Journal of Animal and Plant Sciences
J. Anim. Plant Sci. [ISSN 2071 - 7024]
Volume 14(2): 1931 -1938. Published June 30, 2012.
Projected impacts of temperature and humidity on feedlot cattle in South Africa using temperature humidity index as an indicator of heat stress
Nesamvuni E1, Lekalakala R1, Norris D2* and Ngambi J.W2
1Research Services, Limpopo Department of Agriculture, 69 Biccard Street, Polokwane
2Department of Animal Science, University of Limpopo, Private Bag X1106, Sovenga 0727
Corresponding author email: david.norris@ul.ac.za
Keywords: Climate Projections, Beef Cattle, Feedlot, Heat stress, temperature-humidity index
SUMMARY
In South Africa, feedlot industry accounts for about 75 % of beef produced and about 80 % of the country’s cattle being farmed for beef and the remaining 20 % for dairy. It is hypothesized that increased climate conditions may lead to loss in livestock and its productivity, with unconditioned confined feedlot cattle losses being disastrous. The economic losses owning to cattle death losses may be exceeded several-folds by those associated with reduced cattle performance. In light of this, the aim of this paper was to assess the effects of projected future climate on feedlot cattle in South Africa. This information could be used to inform the process of developing animal production adaptation strategies and policies. Climate stations selected to represent the country’s climate were used to extract the downscaled daily climate projections for A2 emissions scenario from various General Circulation Models, similar to those used in the Intergovernmental Panel on Climate Change 4th Assessment Report of 2007. The climate projections were used to compute an index combining temperature and humidity (THI). A classification scheme was used from literature to reclassify THI to show different degree of potential heat stress in cattle. The results from the projections of heat stress suggests that in the intermediate future [2046 - 2065] and distant future [2081 - 2100] feedlot cattle might experience more stress as compared to present climate scenario, mainly along the northern periphery. This information could be used to inform the process of developing animal production adaptation strategies and policies.
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