Two weeks ago I got a phone call from Lucy whose gelding was at a full gallop when he slipped, fell on rough ground, and slid for a few feet on his right side. After he got up, he favored his right hind leg for a minute and then seemed OK. Lucy asked if I needed to see him. I requested a photo. A few minutes later my phone screen showed a clear picture of the injured leg. There was a scrape 10 inches long and 3 inches wide over the hip. All the hair and a few layers of skin were gone, but there was no blood oozing and no deep damage. It didn’t need sutures or my attention. I called Lucy back and asked what she had done for him so far.
“Well, I figured that he could use some bute, so I gave him 2 grams, and was sure that he needed antibiotics so I gave him 12 SMZ’s. I have enough of those left to last a week. Is there something else that I should do? ”
You probably have a few partial bottles of medicine of your own at home from past illnesses. If you are a horse owner, you’re sure to have a few in the barn as well. I’m betting that among the supplement containers and the partial bottle of bute, there is a half used bottle of the antibiotic pills that we call “SMZ’s”. If the expiration date on the bottle is current, it’s a good thing to have on hand. It is a broad spectrum and well-tolerated drug that is effective for many infections. However, like other antibiotics, it is used far more often than it needs to be. I asked Lucy: “If you had scraped a leg like he did, would you put yourself on antibiotics?” She laughed, and said, “No, probably not.”
I totally get it. You want to help when your horse has a problem, so it’s natural to grab a bottle that might be of benefit because you want to do something. Is there any harm done? In addition to the cost, there is. Let’s step back in history to find out why.
Back in the 1920’s Fleming, a British scientist, noted something unusual on the culture plates on which he was growing bacteria. Some mold had contaminated the plates, and wherever the mold appeared there was a clear zone around it with no bacteria. He could have thrown away the plates because the mold had made them worthless. But, instead, he realized that something in the mold was killing the bacteria! Out of his continued research came penicillin and soon after, the manufacture of other antibiotics.
Antibiotics were used heavily during World War II. It was soon noted that some weren’t working as well as they had been. Bacteria multiply quickly. For example, single E.coli bacteria will start a new generation every 20 minutes. Mutations happen, and some of the “offspring” bacteria start life unaffected by the antibiotics they are exposed to. That resistance becomes part of the bacterial DNA and gets locked into subsequent generations. The widest antibiotic use by far has been in the meat industry where the drugs have been laced into the grain of young animals to promote markedly faster weight gain. The Center for Disease Control has stated that up to half the antibiotic use in animals is unnecessary and inappropriate and makes everyone less safe
We are also somewhat at fault. When we are sick, we wonder whether antibiotics will help. If we don’t recover quickly, we are tempted to use what is left of a bottle that has been sitting there since our last illness. When our animals are sick, we reach for the bottle even faster. However, many illnesses, ours and theirs, are caused by viruses, against which antibiotics are totally ineffective. There is a common misbelief that if a horse has a viral infection, a bacterial infection will follow, so you might as well put him on antibiotics. Antibiotics are not vaccines, and do not work as preventive medicine. In other cases, like the skin scrape on Lucy’s horse, antibiotics are not necessary. The body’s immune system will take care of these minor issues.
I most often see horse owners reaching for antibiotics when their animals have respiratory problems. If a horse has a cough and/or a nasal discharge but is not off feed and or running a fever, the infection is probably viral, and recovery is a matter of time, and support, not antibiotics. Two examples are influenza and rhino. Some well-intentioned owners give antibiotics for a horse with the heaves, confusing it with pneumonia. Antibiotics are of no benefit for heaves.
Other than resistance there are other problems. Some horses will colic when antibiotics are used because the drugs kill some of the normal bacteria necessary for digestion. There are even times when antibiotics are a hindrance to healing. An example of this is “gravel” (the common foot infection of horses.) If the pus from an abscessing foot cannot be released from the bottom by your farrier or vet, you may have to wait for the infection to come to a head and break out at the coronary band. Antibiotics can delay that process. Veterinarians often do not use antibiotics for treating strangles for the same reasons.
Like most other health professionals, I would hate to practice without antibiotics, but I know that they are often unnecessary, and their over-use is having an effect on what they can accomplish. Today’s biggest medical crisis is the presence of super bugs that defy any antibiotics.
When you have a sick or injured horse, first check with your vet as to whether antibiotics are necessary. If you are a good observer and can describe your animal’s condition accurately, a phone call to your vet may be all that is needed. You can often keep that bottle on the shelf.
–David A. Jefferson, DVM