Veterinary experts pretty much agree that getting enough colostrum soon after birth goes a long way to keeping calves healthy and giving them a good start. There are recommendations on ways to measure whether calves have enough colostrum. A few methods are easy enough that they can be used routinely on dairy farms. Farmers can use the same tools they use to check the quality of colostrum before they feed it and to test a calf’s blood to see if it likely took enough protective antibody into its body.
With the consistent emphasis on the importance of good colostrum management, most people expect overall calf health to improve. When U.S. researchers looked at data from their national surveys of dairy calf health, they found that was only partly true. They did find that death losses (mortality) did go down between 1991 and 2014 but that the average number of calves that were treated (morbidity) did not decrease the same way. That was true even though there was good evidence that dairy farmers were doing a much better job meeting the recommended colostrum feeding targets.
Colostrum feeding recommendations were based on how much antibody from colostrum needed to end up in the calf’s blood. You’d measure that on the day after it was born or during the first week of life. Because it is not easy to measure antibody in blood, the recommendations were to check the total protein in the calf’s blood. Total protein is closely related to the amount of antibody in a newborn calf’s blood. The idea was that most calves should have a total protein of or a BRIX reading of 8.4%.
If improved colostrum management contributed to lower death losses in dairy calves but didn’t lower the number of calves that got sick and need to be treated, maybe we need to re-examine colostrum recommendations. That is what happened recently. A group of experts got together to see if adjusting the targets for successful colostrum management would likely lead to better health in dairy calves. Part of that process was to adjust the recommendations but make sure the new recommendations could be achieved on actual farms.
The group was able to use data from thousands of calves on more than 103 U.S. dairy farms. The basic idea was to discern if there was a better alternative to using the simple pass/fail system used now. The group did consider whether simply increasing the BRIX reading used to make the pass/fail decision would be enough to improve health. In the end, they decided that the best system was to set more than one pass/fail point.
The committee proposed that farmers and veterinarians use four ‘levels’ for assessing passive transfer: Excellent, Good, Fair and Poor. They created the different levels by looking at the amount of antibody in the calf’s blood but then offered advice on what values to use on farms. If farmers or veterinarians used total protein (TP), the calves with more than 6.2 grams per decilitre (g/dL) would be excellent; calves between 5.8 and 6.1 would be Good; calves between 5.1 and 5.7 would be Fair; and calves below 5.1 would be Poor.
If you tested the calf using a BRIX, the committee suggested that readings of more than 9.4 % would be Excellent; between 8.9 % and 9.3 % would be Good; between 8.1 % and 8.8 % would be Fair and below 8.1 % would be Poor.
Now everybody knows that nothing is perfect in the real world so not every calf will score Excellent. The committee suggested that farms set targets of more than 40 % of calves rating as Excellent, about 30 % should be Good, only about 20 % should Fair and fewer than 10 % Poor. Those targets were achieved by many of the farms used to create the new guidelines.
These guidelines will be really helpful for farms that want to improve colostrum management and calf health.
Dr. Robert Tremblay is a veterinarian for Boehringer-Ingelheim and lives near Guelph.
