Imagine 10% of the nation's beef and dairy cattle herd infected with a contagious disease causing pregnancy loss and reproductive failure.
What's more, that same contagious disease makes people sick — sometimes with long-term repercussions.
This was the situation in the mid-1930s with brucellosis, a bacterial reproductive disease of cattle.
Implicated for decades as a significant animal and public health problem, USDA, in conjunction with state officials, embarked on a brucellosis eradication program in 1934, remnants of which continue today.
Early eradication efforts consisted of blood-testing and slaughtering infected animals.
While this helped rid herds of a source of infection, it did not prevent those infected cows from spreading the bacteria before they were detected.
That all changed in the early 1940s with the development of a brucellosis vaccine, sometimes called the Bangs vaccine, for cattle.
Named the Strain 19 vaccine, it quickly proved to be effective. Even if it did not prevent 100% of infections, it greatly reduced abortions, and therefore the spread of disease.
In the mid-1990s, Strain 19 was replaced as the approved vaccine by the RB51 vaccine, which offers similar protection but fewer problems with blood test interference.
It took time, but the U.S. brucellosis eradication program can now be considered a success.
Cattle brucellosis has been eradicated across the country, except for areas surrounding Yellowstone National Park, where wildlife remains a reservoir. As a result, many states have dropped requirements for brucellosis vaccination of heifers for their resident cattle, and for animals entering from other states.
If most brucellosis vaccination requirements are no longer in effect, why should cattle producers continue to make the effort?
1. Bangs vaccination time is a good time for other heifer management practices as well. Rules restrict brucellosis vaccination to heifers between 4 and 12 months of age. During this time, heifers identified as replacements can also be given their first dose of prebreeding reproductive vaccine, palpated for reproductive score, pelvic-measured, retagged and had their udders examined. In addition, since brucellosis vaccine must be administered by an accredited veterinarian, it gives the operation a built-in opportunity to use veterinary expertise to help select and prepare replacement heifers.
2. Bangs vaccination automatically gives heifers a USDA official identification. Vaccinated heifers receive an official tattoo designating the year of vaccination, as well as other identification. Even though brucellosis vaccination is not required to cross most state lines anymore, official identification is.
3. Bangs vaccination makes state officials' jobs easier. Brucellosis-vaccinated heifers have their official identification recorded and sent to the state veterinarian's office for storage. Those records and identifications can become invaluable in investigations of disease outbreaks such as tuberculosis.
4. Bangs vaccination still holds value for many heifer buyers. At the very least, it indicates that the heifers have at least had a chance to be examined and managed more closely than those not vaccinated against brucellosis. For beef and dairy producers, the best source of information on how brucellosis vaccination fits into an operation is their local veterinarian.
In Minnesota, the state’s livestock industry takes an active role in surveillance for the disease. One of the state’s packing plants collects blood samples from adult cattle at slaughter for brucellosis testing for a national surveillance program. The Minnesota Board of Animal Health follows up on suspect samples from slaughtered animals by investigating the herd of origin, and testing the herd for brucellosis if necessary.
For more information, visit bah.state.mn.us/cattle/#brucellosis and cfsph.iastate.edu/FastFacts/pdfs/brucellosis_F.pdf.
Sources: Russ Daly, South Dakota public health veterinarian, and MBAH