Making sure calves get this first meal has been a frequent topic of discussion in cow-calf management, but less attention has been given to the factors that determine the quality of colostrum the dam will produce.
This process is termed “colostrogenesis” – the formation and concentration of colostrum in the cow. Optimizing the factors affecting colostrogenesis will result in healthier, more profitable calves.
Antibody stimulation of the cow
As a future dam grows from calfhood to maturity, every disease experience she has adds to her arsenal of antibody defense.
Each exposure to a disease-causing bacteria or virus (pathogen) stimulates the production of antibodies and increases her ability to fight off that disease.
The more immune exposure she has, the more protection she develops and the more protection she will transfer to her calf at birth through colostrum.
In the same way that natural exposure stimulates antibody production, vaccines given to the dam also will increase the level of the most important antibodies.
These vaccine-induced antibodies will improve the health and disease resistance of the dam, but they also will be part of the antibody arsenal that will be transferred to her offspring through colostrum.
In this way, we can immunize the dam prior to calving to increase her level of antibody production, improve the quality of the colostrum she produces and ultimately enhance the health and productivity of her calf.
To make this process of colostrogenesis work optimally for the calf, the timing of getting vaccine to the dam is very important.
Given too soon or too late, the vaccination may not result in the desired concentration of antibodies in the first milk she produces.
Vaccination: Timing is critical
When a cow is vaccinated or exposed to a particular disease for the first time, the pathogen must be recognized by the immune system as a foreign intruder.
Then it is transported to a lymph node where specialized white blood cells begin the process of antibody production against that particular pathogen.
The process takes about two weeks to get ramped up, so significant antibody production is usually evident 14 to 21 days after exposure or vaccination.
The second time this exposure takes place (such as with a booster dose of vaccine), the cellular machinery needed for antibody production is already in place and just needs to be reactivated, so the response time is much quicker. Within five to seven days of giving a booster, good antibody production is well underway.
Once high levels of antibodies are being produced by the dam, they circulate in the bloodstream and can be measured in serum samples.
Over time, antibody production slows down and serum levels begin to decline. The rate of that decline varies with each antigen or vaccine component.
When antibody levels drop below the protective level, it is time for another booster dose of vaccine to stimulate antibody production again.
These concepts of antibody stimulation and degradation are critical in the planning of vaccination protocols designed to increase colostral levels of antibody.
If a pregnant heifer or cow has never been exposed to the components of a particular vaccine before, there must be enough time allowed for initial stimulation of the immune system (primary response) and a booster dose (secondary response).
Getting two doses is required to get optimal antibody production from most killed vaccines. A three-week to six-week interval between the initial and booster doses is considered optimal.
A single annual booster is generally required in the subsequent years after the initial two-dose regimen. Some vaccines may require more frequent vaccination depending on their demonstrated duration of immunity.
Shifting antibodies from the bloodstream to colostrum
The movement of antibodies from the dam’s serum into the mammary gland begins five to six weeks prior to calving and ends a few days before calving.
If serum antibodies are high when this process begins, then ample supplies are available for transport and concentration in the udder.
So a good goal for optimizing colostrum is to have peak serum levels of antibody in the dam five to six weeks before calving.
To achieve that goal in the initial year of vaccination, the first dose of vaccine should be given about 10 to 12 weeks before calving and the booster dose three to six weeks later.
In subsequent years, one booster at seven weeks prior to calving will be ideal. If the dam is vaccinated closer to calving than these suggestions, she may not have adequate time to respond to the vaccine and reach her peak level of antibody production before colostrogenesis ends.
While the rise in antibody production for most vaccine components (antigens) is relatively predictable, the rate at which they decline is much more variable.
Some antigens may induce immunity that lasts several months, but others may last only a few weeks.
Therefore, it is important that vaccines intended to improve colostral immunity be given close enough to calving to be at or near peak concentrations.
If they are given too early, antibody levels may have declined below optimal levels before colostrogenesis begins.
Nutrition of the dam also will have a tremendous impact on colostrum quality. A good plane of nutrition is critical to ensure the cow will respond to vaccination.
If she is deficient in protein, energy, minerals or vitamins, she will not be capable of producing antibodies at the optimal level.
Colostrum is nature’s way of protecting young calves from disease until they are old enough to adequately protect themselves. Improving the quality of colostrum by vaccination of the dam can increase the protection available to the calf and thereby decrease sickness and death loss.
Understanding how antibodies are transferred from the serum of the dam to her colostrum is essential to effectively manage the timing of vaccination.
For the best possible results, vaccinate early enough so the dam has time to produce the desired antibodies, but not so early that you miss the peak of antibody production.
Consult with your veterinarian to develop a vaccination program that will take full advantage of the principles of colostrogenesis and optimize calf health through high-quality colostrum. 
Dr. Kevin Hill lives in Utah and can be contacted at (801) 540-2895. This article originally appeared in Progressive Dairyman.
