Immunity depends on feeding dam’s milk fast to newborn calves


It is the Red Bull power drink for calves, and then some.
We tend to take colostrum for granted, not fully appreciating how amazing this first milk is.
Without colostrum, a calf may as well have a big bulls-eye target on its side, beckoning every germ on the farm to give it its best shot.
There will be few, if any, antibodies to fight those germs off.
Calves are born with zero immunity. They will start producing their own antibodies, but can’t produce enough fast enough for the first few weeks of life.
Passive immunity. The cow spends the last couple weeks before birth preparing to provide the calf with passive immunity (antibodies) that will protect her. This passive transfer of immunity is accomplished through the cow’s colostrum.
During the last couple weeks of gestation, the cow starts sending antibodies, specifically Immunoglobulin G (IgG), from her blood into the colostrum that is being formed in her udder.
She sends so much IgG to the colostrum that her own blood serum IgG levels will drop.
IgG is the big player in the antibody game. Typically, more than 80 percent of the antibodies in the colostrum are IgGs. These are absorbed into the calf’s lymph system through the small intestine.
Two other types of antibodies, IgA and IgM are present in much smaller amounts. IgAs stay in the small intestine as a first line of defense, and IgMs hang out in the blood ready to fight off septicemias.
Your part. Think of it as a race against time and germs. Either you get to the calf’s gut first with the antibodies, or the bad guys – dirt, crud, pathogens – do.
If the bad guys win, it will be an uphill battle to keep the calf alive and healthy. If you and the antibodies win, the calf’s and the calf feeder’s life will be a lot easier.
The clock starts ticking the moment the calf hits the ground. For the first 24 hours, antibodies can pass through the intestinal wall. However, this “open door” starts closing within hours of birth.
You really need to get calves the first hit of colostrum within two hours of birth, followed by another within 12 hours. After 24 hours, the gut has closed the door to large molecules such as the antibodies.
If the calf has not received and absorbed enough antibodies by then, the options are limited to hope, luck, prayer and/or a blood transfusion.
Spotless management in every other way might help, too. There are a number of reasons a calf can have a failure of passive transfer. The obvious ones are not enough colostrum, not getting it soon enough, poor quality colostrum and/or contaminated colostrum.
All of these reasons are fixable before the next calf comes along.
Tough births. We know now that calves who came into the world the hard way are more likely to experience a failure of passive transfer.
The reasons aren’t entirely clear, but after a difficult calving, they may be acidotic and have difficulty regulating their body temperature for the first 48 hours of life.
Absorption of antibodies is impaired compared to calves that had an easier birth. To help these calves, you need to get enough high-quality, clean colostrum into them as quickly as possible.
Multiple, smaller feedings three to six hours apart even out the flow of colostrum through the digestive system and are helpful for compromised calves.
Feeding time. How much is enough? Obviously, more should be given to Holsteins than Jerseys. Holsteins should get up to a gallon in their first feeding and another one-half to one gallon within 12 hours. A Jersey can handle about half that.
First choice is always to feed with a bottle. When a calf sucks, the esophageal groove closes and the colostrum goes directly into the abomasum. It is a short trip from there to the small intestine.
If you have to tube a calf, the colostrum goes into the rumen and can take a couple extra hours to get to the small intestines.
If the calf is too weak or ornery or stupid (full disclosure!) to suck, then a careful tube feeding is essential.
Hurry up! Caring for newborns is a race; a race against time and germs.
The dam provides the tool, a bovine “Red Bull” drink in a calf bottle, but it is up to us to get that drink into the calf and wipe that target off her side.
(The author is the northeast Ohio district dairy specialist with OSU Extension. Send comments or questions in care of Farm and Dairy, P.O. Box 38, Salem, OH 44460.)


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