High environmental temperature reduces the intensity of estrus activity. Bulls are especially vulnerable to heat stress. Overheating can cause damage to semen quality that may last for up to six weeks. Provide artificial shade if ample natural shade is not available in areas where cattle spend most of their time during the heat of the day. It is especially important to have cows pregnancy tested in the fall after drought conditions.
Short pastures can potentially increase parasite loads.
It is known that parasite eggs tend to concentrate more in the lower part of the forage plants, thus short pastures due to drought conditions can increase the potential parasite load. This would tend to suggest that strategic parasite control programs are more important during drought situations. Cattle will sometimes consume potentially toxic weeds when pasture conditions are poor. Some drought stressed weeds accumulate high levels of nitrates and have, on occasion, caused problems. The risk of plant poisoning is minimal, however, if adequate hay and other feeds are provided during drought periods.