Exploring the financial implications of bovine babesiosis

The financial implications of endemic stability as a control strategy for Bovine babesiosis in veld grazing beef production systems of the KwaZulu-Natal Midlands

Industry Sector: Cattle and Small Stock

Research focus area: 

  • Animal Health & Welfare

Research Institute: University of Pretoria

Researcher: Francis Edwardes

Research Team

Title Initials Surname Highest Qualification Research Institution
Doctor W Hoffmann PhD Stellenbosch University
Title Initials Surname Highest Qualification Research Institution
Prof H Hogeveen   WUR

Completion: 2020

Aims of the project

  • Develop a model which can provide an estimate of the economic impact and financial implications of bovine babesiosis has at the herd level of a typical farm in the KwaZulu-Natal Midlands with the available data and existing research efforts.
  • Financially compare the established dipping strategies of the KwaZulu-Natal Midlands as a result of the developed model highlighted in point above.
  • Establish factors in which data relevant to the research problem is scarce or non-existent encountered through the development of the model as in the points above.
  • Establish the need for correct data collection by farmers when confronted with an infected animal in relation to point above.
  • Suggest methods of data collection in relation to Points 3 and 4 and further research opportunities in order to develop more accurate estimates of cost-effective management options.

Executive Summary

In South Africa, cattle production has increased by 46% in 2014 compared with 2005. Local consumption trends indicate that the country is a net importer of bovine meat products, due to the supply not capable of meeting demand requirements. The country’s projected population growth of 1.2% and the expected rise in beef consumption by 24% over the next ten years will require farmers to produce at greater efficiencies to meet local demand and to reverse the trade role it currently finds itself in. However, agricultural production comes with many challenges. Production diseases, such as the myriad of tick-borne diseases, are partly responsible for the challenges agriculturalists face. Amongst these, bovine babesiosis is considered as one the greatest economically important tick-borne diseases in South Africa.

Pathogenic parasites, such as Babesia bigemina and Babesia bovis, are responsible for the cause of this disease. The distribution of the parasites are directly related to the distribution of their vectors; B. bigemina has a greater distribution than that of B. bovis. Primary transmissions of B. bigemina in cattle older than nine months are less virulent when compared with B. bovis. Production losses can occur in the form of mortality, weight loss and abortions by varying degrees for either parasite. These losses coupled with treatment and prevention expenditure can result in significant costs for a farmer.  A prevention strategy that has long been discussed is to apply the concept of endemic stability. This means that the cattle are provided the opportunity to take advantage of their non-specific immunity through less aggressive tick eradication methods in order for herd resistance to develop over time.

Bovine babesiosis is considered a globally important disease and is one of South Africa most economically pertinent tick-borne diseases. However, no conclusive literature has been published regarding the economic impact caused by bovine babesiosis in South Africa and is known to be a problem since at least the early 1980’s. If bovine babesiosis is regarded with such high economic importance, why has there been little economic or financial research conducted internationally? Furthermore, why has South Africa not conducted exploratory economic or financial research studies in the last 35 years in an attempt to address this concern? The concept of developing a state of endemic stability through less aggressive acaricide applications is an intervention which has been suggested and is slowly implemented by the countries farmers, but no economic and financial insight is provided to those who implement this method of control.

The main research question for this study is; what is the value of adopting a strategic dipping option in an attempt to promote the development of endemic stability compared with an intensive acaricide treatment routine? By doing so, this study asks a question pertaining to the economic impact and financial implications of developing endemic stability by implementing a strategic dipping intervention. The study will be conducted at the herd level within the KwaZulu-
Natal Midlands and is compared with an intensive dipping approach.

Results

Preceding model development and the definition of various scenarios, simulations were run and results were analysed. For the sake of this executive summary, only the production, financial and economic analyses are presented.

The production effects of B. bigemina and B. bovis were translated into an economic impact assessment and a financial analysis of each dipping strategy per parasite prevalence.

The economic impact and financial analyses of either dipping strategy and respective scenario were compared. The economic impact assessment included the sum of all discounted costs as a result of disease prevalence and severity after a primary infection had occurred in either the breeding cows, weaners and calves in each one of the fifteen simulated years. The financial analysis included all the cash in- and outflows directly related to the production of beef weaners in the face of a bovine babesiosis challenge respective of the parasite prevalence and resulting disease severity. In light of a B. bigemina infection, the economic impact in Scenario 2 to 4 was greater for strategic dipping but less than intensive dipping in Scenario 1.

The economic consequences for intensive dipping decreased by an average of R21 115.34, with a range from R15 925.43 to R23 954.69, for each decrease in seroprevalence as per the respective scenarios. Adversely, the economic impact of strategic increased with a decrease in seroprevalence. Scenario 1 incurred the lowest impact of R82 082.86 and the greatest consequence of R95 679.96 was achieved in Scenario 4. The greatest component of the economic cost in each strategic dipping scenario was the value of weight lost consisting an average of 76% in each year. Dipping and treatment costs consisted of 10% and 9% in each year. The balance consists of recovery feed and compensatory growth costs. The value of weight lost cost component for an intensive dipping programme was greatest in Scenario 1, 2 and 3 consisting 67%, 63% and 53% of the total economic impact, respectively. This is followed by the dipping expenditure component which made up 21%, 25% and 36% of the total economic cost in each year. Dipping expenditures in Scenario 4 are greatest at 66% of the total economic cost followed by the value of weight lost at 29%. Treatment costs for Scenario 1 to three comprised 9% of the economic costs in each year and 5.0% in Scenario 4. The balance of the economic impact consists of recovery feed and compensatory feed costs. Results of the financial analyses for either dipping strategy and the respective scenarios indicate that the intensive prevention is a better financially viable option regardless of the parasite seroprevalence, and is indicated by the larger NPV and IRR values achieved.

The economic consequences of B. bovis are greater than that of the impacts realised due to B. bigemina. In all scenarios, the total economic cost of B. bovis is greater for strategic dipping when compared with the respective scenarios of intensive dipping. The largest cost component in strategic dipping is the value of weight lost as a result of a greater number of acute deaths and the longer duration of a recoverable infection. The value of weight lost held at an average of 95% of the total economic impact per year for either scenario of strategic dipping followed by treatment costs at 2.0%. The mean value of weight lost for intensive dipping in Scenario 1 to 3 made up 94% of the total economic cost while in Scenario 4 it is 8.0% less. Treatment costs outweighed dipping expenditures in Scenarios 1 and 2 whereas the latter component is greater than the former in Scenario 3 and 4. The economic impact realised in intensive dipping decreased by an average of R320 418.40, with a range from R244 736.00 to R362 558.30, with each decrease in seroprevalence as per the respective scenarios. Adversely, the economic impact increased from R1 255 592.16 to R1 492 277.39 with each respective decrease in seroprevalence. Despite the larger economic impact realised in all scenarios of strategic dipping, the financial analysis indicates that strategic dipping is more financially viable in Scenario 1 where a greater NPV is achieved. The conflict between NPV and IRR is resolved by identifying a cross-over rate of 7.89%. This indicates that strategic dipping is the more profitable prevention programme to choose while the interest rate remains below or equal to the cross-over rate and the seroprevalence of B. bovis is at 90%. In Scenario 2 to 4, intensive dipping is the more financially viable option to choose due to the greater NPV and IRR values realised.

Conclusion

The objectives of this study have been achieved. A dynamic stochastic model was developed to simulate the economic impact of bovine babesiosis a typical beef farm of the KZN Midlands would encounter where one of two dipping strategies are applied. A financial analysis of the cash in- and outflows was performed for either dipping strategy based on the data generated by the simulations. However, the model is limited in its performance due to various assumptions that were specified. Assumptions were made due to data collection difficulties.

Considering the limitations of this model, the overall results indicate that intensive dipping realises greater benefits. These benefits are increased as the seroprevalence decreases towards a 0% situation as demonstrated when NPV results are compared with those of a healthy farm. This suggests achieving a disease-free situation by means of parasite eradication. This study does not attempt to offer economic or financial insight as to the attainment of this state. Eliminating disease through eradication will contribute to an increase in animal welfare since fewer animals will have to undergo clinical infections in order for the farmer to achieve the state of endemic stability. Current results indicate that the concept of creating endemic stability as a control strategy is not a financially viable option. It is imperative to understand that these results are inconclusive due to the lack of available data as well as the limited research efforts concerned with various production effects of the disease. Emphasis is thus placed on the need for more stringent data collection routines and research efforts in order to effectively analyse the impact of various control strategies of bovine babesiosis from an economic perspective. The economic cost component of the model in this study has been developed as a foundation for future economic research in the realm of bovine babesiosis.

Objective Statement

The objective is to establish a set of principles enabling further economic and financial research to be pursued by primarily exploring the value of adopting a strategic dipping option in an attempt to promote the development of endemic stability compared with intensive acaricide prevention. This exploratory research should provide estimates identifying the economic consequences and financial implications of bovine babesiosis at the herd-level for either dipping strategy.

POPULAR ARTICLE

The economic impact of redwater and the need for data associated with the production effects of the disease

WFI Edwardes; Dr W Hoffmann

Bovine babesiosis, more commonly known as redwater in South Africa, is considered as one of the country’s most economically important tick-borne diseases. This is certainly not new information since the disease has been tagged with a label of economic importance for at least 35 years. Despite this dangling red tag of economic threat, little is known about the actual costs incurred by various stakeholders in the South African beef industry. The most recent economic impact estimate is reflected in an average annual expenditure of R5.1 million on babesicides. But how does this information help those that are affected the most by the disease; perhaps the producers? Furthermore, why has there been little to no economic research conducted to shed a little more light on this economically important disease?

