drjustinhigh eh

When the Weather Changes

I’m sure you’ve all heard the old saying, “If you don’t like the weather in Texas, just wait a few minutes and it’ll change.” Well, over the last few weeks that saying has never been truer. From a horseman’s standpoint, the dramatic shifts in temperature, wind speed, pollen count and humidity have been showing up in a variety of different ailments. Horses tend to have times of the year when respiratory infections are more common, other times runny eyes and noses flare up because of allergens.

When all the environmental factors show up within a short period of time that otherwise would be spread out over the course of several months, a horse’s immune system pays the price. One day we’re 85 degrees and sunny, and the next it’s 45 degrees and raining. It’s hard to plan around that.

I don’t know about you, but I have seen this affect the horses I am taking care of in 3 areas.

1. How mares cycle

2. Hair coat shedding patterns

3. Increased respiratory problems

Breeding farm managers seem to say the weather affects mares every year, but I have seen more of it this year than before. A mare will be progressing well in her cycle and getting ready to breed or even set up to breed, then the follicle(s) I am following regress. When a follicle regresses, you’re fairly stuck in a bad spot because you don’t want to quit on a cycle, especially if you’ve already bred on it, and you don’t want to put more money into something that is not going to have a good outcome. Either way, making that phone call to a mare owner is a less-than-ideal part of my day. Not much else to do but wait and see when she cycles again.

Hair coats on horses this time of year are either slick and shiny from a good lighting program, or they are somewhere in between from not being in a good program. The ones that are slick will not hair up just because of a few days with big temperature swings as long as their lighting hours do not change with them. These horses need special attention to be blanketed appropriately so as not to predispose them to illness.

Too heavy of a blanket can be just as bad as not having one at all. Other horses may have a little more natural defense with their remaining hair coats but can look quite odd while stuck in transition. Hair coat is, of course, primarily controlled by daylight length, but the temperature swings we are seeing can have more of an effect on delayed shedding than you think. So, if you think you horse is developing a case of mange, it’s probably just abnormal shedding.

Finally, the most important issue is the increased rate of respiratory problems. These can be both infectious and non-infectious. Going from high temperatures to low temperatures can weaken a horses defense to fending off pathogens that in otherwise healthy horses do not cause a problem. The non-infectious problems typically stem from the inflammatory response of the airway to environmental allergens like pollens, fungus, and mold spores. Most horses suffer like people do with ocular/nasal discharges and red, inflamed conjunctiva. Symptoms can often mimic those of upper respiratory infections, but are actually best treated with topical and systemic anti-inflammatories instead of antibiotics.

In many ways, people and horses are very similar when it comes to the weather. The things that affect them are also what affect us. We have the option of coming inside out of the elements. So, until we are officially in the throes of a hot Texas summer (which will probably start tomorrow since I wrote this), keep an eye on the weather report and one of your horses. I’m sure you will all get along fine. I trust you more than I do the weatherman.

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drjustinhigh eh Justin High, DVM Dr. Justin High is a veterinarian and partner in Reata Equine Hospital in Weatherford, Texas. He graduated vet school from Texas A&M University and completed an internship at The Littleton Equine Medical Center in Denver, Colo. High’s years of practice focuses on the Western performances horse. Send any comments or questions to justinhighdvm@reataequinehospital.com.

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