Scientist Advises on Feeding Cows in Cold

US - Many cow/calf producers are not aware that cold weather brings added nutritional needs for cattle. Or, if they recognize that their cattle are stressed, they aren't sure how - or what - they should do to offset it.
calendar icon 18 December 2008
clock icon 2 minute read

Cold stress occurs when animals are exposed to weather conditions which put them below their lower critical temperature, says James B. Neel, Extension Beef Cattle Specialist, University of Tennessee. For cattle with a dry winter coat, the lower critical temperature is 32 F. If the coat is extra heavy, that number drops to 18 F. If the normal coat is wet, however, the lower critical temperature may become 60 F.

When the environment results in an effective temperature below the animal's lower critical temperature, the animal must increase heat production to maintain a constant body temperature. To produce more heat, the animal either must receive an increase in energy from the ration or draw on body stores. To compensate for the energy deficit created by the cold stress, follow this rule of thumb: Increase the amount of feed 1 per cent for each degree of cold stress. If a wind chill is present, use that temperature. Keeping hay in front of cattle will not take care of the problem.

If the hay is good (cut before it matured and baled before it was rained on), cattle will probably make it through cold weather in good condition. If hay quality is poor, the cattle may be in trouble. A 1,200 pound cow, in good body condition, needs a ration that has a minimum total digestible nutrient (TDN) value of 50 per cent and crude protein (CP) value of 8 per cent under neutral environmental conditions. The TDN value is often used to indicate the energy level of a feed. Concentrates have higher TDN values than forages, but do not generate as much heat. In comparison, shelled corn has a TDN of 90 per cent and soybean hulls, 80 per cent. If hay falls below the 50 per cent TDN minimum, producers should consider supplementing with an energy-dense feed.

If protein levels are too low, rumen microbes cannot efficiently digest fiber. In that case, adding supplemental protein can increase hay consumption and digestion. High-protein feedstuffs include soybean meal (49 per cent CP), cottonseed meal (41 per cent CP) and corn gluten feed (19 per cent CP). If both energy and protein are low, the supplement should contain a balance of both.

Provide some type of shelter such as woods, hills or buildings to protect cattle from winds. Reduce mud in and around feeding areas. Cold mud on cattle draws on their energy stores and body temperature, especially in young calves. Monitor weather reports and make adjustments in feeding 2 to 3 days before the weather front hits the area.

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