A masters research study from Stellenbosch University was established to explore the economic consequences of redwater in veld grazing beef production systems of the KwaZulu Natal Midlands. For producers, research concerning the economic impact of disease is important so that a benchmark cost is known in order to compare the feasibility of other disease mitigation strategies with a current management strategy. Estimating the cost of redwater comes with difficulties due to the scarcity in data concerning the production effects of this disease in various management systems. The lack of data is a regular constraint in other economic impact assessments of disease. To cope with data scarcity, the first objective of our research was to develop a simulation model in which can provide cost estimates of African and Asiatic redwater at the herd- and cow-level based on available data and existing research efforts. The second objective was to establish factors in which data relevant to the research problem is scarce or non-existent encountered through the development of the model, in turn emphasising the need for greater data collection efforts.

A typical farm model was developed for the design of this exploratory research. An intensive dipping management strategy was chosen since it has long been the approach to manage tick populations, and therefore the transmission of the Babesia parasites, before the more recent approach of strategic dipping in order to promote the development of endemic stability. Other prevention measures such as blocking and blooding were excluded due to the lack of data. The chosen factors in which redwater affected production were the cost of mortality, weight loss, compensatory growth. The cost of recovery feed, treatment and dipping is also included. Four seroprevalence scenarios for Babesia bigemina and Babesia bovis, the respective parasites responsible for the cause of African and Asiatic redwater, were simulated. The scenarios included seroprevalence levels of i) 10% as per a situation of minimal disease; ii) 40% as per an endemically unstable situation; iii) 70% as per a situation approaching endemic stability, and iv) 90% as per an endemically stable situation. Using the seroprevalence and the average age of the herd the inoculation rate could be estimated. The inoculation rate is defined as the daily probability that an animal may receive a Babesia infection.

Simulation results, summarised in Figure 1, prove that Asiatic redwater is cause for greater concern. A comparison between the Babesia seroprevalence levels show that the economic cost of Asiatic redwater per breeding cow is on average ten fold that of African redwater. The value of weight loss either as a result of acute deaths or reduced weight gains following an infection is responsible makes up the largest cost component in all scenarios for both diseases, results are summarised in Table 1. Further investigation identified which animal cohort – cow, calf and weaner – yield the greatest economic cost given the inoculation rate for each simulated seroprevalence scenario. As illustrated in Figure 2 the economic impact is greatest in cow cohorts for lower seroprevalence levels. In higher seroprevalence scenarios the economic impact is felt greatest in weaner cohorts. This may be due to the calves being weaned where too few of them have received a primary infection before the age of nine months, resulting in too few attaining a non-specific immunity, but enough such that a risky population of Babesia parasites are harboured in the newly formed weaner cohort. Thus, more weaners receive a primary infection in which a non-specific immunity can no longer be attained. In our research, we attempted to simulate the economic impact of a strategic dipping strategy for the same herd. However, it was quickly discovered that results would not be reliable since there was not enough data to serve as input for this prevention strategy.

The objectives of this research were achieved in which a model was developed to explore the economic impact of redwater at the herd- and cow-level. Through the process of conducting this study, many constraints were encountered. These were largely in the form of scarce or non-existent data. Data concerning the production effects of redwater on Bos indicus cross Bos taurus breeds are not enough. Research efforts have investigated effects of the disease on certain variables such as weight loss, compensatory weight gain during recovery and are more concerned with Bos taurus breeds. Therefore, studies as such should be continued but more focus should be placed on the cross breeds. No studies were available concerning the effect that redwater had on milk production – and the subsequent effects it would have on calf growth, fertility, abortion and replacement. This gap in the literature should be addressed by livestock scientists and veterinarians. Greater knowledge pertaining to the effects of these production variables will lead to better cost estimates and the promotion of various cost-effective intervention strategies. Babesia bovis should continue to be the primary researched parasite due to its greater impact on production. The collection of data by farmers encountering such production effects should also be documented more strictly. Most farmers acknowledge the presence of the disease but do not document it and the resulting production effects; such data can aid research. This, however, is a challenging task as it requires the farmer to know the current seroprevalence amongst his/her heard and to continuously check its status throughout the year, to maintain strong relationships with the veterinarians in the area in order to correctly diagnose a sick animal and to communicate the data between the actors effectively. This may be costly for a farmer and lead to further economic studies researching the economic value of continuous Babesia seroprevalence monitoring in a herd.

In conclusion, this research has laid down the first stepping stone in the path of exploring the economic impact of redwater. Estimating the economic impact of redwater may only tell us something we already know, but without a cost estimate of redwater research can not compare the costs of alternative management strategies to a “norm”. Therefore, the need for more data associated with the production effects of redwater is emphasised. With the collective efforts of those in practice and research with an aim to collect data, more light will be shed on redwater for the benefit of the beef industry.

Please contact the Primary Researcher on the project if you need a copy of the comprehensive report – franco.edwardes@gmail.com

Detection of Mycobacterium spp. in slaughter cattle at Gauteng abattoirs

Prevalence and characterization of Mycobacterium spp. in slaughter cattle at Gauteng abattoirs: Food safety implications for meat consumers-A pilot study

Industry Sector: Cattle And Small Stock

Research Focus Area: Animal Health & Welfare

Research Institute: ARC – Onderstepoort Veterinarary Institute

Researcher: Dr Tiny Hlokwe

Team:

Title Initials Surname Highest Qualification Research Institution
Mrs V Mareledwane MSc ARC-OVR
Title Initials Surname Highest Qualification Research Institution
Prof AA Adesiyun PhD University of Pretoria
Prof P Thompson PhD University of Pretoria

Year of completion : 2020

Aims Of The Project

  • To isolate and identify Mycobacterium spp. from granulomatous/tuberculous lesions, lymph nodes (i.e. mesenteric, supra-mammary, retropharyngeal and internal iliac) and lungs of slaughter cattle
  • To determine the prevalence of bovine tuberculosis in slaughter cattle in selected abattoirs (high throughput, low throughput and rural/informal by using cell-mediated immune assays.
  • To characterize the isolates of Mycobacterium spp. recovered from cattle regarding their species identification and genotypes.
  • To obtain demographic information on farm management (feedlot, cow-calf or communal); animal information (age: adult or young, sex: male or female; and breed) by linking abattoir data back to the farms of origin and to visit farms from which seropositive animals originated to assess the existing risk factors for infection.

Executive Summary

Tuberculosis is a disease that is caused by a group of acid-fast gram-positive bacteria belonging to the Mycobacterium tuberculosis complex. Tuberculosis has a wide species range but not all species are equally susceptible and are divided into maintenance hosts and spillover hosts. M. tuberculosis is mostly the causative agent in humans while M. bovis is the predominant causative agent of tuberculosis in animals. In animals, cattle and buffaloes are the reservoirs of the disease in South Africa. TB is a zoonotic disease with great economic impact estimated to billions of dollars annually. This is because, for many farmers, cattle are a source of income. The impact is greatly felt in productivity. The zoonotic potential of the disease is a very big concern to public health. In addition, the interference of non-tuberculous mycobacteria in the diagnosis of BTB cannot be underestimated.

Globally, abattoirs are used for passive and active surveillance of diseases of both economic and public health significance such as tuberculosis. Surveys by serological and bacterial culture assays of slaughter animals may be used to detect newly introduced disease agents and in monitoring disease control and eradication programmes. Information generated from abattoir surveillance could provide an early warning system for impending epidemics or failures of intervention programmes such as vaccination of livestock against certain diseases, thereby allowing early intervention efforts to prevent epidemic loss of animals. Losses may result from mortality in animal population, cost of quarantine, isolation and treatment and in some cases loss of international trade. The usefulness of data obtained from abattoirs during surveillance for selected diseases is however dependent on the accuracy of the data obtained, data analysis and interpretation. Data generated from abattoirs could also be used to measure the potential health risk to farm workers, veterinarians or veterinary assistants attending to such animals, abattoir workers and consumers of products from the live animals, such as milk. The risk of zoonotic diseases, such as tuberculosis to workers who are exposed to infected animals pre-, during and post-slaughter, cannot be over-emphasized. Abattoirs in any country, if properly managed, are invaluable facilities for ensuring that only safe meat reaches the consumers, as well as preventing or reducing the potential health risk posed by infected or diseased animals to workers at these facilities.

Developed countries usually run efficient abattoirs and slaughterhouses and have effectively used them in the surveillance of diseases like tuberculosis and brucellosis in the USA, leptospirosis in New Zealand, and cystic echinococcosis in Spain. Reliable data obtained from abattoirs and slaughterhouses are used pro-actively to drive, monitor, change or formulate policies. In South Africa slaughterhouses are registered by government and closely inspected and audited for hygienic slaughter practices. Use of data obtained from these abattoirs for surveillance and diseases control purposes is however limited. The same applies to most other developing countries where, in most cases, slaughter practices in the abattoirs are not closely monitored by government and livestock diseases data are not captured and adequately used for surveillance and disease control.

In South Africa, as in most developing countries, there are also a number of unregistered informal slaughterhouses and small butcheries where virtually no hygiene monitoring, meat inspection or record keeping take place, thus creating a potential health risk to consumers. Records on zoonotic disease including Tuberculosis may be available at some abattoirs or laboratories country-wide, and these need to be accessed and analysed by researchers or veterinary officials as part of disease surveillance. This useful information may also be used for policy formulation on disease control. Furthermore, although some published reports exist on the detection of tuberculosis in livestock and wildlife diseases, the prevalence of the infections is largely unknown, particularly in communal livestock

Objective Statement

The current study was conducted at selected abattoirs in the Gauteng province, South Africa and the main objective was to determine the prevalence of livestock TB in slaughter livestock in these abattoirs using a cell-mediated immune assay (IFN-γ) and culture based methods.

