Twenty years ago or so, antibiotic resistance wasn’t on the radar for most cow-calf producers. If a calf got sick, you gave it a shot and it generally got better.
That began to change about 10 years ago, says Amelia Woolums, a veterinarian and professor of pathobiology and population medicine in the College of Veterinary Medicine at Mississippi State University. “Around 2011, we started to see bacteria classically associated with BRD (bovine respiratory disease) being found with multiple resistance genes.”
That was in lung samples from cattle that died from BRD. What about incoming cattle? Are the bacteria in those cattle carrying antibiotic-resistant genes?
So she and others did a small in-house trial on 50 newly arrived high-risk calves. The calves all got an antibiotic on arrival and were nasally swabbed to see if any had highly resistant Mannheimia bacteria. On arrival, one calf tested positive. Fourteen days later, 88% had multidrug resistant Mannheimia on their nasal swab, she says.
That alone raised plenty of eyebrows. Then there was this: “By day 14, all of the Mannheimias were also resistant to Baytril and we hadn’t even given the cattle Baytril.”
Without getting into the private lives of bacteria, the basic thing at work is that they can swap chunks of DNA. As that happens, genes that create resistance to antibiotics can spread. Even more fascinating as well as alarming is that the bacteria don’t have to be closely related for that to happen.
None of this is breaking news any longer. Antibiotic-resistant bacteria has been a concern in both human and veterinary medicine for some time now.
It still is. That’s where you come in.
Weaning time approaches, and for some in drought areas, it may come sooner rather than later. As we plan for that annual ritual, now is a good time to revisit why the judicial use of antibiotics is so important.
Even more, it’s time to revisit why a herd health program that includes vaccinations is important. “You know, people have been able to use antibiotics to cover up bad management and I feel like we can’t rely on that any more,” Woolums says. “We’ve got to go back to good management, really good cattle care. And then, when you need to use an antibiotic, try to pick the right one.”
That’s because different antibiotics work best on different bacteria. So that means working with a veterinarian to use the right product appropriately.
What’s more, it means managing your cattle so they don’t get sick in the first place. “I think we need a renaissance of good husbandry,” she says. “Then, if we are a little more careful with how we use antibiotics, maybe they’ll still be functional when we need them.”