I don’t know about you, but I have not enjoyed the recent 100 degree heat wave. Most likely, cattle in the area have not enjoyed it either. Cattle have a temperature comfort zone that ranges from zero to seventy-five degrees Fahrenheit. When the temperature rises above 75 degrees, cattle begin to experience levels of heat stress. They can generally cope with this heat stress until the temperature reaches 90 degrees. After that many cattle begin to exhibit noticeable signs of heat stress. One of these signs is for the cattle to reduce consumption of feedstuffs. There are some management tactics that have been used in an effort to maintain feed intake.
Maintain an ample water supply. Cattle will drink more water when they are suffering from heat stress. The extra water consumption helps the animal dissipate body heat, through sweating and urination. It is important to make certain that cattle have adequate mineral during these times, as the increased urination removes minerals from the body. Feedlot cattle should have at least three linear inches of water trough space per animal in the pen, during periods of extreme heat. Some producers will add extra water tanks in the pens. Others have lined feed bunks with plastic and filled them with water. The water should be fresh and clean. This will promote dinking. Cattle do not like the taste of stale, dirty water. Also, it is beneficial to provide cool water. The rumen temperature can be influenced by the temperature of water that is consumed. In turn, the animal’s blood temperature reflects the rumen temperature and signals the nerve centers in the brain that control feed consumption. Therefore, the consumption of cool water can increase feed consumption.
Another way to maintain feed intake during hot periods is to add and adjust feeding times. Fresh feed is generally more palatable to cattle than feed that has been in the bunk for a while. This is especially true when silage or fats are included in the ration. So by feeding less feed, more times per day you can increase the amount of time that available feed is fresh. Another feed-time factor relates to temperature patterns during the day. During hot periods, cattle will eat more when the daily temperature is decreasing. So if you feed 70 percent of the day’s total ration between two and four hours following the peak heat of the day, cattle are more likely to maintain intake. Research suggests that this late day feeding schedule can help prevent sub-clinical acidosis during heat waves.
In theory, digestibility and quality of feedstuffs can also be factors in maintaining feed intake during excessively warm periods. Producers often refer to “hot” and “cool” feeds. Typically, hot feeds refer to high energy items, like corn; while cool feeds are low energy, such as grass hay or straw. Many feeders don’t like to back cattle down from hot rations, once they have stepped the animals up to a new level. However, research suggests that lowering the energy level of a ration, or switching to a storm ration, during periods of heat stress can reduce the animal’s metabolic heat load. On the other side of this argument, concentrates like corn are far more digestible than the cool feeds. This infers that the heat of digestion that is created when feedstuffs are broke down is less significant when cattle are consuming grain when compared to forage digestion.
These are just a few thoughts to consider when feeding cattle during heat stressed times. There are many other management practices that can help your livestock in hot weather. I hope that you find this article helpful and feel free to contact your local Colorado State University Extension office if you have questions about this.