Results

A total of 410 fresh blood samples were collected from slaughter livestock (369 cattle and 41 sheep) from 15 abattoirs, and analysed using Bovigam® test kit.

Of the 369 cattle sampled, valid IFN‐γ results (i.e. test samples passed quality control checks) were obtained in 318 (86.2%) of the cattle. The estimated prevalence of cattle positive for bTB was 4.4% (95% CI: 2.4-7.3%) (Table 1). Of the eight variables analysed, seven (animal species, sex, breed, district, municipalities, origin of animals and abattoir throughput) were not associated with the estimated prevalence of bTB. However, prevalence varied significantly between abattoirs (p=0.005), ranging between 3.6% (95% CI: 0.09-18.3%) in abattoir I to 23.1% (95% CI: 8.9%-43.6%) in abattoir B. The estimated prevalence of avian reactors was 5.9% (95% CI: 3.6-9.2%) (Table 2), also varying significantly between abattoirs (p=0.004), ranging from 3.6% (95% Cl: 0.09-18.3%) in abattoirs E and I to 20.7% (95% CI: 7.9-39.7%) in abattoir J. The prevalence of avian reactors in cattle was not significantly different to that of bTB. The estimated prevalence of cattle tested reacting to Mycobacterium spp. (combined bTB and avian reactors) was 10% (95% CI: 7.0-14%) (Table 3). In the univariate analysis, prevalence varied by sex of animal (3.0% in females and 11.9% in males) and by breed (5.4% in Jersey, 13% in Bonsmara, 0% in other breeds), but these differences were not significant after adjusting for confounding using exact logistic regression. Of the 41 sheep sampled, valid IFN‐γ results were obtained in 22 (54%) of the animals and none were positive for bTB nor were there any avian reactors (95% CI: 0-15%) (Table 1-3). No isolation was made from all the tissue samples cultured. However, non tuberculous mycobacteria were isolated from the environmental samples collected as confirmed by 16S rRNA gene analysis (see fig 1).

Conclusion

Meat inspection is a long-standing form of disease surveillance for both food safety and animal health. For diseases that produce slowly progressive but evident lesions, such as bTB, slaughterhouse inspection is an effective surveillance tool. The detection of positive bTB reactors in our study has, however, clearly illustrated the limitations of this method of disease surveillance, as the study also established that the abattoir source of the animals sampled significantly (p=0.005) affected the prevalence of bTB. The potential zoonotic risk of transmission to abattoir workers as well as food safety hazard to consumers, can therefore not be over-emphasized. Our study highlights the potential for the use of the IFN‐γ assay in reducing this risk. Studies have demonstrated that the use IFN‐γ assay in combination with other TB tests leads to a more accurate screening of bTB in cattle. Follow-up studies, with the intervention of the relevant area State Veterinarians, should be conducted to include using the animal information from the abattoir to trace back to the herds of origin and further testing of the whole herds.

Our study highlighted the inadequacy of meat inspection alone to detect bTB in cattle slaughtered for human consumption. It is therefore imperative to apply additional methods, such as the gamma interferon assay, to accurately determine the TB infection status in slaughter cattle from abattoirs. This approach will provide a true assessment of the risk of TB posed to abattoir workers and consumers of meat from infected cattle. Although we could not detect any Mycobacterium species by culture based method, we are not surprised by by these outcome, as all slaughtered livestock were cleared of having suspect lesions.

Popular Article

Inadequacy of Meat Inspection in the Surveillance of Bovine Tuberculosis: A Zoonotic and Food Safety Risk Concern

Authors: Vuyokazi Mareledwane1,2, Abiodun A. Adesiyun1,3, Peter N. Thompson1, Tiny M. Hlokwe4#

1 Department of Production Animal Studies, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, 0110, South Africa. 2 Vaccines and Diagnostics Programme, Agricultural Research Council-Onderstepoort Veterinary Research, Private Bag X05, Onderstepoort, 0110, South Africa. 3 School of Veterinary Medicine, Faculty of Medical Sciences, The University of the West Indies, St. Augustine, Trinidad and Tobago. 4Diagnostic Service Programme, Agricultural Research Council-Onderstepoort Veterinary Research, Private Bag X05, Onderstepoort, 0110, South Africa.

Background

Bovine tuberculosis (bTB) is a zoonotic disease with serious consequences for the livestock and wildlife industries around the world. The causative agent, normally Mycobacterium bovis (M. bovis), has a broad host range (domestic and wild animals). Meat inspection represents a long-standing form of disease surveillance that serves both food safety and animal health.

Occurrence of bovine tuberculosis in cattle

Although test and slaughter programme reduced the prevalence in commercial cattle in South Africa, disease outbreaks in different regions of the country still occur. Bovine tuberculosis is a zoonotic disease with great economic impact estimated to be billions of dollars annually. This is because, for many farmers, cattle are a source of income. The impact is greatly felt in productivity.

Bovine tuberculosis as a zoonosis

Mycobacterium bovis is known to cause tuberculosis in both animals and humans, which makes this bacterium a potentially important zoonotic species. People are most commonly infected with M. bovis by drinking or eating contaminated and unpasteurised milk and milk products. Infection can also occur through direct contact with a wound of an infected animal during slaughter.

Use of abattoirs in the surveillance of bovine tuberculosis

Globally, abattoirs are used for passive and active surveillance of diseases, such as bTB, of both economic and public health significance. Our team, consisting of researchers from the University of Pretoria and Onderstepoort Veterinary Research recently conducted a study to investigate the prevalence of bTB in slaughter livestock at 15 abattoirs in Gauteng, South Africa. A total of 410 fresh blood samples were collected from slaughter livestock (369 cattle and 41 sheep) and analysed using Bovigam® test kit.

Outcome and implications

The estimated prevalence of the disease in cattle was 4.4% (95% CI: 2.4-7.3%), and varied among abattoirs, ranging from 0 to 23%; however, there were no significant differences among genders, breeds, municipalities, districts, origin of animal (feedlot, auction or farm) or throughput of abattoirs. None of the sheep sampled was positive for the disease. Results obtained clearly illustrated the limitation of disease surveillance using a meat inspection approach alone, considering that all the 410 slaughter animals sampled had passed visual abattoir inspection and therefore classified as free of bTB.

Zoonotic risk and food safety implications for meat consumers

Our findings therefore emphasize the zoonotic risk of transmission of bTB to abattoir workers and a potential food safety hazard to consumers. Furthermore, our study highlights the potential to use of the blood assay (Bovigam® test kit) for bTB surveillance at abattoirs.

Research Funding

The research was made possible through funds kindly provided by the Red Meat Research and Development (RMRD)-SA and the Gauteng Department of Agriculture and Rural Development (GDARD).

Figure 1 shows different ways in which bovine tuberculosis can be transmitted from cattle to people

Figure 2 show PhD students Vuyokazi Mareledwane and Maruping Mangena getting ready for abattoir sampling

Figure 3 shows a student analyzing test results in the laboratory

Please contact the Primary Researcher if you need a copy of the comprehensive report of this project –
Nicholas Rivers-Moore on blackfly1@vodamailcom

Figure 1 shows different ways in which bovine tuberculosis can be transmitted from cattle to people
Figure 2 show PhD students Vuyokazi Mareledwane and Maruping Mangena getting ready for abattoir sampling
Figure 3 shows a student analyzing test results in the laboratory

Larvicide testing for blackfly control

Testing the blackfly organophosphate larvicide Abate® for viability in the Orange River Blackfly Control Programme

Industry Sector: Cattle And Small Stock

Research Focus Area: Animal Health and Welfare

Research Institute: University of KwaZulu-Natal

Researcher: Dr Nicholas Rivers-Moore PhD

Research Team:

Title Initials Surname Highest Qualification
Dr Helen Dallas PhD
Dr Robert Palmer PhD
Mr Shahin Naidoo BSc (Hons)
Ms Esther Ndou BSc (Hons)

Year of completion : 2017

Aims Of The Project

  • To confirm non-resistance to Abate in the Orange River pest blackfly populations;
  • To investigate the potential for re-activation of Abate as an alternative larvicide to Vectobac for control under high-flow conditions.

Executive Summary

Downstream flow alteration resulting from river impoundment or inter-basin transfer schemes, while improving water supply assurance levels, has been shown to have negative ecological consequences, including outbreaks in pest blackfly.  Outbreaks along the middle and lower Orange River have the potential to cause losses to livestock production estimated at US$13.3 million per annum (Rivers-Moore et al. 2014).  This figure is a conservative estimate as it excludes losses in the tourism and irrigated agricultural sectors through lost revenue and labour days.  Economic losses occur approximately 1200 km along the middle and lower reaches of the Orange River (Palmer 1997).  This is the river segment downstream of Van Der Kloof Dam, the major impoundment regulating flows in the Orange River.  The major pest species is Simulium chutteri, with more than 250 breeding sites (riffles) identified along the affected river sections, however S. damnosumS. nigritarse and S. adersi are also of concern (de Moor 1994, and citing others).

