Vaccinating replacement heifers requires special consideration to minimize disease challenges
It’s the season for ranchers to start evaluating their heifer replacement prospects. During the process, South Dakota State University (SDSU) Extension Veterinarian Russ Daly encourages producers to consider vaccinating heifers for the prevention of reproductive diseases and to help them build up resistance.
“Replacement heifer health really starts from when that replacement heifer is born. How we do that on our farm, as far as overall health, will dictate how healthy those candidates are going to be,” Daly said during a webinar about disease risk protection in heifer development programs.
Infectious reproductive diseases, as well as respiratory diseases, digestive diseases and parasitism can all impact the heifer’s ability to grow, cycle, rebreed, maintain pregnancy and have good milk production.
“The general things we do to take care of our animals, we have to do for our heifers, too,” he explained.
Vaccinating for reproductive diseases like Leptospirosis is important.
“There are basically two kinds of Lepto. One is the Lepto that is in the five-way vaccine, and the other is Lepto hardjo-bovis,” he explained.
The general type of Lepto common in the Northern Plains is primarily a disease in wildlife populations. Cattle are exposed to the disease by drinking water that wildlife have contaminated by excreting bacteria through their urine into the drinking water.
In cattle, the disease can cause early embryonic death, decreased pregnancy rates and repeat breeding reductions. Occasionally, late-term abortions and weak calves may also occur, Daly noted.
“The disease is widespread but sporadic,” he commented.
Lepto hardjo-bovis is a different strain of leptospirosis that uses cattle as its host, Daly said. It is more common in the southern states.
“Transmission is still through urine, but the mucous membranes, kidneys and reproductive tract can also be affected,” Daly said. “It can show some of the same issues as the other type, like early embryonic death, and reduced pregnancy rates and repeat breeders, but it can become more of a herd problem.”
“If ranchers suspect a problem, it can occur more in heifer groups,” he continued. “It doesn’t wait until breeding age to cause a problem. Calves may become colonized at a young age.”
“If we live in an area where it’s a problem, we may need to vaccinate the heifers at weaning, rather than waiting till breeding,” he explained.
With brucellosis virtually wiped out in the U.S., except for in a population of wildlife in the Greater Yellowstone Area, Daly said he’s commonly asked by producers whether to vaccinate for the disease.
“It is so rare, it is not necessary to vaccinate cattle for brucellosis from a basis of disease prevention,” he responded. “However, what I do like about the program is the metal tag that can help identify animals through interstate movement.”
Brucellosis vaccinations are given by an accredited veterinarian to protect cattle against Brucella abortis. Heifers receive a live vaccine between four and 12 months of age.
“I like the fact that people give bangs vaccinations when they run their calves through the chute. It forces them to do some management after weaning. While the calves are receiving vaccinations, it is also a good time to pelvic measure and palpate their reproductive tract,” he said.
Daly also recommended to ranchers that heifers receive vaccinations for Bovine Viral Diarrhea (BVD), Infectious Bovine Rhinotracheitis (IBR) and Vibriosis (Campylobacter fetus venerealis).
Diarrhea is not the main effect of BVD, Daly explained.
“It causes infertility, persistent infections and abortions. The virus is really tricky and has different effects on the animal,” he explained.
IBR, also called red nose, and Vibrio can also cause infertility and abortions, he noted.
Daly recommended consulting with a veterinarian to determine what vaccinations to give replacement heifers.
“There are a lot of products available out there for pre-breeding shots. If ranchers are considering a change in their vaccination program or the timing, I would recommend having a conversation with their veterinarian,” Daly emphasized.
He continued, “Vaccination programs will be different in every herd. Ranchers with a closed herd may need different vaccinations than someone who has animals coming in and going out all the time.”
Vaccinations given too close to breeding can cause infertility and cycling problems, Daly noted.
Sharing some research from SDSU, conception rates in cows and heifers are worse when vaccinations are given within 27 to 37 days before breeding versus 46 to 89 days pre-breeding. The first pre-breeding vaccine can be modified live (MLV) or killed vaccine (KV), but if producers give a killed vaccine, Daly recommended giving two doses 30 days apart.
“Other research indicates as long as we set the heifer up with MLV early in life, especially IBR and BVD, it primes the immune system for later in life,” he said.
Purchasing replacement heifers
Daly offered some final thoughts to ranchers who purchase their replacement heifers.
“Know our seedstock source well. Ask for their past reproductive performance records, if they investigate abortions or stillbirths and have disease testing programs in place. What previous vaccinations have been given to the heifers, and what products were used and when? I also wouldn’t be afraid to have my veterinarian consult with theirs,” he explained.
Ranchers should use this information to evaluate if the seedstock source is a good match with the rancher’s existing herd health program.
“If ranchers purchase replacement heifers, I would segregate them for 30 to 60 days from the rest of the herd,” he explained.
He also told producers to take any dead animals to the veterinarian and have them posted quickly, before decomposition sets in.
“If it is an abortion, take the placenta, too. It could tell the veterinarian a lot about what happened,” he said.
Gayle Smith is a correspondent for the Wyoming Livestock Roundup. Send comments on this article to email@example.com.