3 November 2022

5 minute read

By: Dr. David Prentice

Key Takeaways

• The administration of ample quantities of high-quality colostrum remains a critical component of animal health within the growing calf and throughout its life.
• The production of colostrum, called colostrogenesis, starts inside the cow several weeks before calving.
• Vaccinations help cows create more antibodies which can be transferred to the colostrum, thereby improving colostrum quality.

The old colostrum standards failed any colostrum with a Brix refractometer score of less than 24. That means that medium quality colostrum (Brix score of 18 to 24) was discarded. This colostrum can be supplemented to make it available for feeding, especially on second-day feedings. However, the ultimate goal is to have your cows making the best quality colostrum possible.

Colostrum quality, measured in immunoglobulin (IgG) levels, can range from 10 mg/ml to more than 150 mg/ml.¹ ² Any colostrum over 50 mg/ml or a Brix score of 22 or higher is considered high quality from an IgG standpoint, and it also should be free of blood and have a standard plate count, which indicates bacterial levels, of less than 50,000 colony forming units per ml.

The cow’s ability to make high-quality colostrum can depend on a number of factors, including breed, age of the cow, season of the year, the cow’s vaccination and disease history, and volume produced. Management factors also have an impact on colostrum quality before it’s harvested.

More IgG, Better Colostrum

The making of colostrum, or colostrogenesis, starts around five weeks prior to calving. This process includes transfer of immunoglobulins (predominately IgG1) from the maternal circulation into the mammary gland. The onset of colostrogenesis is complex, but a decrease in progesterone and increase in estrogen late in pregnancy are involved in the process.³ 

If higher quality colostrum contains more immunoglobulins, then it would make sense that cows with more immunoglobulins to transfer during colostrogenesis would equate to higher quality colostrum.

Cows develop antibodies (which are immunoglobulins) when exposed to pathogens. Therefore, if a cow is exposed to more disease pressure throughout her lifetime, more antibodies will be available to fight off the disease and for transfer to her calf through colostrum.

Vaccines Boost Antibodies

Vaccination plays two important roles: the creation of higher antibody levels for specific diseases that enhances resistance for the cow, and the development of more antibodies that can be transferred into the colostrum.

Antibodies persist for some time inside the cow with levels (measured as titers) dropping over time if the cow is not re-exposed to the specific antigen that produced the antibody. Therefore, booster vaccinations are used to re-expose the cow to bolster antibody production.

Vaccination timing is important to take full advantage of colostrogenesis. A cow doesn’t immediately start producing antibodies the second a vaccine is administered. The cow’s immune system must recognize the antigen, then specific B-cells must propagate and start making antibodies. That process takes around a week to get going, with significant antibody production occurring two or three weeks later.

Transfer of antibodies out of the blood stream into colostrum begins around five weeks prior to calving.⁴ With this timing in mind, producers should target vaccinations in heifers 8 to 16 weeks prior to calving with a booster 3 to 4 weeks later depending on the vaccine used (consult with your herd health veterinarian). In subsequent years, a booster at eight weeks prior to calving will suffice.

Watch for Scours

The health of your calves will indicate if your colostrum management is adequate. If your calves are relatively free from scours, it’s likely your calf team is doing a good job of both controlling pathogens and bolstering calf immunity with high-quality colostrum. Try not to confuse soft feces with scours. Early in life calves are on an all-liquid diet that can contain a lot of protein, and we should not expect firm feces with this kind of diet. Work with your herd health veterinarian to properly evaluate and diagnose disease versus nutritional scours.

Vaccinating cows prior to calving can help with passive immunity, including the potential to control scours-causing pathogens.

A 2021 study by Elanco showed the effectiveness of vaccinating cows with a scours vaccine.⁵ The study was carried out in a commercial herd where cows were vaccinated with a scours vaccine (Scour Bos® 9) 8 to 9 weeks prior to calving and again 4 weeks (Scour Bos 4) after the initial vaccination. Results showed that animals vaccinated with Scour Bos had significantly higher colostral antibody titers to Bovine Coronavirus and Bovine Rotavirus than unvaccinated animals. This means calves consuming this higher-antibody colostrum will have a greater chance of providing passive immunity and fighting off disease pressures after birth.

Supporting colostrum development can result in better quality colostrum and more adequate immune transfer to the calf. This can be achieved by creating adequate antibody levels to transfer to the colostrum during colostrogenesis. The proper harvest, storage and administration of the colostrum will help ensure calves have the appropriate resources to build immunity and fend off harmful pathogens.

The label contains complete use information, including cautions and warnings. Always read, understand and follow the label and use directions.

References:

1 Baumrucker, et al. Colostrogenesis: Mass transfer of immunoglobulin G1 into colostrum. J. Dairy Sci. 2010;93:3031–38.

2 Morrill KM, et al. Nationwide evaluation of quality and composition of colostrum on dairy farms in the United States. J. Dairy Sci. 2021;95:3997–4005.

3 Barrington GM, et al. Regulation of colostrogenesis in cattle. Livestock Production Science 2001;70:95–104.

4 Brandon MR, et al. The Mechanism of Transfer of Immunoglobulin Into Mammary Secretion of Cows Aust. J. Exp. Biol. Med. Sci. 1971;49:613-23.

5 Elanco Animal Health. Data on file.