The Orange River Blackfly Control Programme, established in the early 1990s, was originally based on alternating use of two larvicides, viz. a bacterial larvicide (Vectobac®) and an organophosphate (Abate®; active ingredient is Temephos).  This programme extends over some 850 km of the middle and lower Orange River, where 148 rapids have been identified as optimal breeding habitat for pest blackfly species (Palmer et al. 2007).  The success of the control programme depends largely on correct timing of larvicide applications.  It is based on monitoring using a ten-point scoring system for larval and pupal densities developed by Palmer (1994), which is scientifically robust and user-friendly.  Larval density data are scored by the Department of Agriculture, Forestry and Fisheries (DAFF; Upington and De Aar regional offices) on a two-weekly basis, using the 10 point scale developed by Palmer (1994), reflecting seasonal changes of larval densities of the main blackfly pest complex comprising Simulium chutteri and S. damnosum.  The blackfly control programme along the middle and lower Orange River is based on aerial applications of larvicides to control the pest species Simulium chutteri.  Larvicides are generally applied three times in autumn and six times in spring (Palmer and Palmer 1995).  The two larvicides registered for blackfly control in South Africa are Vectobac® (produced from the naturally occurring bacteria Bacillus thuringiensis var. israelensis (Bti)and Abate® (organophosphate temephos) (Palmer and Palmer 1995).  However, wide scale application of the Abate larvicide, and blackfly larvae’s continuous exposure to it, has resulted in resistance being developed (Palmer and Palmer 1995).

Both larvicide options had advantages and drawbacks to their use.  In the case of Vectobac, the likelihood of pest blackfly developing resistance was low, but the higher viscosity and lower concentration of this larvicide in solution came with drawbacks including the need for more helicopter doses and clogging of nozzles.  While Abate does not result in these application drawbacks due to its more concentrated, lower viscosity formulation, its over-use was cautioned against because of the higher likelihood of resistance developing in Simulium chutteri.

By 2005, due to overuse of Abate, larvicidal resis been confirmed (Palmer et al. 2007), and a study completed in 2007 was unable to recommend any viable alternatives.  With ten years after the last use of Abate in the Orange River, it was hypothesized that larval resistance had diminished to the point where Abate could be used again.  During this period, where blackfly take 12-24 days to complete a life cycle, there is likely to have been at least 120-240 generations.  The purpose of this study was to establish whether blackfly larval resistance to Abate has subsided, thereby re-establishing a second larvicidal alternative for blackfly control on the Orange River.

Results

In the Great Fish River trials, larvae were a mixture of Simulium damnosum and S. chutteri in approximately a 3:1 ratio, while the reverse applied to pupae, and pupae dominated. Stock populations of blackfly larvae for the larvicide trials were low, with median values on the reeds sampled being 6.5 ± 1.4. Turbidity was relatively high, and flow rates were very low. Water was slightly alkaline, but with very high conductivity. In the Orange River, larvae were dominated by S. chutteri, with S. damnosum present, while pupal cases were almost exclusively S. damnosum with few S. chutteri present. Stock populations of blackfly larvae for the larvicide trials were higher than in the Great Fish River, with median values on the reeds sampled being 4.0 ± 1.4. Turbidity was relatively low, with prolific algal growth on rocks. Flow rates in the main river channel were normal; water was slightly alkaline, with conductivity comparable between river channel and irrigation canal.

Two concentrations of Abate were used: 0.3 mg.l-1 0.5 mg.l-1. Gutter trials of the efficacy of Abate on blackfly in the Great Fish River confirmed viability of the product, with mortalities of 95 and 97% respectively. Trials on Orange River populations showed similar trends at the same concentrations of larvicide. In all instances, declines in density classes were statistically significant (p < 0.05). In contrast, the class changes in the controls were not statistically significant (p < 0.05).

Conclusion

A downward change in density classes of blackfly larvae is expected to occur in both the control and trial gutter channels, due to a degree of downstream drift, where some larvae are dislodged and wash out of the gutters.  Despite this, there was a clear differentiation between changes in density scores between control sample populations and samples exposed to larvicide.  Not only was the viability of the Abate stocks confirmed after prolonged storage, but mortalities on the Orange River were significantly marked to indicate that larval resistance has subsided for concentrations of 0.3-0.5 mg.l-1.  In the project proposal, the original intention was to conduct larvicide trials on blackfly mortalities at a range of concentrations (0, 0.5, 1.0, 5.0 and 20.0 mg.l-1).  This range of concentrations was designed to range from the dosage concentration recommended by the manufacturers of Abate (0.10 ppm = 0.1 mg.l-1 or 30l per 100m3 where flows can be accurately determined), to higher concentrations to enable confirmation of larvicidal viability.  In this study, undertaking this full spectrum of trials was not possible due to the limited numbers of blackfly larvae available.  Additionally, it was demonstrated that Abate was effective at concentrations of 0.3-0.5 mg.l-1, which is within the magnitude of range recommended by the manufactures of Abate.

After a dormancy period of 10-15 years, blackfly larval resistance in the Orange River appears to no longer be a constraint in the use of Abate for blackfly control in the Orange River.

Objective Statement

  • Aim 1 (confirm non-resistance to Abate in the Orange River pest blackfly populations) has been successfully achieved.
  • Aim 2 (investigate the potential for re-activation of Abate as an alternative larvicide to Vectobac for control under high-flow conditions) will be an ongoing process. The Upington DAFF staff assisted with field trials. Further discussion will be required with DAFF (Upington and head office).

POPULAR ARTICLE

New hope for reintroduction of second larvicide to control muggies on the Orange River

Dr. Nick Rivers-Moore.

Red Meat Research and Development SA funded a recently completed study that tested a second larvicide for controlling pest blackfly on the middle and lower Orange River.  Mnr. Hoffie Joubert from KLK was also instrumental in assisting with project supplies.  While the larvicide is not new, it became ineffective in the mid-2000s for controlling pest blackfly here, because of a build-up of resistance to the product in the local blackfly population.  This means that only one larvicide, a bacterial larvicide called Vectobac, has been available for controlling blackfly for the past 10-15 years.  The Orange River Blackfly Control Programme, established in the early 1990s, was originally based on alternating use of two larvicides – a bacterial larvicide (Vectobac®) and an organophosphate (Abate®).  Both options had advantages and drawbacks to their use.  In the case of Vectobac, the likelihood of pest blackfly developing resistance was low, but the higher viscosity and lower concentration of this larvicide in solution came with drawbacks including the need for more helicopter doses, clogging of applicator nozzles.  While Abate does not result in these application drawbacks due to its more concentrated, lower viscosity formulation, its over-use was cautioned against because of the higher likelihood of resistance developing in Simulium chutteri.

By 2005, due to overuse of Abate, larvicidal resistance had been confirmed, and a study completed in 2007 was unable to recommend any viable alternatives.  With more than ten years after the last use of Abate in the Orange River, it was hypothesized that larval resistance had diminished to the point where Abate could be used again.  During this period, where blackfly take 12-24 days to complete a life cycle, there is likely to have been a few hundred generations, with resistance being bred out.

Dr Nick Rivers-Moore, an aquatic ecologist with fifteen years of research expertise on blackfly ecology, recently re-tested the efficacy of the larvicide Abate on pest blackfly.  This was first tested for product viability at a site about half an hour’s drive from Grahamstown on Great Fish River.  Here, the same species of blackfly which cause the outbreak problems on the Orange River have not been exposed to Abate.  Next, the gutter trials were repeated on the Orange River near Upington in the Northern Cape.  In all trials, larval mortalities were significant after application of the larvicide.  Dr Rivers-Moore said that “after a dormancy period of 10-15 years, blackfly larval resistance in the Orange River appears to no longer be a constraint in the use of Abate for blackfly control in the Orange River.”  These results were met with enthusiasm by the Blackfly Control Programme officers in the Upington DAFF office.  However, he says that “it is recommended that upscaling of these results is considered prior to re-introduction of Abate as a second larvicide for controlling pest blackfly on the Orange River.”

Please contact the Primary Researcher if you need a copy of the comprehensive report of this project –
Nicholas Rivers-Moore on blackfly1@vodamailcom

Nick Rivers-Moore

TrichLabCheck – A voluntary trichomonosis inter laboratory comparison project

TrichLabCheck – A voluntary trichomonosis inter laboratory comparison project in South Africa

Industry Sector: Cattle and Small Stock

Research focus area: 

  • Animal Health and Welfare

Research Institute: University of Pretoria

Researcher: Dietmar Holm

Research Team

Title Initials Surname Highest Qualification Research Institution
Dr T Zangure BVSc University of Pretoria

Completion: 2020

Aims of the project

  • This study aimed to validate the accuracy of voluntarily enrolled private (n = 8) and state-owned (n = 5) laboratories that perform trichomonosis diagnostic tests by estimating the sensitivity (Se) and specificity (Sp) per laboratory. It was hypothesized that diagnostic laboratories in South Africa play an insignificant role in the inaccuracy of the diagnosis of trichomonosis.

Executive Summary

Trichomonosis is currently the most important venereal disease of cattle in South Africa with adverse economic implications to the beef production industry due to cow abortions, infertility and culling of carrier bulls. Once diagnosed in a herd, eradication is difficult due to financial and biological implications. Bulls are asymptomatic carriers and susceptibility increases with age. In infected females, clinical signs include embryonal death, abortion, pyometra, foetal maceration and uterine discharge.

Diagnostic accuracy is one of the major clinical problems preventing easy eradication of trichomonosis from a herd and can be influenced by biological variance in the occurrence of the organism, sampling errors, sample degradation during sample transport and diagnostic laboratory inaccuracies.

