Summer heat is upon us, and if the past few days are any indication, the summer of 1996 may be a repeat of the scorcher of 1995.
Dairy Pipeline: June 1996
Tom L. Bailey
Dairy Production Medicine
Virginia-Maryland Regional College of Veterinary Medicine
Heat stress will contribute to lower milk production, decreased heat detection, decreased pregnancy rates, an increase in respiratory problems, and death in cattle. Planning now to deal with heat stress can significantly decrease the impact this problem will have on total herd productivity. Water, shade, fans, sprinklers and feeding changes are the areas that deserve the greatest attention during this time. Water should be available at all times, in a location convenient to the cows and in large quantity. Watering tubs, with large (2") water inlets, will allow more cow access and create faster water turnover providing cooler water. Small, individual cow water bowls do not provide the volume of water needed for drinking. Research has shown cows will drink for a limited amount of time, not until their thirst is quenched. Water should also be available in the holding area. Keep holding area time to a minimum (less than 45 minutes) and avoid crowding. Cows should not be packed in a holding area, but should have ample room for air circulation between cows. This may require additional labor in cow management and movement, but can greatly reduce heat stress. Fans and sprinklers in the holding area will also aid in decreasing the effects of crowded cattle. Fans and sprinklers over the feed bunk will keep cows at the feed bunk longer. Water should thoroughly soak the cows for approximately 10 minutes and then shut-off. With air movement from fans, this will create evaporative cooling for cow comfort. Provide portable shade for cows at pasture. Cow congregation under trees create mud bogs, damaging the root system and killing the trees. Portable shades can be moved allowing clean ground for cow comfort. Fans in the free stall area are a must. For many producers, the best investment they can make in reducing heat stress is a crowbar. Remove sides from freestall barns for air flow and adequate ventilation. Keep feed fresh and the bunks clean, removing any moldy feed during hot weather. Heat stress will take its toll this summer. Make plans now to implement heat stress prevention programs. Consult your veterinarian, Extension agents, nutritionists, and agricultural engineer to formulate a plan to deal with this problem.