With daytime high's projected to top out near the century mark later this week, it is important to understand how the conditions not only impact us humans, but our animals as well. The following is an excerpt from agweather.mesonet.org.
Heat stress can cause reduced productivity in beef and dairy cattle herds. The effects of severe heat stress are often seen in the form of reduced reproductive performance, reduced daily weight gain of growing cattle and reduced milk production. Cattle are more sensitive to heat stress than humans, although cattle do seem to have a wide range of heat tolerance. From an environmental perspective, heat stress is a combination of temperature, relative humidity, and wind speed. However, animal factors, such as age, hair coat length, hair coat color, and nutrition status, interact with these environmental factors to determine the severity of heat stress.
What can you do in a heat stress situation?
Provide ample water.
On days when the index is mild or higher the cattle may need more than 2 gallons of water per 100 pounds of body weight. Provide enough tanks for cattle to be able to get the water they need. If possible, water should be cooled. Tanks should be cleaned weekly to encourage water consumption. Making water available under a shaded area will increase cattle water consumption.
Avoid handling cattle:
Handling cattle can elevate their body temperature by as much as 3.5F. If cattle must be worked on days when the Cattle Stress Index is likely to go over 80, try to do the work before 8:00 AM and keep the maximum time in the holding facilities to no more than 30 minutes. On days when the index will be 80 or above, do not work cattle after 10:00 AM. The 60-hour forecast component of the cattle stress index, will allow you to schedule management practices to best maintain cattle health.
Change feeding patterns:
Shift the feeding schedule toward evening on days when the Cattle Stress Index is mild or above. Try to deliver 70% of the daily scheduled feed two to four hours after the peak air temperature. Providing only small amounts of feed during the heat of the day, will decrease the metabolic heat of digestion.
Provide shade:
A shade tree is just as welcome a relief for cattle as humans on a hot summer day. Shade can also be constructed. Shade height should be 8-14 feet tall and should be large enough to provide 20-40 square feet per animal. The most effective shade is a solid reflective roof constructed of white colored, galvanized, or aluminum materials. Shading with wooden slats, plastic fencing, or other materials that allow flecks of sunlight to hit the animals are less effective. If possible two shaded areas are recommended, one over the feed area to increase feeding time, and another away from the feed area to encourage the cattle to rest. Water should be made available under both shaded areas, to increase the water consumption during heat stress period. If the structure is left up year-round, construct a frame adequate for snow load. Shade is insurance against mortality loss. Any performance benefits are a bonus.
Improve airflow:
Consider where the cattle are located and if there is any air restriction. Buildings, high fences, or vegetation can block airflow. A 6-foot high windbreak can obstruct airflow for 60 feet downwind.
Provide water mist:
Providing a spray of water will help to cool the animals down. However it is important to place misters over a clean, concrete area. Running misters over dirt creates mud and increases the potential for mastitis or other bacterial diseases. A timer should be used to run the mister long enough to cool, but not wet the cattle. Do not allow mist to wet nearby feed. Wet feed spoils rapidly with Oklahoma’s summer heat.
Control biting flies:
Stable flies cause cattle to bunch and disrupt cooling. Monitor the situation and control the flies as needed. Eliminate any shallow pools or muddy areas nearby, since they are common breeding areas for flies.
Reference:
Managing Feedlot Heat Stress, Nebraska Extension NebGuide G00-1409-A, August 2000.
