WOOSTER, Ohio – Colder, icy, harsh winter weather means producers need to be aware of increased livestock energy requirements to ensure their animals are able to withstand the extreme outdoor conditions, according to a forage expert from Ohio State University’s College of Food, Agricultural, and Environmental Sciences.
Livestock metabolism
And even though the temperatures are forecast to rise slightly over the next few days, the rain that is predicted still means that producers need to be vigilant to ensure livestock are prepared for the weather, said Rory Lewandowski, agriculture and natural resources educator for the college’s outreach arm, Ohio State University Extension.
Cold temperatures, cold rains and muddy conditions can significantly increase the energy required by livestock metabolism to provide enough heat for the animal to maintain its body temperature, he said.
“All of these winter weather conditions can negatively impact livestock performance and increase the energy requirement of the animal,” Lewandowski said. “With the colder than average temperatures the region has experienced in December, it’s time for producers to start thinking about their livestock and their body condition.”
Extreme temperatures
Ohio’s weather rarely reaches the kinds of extreme temperatures or conditions where producers have to provide indoor shelter or supplement heat for livestock, Lewandowski said. But producers still need to evaluate their animals’ body conditions and whether the herd can go through adverse weather, he said.
“Livestock generally are given a body condition score on a scale of 1 to 9, where 1 is an emaciated animal with skin and bones and 9 rated as obese,” Lewandowski said. “We typically want to see cattle in a 5 to 6 body condition score going into winter. “Livestock in good body condition can call on fat reserves, but if they are in colder temperatures for longer periods, they need the increased energy content in rations to help them alleviate cold stress.”
Thermoneutral zone
Animals have a thermoneutral zone – a temperature range in which the animal is most comfortable, is not under any temperature stress, and that is considered optimum for body maintenance, health and animal performance. But when livestock experience cold stress below the lower boundary of that zone, they reach lower critical temperature (LCT) and the animal’s metabolism must increase in order for it to keep warm, he said.
“An increase in the metabolism of the animal, generally by shivering, in order to maintain body temperature is one method of how it deals with cold stress,” Lewandowski said. “In order for the animal to do this, it requires more energy either from stored fat or more energy intake in the animal’s diet. “Generally, energy intake must increase by 1 percent for each degree of cold below the LCT.”
Critical temperature
Lower critical temperature is influenced by an animal’s size, age, breed, nutrition, housing conditions, and hair coat or wool thickness. The thicker the hair coat or wool, the more the LCT decreases, he said. But, Lewandowski cautioned, with a wet hair coat, the lower critical temperature increases to 59 degrees for cattle, horses and goats regardless of how heavy its hair coat is because hair coats lose insulation ability when wet.
Sheep wool, however, is able to shed water, he said.
The lower critical temperature for beef cattle, dependent upon the development of the hair coat, is:
• Summer or wet: 59 degrees
• Fall: 45 degrees
• Winter average hair coat: 32 degrees
• Winter heavy hair coat: 18 degrees
The lower critical temperature for goats is generally considered 32 degrees and for sheep, 50 degrees, he said.
“For most livestock, it really is a matter of adapting to the weather,” he said. “Cattle will adapt to cold with a thicker coat if they have the feed source. “If the animal is in poor body condition or doesn’t have a good winter coat developed, producers may have to supplement it with higher energy feed and get it out of the wind to get the animal through the weather.”
Harsh winter weather
Another measure producers can take to care for livestock in harsh winter weather is to ensure the animals are blocked from the direct force of the wind to help protect them from wind chill, Lewandowski said.
Producers whose animals don’t have regular access to a barn can:
• Provide windbreak protection to reduce the effects of wind chill on energy requirements.
• Increase access to better quality forage. Livestock can increase intake to some extent under cold conditions and if forage is of good quality, then energy intake is also increased. With poorer quality forages, grinding to decrease particle size can allow more intake and increase digestibility.
• Limit feeding of corn, or use of a high-energy, non-starch feedstuff.
• Move livestock out of muddy conditions or take steps to reduce the mud by using a feeding pad.
