As we learn more about the negative impact heat stress has upon cattle, technological advances provide options to make your dairy operation more profitable during summer heat. Some technologies include capital investments, such as fans, misters, shades and other cooling apparatuses, to reduce the ambient temperature in the cow’s environment.

Other technologies focus on feed additives or other methods that reduce the amount of heat cows generate while ruminating. While most all these add more expense, their cost should be justified by considering the average annual severity of heat stress on your dairy, price of milk, total cost of the investment and the projected return on investment.

I suggest you also consider another investment that incurs no additional cost to reduce heat stress – increase your management energy. This is the time and effort you put into working with your employees to train them how to help animals during the hot summer months.

Primer on heat stress
In an article I wrote for the current issue of El Lechero, I explain the basis for why and how cows suffer from heat stress for your employees. I describe the cow, simply, as a walking furnace. Every hour of the day her body converts feed to milk. This reaction produces excess energy that she must eliminate through respiration.

As long as the outside temperature is lower than her body temperature (101.5 degrees), she rids herself of the extra heat by breathing it to the outside. But when the outside heat and humidity are higher than her body temperature, the cow starts panting in an effort to rid herself of that heat buildup. This produces stress, discomfort, possible accumulation of toxins and reduced immune response in cows susceptible to infection.


Normal cows suffering from heat stress eat less, produce less milk, lose body condition and have lower pregnancy rates. Sick, heat-stressed cows suffer even more. Cows with retained placentas, metritis, mastitis and pneumonia that normally respond well to treatments may not respond or even die when heat stress complicates their problem.

Even if you invest in heat abatement technologies, there are still practical management principles that you, your herdsman and workers can implement to reduce the negative impact of heat stress.

Management tips for groups of animals
1. On dry lot dairies where cows are locked daily for routine management tasks like breeding, repro shots, vaccinations or pen moves, tell your employees to plan their work so that cows are locked, worked, then released as fast as possible.

Time how long your cows stand in headlocks. Communicate that amount of time to employees. Can they do their work more efficiently? Don’t penalize cows susceptible to the effects of heat stress by forcing them to stand longer than necessary because your workers are not efficient, not focused or are unaware of the negative impact they’re having on cows.

2. Change milking times so that high-producing cows leave the parlor in the cool of the early morning so that routine cowside work can be accomplished before daytime heat builds up. This is something that most likely only you or your manager can control. Explain the reason for the change to your milkers.

3. On freestall dairies, increase how frequently cow pushers clean and eliminate manure and wet, soiled areas on the back-half of freestall beds. Klebsiella and coliform bacteria multiply at high rates in heat and humidity. Keep clinical mastitis under control with added maintenance.

4. Deliver fresh feed more often in the summer; increase the amount fed (and eventually consumed) during evening and early morning hours.

In the article in El Lechero, I offer some individual animal care tips for your employees. Training employees to use them will help your workers reduce heat stress in other areas of your dairy.

Don’t forget to encourage
Step up your management energy during summer heat stress. Good workers can get frustrated and discouraged when the number of sick cows increases, when these cows stay in the hospital pen longer and when death rates escalate. Managers need to be accountable for these issues.

However, if health problems increase during hot periods because workers aren’t focused, organized or treating according to specific protocols, management energy is your firm but positive reinforcement to have your employees bear down, seek out and treat sick animals correctly.

Even if some unavoidable problems arise or you just can’t justify the cost of heat abatement technology this year, management energy is your positive reaffirmation tool. It will communicate to employees, “We are doing OK, and we will work our way through this.”

Heat is tough on both animals and people. Abatement technology may not always be cost-effective; when you can justify it, there is proven benefit for animals. However, management energy is always cost-effective. It is the only tool you have that benefits both your workers and your cows. PD

Tom Fuhrmann

Tom Fuhrmann, DVM
Dairy Works