Last week in the Cow Calf Corner Newsletter we examined management practices that would reduce the risk of calf diarrhea (scours) by reducing the exposure of the calf to the pathogens that could cause the disease. This week we will look at methods of increasing the immune status of the baby calf so that when the calf comes in contact with the pathogens, he will have a much better chance of fending off the disease entity.
Make certain that calf gets passive immunity.
Baby calves are born without the presence of antibodies that fight disease organisms in the environment. They receive the antibodies via the first milk called colostrum that is provided (in most cases) by the mother. There are numerous factors that impact the success or failure of this passive transfer of immunity:
1. The amount of colostrum produced and available to the calf
a) First calf heifers must be in good body condition at calving to produce the maximum that they are genetically capable of producing. Calves born to thin heifers have been shown to have lowered levels of disease-fighting antibodies 24 hours after birth compared to calves born to heifers in good body condition (BCS=6).
b) The calf must be vigorous enough to find the teat and nurse within a short time after birth.
c) Calves that do not have access to good milking mothers need a commercial colostrum replacer or at least 2 quarts of properly thawed frozen colostrum from another cow.
2. Calves need the colostrum (or replacer) within 6 hours of birth
a) Calves born after a long difficult delivery will often be sluggish and slow to get up. Plus they may have respiratory acidosis which will impair the ability of the calf to absorb the large proteins (antibodies or immunoglobulins). Use calving ease bulls to reduce the risk of dystocia and assist those calves that help in a timely manner.
b) Feed sluggish calves the colostrum replacer or the natural colostrum from another source first. Do not feed them whole milk before the colostrum. Any milk product will speed up the process of intestinal closure (whereby the gut is losing its capability to absorb the large protein antibodies). Make certain colostrum or colostrum replacer is fed first. A second feeding of colostrum should follow within 12 hours of the first.
c) When purchasing colostrum substitutes know the difference between a “replacer” and a “supplement”. A colostrum “replacer” should contain 100 g of immunoglobulin per dose and research has shown can replace a feeding of natural colostrum from a cow. The colostrum supplements will contain much less than 100 g of immunoglobulin and will be used to supplement a poor-milking mother’s colostrum. Remember to give the supplement after the calf has consumed the natural colostrum first.
d) Timing is everything. Colostrum absorption by the intestine of the calf is declining rapidly after birth. Therefore it is critical that the baby calf receive a full dose of colostrum within the first 6 hours of life (the sooner the better).
If the management procedures discussed last week (reducing exposure to pathogens) and this week (increasing passive immunity in the calf) do not solve most of the scour problems on your operation, then visit with your local veterinarian about other options. One additional option to consider would be a pre-calving vaccine for the cows and pregnant heifers. This is given far enough before the calving season so that the colostrum in your cows will contain more antibodies designed to fight calf diarrhea organisms.
Calf diarrhea continues to be one of the most costly diseases in the beef industry. Losing a calf to scours is particularly painful at today’s weaned calf prices.