Some diseases affect reproduction, interfering with the cow’s ability to carry a calf to term. Several of these can be prevented by making sure cows and bulls have adequate immunity before breeding season.
Dr. Tom Hairgrove, Extension veterinarian at Texas A&M University, says producers should talk with their practitioner and design a vaccination program that fits their situation. “You may have different risks than some other ranch; it may depend on who your neighbor is. If it’s someone with a herd of llamas, risks will be less than if it’s a cattle trader, bringing new animals into pastures next to yours.”
Heifers or bulls should have been vaccinated against blackleg (included in the 7- or 8-way clostridial vaccines) as calves, and in many regions an annual vaccine should include C. hemolyticum,which causes redwater. All clostridial diseases are deadly, and the vaccine is relatively cheap.
“Select the clostridial vaccine that fits your area. Some places there are risks for tetanus. We occasionally see wrecks with tetanus, especially when calving heifers that experience dystocia,” Hairgrove said.
“In Texas I recommend giving the cow herd a clostridial booster annually to provide protection for the calf via colostrum. Sometimes we also see cows die of C. chauvoei(blackleg) and in older cows it may be atypical and affect the heart muscle rather than the skeletal muscles,” he said.
Viral diseases are also an issue and he recommends IBR-BVD (infectious bovine rhinotracheitis-bovine viral diarrhea) vaccines. It’s important to have good immunity prior to breeding. The question is when to give these vaccinations.
“Some veterinarians recommend vaccinating the pregnant cow so she’ll have good protection for her unborn calf. Even though this is important, the biggest losses with these diseases are reproductive. We want to give these vaccinations pre-breeding, if possible. If the only time a producer runs cows through a chute is at preg-check time, we have to give it then—but then it’s important to consider the type of vaccine given to the pregnant cow,” he explained.
“There is controversy regarding risks and safety and difference between modified-live vaccines (MLV) and killed vaccines. They are both good, and both have a place in different management programs.”
The MLV vaccines can be safe for pregnant cows if those cows already have some immunity from earlier vaccinations with that product; a subsequent vaccine acts as a booster. But it can be a disaster if you don’t know their vaccination history.
“There isn’t a yes or no answer regarding whether to use MLV or killed vaccine; it all depends on the producer’s situation. Follow directions on the label, and work with your vet,” he said.
This is also important when selecting vaccines. “You can get into problems if you double up too many gram-negative vaccines,” Hairgrove explained.
Assess your risk, then choose appropriate vaccines. “Is BVD a risk? If a person is buying new heifers and adding them to the herd with no knowledge of their background, this could skew everything. No vaccine is 100 percent protective.”
If replacement heifers have good immunity, this is the foundation for future immunity. “Boosters are necessary each year, but it’s all about that initial foundation—like giving kids their shots before they go to school.”
He recommends using vibrio vaccination (campylobacter) if you don’t have a closed herd or don’t know the status of neighbors’ cattle, or run yours in a community pasture.
“Clinically, trich and vibrio look alike. The bull shows no signs and the cow usually doesn’t show much (maybe a little discharge), but you have more open or late-calving cows for next year. If you buy cows without knowing their history, include the vibrio vaccine pre-breeding, to protect your cows,” Hairgrove said.
“Some vaccines have longer duration for protection than others. Oil-based vibrio vaccines have a longer span of protection than aluminum hydroxide-based vaccines. If the only chance you have for vaccinating cows is when you preg-check, you may not get good results from non-oil-based vibrio vaccines,” he explains. Best protection is gained if you can vaccinate cows prior to breeding.
“If you vaccinate prior to breeding (after the cow has calved and before rebreeding), any of those combination products would be fine,” he says.
Some people vaccinate cows for trich as well as vibrio. The trich vaccine does not prevent infection but imparts some short-lived immunity. “It must be given twice the first year, pre-breeding. Follow label instructions; it is not very effective if only given at preg-check time,” Hairgrove said.
Leptospirosis is another disease that can cause abortions and early pregnancy loss. “We falsely think of lepto as being a disease that only occurs in wet regions. In cattle, lepto can cause two different disease scenarios. There are several kinds where wildlife such as skunks and swine are the natural host and disease reservoir. If cattle become infected from feral swine or skunks urinating in water supplies, they often abort, and/or get sick and die,” he said.
Cattle are the natural host and reservoir for Lepto hardjo bovis, and this kind of lepto behaves differently in cattle. “With this host-adapted Lepto the cow suffers reproductive loss but seldom shows signs of being sick.” If hardjo bovis is prevalent in your herd you could have 10 percent or more of the cows suffering pregnancy loss.
“I always recommend adding a lepto vaccine to annual vaccination programs. It’s best to give it pre-breeding, to protect the cow starting in early pregnancy,” he said.
Be careful in vaccine selection, focusing on disease risk. Many people purchase vaccines without reading the label. “For example if they vaccinate for lepto they might get the lepto/vibrio combination and also purchase an IBR/BVD vaccine which often has a lepto component. If they aren’t careful, they may be putting two or even three lepto vaccines into their cattle,” Hairgrove said.
“Lepto is a gram-negative product and if you double up the lepto injections you may start interfering with the immune process and create negative responses that may actually kill cows,” he explained.
There are several gram-negative organisms that we may be vaccinating against—lepto, vibrio, haemophilus somnus (now knownas histophilus somnus, which sometimes causes respiratory disease and abortions) and pinkeye.
“If you start adding these together it can cause a problem, especially if you are giving several combination vaccines that include lepto or vibrio or even a trich vaccine that contains vibrio (and maybe lepto). You need to know what’s in each product.”
There is also some risk in vaccinating cows and bulls the day you turn the bulls out. It’s better to vaccinate at least 30 days prior to turnout, as vaccinating close to breeding can cause pregnancy loss.
“I recommend vaccinating replacement heifers at weaning—with the MLV vaccine—and a booster pre-breeding, preferably at least two or three weeks before breeding. Many people are using AI on heifers and want to give that last MLV dose when they have them in the chute to synchronize. There is controversy in the literature regarding whether to use MLV vaccine at that time, so I recommend using a killed product.”
Other vaccines commonly used include pinkeye. “There’s nothing wrong with that product, but make sure you really need it, because it’s another gram negative. You may not want to give it at the same time as other gram-negative vaccines.”
Ranchers should not neglect to vaccinate bulls. Even though reproductive losses are mainly in females, bulls need to be on an adequate vaccination program to make sure they are healthy and won’t spread disease to the cows. — Heather Smith Thomas, WLJ correspondent