Calf Care & Vaccines

The question of what vaccines to use and when to use them in young calves is difficult to answer. The objective of using vaccines is to provide protection to the calves from disease causing organisms. An assumption commonly made is that by vaccinating an animal, we protect that animal against that disease. However, that may not be the case, even in a best case scenario.

Before we discuss specific vaccine use, some basic principals need to be considered. The capabilities of the immune system change as a calf grows. How a vaccination program is structured must take into account these age-related considerations. Here are some basic concepts to consider:

• Energy is limited in young calves – delegated for homeostasis (maintaining temperature especially), normal organ function, growth and immune system.
• Energy allocation based on body’s proprieties. Needs to maintain body temperature and vital organ function first. Immune function comes next followed by growth.
• When vaccines are given, the body has no choice but to divert energy to dealing with those antigens.
• Calves deal with natural exposure to many pathogens. This is compromised if immune system has to respond to a vaccine challenge.
• The vaccines mostly produce antibodies. A fully functional immune system resists disease in a multitude of ways.
• Oral antibodies affect the microbiome, thus reducing the efficacy of one of the parts of the immune system.
• Antibodies absorbed from colostrum circulate in the blood stream. Being specific to particular pathogens or subunit of the pathogens, they will attach to those sites whenever they come in contact. This applies to an infective organism or a vaccine for the same organism. The consequence of this is the antibodies from the colostrum can interfere with the efficacy of the vaccine and prevent a meaningful response to the vaccine.
• Interference by the circulating antibodies differs with the organism. As an example, the BVD organism antibody can interfere with a vaccine for 8 months.
• A tremendous amount of variation exists in how reactive a vaccine is in the calf. Some vaccines are very smooth and will cause minimal side effects in the calf and the others will cause a depressed calf that goes off-feed for a few days.
• Don’t vaccinate a sick calf! A calf that is trying to recover from any disease process will not be able to properly respond to a vaccine. In my opinion, herein lies one of the biggest problems in many vaccination protocols – if there are too many vaccines to administer they are given, regardless of the condition of the calf, simply to be checked off the list. 
• Vaccination programs need to take into consideration the varying conditions of a particular group of calves. 

Vaccinations for calves > 2 months of age

• By this age, calves should be consuming starter and hay, meaning energy levels should not be limiting.
• Vaccines administered at this time will be a reflection of what specific diseases are prevalent on the farm.
• In my opinion, vaccines (or dehorning or castrating) would never be given at weaning. Ideally, these are done prior to weaning or 2 weeks after weaning.
• Remember that interference from colostral antibodies can persist, meaning that not every calf vaccinated will be able to respond by producing its own antibodies.