.53b 4.44bc 3.67a 310b 234a
Spleen 7.57b 406a 30.8a 0.29b 22.8a 3.60ab 409a 112c
Tongues 17.7b 184d 24.0a 0.31b 1.50bc 2.83ab 276b 102cd
P-value <0.001 <0.001 0.132 <0.001 <0.001 <0.001 <0.001 <0.001

Note: Means with different superscripts in a column differ significantly

Table 3: Mineral content of 100g edible portion cooked mutton offal

Ca P Mg Cu Fe Zn K Na
n=3 mg/100g mg/100g mg/100g mg/100g mg/100g mg/100g mg/100g mg/100g
Intestines 16.6b 112c 16.9cd 0.15b 1.69e 2.55b 50.2d 29.5e
Lungs 11.0bc 250b 19.4bcd 0.41b 10.7a 2.62b 285bc 190b
Hearts 6.00c 223b 24.8ab 0.65b 4.54c 2.74b 275bc 97.5cd
Livers 5.60c 399a 26.2ab 31.87a 7.96b 4.38a 326bc 78.7cde
Stomachs 24.6a 112c 15.9d 0.25b 2.70de 3.37ab 104d 58.7de
Kidneys 15.6b 400a 30.7a 0.56b 4.34cd 4.49a 279bc 270a
Spleen 6.00c 414a 31.4a 0.15b 11.7a 3.61ab 472a 112cd
Tongues 8.70c 142c 23.3bc 0.20b 1.81e 2.91b 235c 122c
P-value <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001

Note: Means with different superscripts in a column differ significantly

Table 4: Contribution to NRV’s and nutrient content claims per 90g cooked offal meat
INRV according to the Foodstuffs, Cosmetics and Disinfectants act (DOH, 2014)

Protein Calcium Phosphorus Magnesium Iron Manganese Zinc Potassium Sodium
NRVI 56g 1300mg 1250mg 365mg 13mg 2.3mg 10mg 4700mg 2000mg
Mutton % of NRV per 90g servingII III
Intestines 25IV 11 8 0 12 0 23 IV 1 1
Lungs 37v 7 18 IV 0 74 VI 0 24 IV 5 9
Hearts 33 0 16 IV 0 31v 0 25 IV 5 4
Livers 37v 0 29 IV 0 55v 0 39v 6 4
Stomachs 29 IV 2 8 0 19 IV 0 30v 2 3
Kidneys 52v 1 29 IV 0 30v 0 40v 5 12
Spleen 45v 0 30v 0 81 VI 0 32v 9 5
Tongues 25IV 1 10 0 13 0 26 IV 4 5
Lamb % of NRV per 90g servingII III
Intestines 23IV 1 9 0 10 0 23 IV 1 2
Lungs 34v 1 19 IV 0 58v 0 23 IV 6 7
Hearts 31v 0 14 0 27 IV 2 22 IV 5 5
Livers 38v 0 30v 0 42v 10 38v 6 3
Stomachs 40v 4 12 0 34v 8 35v 3 4
Kidneys 39v 1 24 IV 0 31v 2 33v 6 11
Spleen 47v 1 29 IV 0 158VI 0 32v 8 5
Tongues 31v 1 13 0 10 0 25 IV 5 5

 II 90g is the prescribed portion size for lean meat according to the Food-based dietary guidelines for South Africans (Schönfeldt, Pretorius, & Hall, 2013)

III Values do not take bioavailability into account

IV ” Source of” as per the Foodstuffs, Cosmetics and Disinfectants act (DOH,2014)

v “” High in” as per the Foodstuffs, Cosmetics and Disinfectants act (DOH,2014)

VI ” Excellent source” as per the Foodstuffs, Cosmetics and Disinfectants act (DOH,2014)

South African lamb and mutton offal can be considered a good source of protein and a nutrient dense food. In the case of protein, zinc and iron, three nutrients of concern in South Africa, all lamb and mutton organ meats were at least a source of two out of these three nutrients with lamb and mutton spleens and lamb and mutton lungs being excellent sources of protein. In view of the current disturbing state of nutrition in South Africa, as well as efforts to reduce food waste, lamb and mutton organ meats were found to be important food commodities and it was suggested that the promotion of offal should be prioritised.

Quantitative food data goes hand in hand with the nutrient composition tables used in a given country, because it provides supporting information on the food items included in the nutrient composition tables. Good quality nutrient composition and quantitative food data play an integral role in reporting the nutrient intake of a population, as well as interpreting results of certain epidemiological research. A new set of quantitative data on the nutrient and physical composition (meat, bone and fat fractions) and yield of different offal cuts were generated to assist researchers in collecting more precise, product specific data to measure nutrient in South African food consumption studies.

Please contact the Primary Researcher if you need a copy of the comprehensive report of this project – Beulah Pretorius on beulah.pretorius@up.ac.za