Hot or cold, extreme temperatures can challenge cattle’s health. Typical summer stressors, like heat, dust, crowding and a change in nutritional profile, amplify a range of risks, including bovine respiratory disease (BRD). To maintain healthy herds and consistent performance, producers need to understand how cattle respond to heat in order to make good decisions about the health of their animals during the summer months.
Cattle are affected by heat differently than most animals. Not only do they have to deal with environmental temperatures, but in ruminating animals the heat of fermentation also has an effect. Unable to sweat as humans do, cattle cope with heat stress by increasing respiration and water intake, backing off feed and staying close to areas with shade or water. These strategies minimize heat created by movement and digestion, but invite crowding and nutritional instability. Heat tolerance varies widely across breeds, but constant temperatures of 75 degrees or above is usually enough to trigger a stressful event.
Secondary consequences of heat, like decreased forage quality and throat and lung irritation from dry, dusty air, add to the risk of all forms of BRD, including summer pneumonia, acidosis or impaired reproductive readiness. Combating heat stress starts with an ample, well-spaced water source. This, along with adequate cover and shade, preferably oriented to take advantage of any prevailing breezes, will help to reduce crowding and give animals a rest from direct sunlight by allowing their bodies to dissipate heat via conduction. This also can be done by wetting the cattle under sprinklers to provide a cooling effect and limit dust.
Cattle will congregate around water in periods of heat stress. This can have a detrimental effect on pasture quality, contaminate water sources and negatively affect nutrient utilization in your operation. Hot conditions not only reduce intake at the bunk and change the nutritional value of forage, they can affect water quality. Water sources that were once safe can now have levels of detrimental components. Constant monitoring and consultation with a nutritionist can help producers determine if a supplement is necessary to complete the ration or forage already provided.
The specific challenges of every region and every operation are different. Remember that taking a multi-step approach may help shed more light than dealing with individual cases on a day-to-day basis. How do you prepare your facilities and your cattle for the challenges of summer?