Bang’s Vaccination: Is It Still Required?
By Heather Smith Thomas
Often called Bang’s disease, brucellosis is the most common cause of abortion in cattle worldwide, except where it has been controlled or eradicated. The primary way this disease is spread is via infected fetuses, fetal membranes, and discharges from infected females. Brucellosis affected about 25% of cattle in the U.S. before disease control programs and use of vaccination. Because of its threat to human health, a rigorous program to eliminate brucellosis in cattle was begun as soon as a vaccine was developed. Vaccination is not 100% effective, so a test-and-slaughter program was also used.
In recent decades brucellosis hasn’t caused concern except in states surrounding Yellowstone National Park in the Greater Yellowstone Area (GYA). Brucellosis continues to be a challenge for Idaho, Montana and Wyoming; the disease exists in elk and bison in the park, and they come out of the park and mingle with cattle.
These states have Designated Surveillance Areas (DSA) where the disease is in wildlife, and in cattle in recent years. Idaho, Wyoming and Montana have rules for livestock which include surveillance testing and vaccination, cattle identification, etc. Elk in certain areas are also monitored, to determine level of infection in herds.
Dr. Debra Lawrence, Idaho State Department of Agriculture Veterinary Medical Officer, says vaccination mainly prevents abortions, minimizing spread. “Vaccination does not prevent a cow from becoming infected by contacting infected tissues from non-vaccinated animals such as elk. If a vaccinated cow is exposed to brucellosis, her body will be infected, but she’s much less likely to abort and spread infection,” she says.
Female cattle in Idaho that will be breeding, grazing or used for dairy must be vaccinated. “Most of our neighboring states require vaccination, though producers east of the Mississippi don’t worry about brucellosis, and most states don’t require vaccination,” says Lawrence.
Dr. Jim Logan, Wyoming State Veterinarian, says Idaho, Wyoming and Montana have good control programs and have worked on this for many years. “In Wyoming we went brucellosis-class-free in 1985. We did not find another case until 1988, but had a few cattle test positive in recent years. Montana has also had some positive tests.”
“We have to make sure we’re not letting brucellosis out of our DSA, to affect another producer—whether in our own state or somewhere else. If we can assure everyone that we’re clean, we have open marketability,” he says.
Though some heifers from these states go to feedlots, destined for slaughter (not breeding), the only safe thing is to have them all vaccinated as calves, or at least identified. “It depends on the state they are going to, in terms of what’s required. If heifers are going for feeding and are less than 12 months of age, most states accept them, but veterinarians who are writing health certificates should call the states of destination, to know what they require. As long as animals leaving Wyoming’s DSA have met our requirements, they can go, but they also have to meet the requirements of the state of destination,” he says.
In some instances, heifers purchased for feedlots were eventually sold for breeding. “This makes other states a bit nervous about accepting unvaccinated heifers without a test. This is up to the state of destination, but there have been situations where heifers that came out of a DSA went to a feedlot but didn’t stay there—and this can put producers at risk.”
Many states don’t require that cattle coming into their state be vaccinated, but some require tests if cattle are coming from Idaho, Wyoming or Montana, especially if coming out of a DSA. “Brucellosis potentially has significant economic impacts to producers and trade,” says Lawrence. “Fortunately, since 2002 no infected cattle from Idaho have moved interstate. A diagnosis in exported cattle could have an immediate impact with domestic or international trading partners.”
Idaho requires intact adult cattle from the DSA be tested for brucellosis if they change ownership or leave the DSA, unless going to slaughter where they will be tested. “Brucellosis cases in cattle in Idaho in recent years have all been traced to elk exposure. We’ve not had any cattle-to-cattle cases.” Brucellosis will continue to be a problem as long as it exists in elk and bison. There’s no effective way to eliminate the disease in wildlife.
Dr. Keith Roehr, Colorado State Veterinarian, says his state no longer requires vaccination since it simply reduces incidence of abortion and outbreaks. “There was acknowledgment, however, that in areas of wildlife exposure there’s good reason for cattle imported into those areas to be vaccinated. Two states in the GYA allow for adult vaccination upon arrival,” he says.