Raising Healthy Calves in Cold Weather

Calves’ energy intake is the sum of the starter and milk/milk replacer consumed. So you might ask, “can’t the calves just eat more starter to compensate?”  Yes, they can, if they’re ruminating and if they’re eating one to two pounds of grain per day. But most calves less than two weeks old are not. Milk or milk replacer is often the sole source of energy for pre-ruminating calves, and a significant source for the remainder of energy needed by ruminating calves.

A newborn calf’s thermo-neutral temperature is about 50 to 80 degrees. By a month old, a calf’s lower critical temperature is more like 32 degrees. Depending on a number of factors, newborn calves are neither heating nor cooling themselves somewhere between 50 and 80 degrees. Some of these variables are:

Calves may need one-third more energy when temperatures drop from 55 degrees to 25 degrees. Realize, though, that the extra energy required is not used or available for growth or support of a developing immune system – the extra energy is diverted from weight gain and growth to maintenance of core body temperature. Some researchers estimate that 20 percent more energy yet is required for immune system development.

On an as-fed basis, a typical all-milk protein milk replacer will contain:

Why not double for a 20 percent fat product versus a 10 percent fat product? The difference is the energy displacement of fat versus lactose.

Fat supplements add energy, but feeding over 0.25 pounds of fat supplement per day often results in reduced starter intake – counterproductive!

Calves will take off muscle as well as fat if they are below their maintenance energy requirements. This can be caused by temperature alone, but is exacerbated by the environmental factors listed above, plus:

Research has shown that calves will maintain health and acceptable weight gain with a 50 percent higher milk replacer feeding rate during cold weather.