On Saturday morning last week I was working in the garden and noticed Mac lying down in the upper field. This is not uncommon, as both Mac and Rem will rest after a morning of grazing. But today he was putting his down on the grass. What I saw did not look right. Our favorite quarter horse has been under the weather for a few days, with a less than enthusiastic approach to his morning and evening bucket of grain. There was some mild swelling in his hind legs, too.
When we checked on him it was clear that a call to the vet was in order. Mac’s rectal temperature was close to 106 degrees. In short, Mac was in distress, his fever scary high. Thankfully, we were able to reduce his temperature, rehydrate him and start a course of antibiotics.
Equine colitis, an inflammation of the large intestine, or more specifically Potomac horse fever caused by Neorickettsia risticii, is the likely diagnosis. Though we are not sure. Mac has had no diarrhea but along with his fever both his heart rate and respiratory rate were elevated.
Unlike ruminates like cattle, horses have stomachs that function much like a human’s. And the equine digestive tract is unique in that it digests portions of its feeds enzymatically first in the foregut and ferments in the hindgut. Horses have delicate digestive systems and Mac is only able to eat hay as we work to restore his microbial flora.
Though we are concerned about endotoxaemia, which may lead to laminitis, and other secondary concerns, at this point we are just thankful we caught the fever and dehydration before it was too late.