Colostrum conundrum

While natural colostrum from cows helps ensure your calves get enough natural immunity from their mothers, it can also transmit disease. Using commercial colostrum replacers could reduce disease transmission, but we need to know more about optimum feeding and their long-term effect on productivity.

To raise healthy, productive herd replacements, feeding good quality colostrum, or first milk, to your calves in the hours immediately after birth is essential. This management practice ensures the calf absorbs essential immune factors-known as immunoglobulins-produced by its mother and passed on through her colostrum.

In 1993, the U.S. National Dairy Heifer Evaluation Project concluded dairy farmers needed to improve colostrum management. The project reported 40 per cent of dairy heifers lacked an acceptable blood serum immunoglobulin G (IgG) level of more than 10 milligrams per millilitre of serum one to two days after they were born. This indicated that optimal immune protection wasn't being achieved and could leave calves vulnerable to pathogens.

Colostrum provides nutrients and immunoglobulins that benefit calves, but can also expose them to potentially harmful bacteria such as E. coli, Salmonella and Mycobacterium avium paratuberculosis, which causes Johne's disease. That has prompted some interest in products that can replace maternal colostrum. They could be used when colostrum is in short supply or completely replace it as a strategy to eliminate disease transmission via colostrum feeding.

Research has shown commercially prepared replacers should have a minimum 100 grams of IgG per dose, so calves achieve the desired blood serum level of 10 mg per mL. Commercial colostrum replacers should also have protein, minerals and vitamins included as standard ingredients.

University of Minnesota scientists recently published a study that compared a commercial replacer with maternal colostrum. They conducted their research on 12 commercial dairy farms in Minnesota and Wisconsin with herd sizes ranging from 190 to 1,550 cows.

The study was designed so each farm continued managing colostrum administration in its usual way. Heifer calves were divided into two groups on each farm: those receiving maternal colostrum and those receiving the replacer. On each farm the number of feedings and timing was the same for both groups.

However, normal practices on the farms differed in the number of colostrum feedings and amounts offered. Five of the 12 farms offered one 3.8-litre feeding of colostrum and then switched to milk replacer. Six offered two feedings of colostrum, one of 3.8 litres and a second feeding of 1.9 litres about eight hours later. One farm offered 1.9 litres of colostrum at each of two feedings.

The colostrum replacement was prepared according to manufacturer's directions and contained 125 grams of IgG per dose mixed in two litres of warm water. Calves on farms that offered a second feeding received a colostrum supplement containing 45 grams of IgG per dose mixed in 1.9 litres of milk replacer. Technicians visited each of the 12 farms and took blood samples from the calves between one and eight days of age, and collected colostrum samples.

Key findings the researchers reported were:

• poor overall colostrum cleanliness. Total plate count was 16.1 million and total coliform count was 2.7 million colony-forming units (CFU) per mL. These values are well above the recommended maximums of 100,000 and 10,000 CFU per mL for total plate count and total coliform count, respectively. These 12 farms had a lot of room for improvement in colo-strum handling;
• no difference in blood serum IgG concentrations in calves receiving either one or two feedings;
• serum IgG concentrations of 14.8 mg per mL in the calves receiving maternal colostrum versus 7.0 mg per mL in those receiving commercial colostrum replacer;
• calves not receiving adequate immune protection was 28 per cent for the maternal colostrum group and 93 per cent for the commercial replacement group;
• Pre-weaning death to 56 days of age was not statistically significant between the two groups at 10 to 12 per cent.

The big difference between the blood serum IgG concentrations in the two groups is related to dose received: maternal colostrum contains more IgG than the commercial replacer. This explains the high percentage of calves in the replacer group absorbing inadequate amounts of immunoglobulins.

The researchers are also following the same calves in a long-term study to examine Johne's disease transmission, longevity and production economics. It may have been possible for calves to consume some maternal colostrum since they were not separated from their mothers immediately, the researchers noted. This may not have significantly affected the calves' immune status, but may present problems for assessing their future health status.

Further on-farm evaluation of colostrum cleanliness and amounts of commercial colostrum replacer needed to ensure proper feeding are necessary. However, this study showed maternal colostrum is still the gold standard. The long-term study will offer valuable information for use of commercial colostrum replacer in terms of Johne's disease and production economics.

Table 1: Study averages comparing calves that received maternal (239 calves or commercial replacement (218 calves) colostrum

*FPT: Failure of passive transfer, defined as the failure of a calf to absorb sufficient immunoglobulins from colostrum to achieve a level of 10 milligrams IgG per millilitre in blood serum.

Reference:

Swan, H., S. Godden, R. Bey, S. Wells, J. Fetrow, and H. Chester-Jones. 2007. Passive transfer of Immunoglobulin G and preweaning health in Holstein calves fed a commercial colostrum replacer. J. Dairy Sci. 90: 3857-3866.

This article first appeared in the Ruminations column of The Milk Producer Magazine, November, 2007.