Nationally, 75-80% of the death loss in calves occurs at birth or in the first two weeks of life. If the calf doesn't survive this period, there is not much we can do with it later.
Beyond this initial death loss, this critical period sets the stage for the rest of the calf's life. Studies show that - from birth to weaning - calves with insufficient antibodies from colostrum were three times more likely to become ill before weaning and five times more likely to die before weaning. In addition, calves that became sick the first 28 days of life were 30 lbs. lighter at weaning.
And, this increased sickness and loss of performance carried through the feedlot. It also affected the longevity of the females placed in the cowherd.
A few factors are at work here - a good breeding program to minimize hard births, proper pre-calving nutrition of the cow and ensuring the newborn calf quickly receives high-quality colostrum.
In the last three months of pregnancy, the fetus makes 75% of its growth, 40% in the last 40 days. This critical period comes immediately after the cow's requirements are the lowest of the reproductive cycle - the second trimester.
Protein and energy needs increase up to calving. At calving, the energy requirement doubles during lactation. According to the National Research Council, the energy needs of an 1,110lb. cow grow from 9.5 lbs./day to 19.9 lbs.
Lactation is the period when most producers often don't provide enough energy. The cow is generally not able to eat enough hay to provide the amount of energy required, although a lot of producers just feed hay at this time.
Feeds with a higher energy value should be supplemented at this time. I recommend ear corn, wheat midds or corn gluten, although others are available in some areas.
While ear corn, wheat midds or other starchy feeds are good sources of energy, grains should not be fed over 3% of the total feed or the efficiency is reduced.
The newborn calf needs 2-4 quarts of good-quality colostrum as soon as possible. The importance of timely colostrum intake - the calf's only source of antibodies and nutrition - can't be overstressed. The absorptive capacity of the small intestine for antibodies is reduced by 50% 12 hours after birth and is almost entirely gone by 24 hours.
A cow's first milk after calving contains twice the immunoglobulin content of subsequent milkings. Colostrum contains twice the fat and calcium and four times the protein as normal milk. It also has 2.5 times as much phosphorus and eight times the vitamin A level. As a result, it's critical to get the first milk into calves quickly.
Some other interesting notes on colostrum:
- Older cows have higher quality colostrum than first- or second-calf heifers. This colostrum should be used to supplement others as needed if saving it is possible.
- Calves that suckle the cow absorb more antibodies than those force-fed or that drink from a bottle. This doesn't mean, however, that we should not force-feed weak calves or those from first-calf heifers that may need supplemental colostrum.
Several good colostrum supplements on the market use bovine-derived antibodies. While these can't replace the mother's colostrum, they're better than none at all. I've used several, and they seem to provide some benefit.
- Immediately after birth, colostrum bypasses the rumen and goes directly to the small intestine where the lining allows absorption of immunoglobulins.
Unfortunately, the intestinal lining is not specific for immunoglobulins. Other protein molecules - and bacteria - may be absorbed into the blood stream. By feeding colostrum, absorptive sites can be saturated or used up, thereby reducing the chance of bacterial invasion.
- Calving difficulty or dystocia has a significant effect on the immunoglobulin level in calves. Antibody levels in calves from hard births are significantly lower compared to calves with normal births.
This may be due to the fact that dystocia calves usually have respiratory acidosis and are less efficient at absorbing colostral antibodies. In addition, these calves usually take longer to get up after a hard birth and may not nurse quickly, thereby compounding the problem.