Weather this week is likely to pose challenges for feedlot operators and cattle producers.
Above-average rain fall across the state has created greater humidity and has deteriorated pen conditions, according to a press release from Randy Saner, Extension educator in North Platte. Weather forecasts predict above-average temperatures this week, “creating heat indexes that will reach critical heat stress emergency,” Saner said.
Thursday and Friday will be critical days across the state as little cloud cover is expected and wind speeds will be at or below 10 mph across the region, he said.
Saner recommends that livestock producers take these precautions:
» Utilize empty pen space to allow cattle greater room and access to water.
» Supplemental water tanks may be needed to ensure ample water intake to those animals exhibiting signs of stress.
» Consider placing cattle in pens where cattle can be away from windbreaks to catch what little wind the area may have.
Livestock producers can find steps to take during high heat days at BQA.unl.edu/heat-stress-resources.
Dr. Terry Mader, UNL professor emeritus, provided insight on heat stress and steps to take in the following webinar at beef.unl.edu/webinar/heat-stress-mitigation-feedlot-cattle.
Additional steps may be considered. Saner said work by Dr. Robbi Pritchard has shown that manipulating the amount of feed delivered the day before the highest heat index will help cattle keep their internal temperatures lower.
“By cutting the morning feeding by 25% we were able to keep cattle cooler in the hottest part of the day,” Prichard said. “The cattle recovered sooner and ate their feeding in the afternoon and had less heat load throughout the night.”
The heat of fermentation, digestion and metabolism of the feed consumed in the morning become critical on the day that cattle hit the heat stress limit.
“If we take that feed away before cattle back away from feed we greatly improve the survival of the cattle,” Saner said.
To do this, Saner said, producers should watch the heat index forecasts closely. For example, cattle may seem fine one day, but if there is not enough night cooling (hours below 70 degrees with wind) and the heat index will remain high the next day, one should consider taking away some of the morning feed delivery. This lowers the heat load midafternoon, which reduces the amount of heat that must be shed overnight.
“We typically reduce the morning feed delivery by 25% today, and that may increase to a 50% reduction the morning of high heat index, depending on conditions and cattle status,” Prichard said, “If we wait for cattle to refuse feed, it is too late.”
Afternoon deliveries are not adjusted. If the cattle eat afternoon deliveries, that feed generates heat during the night when there are lower temperatures and less solar gain, lowering the total heat load accumulating in the body.
When asked about increasing roughage in the diet, Pritchard said, “A move to higher roughage diets is not recommended. Under normal conditions cattle will react to a diet change by increasing meal size and forage has proportionally higher heat of fermentation than concentrates. Both of these factors will exacerbate the heat load problem. Staying with the current diet and controlling intake works best for us.”
The Nebraska State Climate Office’s Nebraska Mesonet site calculates a cattle comfort index score. Stonie Cooper, manager of the Nebraska Mesonet, reported that cattle comfort indexes will reach close to 120 in parts of the state. “Precautions should be taken to provide additional care to not only cattle on feed but to all animals across the state,” Cooper said.
Additional information on heat stress can be found at beef.UNL.edu.