Vaccination is one of the tools livestock producers use to keep animals healthy. Maximizing immune response with a good vaccination program raises the threshold for disease challenges, reducing the need for antibiotics and increasing the percentage of calves that stay healthy the rest of their lives.

It can be a challenge to figure out which vaccines to use and when to use them. It helps to work with your herd health veterinarian to develop a total herd health program for your particular operation.

Even though good management and biosecurity measures can greatly minimize disease risk, some diseases can still be a threat — spread by wildlife, insects or bacterial spores that may be ever-present in the environment. Leptospirosis, for instance, can be carried by wild animals like deer, canines or rodents urinating in haystacks or water sources. Many clostridial diseases (such as blackleg, Redwater, Black disease, malignant edema or enterotoxemia due to Clostridium perfringens) are not spread by animal-to-animal contact, but by spores in the environment or the animal’s digestive tract. They cause disease when conditions are just right for the spores to “come to life” and proliferate. Which diseases to be concerned about will depend somewhat on your location and the risk for transmission.

Veterinarian Rhyannon Moore-Foster, livestock field service assistant professor at Colorado State University, has worked with beef producers for many years.

“Most people utilize vaccination against respiratory diseases,” she says. “Typically, these come in a combination product, covering several viral diseases and maybe also some bacterial respiratory diseases. There are many products available, and any of the major brands tend to be reputable and effective since they have the trials to back them up.”

Modified-live virus (MLV) vaccines typically have two components — a dry powder in one bottle and sterile diluent or some other fluid to mix with it just before you use it. Follow label directions because often both components contain an important part of the vaccine, Moore-Foster advises.

Don’t save any leftover fractions once those are mixed.

“The modified-live virus only lasts a few hours, and the bacterial components won’t last more than 24 hours; the vaccine is no longer viable,” she says. “If you only have a few animals to vaccinate at the same time, buy the smallest-dose bottle so you don’t have to waste so much when you throw away what’s left.”

“There are many products available, and any of the major brands tend to be reputable and effective since they have the trials to back them up.” — Rhyannon Moore-Foster

Always read the label to know if the product given needs a booster dose in a few weeks.

“Typically, a modified-live vaccine given to an animal for the first time — such as a replacement heifer — will need at least two doses about three to four weeks apart. It will take more than one dose to gain maximum immunity,” Moore-Foster says.

“It’s also important to not give pregnant animals a modified-live vaccine unless they’ve had a vaccination prior to becoming pregnant and have some immunity already. Otherwise, it’s best to use a killed vaccine to eliminate the risk of causing that animal to abort.”

The killed vaccine will be safer, she says, though the downside to using a killed vaccine is that it won’t stimulate as great an immune response and will need to be boosted more often.

Many beef calves are vaccinated at branding time. They should be vaccinated at 2 or 3 months of age even if you don’t use branding as proof of ownership. If tetanus is a problem in your area, says Moore-Foster, it’s even better to give clostridial vaccines before you castrate calves, because the clostridial spores that cause tetanus are always present in the environment.

“Since it takes time for the animal to mount an immune response, you might want to give those calves a clostridial vaccine (that includes tetanus) ahead of when you castrate them,” she says. “If you can’t do that, at least give those vaccines at branding or processing those calves.” This will be better than nothing, and the calves definitely need protection against the other clostridial diseases during their first year of life.

Editor’s note: Heather Smith Thomas is a freelance writer and cattlewoman from Salmon, Idaho. [Lead photo by Leann Schleicher.]

Angus Beef Bulletin EXTRA, Vol. 17, No. 2-B