Objective Statement

The objective of the project was to determine the role that diagnostic laboratories play in the inaccuracies of trichomonosis diagnosis in South Africa.

Results

Laboratories performed either the culture method (n = 5), polymerase chain reaction (PCR) (n = 6) or a combination of culture and PCR (n= 2). Fresh preputial scrapings from four bulls with known negative status for trichomonosis were pooled in 200ml of phosphate buffered saline (PBS) to form the sample base for 12 subsamples of 13ml each. Duplicate subsamples were then contaminated with 2ml originating from four different laboratory cultures of Tritrichomonas foetus or 2ml of culture medium for four negative samples. Aliquots of the subsamples were transferred to an anaerobic transport medium, and the final concentration reached in these samples submitted to the laboratories, were categorised as follows: weak (30 organisms/μl). A total of 312 samples were sent by courier in two separate rounds: eight (4 duplicates) positive and four negative samples per round. Multiple logistic regression was performed on sensitivity, using sampling round, laboratory sector, diagnostic test type and sample concentration as independent variables, and removing variables in a stepwise manner based on the highest P-value.

Two public laboratories only reported on one round of sampling, and one batch of 12 samples was severely delayed in reaching another public laboratory. The sample identifications of a further two batches were not recorded by the respective private laboratories. The results from these 60 unreported samples were not included in the analysis. Laboratories that performed the PCR assay (solely, or in addition to culture) were grouped for data analysis. The overall specificity (Sp) was 100% and the sensitivity was 88.7% (95% CI 83.9% – 93.5%). Laboratories using PCR recorded higher sensitivity than those using the culture method (95.5%; 95% CI 91.0% – 99.9% and 81.3%; 95% CI 72.5% – 90.0% respectively, P < 0.01), and private laboratories recorded higher Se than public laboratories (96.4%; 95% CI 92.9% – 99.9% and 73.2%; 95% CI 61.2% – 85.2%, P < 0.01). For laboratories using PCR, weak positive samples recorded a lower sensitivity than strong positive samples (86.4%; 95% CI 70.8% – 101.9% and 100%; 95% CI 100% – 100%, respectively, P < 0.01). One public and six private laboratories obtained 100% accuracy during the two sampling rounds.

In the logistic regression model, private sector (compared to public), an increasing concentration of organisms in the sample and the second round of sampling (compared to the first round) were independent predictors of laboratory sensitivity for the detection of Tritrichomonas foetus.

Conclusion

It is concluded that inaccuracies in the diagnostic laboratory contributes to the deficiencies in diagnostic sensitivity for trichomonosis in South Africa, but does not influence diagnostic specificity. It is further concluded that diagnostic sensitivity was independently influenced by the sector in which the laboratory operates (private vs public) and the concentration of Tritrichomonas foetus organisms in the sample.

POPULAR ARTICLE

Trichomonosis: what role does the laboratory play in combating the disease?

Prof Dietmar Holm

INTRODUCTION

Trichomonosis is a venereal disease of cattle that results in significant losses to the beef industry in particular, due to a severe reduction in the reproductive potential of beef herds. The disease occurs worldwide and is currently widespread in South Africa. In many cases herds are infected without the knowledge of the farmer, because there are often no external signs visible in the cattle. This means that without knowing, farmers loose thousands of rands in potential income due to the loss of unborn calves.

The diagnosis of trichomonosis is done on bulls, and must be performed by a qualified veterinarian only. Incorrect sampling results in incorrect diagnosis, which means that a farmer will remain in the dark about the status of his or her cattle herd. After collecting samples, they are submitted to a laboratory for diagnosis. This diagnosis can be done using different types of tests and must also be done under strict controlled conditions. Several laboratories in South Africa perform this service for veterinarians.

The nature of the disease is such that the diagnostic test is not 100% accurate, even when done by the correct professionals. In a recent study performed by the Faculty of Veterinary Science at the University of Pretoria, the role of diagnostic laboratories in the accuracy of the diagnostic test for trichomonosis was investigated. The TrichLabCheck research team, led by Prof Dietmar Holm, found that indeed in South Africa, amongst the 13 laboratories that voluntarily participated in the research, several false negative results were reported. There were no false positive results reported in this study to date, which is in line with similar studies done elsewhere in the world. This is important information for veterinarians and farmers in South Africa, who need to consider that in some cases a bull that tested negative may in actual fact be positive and needs to be tested again to confirm his negative status. It was found in this study that the average diagnostic sensitivity of all participating laboratories to detect trichomonosis was 88.7%. This means that potentially for every 10 positive bulls tested in South Africa, at least 1 will provide a false negative test result.

The research emphasises the need to perform repeated samples on individual bulls to confirm their individual negative status, or to test a large number of bulls in a given herd to confirm the negative status of a herd. It also highlights the fact that a negative test result of a single bull in a positive herd must be interpreted with care, because it may just be that the particular bull gave a negative test result when in fact he may be infected with the disease.

“Trichomonosis has been an increasing problem in South African beef cattle over the past decades, and we are hoping that farmers and veterinarians will use this research to be more vigilant in their diagnostic approach towards the disease”, prof Holm stated.

The research further confirmed that the number of Trichomonas organisms in the sample contributes to the accuracy of the test. This emphasises the importance of using only a qualified veterinarian to perform this important task on farms. Dr Tinashe Zangure, the masters student and veterinarian involved in this study confirmed that he gained excellent knowledge not only about the disease, but also about the importance that bull sampling and laboratory techniques play in the effort to combat the disease in cattle herds.

The University of Pretoria, in collaboration with the Ruminant Veterinary Association of South Africa, will soon be publishing a list of laboratories with acceptable levels of accuracy for trichomonosis. The research will be ongoing, and the list will be updated in an effort to ensure that the veterinary industry strive towards diagnostic excellence in South Africa.

Please contact the Primary Researcher on the project if you need a copy of the comprehensive report – dietmar.holm@up.ac.za

Inheritance patterns of the Polled and Scur genes in South African beef cattle breeds

The genetic mechanisms and inheritance patterns of the polled and scur phenotypes in local South African beef cattle breeds

Industry Sector: Cattle And Small Stock

Research Focus Area: Animal Health and Welfare

Research Institute: Department of Animal & Wildlife Sciences, University of Pretoria

Year Of Completion: 2019

Researcher: E van Marle-Koster

The Research Team

TitleInitialsSurnameHighest QualificationResearch Institution
DrM.M.ScholtzPhDARC-AP
ProfEvan Marle-KosterPhDUP
MrsA. Theunissen MSc Vaalharts Research Station

Executive Summary

Introduction

It is standard practice to dehorn cattle at a young age by means of physical dehorning, but in most cases without the appropriate pain relief. The practice of dehorning has increasingly become a welfare concern and alternatives to dehorning are advocated worldwide. Breeding genetically polled cattle is a long-term, non-invasive and welfare friendly alternative to dehorning. Identification of genetically polled animals through a diagnostic test would therefore be advantageous, but a specific commercial diagnostic test for the polled phenotype is not currently available in South Africa.  The DNA tests that are available internationally are applicable to European Bos taurus breeds, which can give inconclusive results for indigenous South African and Sanga cattle breeds. Furthermore, the commercial diagnostic tests available for Taurine breeds can not identify carriers of either the scur gene or the African horn gene.

Over the past two decades commercial beef producers and feedlots in South Africa have indicated a preference for polled breeds, due to increased awareness of animal welfare and market preferences. In South Africa there are a number of polled breeds of European descent such as the Hereford, Angus, Charolais and Limousin, as well as a few local breeds, including the South African Bonsmara, Tuli and Drakensberger, that introgressed the polled gene. The Bonsmara breed requested research on the identification of homozygous polled bulls and the first research project in South Africa was performed at the Department of Animal and Wildlife Sciences, UP (Schmulian, 2006). This study was based on three Bonsmara families and the available microsatellite markers at that time were used. The study by Schmulian (2006) found linkage between the polled phenotype in the South African Bonsmara and alleles of nine microsatellite markers located on BTA1. Since the completion of this research project, the Bovine genome sequence has been completed in 2009 with high through-put molecular technology (Bovine HapMap Consortium, 2009), providing genomic information and high-density SNP chips.

The majority of previous research on the POLLED locus and polledness has been performed in European breeds, which does not provide a basis for identification of the causative mutation for polledness or scurs in indigenous South African cattle breeds. These breeds are genetically distinct from the European Bos taurus breeds (Makina et al., 2014) and besides the two main types of cattle, Bos taurus and Bos indicus, indigenous African cattle, such as the Sanga, are also found in South Africa.

Objective statement

This study focused on local South African beef cattle breeds to gain an understanding of the genetic basis and inheritance of the Polled and Scur genes by using pedigree data from phenotyped animals, as well as high density SNP data. The availability of DNA and high through-put molecular technology holds the potential to provide insight on the genetic mechanisms of polled and scurred animals with higher precision, compared to the microsatellite markers that were previously available.

Project Aims

  1. To evaluate whether the Celtic mutation on the POLL locus is the causative mutation for polledness in Bonsmara and Drakensberger
  2. To perform a genome wide association study of the Polled and Scur genes based on phenotypic data and genotypic data from the GGP Bovine 150K SNP bead chip
  3. To apply sequence data available from the Bovine Genomics Program to finemap the suspected regions for the Polled and Scur genes

Results

A total of 890 Bonsmara and 224 Drakensberger animals were screened for their status for the Celtic mutation at the POLLED locus using a PCR-based diagnostic test. It was possible to distinguish between heterozygous and homozygous polled individuals, but scurs could not be identified on a genotypic level based on the Celtic variant. The majority of animals screened, tested heterozygous polled, with homozygous polled animals occurring at a relatively low frequency. Based on the results of this Celtic screening, a total of 217 Bonsmaras (including homozygous polled, heterozygous clean polled and scurred animals) were genotyped using the GGP Bovine 150K SNP bead chip. Additional genotypes from the Bovine Genomics Program (BGP) were also included in this study.

