How Do Newborn Baby Animals Stay Warm?
My family enjoyed the holiday season. My wife loves looking at all the lights and decorations that are put up in the yards each winter during Christmas and the New Year. I always take an interest in the livestock arrangements placed around nativity scenes at the local churches and homes at Christmas time. There is always the little newborn baby lying out in the cold on a little bit of hay. It just looks miserable! Then I think about all the animals that are born in barns all the time.
Have you ever wondered about the ability of baby calves, lambs, kids, or deer to stay warm when born in the winter months? They come into the world wet and lay on cold, sometimes wet, grassy fields. Some lay in damp hay or sawdust on the floor of a barn. They get up, fall down, get up again, and stumble around with no hands to guide them to their mother’s milk. Their mother has only her tongue to lick them dry. She has no “swaddling” clothes in which to wrap her baby.
So why don’t these baby animals get sick and die? What are the mechanisms that keep these little ones warm in the first hours and days of life? Scientists have noted that the calf, lamb, kid, and deer tend not to shiver at all the first days after birth. Based on research, scientists have found that these young ones have large amounts of “brown fat” rather than “white fat.” Brown fat is uniquely able to rapidly produce large amounts of heat through the activation of proteins in the fat. These proteins are stimulated by the nervous system, which is affected by the cold around the animal. This heat is produced by a chemical reaction and has been measured at 300 watts/kg compared to white fat producing only 1 watt/kg.
The white fat can be compared to a light bulb in our house which produces light and a small amount of heat. Brown fat is like a heat lamp used in the bathroom to keep us warm when stepping out of the shower. Both of these are lights, but one produces much more heat than the other. The question is, “How does brown fat get into the baby?” The mama, of course!
The farmer needs to provide the right nutrients for the mama cow to be able to provide good amounts of fat in her baby calf. Proper cow nutritional management means monitoring the cow during pregnancy. A farmer does this by looking at the cow’s ribs and other places where fat is stored during pregnancy. If a cow has 3 or less ribs showing, he can assume the pregnant cow will have the nutrients necessary to produce a healthy calf.
In order for scientists and farmers to communicate this, a scoring system has been developed. A cow with 3 ribs showing would score a 5 on a scale of 1-9. Any cow that has more ribs showing is scored lower. Cows scoring less than 5 (showing more than 3 ribs) will produce less colostrum and less milk. Calves born to these thin cows will be slower to stand and slower to nurse which causes lower antibody protection (which is another story). The calves of thin cows will tend to have diarrhea and have lower brown fat reserves in their bodies.
So as you sit by your fire in your warm house and think about babies born in the barn, remember baby animals have a wonderful mechanism to stay warm at birth. Good cattlemen watch their animals closely all year around to provide correct nutrition and care.
The N.C. Cooperative Extension Livestock Agent in Lincoln County, Glenn Detweiler, and all N.C. Cooperative Extension Agents welcome any questions or information you may need on livestock, crops, gardening, or yards. Also, if you want children or youth to develop skills in these areas many clubs and projects are taking place, for example, a dairy steer project is starting this week for youth. So, give us a call at 704-736-8461.