Kentuckians already are deep in the throes of winter with a long stretch of below-freezing temperatures and bitter wind chills. Lingering periods of extreme cold put livestock at risk.

“Normal temperatures this time of year are supposed to be in the low-to-mid 40s, with lows dipping into the 20s,” said Matthew Dixon, meteorologist for the University of Kentucky (UK) College of Agriculture, Food and Environment. “Statewide temperatures from Dec. 27 through Jan. 2 averaged 18 degrees below normal, with sub-zero temperatures widespread on the morning of Jan. 2. The last time Kentucky had widespread sub-zero temperatures was in late winter of 2015.”

As arctic air builds, livestock become vulnerable to deteriorating outside conditions. Dixon said that over the next week and possibly into early February, the livestock cold stress index will hover in the danger and emergency categories for much of Kentucky.

“We want to remind livestock producers to take proper precautions to keep their animals safe during periods of cold stress,” said UK livestock specialist Jeff Lehmkuhler. “Don’t forget to keep yourself warm while caring for your animals avoid getting frostbite, especially when working on waterers to keep the water flowing.”

Livestock producers should ensure animals have adequate shelter, water, dry bedding, and feed to make it through this cold spell. Pet owners should bring pets indoors. Livestock specialists at UK said animals have a higher requirement for energy in the colder months, so producers should have high-quality forages and grains on hand to meet their needs.

“There’s always a risk for animals falling through the ice, as they search for water sources and end up walking out onto ice-covered ponds,” Lehmkuhler added.

The average horse, with a lower activity level, should eat between 1.5 and 2 percent of his body weight in feed per day to maintain its weight. Bob Coleman, PhD, UK equine specialist, said that feed requirement increases in the winter as the horse uses more calories to keep warm. He recommended providing extra hay and adding grain to the diet if forage supplies are not adequate. For mature horses at maintenance, a good quality legume-grass mixed hay should be adequate, while young, growing horses or broodmares in late gestation require a concentrate in their diets to meet the increased calorie needs due to the colder temperatures. Owners adding concentrate for the first time should do so gradually to prevent digestive upsets.

In addition, horses need shelter from the wind and precipitation. It’s also important for horses to have access to clean water to reduce the risk of impaction colic. Owners need to take extra time observing horses during cold snaps, as some will need extra attention.

Ambient temperatures can impact the amount of dry matter cattle eat, providing an opportunity to compensate for increased maintenance energy needs. Producers either need to increase their animals’ feed intake or increase the energy density of the diet by feeding higher-quality hay or adding more grain or fat to the grain mix, Lehmkuhler said.

He recommended that producers continue to monitor cows during the winter and make sure to maintain the animals’ body condition.

“Poor-quality hay may not provide adequate energy to maintain gestating cows that are entering the third trimester,” he said. “Consider having your hay tested to determine if you need to supplement during times of possible cold stress, especially for the enduring cold spells.”

He said to consider separating younger and thinner cows that might not have the same internal insulation as conditioned older cows and supplement them accordingly or offer them higher quality forage if available.

Coleman said horse owners can employ similar strategies and separate animals according to body condition score.

“Producers should move cows to fields with natural windbreaks or provide man-made windbreaks, which are not the same as a barn,” Lehmkuhler said. “Poorly managed barns combined with poor ventilation may actually hamper efforts to improve the environmental conditions. Remember, energy, or calories, are what animals really need. If the protein level in the forage is adequate, do not make supplement decisions based on protein level; rather purchase the most affordable calories.

The lower critical temperature (LCT) value for cattle is the lowest temperature or wind chill at which cattle require no additional energy to maintain core body temperature.

“As the temperature declines below this lower critical value, the maintenance energy value for the animal is increased to maintain core body temperature,” he said. “Animals maintain core body temperature by increasing their metabolism resulting in greater heat production, as well as other heat conservation strategies such as reducing blood flow to the extremities, shivering and increased intake.”

Lehmkuhler said several things can influence lower critical temperature value.

“Both external and internal insulation influences the LCT,” he said. “External insulation is basically the depth and thickness of the hair coat, condition of the hair coat and thickness of the hide. Thin-hided breeds such as dairy cattle tend to have a lower insulating factor than most beef breeds. The condition of the hair coat is extremely important as an external insulation barrier.”

The hair coat acts as insulation similar to home attic insulation that traps air, enhancing the insulating value. If the hair is wet and full of mud, air is excluded, reducing the insulating value and increasing heat loss from the skin to the environment. The hair coat’s density and if it is wet or dry impacts the wind chill temperatures at which cold stress is considered mild, moderate, or severe. As little as 0.1 inch of rain can immediately impact cold stress severity by matting the hair down reducing its insulating ability. Acclimation time, hide thickness, fat cover, and other factors will also influence the degree of cold stress that animals experience.

Extreme cold can have other detrimental impacts on livestock. Frostbite on bulls’ scrotums can reduce fertility for a couple months. Lehmkuhler recommended that all bulls have a breeding soundness exam conducted by a veterinarian prior to the breeding season, especially after a severely cold winter. Those calving during winter months should be prepared to warm calves if needed. Advanced planning to warm calves born in winter months can increase newborn survival.

Author: Aimee Nielson