Haplotype analysis of the POLLED locus revealed a reduced genetic diversity around the Celtic allele, with only two haploblocks (1.0-2.2 Mb) observed in the homozygous polled animals investigated. One of these haploblocks of six SNPs encompassed the Celtic mutation and presented only three distinct alleles with major differences in terms of frequencies. This result suggests that the Celtic allele was introgressed in the Bonsmara breed from a very limited number of founders. A low haplotype diversity combined with an intense selection on the polled phenotype in the Bonsmara breed can result in the selection of deleterious alleles linked with the Celtic mutation through a hitchhiking mechanism. Therefore, it is of primary importance to maintain some genetic variability around the Celtic allele.

Preliminary results of the GWAS study, based on 150k SNP chip data, indicated significant association for the scurs phenotype with three SNPs on BTA5, which contradicts previous findings that mapped the SCURS locus to BTA19. For the POLLED locus, preliminary results show significant association between the polled phenotype and BTA1, as expected. Of interest is another significant association with the polled phenotype that were observed on BTA28, which was not reported in previous studies. The significant SNPs that were identified in the GWAS analysis of the POLLED and SCURS loci will be annotated to identify candidate genes and to investigate the potential significant physiological pathways of these SNPs.

Conclusion

The POLLED Celtic variant was validated as the causative mutation of polledness in three South African beef cattle breeds and can be used as an efficient diagnostic test for polledness. This study also highlighted the current difficulties and limitations of accurate phenotypic recording of the horn status. It also confirmed that scurs cannot be identified on a genotypic level with the Celtic screening. Preliminary results of genotypic SNP data indicated significant association for the scurs phenotype on BTA5 in the Bonsmara, but these results need to be further investigated.

The following scientific output were achieved for the project:

Grobler, R., Visser, C. & van Marle-Köster, E., 2017. Accelerating selection for polledness in the South African Bonsmara using DNA technology. 50th South African Society for Animal Science (SASAS) Congress, Port Elizabeth, 18 – 21 September 2017.

Grobler, R., van-Marle-Köster, E., Visser, C.& Capitan, A., 2018. Haplotype variation at the POLLED locus in the South African Bonsmara cattle breed. World Congress on Genetics Applied to Livestock Production (WCGALP) 11-16 February, Auckland.

Grobler, R., Visser, C., Capitan, A. & van Marle-Köster, E., 2018. Validation of the POLLED Celtic variant in South African Bonsmara and Drakensberger beef cattle breeds. Livestock Science. 217, 136-139.

Popular Article

Introduction

Identifikasie van poena status in die Bonsmara met behulp van DNA tegnologie

Rulien Grobler (PhD Kandidaat)

Departement Vee- en Wildkunde, Universiteit van Pretoria

Inleiding

Die voordele van poenskop beeste vir die kommersiële vleisbeesindustrie is alombekend en wêreldwyd word die druk vir meer menslike praktyke in terme van dierebehandeling hoër, as gevolg van die impak op dierewelsyn. Alhoewel die opsie daar is om kalwers te onthoring, dui navorsing aan dat dit n pynvolle prosedure is, ten spyte van die tegniek of voorsorgmaatreëls wat gebruik word. Behalwe dat die onthoring van kalwers nie welsynsvriendelik is nie, is dit ook tydrowend en arbeidsintensief,en veroorsaak dit ook stres wat die groei van die kalf negatief kan affekteer. Hierdie faktore het dan ook ‘n verdere ekonomiese implikasie vir die boer. Dit is ook n opsie om poenskop beeste te selekteer gebaseer op fenotipiese rekords, maar hierdie proses is egter tydrowend en oneffektief, en veroorsaak stadige genetiese vordering. Deur gebruik te maak van DNA tegnologie om poenskop diere te identifiseer, kan seleksie vinniger en meer effektief plaasvind en genetiese vordering sal ook vinniger toeneem. Verder is dit ook ‘n welsynsvriendelike alternief, so wel as n langtermyn oplossing vir die onthoring van kalwers.

Poenskop oorerwing

Die Poena geen is outosomaal dominant en indien teenwoordig, sal die uitdrukking van die horing fenotipe onderduk word. Daar is twee allele teenwoordig by die Poena geen, P en p, en diere wat die dominante P alleel dra is fenotipies poenskop. Homosigotiese poenskop diere dra twee dominante P allele (PP), terwyl heterosigotiese poenskop (Pp) diere een dominante P alleel dra en een horing alleel. Dus, diere wat twee p allele dra het dan die horing fenotipe (pp). As gevolg van dominansie, kan daar nie onderskei word tussen die homosigoot en heterosigoot poena fenotipe nie. Dus is dit nodig vir n genetiese toets om draers van die poena en horing allele te identifiseer.

Afhangende van die poena status van die moer en vaar, word die poena allele in verskillende proporsies oorgedra na die nageslag (Figuur 1). Bv. Wanneer n homosigotiese poena (PP) bul, wat dan twee dominante poena allele dra, geteel word met n horing koei (pp), is daar ‘n 100% kans dat die nageslag fenotipies poenskop sal wees, omdat die nageslag een dominante P alleel kry van die vaar en een horing alleel van die moer. Maar wanneer n heterosigotiese poena (Pp) bul gebruik word, verminder die kans vir poenskop nageslag met 50% (Figuur 1).

Figuur 1 Die moontlike genotipiese proporsies vir verskillende paringsituasies van horing, hetero- en homosigotiese poenskop individue

Die oorerwing van die poena geen word verder gekompliseer deur die scurs fenotipe, as gevolg van epistatiese interaksie tussen die Poena en Scurs gene. Scurs is klein horingagtige vergroeisels wat op dieselfde plek as horings op die kop voorkom, maar hierdie abnormale vergroeisels is losweg aan die skedel geheg en is beweeglik (Figuur 2). Scurs is geslagsbeïnvloed en word gevolglik verskillend oorgeërf in manlike en vroulike diere. Dit is waargeneem dat scurs kan voorkom in diere wat heterosigoties poenskop is, en dat scurs meer in manlike diere as in vroulike diere voorkom.

Figuur 2 Die poenskop (A en B) en variasie van die scurs (C – F) fenotipes soos waargeneem in die Bonsmara

Die Poena Projek by UP

Die Poena geen is geleë op chromosoom 1 (BTA1) en minstens twee verskillende variante is verantwoordelik vir die poenskop fenotipe in beeste, naamlik die Celtic (PC) en Friesian (PF) variante (Allais-Bonnet et al., 2013).  Die Celtic (PC) variant is verantwoordelik vir die poenskop fenotipe in die meeste Bos taurus rasse van Europese herkoms, terwyl die Friesian (PF) variant hoofsaaklik voorkom in die Holstein Friesian ras.

In samewerking met ‘n navorser van Frankryk (INRA), is Bonsmara diere getoets vir beide die Celtic (PC) en Friesian variante (PF). Dit is vasgestel dat al die Bonsmara diere met n poenskop fenotipe, dra ten minste een alleel van die Celtic variant en geen diere is positief getoets vir die Friesian variant nie. Hierdie bevinding is in lyn met die geskiedenis en ontwikkeling van die Bonsmara vanuit n Europese Bos taurus ras. ‘n Groter groep Bonsmaras is getoets vir die Celtic variant (PC) en dit is bevestig dat die Celtic variant (PC) van die Poena geen verantwoordelik is vir die poenskop fenotipe in die Suid-Afrikaanse Bonsmara (Grobler et al., 2018).

Deur gebruik te maak van ‘n haarmonster, word DNA geëkstraeer uit die haarwortels. Die DNA word dan gebruik om die dier te toets vir die Celtic variant (PC) deur gebruik te maak van ‘n PCR-gebaseerde diagnostiese toets. Gevolglik kan draers van die PC variant geïdentifiseer word en sodoende kan diere ook as homo- of heterosigoties poena geïdentifiseer word op ‘n genotipiese vlak.

Bonsmara bulle en koeie, asook sekere kalwers, is uit spesifieke kuddes geselekteer om poenskop diere te identifiseer en tot dusver is n totaal van 890 Bonsmaras getoets vir die Celtic variant (PC) met die bogenoemde diagnostiese toets. ‘n Hoë frekwensie poenskop diere is waargeneem, waarvan die meerderheid diere heterosigoties poena getoets het (Figuur 3). Dit beteken dat hierdie diere slegs een PC alleel dra, asook een horing alleel, wat dan moontlik oorgedra kan word aan die dier se nageslag. Alhoewel homosigotiese poena diere wel waargeneem is, is dit waargeneem in slegs 12% van die diere wat tot dusver getoets is (Figuur 3). Die Bonsmara diere wat horing getoets het, is by n relatiewe hoë frekwensie van 42% waargeneem (Figuur 3). Dit is tog nodig om te noem dat die meerderheid van die homosigotiese poenas in een kudde waargeneem is wat vir meer as twee dekades al spesifiek selekteer vir die poenskop fenotipe. Alhoewel hierdie toets kan onderskei tussen homo- en heterosigote poenskop diere, kan die toets nie scurs op ‘n genotipiese vlak identifiseer nie en verdere navorsing is nodig vir scurs.

