Your horse picks up some types of internal parasites by grazing on larvae-infested pasture.

I’ve heard that parasites can lurk in common drinking areas, such as in the water troughs at trail-ride staging areas and in campgrounds. Which parasites are these, specifically? And, is there anything my horse can pick up off the ground, when grazing on trail? If so, what’s the best way to protect my horse, and keep him parasite free? 

Amy Showalter
Medford, Oregon

Amy, parasites in horses are like parasites in any species; that is, mostly they’re not a problem except under “filth” conditions. Yes, many trailheads can be filthy, and yes, your horse can be exposed to several parasite species when frequenting those areas.

However, it’d be difficult for your horse to pick up parasites in a community water trough; most gastrointestinal parasites (those that thrive in the digestive tract) are contracted by grazing in infected areas.

Here’s what happens: Your horse ingests worm larvae that live in his manure and contaminate the feed in his environment, including pasture soil. Once ingested, some larvae types (such as large and small strongyles) migrate through your horse’s body tissues and settle into the intestines, where they mature and lay eggs.

Your horse then passes these eggs in his manure, where they hatch into larvae and spread. Your horse ingests the larvae, and the cycle is repeated. Parasites are also passed to other horses in this manner. This in mind, it’s a good idea to keep your traveling trail horse from grazing in areas frequented by a number of other horses, such as rest stops and trailheads.  

Actually, low parasite counts are beneficial, because they’ll help your horse maintain a level of resistance so he doesn’t become heavily parasitized.

Your veterinarian can check your horse’s fecal sample for egg counts to tell you how heavily your horse is infested. Most vets recommend deworming every two to six months, depending on environment, geography, climate, and exposure. Ask your vet to suggest a deworming routine for you that best suits your horse’s needs.

Can you tell me about choke?  My horse had choke once, and I almost lost him. What exactly is choke, what are the symptoms, and how is it typically treated? What should I do if it happens again?

Kim Dodson
Tucson, Arizona

Kim, choke in equines is fairly common, especially with the advent of pelleted feeds. Most cases occur within minutes of introducing a meal of pellets, which the horse consumes very quickly. But horses can choke on most any type of feed, including hay.

Choke refers to a blockage in the esophagus, and is less serious than choking, which refers to blocked windpipe. If your horse suffers choke, the first thing he’ll do is stretch his neck and repeatedly attempt to swallow. Next, he’ll drool heavily, and exhibit unusual head and neck movements as he tries to dislodge the obstruction.

If these attempts fail, most horses will soon relax and become passive, showing no further symptoms. When this happens, the horse has progressed to the dangerous phase. The blockage can become so hard and dry that it can actually damage or even rupture the horse’s esophagus. This is serious, as the equine esophagus heals very poorly.

Most chokes occur at the thoracic inlet, which is where the esophagus enters the chest. These are the easiest ones to relieve and are relatively uncomplicated. If the choke is at the cardia of the stomach, the chance of perforation is much greater.

Either way, choke almost always requires veterinary assistance, so if you see symptoms, call your veterinarian immediately. To relieve the choke, your vet will pass a stomach tube to the blockage and flush the esophagus frequently.

Once the choke is relieved in acute (short, but relatively severe) cases, the horse is fairly normal and can go back to his regular routine. If the case is chronic (that is, lasts a long time) and it takes several hours for the vet to relieve the condition, then the horse should be taken off feed or given liquid diet for several days.

Fall Health Care
Fall is here, and it’s time for those fall vaccinations, deworming, and other routine health care. It looks like we had another great year for West Nile virus. At this writing, very few cases have been reported, and you can bet vaccination had something to do with it. Let’s keep it up. Sure hope you get some good trails behind you this fall.

Barney Fleming, DVM, vets more than 60 endurance rides per year, gives endurance clinics and workshops, and is a professional lecturer on the sport of endurance riding and other equine subjects. He and his wife, Linda, own and operate

Spirit Horse Escape, a horse camp and bed-and-barn in Custer, South Dakota (www.spirithorse-escape.com), and an overnight horse facility in Deming, New Mexico (www.equinedoc.com).