As the chilly weather sets in, producers know it won't be long before calves start to arrive. But extremely cold winter nights can threaten calves' well-being, and reviving newborns from cold stress is a serious task.
But what's the best re-warming method? Oklahoma State University Emeritus Extension Livestock Marketing Specialist Glenn Selk has some options, based on a comparison by Canadian animal scientists.
The researchers measured rectal temperature and heat production in 19 newborn calves during hypothermia, along with recovery when four different means of assistance were provided, comparing each.
Extreme hypothermia of about 86 degrees Fahrenheit rectal temperature was found in the calves before re-warming was initiated.
Re-warming in warm air environment. Calves were re-warmed in a 68 to 77 degrees air environment where thermal assistance was provided by added thermal insulation or by supplemental heat from infrared lamps.
Re-warming by immersion in warm (100 degree) water. Calves were re-warmed by immersion in warm water at 100 degrees, with or without a 40cc drench of 20% ethanol in water.
Researchers found the time required to lift a rectal temperature of 86 degrees F to normal body temperature of 103 degrees F was: 90 minutes for calves with added insulation, 92 minutes for calves under heat lamps, 59 minutes for calves in warm water and 63 minutes for calves in warm water plus an ethanol treatment.
By immersion of extremely cold stressed calves in warm water, normal body temperature was regained most rapidly and with minimal metabolic effort, the research found. No advantage was evident from oral administration of ethanol.
Total heat production from body stores during recovery, however, was nearly twice as great for the calves with added insulation or exposed to the heat lamps than for calves in warm water and in warm water plus an oral drench of ethanol, respectively.
Selk reminds producers that if a calf is re-warmed using warm water, do not forget to support the head above the water to avoid drowning. Also, dry the calf before returning it to the weather outside.
Warming the calf by drying with a gunny sack and then putting them under a heat lamp or in the floorboard of the pickup cab – both time-honored drying methods – will still be helpful to many calves born in cold weather.
These methods may not re-warm the calf as quickly or be quite as effective for the severe case of hypothermia, Selk says.
Original research cited was conducted by Robinson and Young from the Univ. of Alberta in the 1988 Journal of Animal Science.