Calf immunity #3 – Optimizing absorption and achieving the benefits of colostrum
*Post contributed by Julia Hamann, D.V.M., Field Technical Specialist Diamond V
This is the last of the three-part series by Dr. Hamann. Check out the first two blog posts if you haven’t done so already!
Calf immunity #1 – The three components of immunity in the calf.
Calf immunity #2 – Colostrum and the calf’s gastrointestinal development
When feeding colostrum, its quality should not only be measured by IgG content (>50g/L) but low bacterial content (total coliform count <10,000 cfu/ml; total plate count <100,000 cfu/ml) as well. Most of the colostrum contamination occurs during the harvesting, storage, and re-heating process.
Colostrum harvest should occur within the first six hours after calving. Waiting longer could result in reduced IgG concentration of up to 50%. When milking fresh cows, technicans should follow the same cleanliness and milking procedure as the one for your saleable milk. To ensure a minimal contamination during the milking process, pay close attention to the cleanliness of colostrum collection buckets, milking units and all feeding equipement used for colostrum. Regularly, have your veterinarian or nutritionist evaluate the cleaning process as this is a common area for protocol drift.
Colostrum should be fed as soon as possible after collection or should be prepared for storage (cooled) if not fed within one hour following collection. Bacterial numbers in colostrum can double within 20 minutes if it is not cooled to 40 F (4 C) or lower. Store colostrum in containers labeled with harvest date, BRIX % and donor name/number. Colostrum can be refrigerated at 40 F (4 C) for up to 48 hours or frozen for up to one year.
If colostrum feeding or cooling cannot be done between the first hour after harvested, a mixture of potassium sorbate can be added at a rate of .3oz or 10 ml / gallon. This will help slow down colostrum’s bacteria growth. However, every effort should be made to cool or feeding colostrum as soon as possible!
If one of your goals is reduced transmission of diseases, such as BVD, M. Avium subsp. Paratuberculosis (Johne’s), E. coli, Salmonella spp., and Mycoplasma spp., consider heat treating colostrum at 140 F or 60 C, for 60 minutes.
To prevent damage of IgG during reheating, avoid water , avoid water temperatures greater than 140 F (60 C).
Consumption of adequate amounts of colostrum with a low bacteria count is essential to inferring immunity to the calf. Strive to feed at least 200 g of IgG (50g/L and 4 liters) with a standard plate count of < 100,000 cfu/ml as soon as possible but within 6 h of birth. Consider heat treatment of colostrum when there is risk of disease transfer from the milking herd. The development of the immune system in the calf progress slowly from conception to about 6 months of age. Feeding to support the immune system of calves during this period, combined with good management, will help optimize the overall health, growth, and productivity of your animals.
Note: See the December 12, 2022 blog post on the value of colostrum replacers by Dr. Adam Geiger.
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References available upon request.