Record heat across the West in recent weeks has driven home a sad and expensive reminder for some dairies: heat stress can kill calves.For those that live, the negative effects of heat stress can drag on for months. Reduced growth rate and weakened immune systems that put calves at greater disease risk are two of the biggest.
Just like other cattle, the main heat stress threats to calves are prolonged exposure to direct sunlight, not enough ventilation, not enough fresh water and overcrowding. Calves are resilient little things, but they need help when it is hot and humid – especially if nighttime lows aren't very low.
Simply put, calf cooling and comfort have to be a management priority, not an afterthought. Ignoring heat stress won't make it go away, but it will guarantee dead calves and poor doers.
Researchers consistently agree that "musts" for helping calves cope with heat stress are providing plenty of shade, plenty of ventilation (natural or mechanical), and plenty of fresh drinking water.
Additional suggestions include making sure that grain is fresh as many times per day as possible; making sure bedding is dry as many times per day as possible; making sure fresh water is constantly available within two days of birth; working calves only during cooler early morning hours if possible; and increasing milk replacer quantity or quality to make up for the drop in grain starter consumption and caloric intake that heat stress is likely to cause.
Like everything else at a dairy, raising calves takes time and effort to do well, and shortcuts tend to cost more in the long run.
The author has served large Western dairy readers for the past 36 years and manages Hoard's WEST, a publication written specifically for Western herds. He is a graduate of Cal Poly-San Luis Obispo, majored in journalism and is known as a Western dairying specialist.
