Cattle and cold temperatures

The recent cold snap across the province has been a concern for humans and livestock. Barry Yaremcio, beef and forage specialist at the Alberta Ag-Info Centre, looks at ways to lessen the stress on cattle created by cold temperatures.
Yaremcio says to start by adjusting rations to meet requirements, as there is a limit to the amount of heat cattle can produce by digesting feed.

“You can’t just let them pick extra hay or pick straw off the bedding pack to make up the intake differential. Straw is a low protein, high fibre, low energy feed that takes a long time for the animals to digest. If they eat extra straw, the total protein content in the ration goes down, and bacteria can’t digest the fibre. In reality, their feed intake in reality may drop two, three or four pounds a day, and you’re just going backwards by letting them have the extra straw.”

“I am referring specifically to cattle, but these principles apply to other animals staying outside right now,” he says. “Cattle can stay warm down to -20 C without wind chill, and the heat from digestion when they consume their feed will keep them warm.”

It is a natural response for animals to eat more feed when it gets cold. Provide extra hay or silage but extra grain is needed as well. Feed intake changes when the temperature drops below -20 C.

“At -30 C, increase grain intake by an extra two lb. of grain per head per day over and above what was previously being fed at -20 C. If temperatures drop to -40 C, four lb. of extra grain per head per day needs to be added,” says Yaremcio.

Thin animals get colder faster than those that are in good shape, as they do not have the fat layer that provides insulation.

“That four lb. of additional grain during the cold weather might have to be stepped up to six or seven lb. to maintain their body weight or hopefully get them to gain a little bit,” explains Yaremcio. “it is difficult to do in cold weather but it is a possibility. Judge accordingly, and watch the manure. If the manure looks normal, you can see that your ration is providing an adequate amount of protein.”

He adds that providing shelter behind a wind fence and providing a lot of bedding helps reduce the amount of energy needed for an animal to keep warm. If possible, move the thinnest animals into a barn to protect them from the weather.

“A cow laying on snow could potentially lose 25 per cent of her body heat, especially if that snow is wet or dirty.”

The implications of not lessening the stress from cold temperatures could compromise the animals, says Yaremcio. “During cold weather, cows can lose anywhere between one to three pounds a day. If the cow is losing weight in the last trimester of pregnancy, it is possible there will be more calving difficulties because the cow’s muscles are not as strong as they should be. Nutrient requirements for a lactating cow increase by 25 per cent compared to one in late pregnancy. That is when the large weight losses can occur.”

“Colostrum quantity – and possibly quality - will be compromised if the cow is losing weight prior to calving. The calf may not be as healthy, and get up rapidly after birth if the cow has lost weight in the cold weather. You could have a little more problems with disease. A cow with very little fat reserve will not be able to produce as much milk as one that is in good condition. The growth rate of the calf is probably going to be reduced as well. Long term, if that cow stays skinny all the way through lactation, it can reduce reproductive efficiency by 20 to 30 per cent.”