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

Team members:        Dr       D         Coetzee           BVSc

Dr       T          Brink              BVSc

Dr       R         Leask              M. Med. Vet

Prof    G         Fosgate           Ph.D

Aims Of The Project

3.1 To establish the extent and incidence of HW by a structured questionnaire sent to farmers and veterinarians in heartwater areas
3.2 To establish changes that may have occurred in these areas
3.3  To identify possible reasons for the changes observed.

3.4 To make recommendations for further action

Completion Date: 7 Feb 2017

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

Heartwater Survey – 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

Formal and Informal Red Meat Industry in the Western Cape

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

Industry Sector: Cattle and Small Stock

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

Research Institute: Agriculture Research Institute – Animal Production Institute

Researcher: Dr Nick Vink PhD (Agric)

Title Initials Surname Highest Qualification
Mr. Michael McCullough M

Completion Date 23 August 2018

Aims Of The Project

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

Executive Summary

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

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

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

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

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

Animal welfare, stress biomarkers and meat quality

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

Industry Sector: Cattle And Small Stock

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

Research Institute: Fort Hare

Researcher: Dr. Voster Muchenje PhD

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

Final Report Approved: 23 August 2018

Aims Of The Project

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

Executive Summary

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

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

Popular Article

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

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

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

Methane and nitrous oxide from beef cattle manure

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

Industry Sector: Cattle and Small Stock

Research focus area: Sustainable natural resource utilization

Research Institute: University of Pretoria

Researcher: Dr JL Linde du Toit

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

Final report approved: 23 August 2018

Aims of the project

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

Executive Summary

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

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

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

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

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

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

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