Fact Check 6: Livestock Disease Production Burdens
Citation
Does disease cause the preventable death of one in four young ruminants and one in ten mature ruminants?
Animal disease can impact the livestock sector both directly (for instance production losses, increased mortality and lost traction power for cropping) and indirectly (for instance market and trade disruptions, livelihood risks, zoonotic disease and food-borne illnesses)1,2. Experts suggest that these impacts are significant, particularly in low and middle income countries (LMICs), where income and nutrition from livestock is critical for development, and thus deserve greater attention from the global community3. In particular, current understanding does not allow us to effectively answer questions such as4:
How much less milk do infected cows produce?
How much less do infected goats weigh?
How many chickens die due to disease?
Verifying reported global figures
Advocates for increased investment into animal health do make impact claims, for instance “one in four young ruminants, and one in ten adult ruminants, die from preventable causes”, and “one quarter of the animals owned by poor livestock keepers die from preventable and treatable diseases”5, 6. However, such statements are commonly made with no source citation. We suggest these numbers were derived from mortality risk percentages presented in a systematic review (of over 400 studies) of ruminant production systems in Sub-Saharan Africa7. The review presented mortality risks for different ruminant species in different production systems; the variation between these is lost when they are grouped into such high level ruminant figures. In addition, the advocacy claims suggest that the mortality risks are preventable, whilst the systematic review does not make this claim. While it could be assumed that some portion of mortality risk is preventable through intervention, however, it would be wrong to suggest mortality could be reduced to 0% under any scenario.
Why do we need to know?
It is important to understand how much diseases limit production from livestock (e.g. reduced milk yields, growth rates or egg production). Accurate quantifications are vital for economic assessments, effective decision-making, and prioritisation and implementation of animal health resources8-10. For instance it is suggested that the significant environmental impact of livestock production (namely greenhouse gas emissions) can be reduced by improving efficiency of livestock production11. Removing the production burden of disease is one option, and being able to quantify the burdens is vital in deciding which animal health options have the greatest and most economical mitigation potentials12, 13.
What do we know?
Typical studies that evaluate livestock diseases according to impact on production rely on asking experts and farmers10, 14. Subsequently, lists of key diseases can be composed15. The symptoms and mechanisms by which these diseases limit production are fairly well understood16, 17, whereas the quantification of the global production burden is not10. There are case studies for particular diseases in particular production systems, which give some detail to associated production burdens18,19. These case studies are often the basis for broader quantifications of disease burdens9, 20, 21.
Future efforts
Case study assessments have shown disease to be a barrier to improved productivity from livestock systems in LMICs, but quantifying a global impact is a challenge. A lack of detail of disease incidence and prevalence contributes significantly towards this limitation10,22. An increasing ability to detect and report livestock disease, offers prospects for improved quantification.
References
- FAO. 2009. The State of Food and Agriculture: Livestock in the balance. Food and Agriculture Organization of the united nations, Rome.
- Rushton, J., & Knight-Jones, T. 2012. The impact of foot and mouth disease. In The FAO/OIE Global Conference on Foot and Mouth Disease Control. 2012. Bangkok, Thailand. Food and Agriculture Organization of the United nations and the World Organisation for Animal Health.
- Perry, B., & Sones, K. 2007. Poverty reduction through animal health. Science, 315 (5810):333-334.
- Mayberry, D., Ash, A., Prestwidge, D., & Herrero, M. 2018. Closing yield gaps in smallholder goat production systems in Ethiopia and India. Livestock Science.
- BMGF. 2012. Agricultural Development: Livestock Overview and Approach. Bill & Melinda Gates Foundation.
- New Scientist. 2008. Gates declares war on farm animal disease.
- Otte, M. J., & Chilonda, P. 2002. Cattle and Small Ruminant Production Systems in Sub-Saharian Africa: A Systematic Review. Food and Agriculture Organization of the United nations. Rome.
- FAO. 2016. Economic analysis of animal diseases. FAO Animal Production and Health Guidelines. Rome.
- Shaw, A. P., Cecchi, G., Wint, G. R., Mattioli, R. C., & Robinson, T. P. 2014. Mapping the economic benefits to livestock keepers from intervening against bovine trypanosomosis in Eastern Africa. Preventive Veterinary Medicine 113, 197-210.
- Perry, B., & Grace, D. 2009. The impacts of livestock diseases and their control on growth and development processes that are pro-poor. Philosophical Transactions B. 364, 2643-2655.
- Gerber, P., Vellinga, T., Opio, C., & Steinfeld, H. 2011. Productivity gains and greenhouse gas emissions intensity in dairy systems. Livestock Science 139, 100-108.
- MacLeod, M., Eory, V., Wint, W., Shaw, A., Gerber, P., Cecchi, G., Mattioli, R., Sykes, A., & Robinson, T. 2018. Assessing the Greenhouse Gas Mitigation Effect of Removing Bovine Trypanosomiasis in Eastern Africa. Sustainability 10, 1633.
- Salmon, G. R., Marshall, K., Tebug, S. F., Missohou, A., Robinson, T. P., & MacLeod, M., 2017. The greenhouse gas abatement potential of productivity improving measures applied to cattle systems in a developing region. Animal 12(4), 844-852.
- LD4D. 2018. Getting to grips with the Global Burden of Animal Diseases: Q&A with Prof Jonathan Rushton. Livestock Data for Decisions.
- OIE. 2018a. OIE-Listed diseases, infections and infestations in force in 2018. World Organisation for Animal Health.
- FAO. 2010. Case Definition of Livestock Diseases. Food and Agriculture Organization of the United nations. Addis Ababa, Ethiopia.
- OIE. 2018b. Animal Disease Information. World Organisation for Animal Health.
- Rufael T., Catley, A., Bogale, A., Sahle, M., & Shiferaw, Y. 2008. Foot and Mouth disease in the Borana pastoral system, southern Ethiopia and implications for livelihoods and international trade. Tropical Animal Health and Production 40, 29-38.
- Ferrari, G., Tasciotti, L., Khan, E., & Kiani, A. 2014. Foot-and-mouth disease and its effect on milk yield: an economic analysis on livestock holders in Pakistan. Transboundary and merging Diseases 61(6), e52-59.
- Knight-Jones, T. J. D., McLaws, M., & Rushton, J. 2017. Foot-and-Mouth Disease Impact on Smallholders - What Do We Know, What Don't We Know and How Can We Find Out More? Transboundary and Emerging Diseases 64(4), 1079-1094.
- Shaw, A., Hendrickx, G., Gilbert, M., Mattioli, R., Codjia, V., Dao, B., Diall, O., Mahama, C., Sidibe, I., & Wint, W., 2006. Mapping the benefits a new decision tool for tsetse and trypanosomiasis interventions. Rome, Italy, Department for International Development, Animal Health Programme, Centre for Tropical Veterinary Medicine, University of Edinburgh, UK and Programme Against African Trypanosomiasis, Food and Agriculture organization of the United Nations.
- Rushton, J., 2017. Improving the use of economics in animal health - Challenges in research, policy and education. Preventative Veterinary Medicine 137, 130-139.
Header photo: Salmon, G. (SEBI)