Producers should pay close attention to cattle activity during breeding season to ensure adequate reproductive performance. Both bulls and cows will experience adverse conditions during the breeding season that can reduce conception rates. Certainly, poor nutrition will result in cows that are too thin, with low body condition scores and reduced fertility. However, even with adequate nutrition, nuisances of heat stress and fly populations can negatively affect cattle behavior during breeding season.
As summer temperatures and fly populations increase, cattle are frequently adversely affected. Ambient temperature has been shown to reduce conception rates of beef cattle. Providing shade during the hottest times of the day can assist cattle fighting the heat. Finding other methods such as water sprays or fans to cool beef cattle that are on pasture during the breeding season is frequently impractical. However, cattle that are stressed from both heat and obnoxious flies will often result in cows crowding together to combat the flies. This crowding behavior, in effect, increases the temperature in that environment and minimizes the animals cooling mechanism. Michigan State University Extension recommends using fly control measures to reduce crowding and improve breeding performance. Insecticidal ear tags, sprays and cattle rubs are cost effective methods of controlling flies.
Bulls should also be observed during breeding season. Some bulls have been found to isolate themselves from the cow herd in an attempt to combat stressful conditions of heat and flies. Bulls should also be observed to ensure they are breeding cows effectively. Many injuries to bulls occur during the breeding season. Bulls that are injured usually cannot service cows naturally.
Observing the cattle herd during breeding season is an important piece of management. Observation alone will not improve breeding performance, but realizing the stressors that are occurring will allow producers to take corrective measures. Minimizing stress from heat, flies and disease will improve pregnancy rates in the cow herd.