LEXINGTON, Ky. – It took longer for winter to truly arrive this year, but it’s making up for lost time with a blast of measurable snow across much of Kentucky. With significant accumulations and temperatures dipping into the single digits and low- to mid-teens, conditions have pushed the livestock cold stress index into the emergency category.
“The combination of cold air and wind create wind chills that cause dangerous and emergency-category periods of livestock cold stress,” said Matt Dixon, agricultural meteorologist for the University of Kentucky College of Agriculture, Food and Environment’s Ag Weather Center. “The wind chills for the overnight of Jan. 6 into Jan. 7 (were) near or below zero in many areas.”
Livestock producers should make sure animals have adequate shelter, water, dry bedding and feed to make it through cold periods. Pet owners should bring pets indoors. Animals have a higher requirement for energy in the colder months, which means they need high-quality grains and forages.
“The average horse, with a lower activity level, should eat between 1.5 percent and 2 percent of its body weight in feed per day to maintain its weight,” said UK equine specialist Bob Coleman. “That feed requirement goes up in the winter, as horses use more calories to keep warm.”
He recommended providing extra hay and making sure horses have shelter to get out of windy, damp weather. Horses must have access to clean, unfrozen water. Coleman said to check often to make sure water sources are open. A decrease in water intake affects dry matter intake.
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, UK beef specialist Jeff Lehmkuhler said.
Lehmkuhler recommended that producers continue to monitor cows during the wintertime and make sure to maintain their body condition.
“Poor quality hay may not provide adequate energy to maintain gestating cows that are entering the third trimester,” he said. “Consider having the hay tested to determine if you need to supplement during times of possible cold stress, especially for the enduring cold spells.”
Producers should consider separating younger and thinner cows that may not have the same internal insulation as conditioned older cows and supplement them accordingly or offer them higher quality forage if available. Coleman said equine 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 suggested. “Poorly managed barns combined with poor ventilation may actually hamper efforts to improve the environmental conditions. Energy or calories are critical. If the protein level in the forage is adequate, do not make supplement decisions based on protein level; rather purchase the most affordable calories. Stay warm and keep the waterers flowing.”
The hair coat acts like home attic insulation – trapping air and enhancing the insulating value. Wet, muddy hair reduces insulating value and increases heat loss. 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.
The lower critical temperature value for cattle is the lowest temperature or wind chill at which no additional energy is required 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 both external and internal insulation influences the lower critical temperature.
External insulation is the depth and thickness of the hair coat, condition of the hair coat and thickness of the hide. Thin-hided breeds such as some dairy cattle tend to have a lower insulating factor than thick-hided breeds like Herefords. The condition of the hair coat is extremely important as an external insulation barrier.
Dairy producers should make sure cows’ teats are dry before turning animals out when temperatures fall below 25 degrees Fahrenheit.
“If you turn out an animal with a wet udder or teats, frostbite is almost a certainty,” said Michelle Arnold, UK extension veterinarian. “Treat signs of frostbite immediately, since damage to the teat ends can quickly lead to damage of the keratin seal and that can allow mastitis-causing bacteria to enter the udder.”
The key is to give animals a draft-free place to get out of the wind during extreme wind chill conditions. “The challenge is to make that space available and still provide enough ventilation to allow fresh air to circulate,” she said.
Dry bedding is also very important. If cows, goats or sheep lie in wet bedding, frostbite is a big risk. Producers also need to make sure the animals’ hair coats are kept dry and as clean as possible.