Advances in Feeding Calves

by HENRY T. CONVERSE

SOMETHING like 5 million heifer calves are raised every year in the United States for replacements in dairy herds. Many males are also raised for herd sires. They all need tremendous amounts of milk for which, in times of shortage, they compete with humans.

For 75 years—at least for so long that the practice has gained the force of habit or tradition—authorities have recommended feeding the dairy calf whole milk for a month or longer before changing to skim milk. It has been recommended also that heifer calves that are to be kept for milkers be fed skim milk to 6 or 8 months of age, leastwise when there is plenty of it. Now and then somebody or other experimented and learned that dairy calves could be safely weaned from milk at 2 or 3 months, but few people paid them much heed, the suggestion being that revolutionary.

The accepted way of feeding new calves whole milk and older ones skim milk takes about 200 pounds of whole milk, besides the colostrum, and at least 1,900 pounds of skim milk for each calf. If the feeding of this whole milk could be dispensed with, at least 8 pounds of butter would be saved per calf, or 40 million pounds for the 5 million calves a year. If calves could be weaned from skim milk at 2 months of age, instead of at 6 months, there would be a further saving of 1,600 pounds or more of skim milk per calf, or 8 billion pounds in all.

In 1933, Edward B. Meigs and I started feeding some calves skim milk only ( except colostrum) at Beltsville. The first calves were fed skim milk properly supplemented with vitamin A, usually 2 to 4 teaspoonfuls of cod-liver oil starting usually on the fourth day—that is, after three full days on colostrum. The skim milk was continued to at least 6 months of age. Since then, 98 male calves have been reared by this schedule to 6 months or older, and 33 Jersey and Holstein females have been similarly reared to producing age. The growth rates of Holstein heifers at least have not been adversely affected. The Jersey heifers did not make quite such good gains as those receiving some whole milk, at least during the first few months. However, as we shall see later, we have obtained satisfactory results by feeding Jersey heifers without whole milk, except colostrum, and weaning them at 2 or 3 months, rather than at the usual age of 6 months.

To conserve milk for human use, a war-emergency experiment was begun at Beltsville in 1942 to find out how much earlier than 6 months calves could be weaned from milk. Calves were fed colostrum for about 3 days and then changed to skim milk with 2 to 4 teaspoonfuls of cod-liver oil daily. At first we weaned calves at 90 days and later at earlier ages. The calves were induced to eat generous amounts of a suitable grain mixture and hay as early as possible. The results of weaning calves from skim milk at 90 days were satisfactory.

Subsequently, 6 Jersey heifer calves were weaned from skim milk at 60 days, 10 Jersey steers were weaned at 60 days, and 18 at 45 days. Two Holstein heifer calves were weaned at 60 days, 2 at 45 days, and 3 at 30 days. Eight Holstein steers were weaned at 60 days, and 19 at 30 days. Ten crossbred steers were weaned at 60 days, and 9 at 30 days.

These 87 calves were fed no whole milk except colostrum and were weaned from skim milk at 2 months of age or earlier. In no case did we use dried skim milk, dried blood, tankage, fish meal, or any other high-protein feeds of animal origin that are usually used in dry calf starters.

The feeds other than milk fed to the calves in these milk-saving experiments were the same as those fed to milking cows in the nutrition herd at Beltsville. The grain mixtures comprised corn meal, wheat bran, and linseed oil meal--sometimes with and sometimes without soybean oil meal.

The hay was mostly good alfalfa hay. Timothy hay was fed in a few instances.

All calves weaned at 90 days and at 60 days survived. One of the 20 Jersey calves weaned at 45 days died when it was 49 days old. Two of the 13 crossbred calves weaned at 30 days died at 52 and 59 days of age, 1 of pneumonia and 1 of scours. Five of the 26 Holstein calves weaned at 30 days died at 35 to 57 days; 4 of the 5 cases had either pneumonia or scours.

We do not believe that early weaning caused the deaths. All these deaths occurred either just before or during the period when dependence for the control of calf scours was placed on the Wisconsin "scour prevention capsules," described later. Since these deaths, 15 Jersey males and 3 Holstein females weaned at 45 days of age have been reared without loss; and 14 Holstein males, 7 crossbred males, and 3 Holstein females weaned at 30 days have been reared without loss. Calves that safely reach 60 days of age usually survive.

It seems that the proper age to wean calves from milk is largely an economic question. If skim milk is plentiful and cheap, it might well be fed to 6 or 7 months of age, but if it is scarce or expensive, as compared to the cost of grain and hay, or if it is plentiful and is needed for hogs or poultry, calves may advantageously be weaned at quite early ages.

If calves are to be safely weaned from milk at 60 days, and particularly if they are to be weaned at 30 or 45 days, they must be trained to eat generous amounts of hay and grain before weaning. Grain and carefully selected hay should be available by the time the calf is 10 or 12 days old. Grain should be rubbed on the nose or placed in the mouth of the calf at convenient times, or a little may be dusted into the bucket just as the milk is nearly finished. The feed boxes should be carefully observed to be sure the calves are eating dry feed before weaning completely from milk.

A few calves in these experiments voluntarily ate as much as a half pound of grain at 20 days of age, and when a handful of grain was mixed into the milk three Holstein calves ate a pound and a half, and two others ate a pound at this early age. At 40 days, several Holsteins—some weaned from milk and some not yet weaned—voluntarily consumed from 1.25 pounds to 3 pounds of grain daily, and in several cases where grain was added to the milk the daily grain consumption was 2 to 3.5 pounds—in one case, 4 pounds. Jersey calves seldom eat more than half as much grain as Holstein calves, at least until after 40 days of age. These experiments indicate that, while Holstein calves can almost always be safely weaned by 45 days, and with extreme care at 30 days of age, Jersey calves should be allowed milk for an extra 15 days as a safety measure.