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Photo credit: Jacob Coon, NJAA/Angus Journal Photography Contest

How Cold Stress Affects Newborn Calves

By Heather Smith Thomas   |   Angus Beef Bulletin EXTRA
2/6/2017

Calves that are chilled soon after birth, without immediate assistance to warm and dry them and make sure they ingest colostrum in a timely manner, have poor survival rates. If a calf’s mouth gets cold before he suckles, he may not be able to get the teat in his mouth and suck and, therefore, he may not obtain crucial energy for keeping warm and the antibodies needed to protect against disease. Also, his ability to absorb the antibodies from colostrum diminishes as he becomes colder.

“The general consensus is that the cold calf does not have the energy for the cellular functions to work properly,” says veterinarian and University of Idaho Professor James England. “A cold calf has used up all his brown fat calories and what little bit of protein was left in the stomach (in the amniotic fluid) trying to keep warm. There isn’t enough energy for the cellular functions for transporting things back and forth in and out of the cells. The motility of the GI (gastrointestinal) tract is also impaired.”

There is a direct correlation between the suckle reflex and the uptake of antibodies. Studies have shown that suckling makes the calf several times more able to absorb the globulins than if colostrum is administered via tube, bypassing the suckle actions.

If you can get the calf to nurse the cow or suck a bottle of warm colostrum, this is best, but if he is too cold to suck, the next best thing is to give the colostrum via tube.

“In that situation you are trying to warm him up and get some energy into him so he can start generating his own body heat,” says England. The problem with a chilled calf is that he’s used up all his energy and has nothing left to operate on.

“The cellular functions are not working to transport fluids across membranes or move the intestines. Everything is shutting down. You have to get some energy into him, and even though colostrum is the best, regular milk is better than nothing,” says England. The calf will benefit from the nutrition and also the warmth. Warm milk can help warm him internally.

“The ideal situation is fresh, warm colostrum from the dam because this contains viable immune cells that help populate the immune system. The big drawback to using frozen colostrum (that you’ve thawed and warmed) is that it is devoid of these living cells. The white cells obtained directly from the mother help establish the newborn calf’s immune system,” he explains.

Colostrum has a much higher protein level and more digestible protein and fat than regular milk, and the proteins handle freezing quite well, but the white cells in fresh colostrum are more functional. “Some people also feel that these cells go into the lymph nodes of the calf and establish a population, but the general consensus is that these are functioning cells that can produce antibodies, eat up bacteria, and give additional protection beyond just the antibodies present in the colostrum,” says England.

Some of these stay in the gut awhile rather than being absorbed through the intestinal lining, and while they are in the gut, they can neutralize ingested pathogens and protect the calf from scours and other diseases early in life. “The key is to get colostrum into the calf as early as possible to give the calf a jump-start,” he says.

Editor’s Note: Heather Smith Thomas is a freelance writer and cattlewoman from Salmon, Idaho.