Newborn calves gain temporary (passive) immunity from disease when they ingest colostrum, since this “first milk” contains antibodies. After a few weeks or months this temporary protection diminishes, so calves must build their own immunities.
Vaccinating at the proper time can help protect them until weaning age. Vaccinating them too soon, however, may not stimulate much immune response. If the calf still has maternal antibodies in its system, these interfere with building its own immunities.
Dr. David Smith of Mississippi State University says many producers may not think about why they are giving vaccines, or when.
“We have our hands on calves at branding, so this is usually when people vaccinate.” That’s not necessarily bad, but we do need to think about the problems we are trying to solve.
“For most producers, the problem they are trying to solve is to prevent calves getting sick after they are weaned, as they go into a backgrounding phase or into the feedlot. Calfhood vaccines are generally given to try to stimulate some immunity to protect calves at weaning time.”
Also, it’s standard practice to vaccinate against clostridial diseases (blackleg, malignant edema, redwater, gut infections caused by Clostridia perfringens, and others) because these deadly diseases may be a risk to calves at any age.
Calfhood diseases include blackleg and some of the other clostridial diseases like enterotoxemia (caused by several different types of C. perfringens) and pathogens that cause scours, along with respiratory diseases like pneumonia.
“Each rancher needs to tailor their vaccine program to protect against the diseases that affect calves on his/her ranch,” says Smith.
This may mean vaccinating the cows prior to calving, to give calves instant temporary protection against certain types of scours.
Smith says that in some situations you can’t vaccinate the calves quickly enough because they might ingest the pathogens (nursing a dirty udder, or born into a dirty environment) at the same time they are ingesting their first colostrum. They wouldn’t have time to mount an immune response from vaccination, but the antibodies in colostrum can protect them.
If producers are seeing scours problems early in very young calves, they may need to vaccinate the cow so she can give the calf immediate protection. Some of the other problems occur later or long term.
No optimal age
For respiratory disease, Smith says research still doesn’t show the optimal age for vaccination, since calves in some herds get what has been termed “summer pneumonia” while they are still nursing age.
“It is important to work with your veterinarian to determine a vaccine strategy,” he says. “In our recent study of summer pneumonia in herds across the Midwest, about one out of five herds (20 per cent) have problems with summer pneumonia in calves on any given year.
“Half of the battle is figuring out when you can get your hands on the calves (or the cows) to give vaccines. The other half of the challenge is determining the most appropriate thing to be doing.”
Vaccination is just one strategy for prevention.
“We also need to address management practices, such as making sure that cows and newborns mother up well and the calves get timely and adequate colostrum intake,” says Smith. “We also need to be cautious about introducing new cattle (and new pathogens) when calves are susceptible, and minimize the opportunities for calves to share pathogens with each other.”
Some diseases such as clostridial infections are difficult to address with management so vaccination becomes an important tool to protect against these diseases.
“The clostridial vaccines are very effective, and good insurance,” Smith says. The only problem is if you are fighting an enterotoxemia in calves that is caused by a type of C. perfringens that is not covered in the vaccines. The typical seven-way, eight-way or “enterotoxemia” vaccine only contains types C & D, yet some intestinal disease in calves may be caused by type A or B. A producer could lose calves in spite of vaccination. If this happens, they need to work with their veterinarian to figure it out.
No two ranches have the exact same situation.
“A ‘typical’ production system doesn’t fit everyone,” says Smith. “People calving in sheds have different risks for calfhood diseases than those with cattle calving out on dry hillsides or clean pastures. This is why you need to talk with your local veterinarian who knows your operation and understands your unique challenges and your own herd and management.”