Pasteurized colostrum is better for the calf, researchers say
Raw milk? Not for calves
By Robert Tremblay
At the risk of offending readers by writing about colostrum again, I want to bring dairy farmers attention to some recent research on a method of pasteurizing colostrum that makes sense for smaller farms.
Pasteurizers come in two general types, continuous flow and batch pasteurizers. Batch pasteurizers heat one load of colostrum at a time, making it more convenient to use. A big problem is that most batch pasteurizers are too big to be really useful on small dairy farms that have only a few fresh cows at a time.
Pasteurizing colostrum destroys bacteria that always manage to get into colostrum. Killing the bacteria helps reduce the calfs risk of illness, especially from scours. Although you might expect that heating colostrum during pasteurization will damage the antibodies in colostrum, pasteurization actually increases the amount of antibodies that calves take into their blood after they are fed colostrum. Getting rid of the bacteria in colostrum through pasteurization improves how well calves absorb the antibodies that the cow puts into the colostrum.
Dairy Tech Inc., a company in Colorado, markets a small, single-use, disposable bag designed to be filled with fresh colostrum. The full bag is then floated in water or milk for 60 minutes at 60 C in a batch pasteurizer. The pasteurized colostrum can be fed directly (once it has cooled down), can be refrigerated or stored frozen. You can buy Dairy Tech Inc. products from distributors in Canada.
A recent research paper reported on how well the system worked by measuring how calves took up antibodies from colostrum that had been processed using the Dairy Tech system. Calves were fed a full bag within two hours of birth. Compared to unpasteurized colostrum, calves ended up with more antibodies in their blood if they were fed a bag of colostrum that was treated and cooled or was frozen then thawed before feeding. Tests also showed that bacteria in the colostrum in the bag were killed by the heat treatment. This looks like a useful system for pasteurizing small volumes of colostrum.
Another research paper reported on a study of Quebec dairy farms looking at opportunities to breed dairy heifers sooner. Experts recommend breeding heifers to freshen between 23 and 24.5 months of age. The actual freshening age amongst heifers on farms serviced by Valacta is 27 months. Delaying freshening adds to the cost of replacements.
The researchers believed that Quebec dairy farmers delayed breeding heifers because they were concerned heifers wouldnt be big enough at calving if they were bred too young. They wanted to determine if there was a way to measure heifers at the ideal age to start breeding them to freshen in the 23 to 24.5 month target zone (that is, when they are 15 months old). They compared the weight and height of heifers at 15 months and 24 months of age to the mature cow weights in each of the four major dairy breeds. They wanted to look at growth rates to find out when heifer size was good enough for heifers to be at the ideal weight at first calving.
The researchers concluded that the growth rate would justify safe breeding between 12.5 to 14.5 months in Holstein, Jersey and Brown Swiss heifers. But not for Ayrshire. The data suggested that breeding Ayrshire heifers would need to be delayed by about a month to make sure the heifers were at the optimal weight at first freshening. The researchers method of measuring weight and height of heifers could be used to identify an ideal time to start breeding for individual heifers and for an individual farm.
Dr. Robert Tremblay is a veterinarian for Boehringer-Ingelheim and lives near Guelph.
