A Different Look At Equine Antimicrobials


Written by:

Bio not available.

Using the right antimicrobial for the job is the rational choice, and Erin Groover, DVM, DACVIM-LA, wants equine veterinarians to ask themselves two basic questions before making a prescription:

  1. Is this the right antibiotic to treat the infection I’m seeing?
  2. Is the animal going to tolerate the antibiotic choice?

Groover is an assistant professor of equine internal medicine at the Auburn University College of Veterinary Medicine. Her session, “Antimicrobials: Rational Use in Horses,” was one of only six selected by the North American Veterinary Community (NAVC) as one of its top sessions of the year.

Groover says the goal of her session was to encourage veterinarians to look at antibiotics in a different way.

“We learned in school about the different properties of antibiotics,” she says. “Once we start practicing, we get used to seeing a disease and giving an antibiotic. That’s fine until you end up with some diseases where the antibiotic choice isn’t appropriate, and there is not a good, rational reason to use an antibiotic that cannot kill the bacteria causing the infection.”

Each antibiotic has its own specific properties. The key is to recognize those properties and pair the antimicrobial to the bacterial infection. For example, an antibiotic like penicillin has a gram-positive spectrum of activity. Pairing penicillin to a gram-negative bacterial infection in a horse is a poor choice for the patient.

Identify the target

Groover advises horse owners and veterinarians to identify the infection first. Then, choose an antimicrobial that is up to the task.

“You’re going to make a lot more headway if you can identify the organism first, rather than just guessing,” she says. “Sometimes, owners don’t want to do the test to obtain samples for bacterial culture. If it comes down to financial constraints – maybe the test is expensive – it’s not always practical in some scenarios. Some types of infection, like pneumonia, are well documented and commonly caused by specific types of bacteria. In those cases, veterinarians can choose the antibiotic for those common bacteria.”

Financial considerations and speed of treatment are two familiar reasons not every infection is cultured and identified, Groover notes. Another consideration is ease of administration, which can affect owner compliance in continuing the treatment.

“Some owners only see horses once a day and can’t give an antibiotic four times a day,” she says. “Not every choice works for every patient. It’s best to go back and evaluate each case separately.”

Rational thinking

Selecting the right antimicrobial is important for patient success, Groover says. Yet, it’s also important to maintain the continued effectiveness of antibiotics. Products used in horses are similar to those used in both humans and livestock. Farm animal antimicrobials are heavily regulated. On the other hand, horses are considered companion animals similar to dogs and cats.

“There is a cultural difference for choices in horses,” she says. “Most owners view their horse as equivalent to a pet. However, the principles are the same.”

Distributor connection

Groover recommends distributors familiarize themselves with specific antimicrobial product labels. Then, understand how the product’s properties make it a good choice for a specific disease.

Groover also recommends distributors understand potential adverse effects of products.

“Having a link between a distributor and a tech services vet makes the relationship more valuable,” she says.

NAVC Session of the Year

Erin Groover’s presentation, “Antimicrobials: Rational Use in Horses,” was chosen as the large animal session of the year by veterinary professionals from around the world through attendee feedback. With a field of 350+ exceptional and nationally renowned veterinary speakers presenting more than 1,200 different sessions, it’s an honor to be voted as a top speaker and session by event attendees.

The full conference proceedings are available online at: http://cms.vetfolio.navc.com/2017-large-animal-proceedings/antimicrobials-rational-use-in-horses

Learn more! Groover recommends these sources for additional reading on antimicrobials in horses:

  • Dunkel B, Johns IC. Antimicrobial use in critically ill horses. Journal of Veterinary Emergency and Critical Care; 25(1): 1476-4431.
  • Weese JS. Antimicrobial use and antimicrobial resistance in horses. Equine Veterinary Journal; 47(6):2042-3306.
  • Weese JS, et al. ACVIM Consensus Statement on Therapeutic Antimicrobial Use in Animals and Antimicrobial Resistance. Journal of Veterinary Internal Medicine; 29(2):1939-1676.
  • Weese JS, Guardabassi L, Jensen LB, Kruse H. Chapter 10. Guidelines for Antimicrobial Use in Horses. In: Guide to Antimicrobial Use in Animals. 2009