South African farmers know that weather is one of the biggest factors determining the success of a farming season.
When El Niño conditions contribute to higher temperatures, prolonged dry periods and below-normal rainfall, the effects are felt across the entire farming operation — from cattle and sheep to wildlife, grazing, water supplies, farm workers, families and the farmer's own health.
Heat stress is not simply a matter of animals being uncomfortable. Extended periods of extreme heat can affect animal behaviour, movement, grazing patterns, water consumption, reproduction, immune function, body condition and ultimately productivity.
Cattle and sheep under pressure
Cattle and sheep respond to extreme heat by changing their normal behaviour. During the hottest part of the day, animals may reduce movement and spend more time seeking shade. Grazing patterns can change, with animals grazing earlier in the morning, later in the afternoon or during cooler periods.
This creates another problem when grazing is already limited by drought. Animals may have to walk much further to find sufficient grass, browse and water. That additional movement uses valuable energy at exactly the time when feed availability is declining.
Cattle can experience reduced feed intake during severe heat, contributing to weight loss and declining condition. Sheep can also lose condition when veld quality and quantity deteriorate. Poor body condition can affect reproduction, lambing, calving and the ability of animals to withstand disease and other health challenges.
Water resources under increasing pressure
Water becomes one of the most critical resources during periods of extreme heat and drought. As temperatures rise, evaporation from dams, farm reservoirs, pans and other surface-water sources increases, while livestock and wildlife may need more water to maintain normal body function.
Farmers can therefore face a difficult situation: water levels are falling while demand is increasing.
Boreholes may have to work harder, pumping costs can increase, and some water sources may become unreliable. When natural springs, rivers and smaller farm dams dry up, animals may have to travel much further to reach the remaining water.
Water quality must also be monitored. As dams and watering points become lower, concentrations of salts, minerals, algae and other contaminants can change. Water that was suitable earlier in the season may need closer monitoring as conditions deteriorate.
The pressure extends to farm families and workers, who depend on the same limited resources for drinking, household use, sanitation and daily farm activities.
For this reason, farmers should monitor their water resources at least monthly — and more frequently during extreme heat and drought. Dam levels, borehole performance, water quality, storage capacity, troughs, pipelines and pumps should all be checked.
Water planning should form part of a farm's long-term drought strategy, rather than only becoming a priority when a dam is nearly empty. Every litre becomes more valuable when temperatures rise and rainfall fails.
Wildlife is affected too
Wild animals are also affected by prolonged heat and drought. Wildlife may have to travel greater distances between feeding and drinking areas, increasing energy expenditure and competition for resources.
As water sources disappear, animals can become concentrated around the remaining drinking points. This can increase competition between species and place additional pressure on vegetation surrounding those water sources.
The condition of wildlife can therefore deteriorate just as it can in domestic livestock, particularly when natural food and water supplies become increasingly limited.
What a world above 1.5°C could mean for South Africa: heat, drought and food pressure
Sickness and animal condition
Heat, drought, poor nutrition and increased movement can place additional stress on animals. Animals in poor condition may be less able to cope with infections, parasites and other health challenges.
Farmers need to watch changes in body condition, behaviour, water consumption, grazing patterns and general activity. Early recognition of problems can make a significant difference.
The hidden effect on farmers and workers
The impact of extreme heat does not stop with the animals.
Farmers, farm workers and their families are also exposed to the consequences of prolonged heat and drought. Workers may spend many hours outdoors checking livestock, repairing water systems, moving animals, maintaining fences, working with irrigation and dealing with the many additional demands created by dry conditions.
Heat exposure can cause immediate problems such as dehydration, exhaustion, headaches, dizziness and reduced concentration. Physically demanding work becomes even harder when temperatures remain high for long periods.
For farmers, the mental pressure can be just as significant. Watching grazing disappear, water levels fall, livestock lose condition and production decline creates financial and emotional pressure. The farmer is not only responsible for animals and land, but also for employees, families and the future of the farming business.
Understanding the long-term effects
As temperatures rise, the real-time effects of heat and drought on agricultural communities deserve greater attention. Research using interviews, health information and wearable technology can help researchers better understand both the immediate and longer-term effects of heat exposure on agricultural workers.
This is particularly important because farm workers and herders can be difficult for conventional healthcare systems to reach. Long-term studies, conducted consistently over several years, can help build a clearer picture of how repeated heat exposure and drought affect human health.
For South African agriculture, preparation is therefore about much more than protecting livestock.
It means protecting water, grazing, animal condition, wildlife, workers, farmers, families and the long-term sustainability of the farm.
El Niño may come and go, but every extreme season reminds us of one important reality:
A healthy farm depends on healthy animals, healthy people, sufficient water and careful management of the natural resources on which both depend.
