The effects of unfavourable weather conditions

Introduction

The El Niño is a climatic phenomenon typically characterised by the anomalous warming of the surface temperature of the central and eastern equatorial Pacific Ocean (Delport, 2023: online). The El Niño forms part of the larger El Niño-Southern Oscillation (ENSO) cycle, that also includes the La Niña, or the ‘cool phase’ of the ENSO cycle. Both warmer and cooler phases have distinct effects on weather patterns globally, therefore it is essential to understand the nature of and differences of the El Niño and La Niña, and consequently its influence on the South African agriculture sector, specifically cattle.

The El Niño phenomenon

Essentially, the El Niño and La Niña are the opposite phases of the ENSO cycle. During the La Niña trade winds are strengthened, and the sea surface temperatures are ‘cooler-than-average’. Trade winds are the wind that flows towards the equator, south-east in the Southern Hemisphere, and north-east in the Northern Hemisphere (Delport, 2023: online). The opposing El Niño is characterized by warmer-than-average sea surface temperature and the weaking of trade winds. Both these cycles have sweeping consequences on worldwide weather patterns.

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These phenomena can affect temperature, storm patterns and precipitation, thus greatly impacting agricultural sectors, ecosystems and water resources. Typically, the El Niño can bring below-normal rainfall patterns to parts of Southern African, causing water scarcity, increased risk of wildfire and lower agricultural productivity. In cases of extreme conditions, the prolonged drought conditions associated with El Niño can cause humanitarian crisis and severe food shortages (Delport, 2023: online).

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In South African borders, the El Niño can significantly impact the agricultural sector, primarily due to its drought conditions and below-average rainfall. A staple crop in South Africa, maize, is particularly vulnerable to the drought conditions as the El Niño causes soil moisture deficits and insufficient water availability that negatively affects crop developments and growth, creating a chain reaction to lower yields and crop failures (Delport, 2023: online). Other crops, such as sugar cane, soybeans and wheat suffer the same consequence.

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Additionally, El Niño conditions affects the livestock industry. Limited and insufficient water sources along with reduced pasture growth leads to inadequate grazing, negatively affecting livestock productivity. Solar radiation, humidity, wind and temperature affects animals directly, with temperature being the greatest direct effect on livestock (Farmer’s weekly, 2020: online). Consequently, heat stress is a common cause of reproductive inefficiency, especially in beef cattle. Heat stress effects the fertility of cattle, particularly decreasing the semen quality in bulls. According to Gerogette Pyoos-Daniels, a junior researcher at the ARC Anima Production Institute, even a singular day of heat stress can reduce the semen quality and potentially the bulls’ fertility (Farmer’s weekly, 2020: online). In the long run, the effects of heat stress exposure will become evident in the decreased number of calves born in the affected herd.

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Additionally, heat stress also affects the females’ fertility. It can cause lowers pregnancy rates in cows and can cause damage to early embryos and oocytes (Scholtz et al., 2021: online). It can also influence the overall growth in beef cattle. Cows in late pregnancy affected by heat stress can produce downstream effects on the performance of their progeny during the suckling period. According to M.M Scholtz et al, in a case study namely: Challenges and opportunities for climate-smart beef production under climate change in southern Africa, it was observed that the average maximum daily temperature during the calves’ suckling period explains up to 42% of variation in their weaning weight in a hot and dry area of South Africa (Scholtz et al., 2021: online). Further indications also point out that heat stress may also affect meat tenderness and colour in beef cattle (Modika & Frylinck, 2020). Other factors such as the changes in the quality and quantity of grazing, and the digestibility of feed have indirect effects on beef cattle. In warmer climates, nutritional stress has a great influence on grazing ruminants. Grazing conditions and natural pastures may have lower nutritional value and tiller density than in temperate regions.

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To mitigate the effects of El Niño, it is crucial to stay informed about possible projections of heat stress. Seasonal prediction models are helpful, as they can provide temperature forecasts for 7 to 14 days, allowing for the acquisition of supplements and licks for beef cattle. These can be formulated to ensure proper cation-anion balance to counteract heat stress (Scholtz et al., 2021: online). Researchers also encourage alternative breeding options, such as crossbreeding and multi-sire breeding with tropical-adapted genotypes to address possible infertility in bulls. However, this method may not be suitable for stud animals, as it is counterproductive in such cases.

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Conclusion

There are limited options for mitigating damage caused by the El Niño phenomenon. While research and expert advice focus on long-term solutions, they do not necessarily address challenges specific to stud-based farming or single-genotype studs. Currently, the best approach is to educate oneself about the El Niño phenomenon to identify key areas that can be supplemented or managed based on seasonal predictions. Efforts can be made to mitigate the effects of prolonged droughts, high temperatures, and the potential for heat stress-induced problems. Additionally, staying up to date on proper vaccinations is crucial to minimize the risk of disease outbreaks and spread among the herd. Both El Niño and La Niña affect global weather patterns, bringing both favourable and unfavourable conditions. Ultimately, staying informed about weather forecasts and global climate trends is the best way to prepare for the challenges posed by El Niño and La Niña seasons.

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Resources:

Delport, C. 2023. Anchor Agri-view: The El Niño enigma – unravelling its impact on SA’s agricultural landscape. [online]. Anchor Agri-view. Available from:< https://anchorcapital.co.za/macro-research/anchor-agri-view-the-el-nino-enigma-unravelling-its-impact-on-sas-agricultural-landscape/#:~:text=Naturally%2C

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%20insufficient%20rainfall%20during

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%20El,and%20prices

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%20of%20these%20products.> [Accessed 18 February 2025].

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Farmer’s Weekly. 2020. Maximising efficiency against heat stress in cattle. [online]. Farmer’s Weekly. Available from:< http://farmersweekly.co.za/animals

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/cattle/maximising-efficiency-against-heat-stress-in-cattle/> [Accessed 18 February 2025].

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Modika, K. & Frylinck, L. (2020). How do environmental conditions affect meat colour / tenderness? Annual Beef Bulletin, ARC Animal Production. pp. 74-75.

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Scholtz, M.M et al. 2021. Challenges and opportunities for climate-smart beef production under climate change in southern Africa. [online]. Available from:< chrome-extension://efaidnbmnnnibpca jpcglclefindmkaj/https://www.dalr

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rd.gov.za/images/Docs/climate-smart-agriculture-book.pdf> [Accessed 18 February 2025].