HEAT STRESS ▶▶▶


Heat hampers pig production in East Africa


Heat stress is a major constraint on livestock welfare and productivity. Increasing temperatures and more humid conditions could make much of East Africa unsuitable for pig production. Accelerated adaptation in the sector is needed.


BY NATALIE BERKHOUT, CORRESPONDENT N 100


10 20 30 40 50 60 70 80 90


0


1981-2010 Historical


Source: Rahimi et al., 2021. 6 49% 49% 55% 53% 73%


15% 19% 17%


25% 23% 18% 8%


2021-2050 RCP4.5


16% 6%


2021-2050 RCP8.5


24%


17% 7%


2071-2100 RCP4.5


10% 15%


3%


2071-2100 RCP8.5


Temperatures will continue to rise Using a multi-model ensemble of climate change projections for 2021–2050 and 2071–2100, the researchers show that the frequency of dangerous heat-stress conditions and the aver- age number of consecutive days with heat-stress events will significantly increase, making much of East Africa unsuitable for exotic pig production.


An alarm bell for policymakers One of the researchers, Klaus Butterbach-Bahl at the Interna- tional Livestock Research Institute (ILRI), Kenya, and the Karls- ruhe Institute of Technology, Germany, said that the results of the study are “an alarm bell for policymakers and anyone


▶ PIG PROGRESS | Volume 37, No. 5/6, 2021


ew research published in Nature Food warns that heat stress in animals caused by rising tempera- tures and higher humidity will occur more fre- quently and for longer periods, affecting pig


production across East Africa, a region home to approximate- ly 10 million swine in 2020. Furthermore, East Africa has the highest population growth on the continent, which has been an important driver of demand for livestock products, with future increases anticipated. In the study, the frequency of “severe/danger” heat events (temperatures that will result in significant decreases in


Figure 2 - Possible scenarios of changes in the frequency of heat stress for future climate conditions, depending on the volume of greenhouse gases emitted. The researchers believe the most likely scenario to be RCP8.5, in which 19% of pork production (~122,000 tonnes of pork) is threatened by 2071-2100.


Severe/Danger Moderate Mild None


productive and reproductive performances) for swine signifi- cantly increased from 1981 to 2010. Swine were exposed to severe/danger heat stress for >50% of the year in roughly 44% of East Africa. Across the region as a whole, the average frequencies of moderate heat-stress conditions (body temperature increases that can negatively impact the livestock’s performance) for swine during the period were approximately 17%. The per- centage of days of the year with severe/danger heat-stress conditions for the different livestock categories differed markedly, but swine were the most affected.


Frequency (%)


PHOTO: KABIR DHANJI | ILRI


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