Breeding vaccinations are critical for biosecurity
Published on Feb. 1. 2020
Dan Thomson, veterinarian and head of Iowa State Animal Science Department discussed the importance of vaccinating for and recognizing leptospirosis (lepto) and vibriosis (vibrio) in beef cattle during his program, Doc Talk.
“Getting cows bred and calves weaned is all part of a good production management system,” said Thomson. “When we talk about preventatives, we need to think of biosecurity, which is preventing the spread of diseases, especially in herds where the disease has not been present historically.”
Thomson explained lepto and vibrio are of particular interest to breeding cattle, including both bulls and cows. They are both bacterial infections that can cause abortion and other reproductive issues.
“When I think of lepto, I think more of animals being exposed to it in their environment because wildlife such as deer and rats can carry it,” Thomson explained. “If an animal carrying lepto were to urinate in a water source, the entire source is contaminated and animals that drink the water can become exposed.”
“The tough part about lepto is it can trick the immune system and remain undetected, making cattle carriers of the bacteria,” he noted. “It can go undetected for months at a time, and the cattle can carry it in their urine and mucus membranes.”
“We have to understand nearly 50 percent of herds in the U.S. carry lepto,” said Thomson. “The period in which the bacteria are a problem varies by region. In the north, the season is much shorter as hard freezes kill the bacteria. In warmer climates, the bacteria are more problematic for a longer period of time.”
He noted with lepto, the abortion rate rarely goes over 10 percent.
“In comparison to lepto, which is picked up in the environment, vibrio is a venereal disease passed between bulls and cows,” Thomson explained. “This is something we need to control via vaccination.”
He noted the signs of vibrio are early embryonic death and abortion, which is more common with vibrio than lepto.
“A lot of times, this won’t show up as a large outbreak of abortions, but rather a large number of cows coming back into heat three to four months after initial exposure to a bull,” said Thomson. “Early embryonic death and cows coming back into heat should be a big concern.”
“If more than 10 percent of the herd is going back into heat, we need to start thinking about what is causing this,” said Thomson. “When we have these types of problems in the herd, we need to pinpoint the cause and find a solution.”
“First things first, we need to rule out whether or not the cows were pregnant to begin with,” Thomson explained. “When we start to see an excessive number of open cows its time to get the vet involved.”
He continued, “Vets have a relationship with diagnostic labs and will be able to see whether abortions and open cows are a theme amongst herds in the same area. They are likely dealing with other ranchers going through similar issues and know reproductive strategies for the area.”
He noted with abortions and early embryonic death, ranchers won’t always find an expelled fetus, especially early on. With later term abortions, hairless fetuses may be found.
“With early embryonic deaths, we want to take a vaginal culture and send them off immediately,” he explained. “The bacteria can’t live very long outside of the host, so it’s imperative to get the sample onto media as soon as possible.”
He continued, “With a later-term abortion, ranchers should send in the fetus and placenta as soon as possible. No matter what, blood samples should be taken from the cow.”
He noted blood samples can show whether there was an antibody response. With newer technology, labs can even determine whether the bacteria present is a vaccine strain or a wild exposure.
Thomson noted many people don’t necessarily plan out specific times to vaccinate, and instead just do it when they are doing other tasks such as branding.
“A lot of times, we pregnancy check, wean and vaccinate all at the same time and that can work for older cows, but younger cows need to be vaccinated twice for lepto and vibrio,” he explained. “Replacement heifers and new bulls need to have one vaccination round at weaning and one 20 to 40 days after as a booster.”
“Older cows will also need an annual booster given prior to breeding,” he said. “The best time to vaccinate is 30 to 60 days prior to cows being exposed to a bull or AI’d.”
“As many cattle operations move towards more confinement style management, is it even more critical to keep up with vaccinations to increase biosecurity measures,” Thomson stressed. “Aside from vaccinations, we need to make sure water tanks, bedding and straw are kept clean.”
He continued, “For operations using AI, its very important to ensure equipment is kept in pristine condition in order to minimize the potential spread of bacteria.”
Callie Hanson is the managing editor of the Wyoming Livestock Roundup. Send comments on this article to email@example.com.