– William P. Shulaw DVM MS, OSU Extension Veterinarian, Beef/Sheep
Absorption of antibodies from colostrum to the calf’s blood serum is extremely important to the health of newborn calves. Colostral antibodies only last for a few weeks but are crucial to getting the calf off to a good start. Timing of colostrum intake, amount fed, and antibody concentration of the colostrum determine the success of antibody absorption in the calf. For maximal absorption, colostrum must be consumed within 6 hours of birth. Preferably, it should be within just 1-2 hours and certainly before exposure to infectious agents in the environment. The calf’s ability to absorb colostral antibody diminishes rapidly after 12 hours and is essentially gone by 24 hours post calving.
Difficult birth, poor teat placement, and large teat size can hinder the calf’s ability to nurse. Antibodies in colostrum from beef cattle are usually present in higher concentration than in dairy cattle. However, calves should still receive at least a quart of high quality colostrum in the first few hours. High quality colostrum has high antibody concentration. Cows usually have more colostrum and it is of higher antibody content than heifers. In addition, there are breed to breed differences in the amount of colostrum produced.
In general high quality colostrum is thick, or syrupy, and yellow to tan colored. Colostrometers, instruments designed to measure antibody concentration, are available from supply houses if a producer wishes to test colostrum he might want to freeze for emergency supply.
Recently researchers at the Meat Animal Research Center in Nebraska studied the short and long term effect of colostral antibody absorption on performance in 263 crossbred calves in a beef herd. Blood samples were collected at 24 hours after birth and the plasma was measured for antibody concentration and plasma protein concentration (often used as an indirect measure of antibody concentration). Samples were categorized as adequate, marginal, or inadequate based on concentration. Sickness and death losses were monitored in the calves from birth throughout the feeding period.
Calves classed as inadequate colostral antibody absorption, as compared with those classed as adequate, were 6 times more likely to get sick in the first 28 days of life and 3 times more likely to get sick for the whole period of from birth to weaning. Sickness in the first 28 days was associated with a 32 pound lower expected weaning weight. These findings were not too surprising. However, the researchers also found that calves with inadequate plasma protein concentration at 24 hours after birth were 3 times more likely to have respiratory sickness while in the feedlot compared with calves classed as having adequate plasma antibody concentrations. It is not immediately clear how the relatively short lived colostral antibody could have an effect over such a long term, but it has been suggested that adequate absorption of high quality colostrum contributes to the development of a fully functional and competent immune system.
This work adds to the already significant body of research that points out the importance of management strategies that maximize calf vigor, enhance colostrum intake and absorption, and reduce exposure to pathogenic microorganisms. The events of the first few days of life are likely to have significant impact on the long term health and performance of calves and replacement heifers.