“For heifer calves you plan to keep as replacements, make sure you include a vaccine to protect against lepto that includes a proven hardjo-bovis vaccine,” says Dr. Tom Hairgrove, Texas A&M University. This can be included in their weaning age vaccination, then boostered appropriately.
Leptospirosis—often shortened to “lepto”—is caused by multiple strains of spiral-shaped bacteria that affect many kinds of animals, including humans. It is often present in wildlife, shedding bacteria in their urine. The leptospires can survive in surface water, stagnant ponds, or moist soil for long periods.
Leptospirosis is a common cause of infertility, delayed breeding, and early embryonic death, abortions or birth of premature and weak calves. The hardjo-bovis strain of lepto infects animals for a longer period of time, sometimes for life, by residing in the kidneys and reproductive tract of cattle that may not show signs of disease.
These bacteria are continually shed in urine or discharges from the reproductive tract, serving as a continual source of infection in the herd. For best protection against various strains, calves should be vaccinated at about 4 to 6 months of age, and cows should be vaccinated once or twice a year.
“You want a good vaccine for lepto, to start building immunity to prevent reproductive problems later on,” Hairgrove continued.
“Talk with your veterinarian to determine the best vaccine protocol for lepto. Depending on the type of lepto, you might see a serious abortion issue, sick calves, or a moderate loss of reproductive inefficiency. It’s similar to different strains of human flu, or different strains of BVD. Some strains of lepto make cattle very sick and they die, while others just cause early reproductive loss,” he says.
“For calves that will be keeper heifers, I stress the importance of a good lepto vaccine, and also BVD and IBR. Follow label directions. If you are giving calves modified live IBR-BVD, do not give this to calves nursing improperly vaccinated dams, and always booster these products as labeled. Killed products always require a booster,” says Hairgrove.
Improperly vaccinating dams or calves with modified live virus (MLV) products can be catastrophic. MLV and killed vaccine are both excellent products, and both have pluses and minuses. Your vaccine program must be tailored to your operation and management.
“For replacement heifers, always vaccinate with what’s appropriate pre-weaning, and after weaning there are several different kinds of combination vaccines that can be used. The modified live and the killed vaccines are all very good, if given properly. You need to discuss this with your veterinarian. Before a heifer gets to breeding age, make sure you have all the immunity into her that you can. You can treat your replacements a bit different from the calves you plan to sell,” Hairgrove stressed.
The heifers’ vaccinations are crucial because they provide the foundation for future immunity for the rest of their lives. “It’s like when your kids start to school. You need to get the initial immunity.”
He recommends vaccinating heifers for brucellosis, especially in Texas. The states around Yellowstone Park (Idaho, Montana, and Wyoming) have mandatory calfhood vaccination programs because there’s still a problem with brucellosis in bison and elk herds in and around the park. Every heifer must be vaccinated between 4 to 10 months of age.
“Consult with your local veterinarian about vaccinating heifers for the important diseases, and don’t forget brucellosis. If your cows ever go to another state, they may need calfhood brucellosis vaccination in order to enter that state,” he says.
“In our drought, when we were moving cattle back and forth, north and south, some states were requiring vaccination. To move cattle, some people had to have them vaccinated, and were vaccinating bred heifers, and caused abortions. Heifers need to be vaccinated as calves. This will give them protection in case brucellosis slips back into your area, and will also allow you to move cattle to other states if we have another drought,” says Hairgrove.
Importance of preventing BVD
Bovine viral diarrhea (BVD) can sneak into a herd, so you want to keep herd immunity high with proper vaccination by making sure all heifers are adequately vaccinated before they enter the breeding herd and keeping up the cows’ annual boosters thereafter. BVD not only causes abortion in cows and respiratory disease but can also compromise the immune system so cattle are more susceptible to other diseases.
“It pays to sit down with your veterinarian to see what your risks might be, and to plan an adequate vaccination program for your heifer calves and for the cow herd. It is very important to try to prevent PI (persistently infected) calves,” says Hairgrove.
“Often when we use vaccines like IBR-BVD-PI3, etc. we are trying to protect cattle from respiratory disease. Yet the most important thing we are really trying to do is protect the cow herd. We want to be sure to vaccinate the cows and replacement heifers as well as the calves,” he says.
Some people don’t vaccinate their cows because the cows don’t get respiratory problems like calves do.
“You don’t see these respiratory diseases in the cow, but you may end up with reproductive losses. My main concern is for the cow-calf herd, because that’s where PI calves originate.”
It’s not just about vaccinating the calves; producers also have to protect the cows so they do not become infected at that crucial stage of pregnancy—that may result in the fetus becoming permanently infected and shedding the virus, after it’s born, for the rest of its life.
“Your own veterinarian is the person who can help you determine the best vaccination protocol for your own herd. He/she knows your ranch situation, who your neighbor is, and what the risks are.” — Heather Smith Thomas, WLJ correspondent
