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Vaccination protocol recommendations provided

by Wyoming Livestock Roundup

Proper health management is critical to successful sheep operations, as noted by American Sheep Industry Association (ASI) Podcast Host Jake Thorne. A vaccination protocol is a major part of the health plan producers should establish. 

University of California Cooperative Sheep and Goat Extension Veterinarian Dr. Rosie Bush joined Thorne on the ASI podcast to share her knowledge on the subject. 

Vaccine background

“Vaccines are a controlled exposure to diseases we are trying to prevent,” explains Bush. “They usually contain a killed or weakened version, or fragments of the virus or bacteria that causes disease to allow the immune system to respond as if the body were exposed, without the harmful effects.”

Many vaccines are delivered under the skin, according to Bush. Recently, some vaccines have been developed to be given closer to the normal means of exposure. 

“Some vaccines are now given in the nose, orally or like the sore mouth vaccine, are delivered by scraping skin and placing the vaccine on top of the skin,” she explains. 

Improved vaccine efficacy

“When we think about how vaccines work, the animal has to be able to amount a really good immune response in order to develop long-lasting immunity,” Bush says. 

Livestock handling and stress management while vaccinating or doctoring impacts how well the animal responds to treatment. 

“Stress certainly can affect the way an animal mounts an immune response,” notes Bush. “Stress when giving a vaccine can impact the response to the vaccine, but also if the animal is stressed after the vaccine, it can challenge the effect of their immune system.” 

General health and nutrition also play a role in the way livestock respond to vaccinations, according to Bush. 

“We have to have a healthy animal to start with,” she states.  

“It is important to consider how vaccines work,” Bush continues. “Usually, we give an initial dose to prime the immune system, which provides small, short-term protection, if any protection at all.”

“Boosters drive the level of protection where it needs to be,” she explains. “Annual boosters are reminders to the immune system to keep the protection levels up. Producers should be sure to use vaccines as directed for full efficacy.” 

Typical pre-weaning vaccination protocol

While vaccinations themselves vary depending on geographical location and what the herd is at greatest risk of contracting, the most common vaccine is for protecting against clostridial diseases and tetanus (CD&T). If producers have noted issues in their herd with multiple diseases, such as blackleg, Bush says seven- and eight-way vaccines are an option. Otherwise, multi-way vaccines have the potential to dilute immune response. 

“Common protocol is for lambs to be vaccinated around three to four weeks of age if the ewe was not vaccinated before lambing,” Bush says. “A booster is usually given as a follow-up around six to eight weeks of age.” 

However, Bush explains some producers have issues with preventing a type D overeating disease in lambs older than one month of age. In this case, a different vaccination protocol will be better. 

“It would benefit those producers to vaccinate their ewes three to four weeks prior to lambing for maternal antibodies in colostrum to protect their lambs for six to eight weeks,” she shares. “If lambs are processed early, producers should consider vaccinating their ewes before lambing. But, if lambs are processed later, producers should consider vaccinating around three to four weeks of age.”

Bush explains producers should remember their lambs will not have full protection until two weeks after the vaccine and the booster is administered. 

Mature sheep vaccination protocol

“I would recommend typically giving a CD&T vaccine to mature sheep, including an annual booster for rams,” Bush notes. “If there is a vaccine program in place, rams should definitely be included.” 

Bush recommends before introducing new rams to the herd, the best disease prevention is screening. She also recommends diagnostics to determine if there are any other diseases a herd should be vaccinated for. 

“The challenge is, vaccines are very specific to a disease,” Bush explains. “It would be beneficial to get a diagnosis to figure out the agent.” 

She also recommends considering the cost-benefit of vaccinations included in the herd diagnosis and comparing that to the acceptable level of risk. 

“If we see above four to 10 percent abortion, we are certainly concerned, depending on the size of the herd,” she says. “If a producer has a smaller herd, they would probably not accept this number.” 

Bush notes a producer often won’t vaccinate for everything included in a diagnosis, but definitely sparks future considerations. 

Averi Hales is the editor of the Wyoming Livestock Roundup. Send comments on this article to

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