by Sally Colby
There are plenty of choices when it comes to vaccinating beef cattle, but the options boil down to a few key points, including preventing preventable diseases and allowing animals to produce the best quality product. Some vaccines protect individuals; others protect the herd. In addition to doing their own research on vaccines, beef producers should work with their veterinarians to establish protocol appropriate for each herd.
Veterinarian Dr. Dan Goehl, owner of Canton Veterinary Clinic in Missouri, said nutrition is important to herd health and plays a role in the effectiveness of a vaccination program. “We have to have a healthy animal to form an immune response,” he said. “We know that without a healthy animal, the vaccine may not be effective at all. You can vaccinate an animal, but that doesn’t necessarily mean the animal is immunized, and an immunized animal doesn’t necessary mean it’s a protected animal. It all starts with nutrition and overall health.” He noted that severely parasitized animals will not have an adequate immune response.
Goehl said the vaccination program should be a systems approach, with all pieces coming together for a healthier animal. “A vaccine is not a herd health program,” he said, “but it’s an important piece of the program.”
One consideration in developing a herd immunization program is disease pressure. “There are situations you won’t be able to vaccinate your way out of,” said Goehl. “BVD is an example of that. If there’s a PI [persistently infected] animal in the herd, there are other things to address before we vaccinate. Set expectations of what we want the vaccine to do, and how effective it needs to be to be a success.”
How is success measured? Should the herd be completely disease-free, or is it sufficient to decrease the incidence or severity of disease? Goehl said pinkeye or scours vaccines probably won’t completely eliminate disease, but clostridial diseases can be almost totally eliminated with proper immunization.
For cow-calf herds, immunizing cows prior to breeding to achieve a degree of immunity in calves is a major consideration. Pathogens that can result in abortion will be the biggest threat in the first trimester, so it’s worth working out the timing of vaccinating to provide optimum protection.
“It’s more about timing related to gestation rather than a time of the year,” said Goehl. “I like to give the modified live 30 days prior [to breeding], and we try not to give a modified live to a pregnant cow. Sometimes at 30 days pre-breeding, if a herd is not tightly synchronized you may still have a few tail-end pregnant cows – we can include them in the vaccination program.” He added that leptospirosis doesn’t often fit the timing in relation to the pre-breeding period because it’s a disease of late gestation. “In a perfect world,” said Goehl, “we’d give the viruses, then and come back later at preg check and give the lepto part.”
Depending on the farm, vaccinating prior to breeding may become a matter of logistics. If the cows are on grass and not easy to access, timing of vaccinations may be less than ideal. Other considerations include how much risk the producer is willing to take, and the value of the pregnancy.
Dr. Ben Abbey, who practices in Montana, stated, “The big thing we work on is timing. There’s good research in the 1960s that talked about how the IBR vaccine can affect the corpus luteum (CL) on the ovary, so if we get too close to bull turnout or AI, we can negatively affect first service conception rate because the cow isn’t growing a good CL to maintain the pregnancy.”
Abbey added, “Just because we can doesn’t mean we should. I’m a proponent of not using modified live vaccines in pregnant cows. Typically, my programs are going to be modified live until the first time we breed the cow, and if we cannot vaccinate her from that time on out, we’ll switch to a killed program. If we can vaccinate her when she’s open, we stay on a modified live program.”
The bull will have the same disease pressures as the females in the herd, but with different ramifications. “Oftentimes we forget about the bull, but he can be a carrier of vibrio and lepto, and possibly a BVD carrier or is PI,” said Abbey. “Typically, we vaccinate them the same as the females.” He he has spoken with vaccine manufacturers about using modified live vaccines in bulls and their effects on sperm production. “We don’t have enough research to say whether sperm production is affected,” he said. “We need more research on using modified live on bulls.”
For bull-bred herds, it’s important to ensure venereal diseases such as vibrio (Campylobacter fetus) and lepto are covered. Abbey said the cattle industry has done a good job with BVD, so there isn’t a lot of pressure from that disease.
“I like to vaccinate cows 30 days pre-breeding,” said Abbey. “The majority of pathogens that cause abortion are going to be in the first trimester, so if we can have the highest antibody titers to those viruses in the beginning of the pregnancy, it’s going to give us the most protection for the fetus.”
When developing protocol for a vaccination program, Abbey said it comes down to the science of the vaccines and following manufacturers’ recommendations. “Most vaccines require a booster to be fully effective and to form a memory response,” he said. “Typically, cows get one shot pre-breeding then it’s repeated annually. I don’t know if that’s good enough as opposed to getting two shots pre-breeding – it’s easy to overlook the booster.”
Goehl emphasized using modified live vaccine in well-managed herds. In herds where modified live isn’t appropriate, he relies on a killed vaccine, which he said works well when it’s followed by another killed vaccine.
Both vets agree that nutrition is essential in achieving a good vaccine response, as is handling and administration of vaccines. “We spend so much money on vaccines, then at the chute, we give the vaccine to the least experienced person because it’s the easiest job to do,” said Abbey. “But it’s also the most important job to do right.”
Abbey suggested BQA certification for the entire crew working cattle to ensure injections are done properly, according to label, and that cattle are handled properly for a successful outcome.