Figuur 3 Die genotipe frekwensie van die Celtic variant (PC) soos getoets in 890 Bonsmaras

Implikasies vir SA Bonsmara

Die diagnostiese DNA toets kan effektief gebruik word om heterosigotiese en homosigotiese poena diere te identifiseer op n genotipiese vlak. Hierdie toets kan egter nie gebruik word om scurs op n genotipe vlak te identifiseer nie, omdat beide poenskop en scurs diere genotipies heterosigoties poenskop toets (Pp). Dit is dan juis waarom dit belangrik is om die horingstatus van diere vroegtydig en akkuraat aan te teken. Die poenskop fenotipe is maklik om te observeer en verander nie tydens die dier se leeftyd nie. Die scurs fenotipe is egter moeiliker om aan te teken, omdat dit dikwels verwar word met horings of eers later uitgedruk word. Daarom word dit aanbeveel dat beeste ondersoek word by n jong ouderdom (gewoonlik tydens speen), asook tussen 18 en 24 maande.

Met behulp van hierdie DNA tegnologie kan die poena status van diere vroegtydig geïdentifiseer word, wat sodoende die genetiese seleksie van poena diere sal vergemaklik, asook versnel. Verder hou dit ‘n ekonomiese voordeel vir telers in wanneer gesertifiseerde poenskop bulle bemark kan word. Meer poenskop diere in die mark sal ook ‘n voordeel inhou deur arbeidskostes te verlaag en diere welsyn te bevorder omdat die onthoring van diere dan metteryd nie meer nodig sal wees nie. Die relatiewe hoë frekwensie van horing diere wat waargeneem is bevestig juis die belangrikheid van ‘n DNA toets, deurdat telers eers die poena status van diere op ‘n genotipiese vlak moet bevestig voordat vermeende poena diere ingesluit word in ‘n paringsprogram. Dit is veral belangrik vir bulle wat vir teeldoeleindes en veilings gebruik gaan word.

Erkennings

Dankie aan elke boer wat haarmonsters en inligting bygedrae het vir die Poena projek, en ook spesifiek vir Charl Uys vir sy hulp. Dankie aan Prof E. van Marle-Köster en Dr C. Visser; die studiepromotors op die PhD projek. Dank aan RMRD SA en die NRF vir befondsing.

Verwysings

Allais-Bonnet et al., 2013. PloS ONE. 8, 1-14.

Grobler et al., 2018. Livestock Science. 217, 136-139.

Footer and Tags and Categorisation

Please contact the Primary Researcher if you need a copy of the comprehensive report of this project on :mmakgahlela@arc.agric.za

Supplementation of ruminants on winter pastures

Supplementation of ruminants on winter pastures

Industry Sector: Cattle and Small Stock

Research focus area: Livestock production with global competitiveness

Research Institute: University of Pretoria

Researcher: Prof Willem.A. van Niekerk PhD (Agric) Animal Science

Research Team:

TitleInitialsSurnameHighest Qualification
ProfLourens. J.ErasmusPhD (Agric) Animal Science
DrA.Hassan
PhD (Agric) Animal Science
MrR.J.Coetzer
MSc (Agric) Animal Science
MrHMynhardtMSc (Agric) Animal Science

Final report approved: 2016

Aims of the project

  • To develop a cost-effective supplementation strategy for ruminants under low quality winter forage conditions
  • To maintain body weight during the wineter season by assessing different sources and levels of nutrients that enhances poor quality roughage utilisation
  • To investigate intake, fiber degradation and microbial protein production when various types and levels of nutrients are supplemented to ruminants kept at maintenance under extensive conditions

Executive Summary

A series of studies was conducted to evaluate differential energy and nitrogen (N) sources as supplemental feed to sheep grazing low quality winter grazing in the High veldt. Knowledge on supplementation under local conditions are limiting as the majority of supplementation studies are funded and performed in the more temperate areas. Results indicated that higher N and energy inclusion levels are necessary to optimize ruminant production under local conditions compared to temperate areas. In addition, the ratio of fermentable energy to available protein is an important parameter in optimizing supplementation programs. It is concluded that the supplementary recommendations from the current feeding tables does not describe the requirements and nutrient quality of the tropical grasses satisfactorily and as such, cannot be used to predict supplementation responses by the tropical forage fed ruminant.  del can be used for further sensitivity analyses and “what if” scenarios as well as a database to answer specific questions.

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SUPPLEMENTATION OF SHEEP GRAZING LOW QUALITY GRASSES WITH UREA AND STARCH

BY:  *H. MYNHARDT, W. A. VAN NIEKERK AND L. J. ERASMUS, UNIVERSITY OF PRETORIA

Every year sheep might lose up to 30% of their summer body weight gain during the dry winter periods in the high veldt.  While these weight losses have an economic impact on its own, it also is associated with an increased susceptibility for diseases and parasitic infestations and decreased reproductive performances. It generally is considered that protein or non-protein nitrogen (NPN) supplementation is necessary to limit these weight losses during these periods. However, due to the type of grass found in the High veldt area of Southern Africa, data is limiting on the effects of supplementation of ruminants grazing these types of grasses (See box: Differences between C4 and C3 grasses). As such, supplementations recommendations derived from current feeding tables seldom satisfy the needs of the grazing ruminant in Southern Africa. Therefore, a series of studies was conducted at the University of Pretoria to determine and quantify the requirements of the ruminant grazing low quality Eragrostis curvula hay commonly found in the Southern Africa High veldt.

* References and correspondence can be obtained from the author: hermanmynhardt@yahoo.com


Box 1: Differences between C4 and C3 Grasses

The acronyms C3 and C4 refer to the first product of the photosynthetic processes in the respective grasses with the first product of photosynthesis in the C3 grass being phosphoglycerate (a 3 carbon structure) while for the C4 plant, the corresponding molecule is a 4 carbon molecule (oxaloacetate). C3 grasses are temperate grasses and are adapted to the temperate regions of the world where rainfall is more constant with maximum temperatures seldom topping 22 OC. In contrast, C4 grasses are more adapted to the subtropical and tropical climates with temperatures frequently topping 25oC during the growth period. These areas also are associated with seasonal droughts and the occasional frost. Due to these extremes in temperatures and seasonal droughts, C4 grasses contain more bundle sheath cells and less available nutrients compared to C3 grasses during all maturity stages. Ruminant production therefore in general is significantly lower in ruminants grazing C4 grasses compared to temperate C3 grasses, especially during the dormant stage of the grass where lignification of the C4 grasses reduces the availability of the nutrients even further. As such, supplementation requirements and responses differ between ruminants grazing these grasses. However, the majority of supplementation studies in the past have been conducted on C3 grasses as it is found more in the European countries where research funding is more available. As such, as more studies conducted on low quality C3 grasses are incorporated in the current feeding tables, supplementation requirements derived from these tables to the low quality tropical forage fed ruminant are not always accurate. As such, the need was established to conduct research through the financial support of the **RMRD-SA on the nutritional requirements of the low quality tropical forage fed ruminant in order to improve ruminant production in Southern Africa.


*RMRD -SA – Red Meat and Research Development, South Africa



Results and Discussion

Forage intake and digestibility was not influenced by either the level of urea or starch supplementation to the wethers. However, CP-balance, measured as CP intake – CP excretion in the faeces and urine, increased from 12.5 g CP/day in the LU wethers up to 70 g CP/day in the EHU wethers. Based on these observations, only the EHU treatment supplied sufficient protein to potentially satisfy the needs of the 50 kg wethers as they require 65 – 70 g CP for maintenance. These recommendations are significantly higher than the recommendations set in the current feeding standards, however, it is in alignment with the observations and recommendations set out by **Leng (1995) studying ruminants grazing tropical grasses in Australia.

Forage intake and digestibility was not influenced by either the level of urea or starch supplementation to the wethers. However, CP-balance, measured as CP intake – CP excretion in the faeces and urine, increased from 12.5 g CP/day in the LU wethers up to 70 g CP/day in the EHU wethers. Based on these observations, only the EHU treatment supplied sufficient protein to potentially satisfy the needs of the 50 kg wethers as they require 65 – 70 g CP for maintenance. These recommendations are significantly higher than the recommendations set in the current feeding standards, however, it is in alignment with the observations and recommendations set out by **Leng (1995) studying ruminants grazing tropical grasses in Australia.

HIGHER LEVELS OF PROTEIN AND ENERGY SUPPLEMENTATION IS NECCESARY TO OPTIMISE THE GRAZING RUMINANT IN THE S.A. HIGH VELDT DURING THE DRY WINTER MONTHS

An important parameter in ruminant nutrition is microbial protein synthesis (MPS) as it gives an indication of the efficiency of the rumen microbes. During the dry winter months, MPS generally decreases due to the lack of available nutrients in the roughages (Leng, 1990, 1995) which decreases the productivity of the animal which is experienced as weight loss by the farmer.  In this study, MPS increased almost 50% from 78 g MPS to 106 g MPS as the level of starch supplemented was increased from 200 (LS) to 280 (HS) g starch/day. This observation is in agreement with suggestions made by Leng, (1990; 1995) that energy is an important nutrient driving MPS in the tropical forage fed ruminant, provided that the protein requirements of the ruminant have been met. Interestingly, energy supplementation for the temperate forage fed ruminant is not always advocated as these grasses contain higher concentrations of water soluble carbohydrates compared to the tropical grass.

Based on the above results, higher levels of both protein and energy supplementation is necessary to optimise ruminant production during the dry winter months in the High Veldt. The question now was asked whether there was an “ideal” quantity of protein and energy to be supplemented to ruminants grazing low quality “tropical” forages.

