As temperatures and humidity soar, dairy cattle may start to show signs of heat stress, explained Tracey Erickson, SDSU Extension Dairy Field Specialist.
"Dairy cattle have a comfort zone of between 41 to 68 degrees Fahrenheit. For each degree ambient temperatures increase above 68 Fahrenheit dry matter intakes drop on average 0.17 pounds.", she said. "Producers need to be vigilant in their heat stress abatement tactics."
Signs of heat stress
Reduction in dry matter intake and increased water intake are indicators of heat stress. In addition, Erickson said producers will see a drop in milk production and butterfat, along with increased reproductive issues such as pregnancy loss.
Other heat stress indicators include: open mouth breathing, increased respiration, sweating, increased amount of time standing, and changes in manure consistency.
So what can you as dairy producers do to help aid in the reduction of heat stress? What follows are some basic tips for dairy cattle heat stress reduction:
- Provide shade if cattle have access to an outside lot.
- Increase access to clean, fresh drinking water. This may involve adding extra tanks of water and checking for appropriate flow of water in drinking fountains.
- Cattle waiting in a holding pen in a milking parlor should be cooled by a combination of air movement, water sprinkling systems, and shade.
- Make sure sprinklers dispense large water droplets (soaking) as small droplets often found in misters will not allow for heat dissipation from the cow. Intermittent application allows time for the water to evaporate and cool the animal before the next cycle. Sprinkle cows with low pressure sprinklers over their backs away from the feed bunks. Trying to keep the udders dry in this process will help minimize the incidence of mastitis.
- Use large fans in combination with sprinklers to help cool cows and the air simultaneously.
- As dry matter intake decreases adjust diets accordingly, utilizing higher quality forages and increasing the energy density of the diet. As diet adjustments are made care should be taken to make sure that there is enough effective fiber to maximize rumination and keep acidosis and displaced abomasums to a minimum. Adding buffers such as sodium bicarbonate to energy dense diets also help aid in maintaining rumen pH under control.
- Diets should contain at least 0.25 lbs. of white salt per cow per day, along with offering access to free choice salt and trace minerals.