Graph 1 is a schematic representation of MPS per unit CP intake (MNS: N intake) while Graph 2 represents the mean rumen ammonia nitrogen (RAN) concentration as influenced by the ratio of starch supplemented to available protein intake.

Graph 1

Urea supplementation across all three starch treatments affected the MPS: CP ratio similarly with the ratio decreasing from almost 3 to below 1 where the wethers were supplemented with the higher urea treatments (HU and EHU). It is important to note that alleviated MPS: CP levels (above 1) could be indicative of CP deficiency as more microbial protein was synthesized in the rumen compared to dietary CP intake. The additional CP required to produce the microbial protein under these circumstances is derived from body protein catabolism which in itself, is an inefficient process, resulting in an excessive body weight loss. As such, in this trial, it is suggested that the protein intake of the wethers supplemented with at least 26.4 g urea/day (HU) was sufficient to meet the requirements of the wethers.

Graph 2

An inverse relationship was observed between RAN and the ratio of starch: digestible protein intake (Graph 2) with RAN decreasing and plateau between 5 and 10 mg RAN/ dL rumen fluid as the ratio increased. An inflexion point was observed where RAN increased exponentially to levels as high as 25 and even 30 mg RAN/dL rumen fluid as the ratio decreased below 2: 1. This graph highlights the importance of supplementation of both rumen available energy sources (starch in this instance) as the supplementation of only RDP sources to the ruminant could lead to an increased risk of ammonia toxicity under these circumstances.

Conclusion

The results from this study suggest that the supplementation requirements of 50 kg wethers grazing low quality tropical forages (2.7% CP) differs to the current feeding standards as:

  • Higher levels of protein (urea supplementation up to 26.4 g urea per day per wether or 3% urea of the total DM intake) is necessary to optimise CP balance in the tropical forage ruminant.
  • Starch supplementation (up to 280 g/wether/day or almost 20% of the total DM intake) in addition to urea supplementation is necessary as tropical grasses not only are deficient in protein, but also in easy available energy.
  • For wethers grazing low quality tropical grasses, the ideal ratio of starch supplemented to digestible protein intake lies between 2 and 3: 1.
  • Additional research is necessary to study the effects of other energy sources and protein sources on rumen environment and the production parameters of the tropical forage fed ruminant as these sources might have different availabilities compared to urea and pure starch within the rumen.

The authors wish to thank the Red Meat Industry and Research Development (RMRD) for their financial support of this study.

Please contact the Primary Researcher if you need a copy of the comprehensive report of this project –
Willem van Niekerk on willem.vanniekerk@up.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.

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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

Heartwater survey on changes and causes

A Survey of veterinary and farmer experiences and opinions on heartwater incidence, distribution and associated factors in domestic ruminants in South Africa

Industry Sector: Cattle and Small Stock

Research Focus Area: Animal Health and Welfare

Research Institute: Faculty of Veterinary Science, University of Pretoria Department of Production Animal Studies

Researcher: Prof     Gareth Bath     ECSRHM

Title Initials Surname Qualification
Dr D Coetzee BVSc
Dr T Brink BVSc
Dr R Leask M. Med. Vet
Prof G Fosgate PhD

Year of completion : 2017

Aims Of The Project

  • To establish the extent and incidence of HW by a structured questionnaire sent to farmers and veterinarians in heartwater areas

  • To establish changes that may have occurred in these areas

  • To identify possible reasons for the changes observed.

  • To make recommendations for further action

Executive Summary

The Questionnaire Survey achieved the aims set out for the project. Sample sizes, structure, demographics, geographic distribution and experience profiles of both Veterinary and Farmer groups were adequate for gathering useful data and for conclusions to be drawn.

There appears to be epidemiologically significant change in the spatial distribution of heartwater in many areas, with serious expansion in some, of up to 150 kilometres, and 48% of veterinarians and 42% of farmers reported seeing increases in the number of farms affected by heartwater. The disease is also increasing in incidence and severity judging by the number of cases seen, increases in occurrence observed and also some indication that there is an increased risk of heartwater in more months of the year than in the past.

Climate change as a causative factor, indicated by observations of increased average temperatures, milder frosts, less rain and shorter rainy seasons, was identified by the majority of farmers but not by as many veterinarians. Respondents in both groups considered vegetation change an important factor. Increasing wildlife, especially antelope, was seen as a major factor by most veterinarians and also many farmers. Both groups identified the movement of livestock and wildlife as an increasingly important factor that must be seen as of major concern for both industries since it leads to the avoidable spread of many diseases apart from heartwater. Movement controls must be reinstated and reinforced by vigorously enforced legislation.

The use of the heartwater ‘vaccine’ is either unchanged or in decline and is apparently causing an increasing reliance on dipping and block treatments. Farmers reported mainly an increase in tick control by dipping and rated this as a very important factor in the management of heartwater; the veterinarians rated it lower. Control achieved by routine, regular block treatments of entire flocks or herds was also seen as a major factor and as increasing in use for both respondent groups, each giving it a high ranking. Relying on intensive tick control and ongoing block treatments leads to loss of efficacy in key acaricides and antibiotics and has very serious implications and consequences for the control of many diseases and parasites of livestock. The lack of a commercially available, safe, effective, practical and affordable true vaccine for the protection of ruminant livestock against heartwater should be of the absolute highest concern and priority. After decades of trials, OVI researchers have developed a very promising candidate vaccine, yet its further development to the commercial stage appears not to be receiving the urgency and attention needed.

Diagnosis of heartwater in post mortem cases is accurate and reliable if backed by appropriate histopathological staining and examination, but far too few farmers have their suspicions confirmed by laboratory tests. This leads to a danger of widespread misdiagnosis and the disease being potentially either under- or over-diagnosed. The problem extends to clinical cases especially, where diagnosis rests mainly on a few ‘typical’ signs. The presence of atypical forms of heartwater further complicates the problem.

Popular Article

Is Heartwater spreading and becoming worse, and why?

A survey of farmers and veterinarians in heartwater-prone areas of South Africa indicates that the disease is expanding in geographic area and increasing in severity. What are the possible reasons for this, what has changed in these areas, and what should be done to limit the impact of a worsening situation? The Heartwater Survey was undertaken by staff of the Faculty of Veterinary Science at Onderstepoort, and generously funded by the financial subvention of RMRD – SA.

A representative sample of veterinarians and farmers with adequate experience in areas where heartwater is a problem agreed to take part in the survey. The survey took the form of a structured, measureable and analysable set of questions in a standard questionnaire. The questionnaire was designed to allow comparisons to be made between the two groups, who were for the most part asked the same or similar questions. The responses of these two groups gave an insight into the current heartwater situation as it is experienced by the farmers and veterinarians in the heartwater areas, and shed some light on the importance of factors believed to be involved in the expansion of areas affected by heartwater and in the changes of its severity.

It was deduced from the responses of both groups that the disease is expanding its range in many areas, and alarmingly so – by an average of perhaps 60km and as much as 150 kilometres in some regions. The reports by both vets and farmers indicated that an increasing number of farms are becoming affected by heartwater, confirming that the disease appears to be spreading. It was also evident that annual losses caused by heartwater can be very high on some farms unless the disease is suppressed by unsustainable practices like intensive dipping or repeated blocking of entire herds and flocks with tetracycline antibiotics. Both groups also reported that the number of cases of heartwater is rising.

Several factors that were thought to be responsible for these changes were identified by the two groups, although they did not always agree on the relative importance of these factors. Climate change, evidenced by higher than average temperatures, milder frosts, lower rainfall and shorter rainy seasons, was seen as a major causative factor by most farmers but considered to be of less significance by the veterinarians. Both groups saw a change in vegetation as an important factor but more so by the vets, who also rated the role of increased wildlife and the movement of antelope as a major factor, more so than the opinion of the farmers. The groups were, however, in agreement about the important role played by the movement of livestock in the potential to increase the areas affected by heartwater.

The survey revealed that the use of the heartwater “vaccine” was stagnant or in decline, which is not surprising in view of the many difficulties encountered in its use, the risks and dangers inherent to it, and the uncertainties around its efficacy. Unfortunately this reluctance to use the vaccine has evidently led to an increasing use of frequent, suppressive tick control or reliance on regular blocking treatments for heartwater for entire herds or flocks. Neither of these control measures are sustainable in the long run, and are almost certain to hasten the onset and rapid development of drug resistance in the bont tick and the heartwater organism. It was also clear from the survey that the diagnosis and treatment of heartwater relies far too heavily on the clinical signs or symptoms seen, especially with the farmers, leading to the dangers of misdiagnosis.

In conclusion, the survey revealed that heartwater is increasing in both its geographic extent and its severity, at least in some areas, and that a number of factors appear to be involved in causing these changes. Chief of these were climate, vegetation, and wildlife and livestock movements. The role of static or declining vaccine usage, leading to an increased reliance on intensive tick control, or alternately the widespread use of whole herd blocking with tetracycline antibiotics was also revealed by the responses of both groups.

The most pressing need now to bring about satisfactory heartwater control is the rapid and prioritised development of a commercial vaccine by OBP that is safe, effective, practical, easy to use and affordable. This development can be based on the very promising candidate vaccine developed by OVI. Ensuring that the movement of both wildlife and livestock is properly controlled to try to reduce the spread of the disease is another priority requiring urgent attention.

Please contact the Primary Researcher if you need a copy of the comprehensive report of this project – Gareth Bath on gfbath@gmail.com