(Un)invited Guests

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The new horse is the picture of health as he steps off the trailer. He seems to settle in well. But a few days later, you find him moping in the corner of his stall. He’s left his grain half eaten, and thick discharge is streaming from his nose. And that’s just the start of your problems. Before long other horses in your barn are showing the same signs. The newcomer brought strangles in.

Whether your business focuses on boarding, sales, lessons, shows, or breeding, it’s a given that horses will come and go. Each time a new horse arrives, there’s a chance that disease will sneak into your barn with it. Vaccinations are your first line of defense, but they don’t provide ironclad protection.

Safeguard your stock by quarantining new arrivals. For advice on how to do this, we turned to Roberta Dwyer, DVM, a specialist in disease prevention and control at the University of Kentucky’s Maxwell H. Gluck Equine Research Center.

Why Quarantine

Strangles isn’t the only concern. Influenza, equine herpes virus (rhinopneumonitis), salmonellosis, rotavirus (in foals), and equine viral arteritis are among the contagious diseases that a new horse can bring into your barn, Dwyer notes. These diseases are caused by viruses and bacteria, and they can infect your stock before you’re aware of them. That’s because a horse can shed the disease-causing agents during the incubation period, before symptoms of the disease appear.

A quarantine period of two weeks will safely get you through the incubation period for most, though not all, infectious diseases. “Three weeks would be even better, but is usually not practical for most horse farms,” says Dwyer. A two-week quarantine will protect you if, for example, a newly arrived pregnant mare develops equine herpes virus infection. She may abort her foal, but the rest of your broodmares will be at a much lower risk.

Strangles, which is caused by Streptococcus equi bacteria, is especially sneaky. A small percentage of horses that have had this disease continue to shed bacteria for up to a month after clinical signs are gone. If a new horse comes in from a site where there’s a high risk of this disease, such as a sale or a high-turnover dealer’s barn, consider a longer quarantine, or talk to your veterinarian about having the new horse tested to be sure it isn’t shedding Strep equi.

How to Do It

The ideal quarantine facility has everything separate—“a separate barn and fields for incoming horses; separate caretakers, and separate equipment,” says Dr. Dwyer. In the real world most farms can’t provide separate facilities, but effective quarantine is still possible.

“You can quarantine a horse at one end of a barn and keep the horse and all stall materials from contacting other animals,” Dwyer says. “Even better, put the horse at the end of the barn with an empty stall immediately next to it, so no nose-to-nose contact occurs.” Turn the newbie out in a separate paddock, ideally one where he can’t reach across the fence to rub noses with other horses. If your turnout facilities don’t allow that, schedule separate turnout times to prevent contact between horses.

Nose-to-nose isn’t the only route by which disease can spread. Workers, riders, even barn cats can carry disease-causing agents from stall to stall. So limit access to the quarantine stall and make sure it’s last in line for everything, Dwyer advises. Muck that stall last, and then disinfect the equipment (more on this below). Feed the new horse last, and use separate equipment for grooming. “Basically, eliminate any cross- contamination—no common bits, buckets, or other equipment,” says Dwyer. “Or use equipment on resident horses first, disinfect it, use on the new horse, and disinfect it again.”

Washing up after you handle the new horse is another sensible precaution. For extra protection, keep a pair of coveralls on hand to wear when you work on the horse or in its stall; take the coveralls off and thoroughly wash your hands before you handle other horses.

If possible, stalls and aisles in a quarantine area should be made of nonporous materials—varnished wood or painted concrete block walls, and asphalt, sealed rubber mats, or poured textured rubber flooring. The idea is to eliminate cracks and cavities where disease-causing agents can lurk.

What to Watch For

During the quarantine period, monitor the horse closely for signs of illness—anything from loss of appetite or a depressed attitude, to a cough or nasal discharge, to diarrhea or fever. “Taking the horse’s temperature every day is a good way to get a heads-up on any impending infectious disease problem,” Dwyer says.

Contagious diseases aren’t the only things to watch for, she adds. Shipping fever (noncontagious pneumonia and/or pleuritis), stress-induced diarrhea, colic and dehydration are also potential problems.

Obviously, if the horse shows signs of illness you should call your veterinarian at once. But even without signs of illness, it’s a good idea to review the new arrival’s health and history with your vet during the quarantine period. The vet can advise you on when and if to deworm and vaccinate for diseases in your area, based on the newbie’s vaccination/deworming history (if you have it), health, shipping stress, age, and other factors.

“A horse from Montana that has never had EEE/WEE vaccine and is shipped to Florida in July is at high risk,” Dwyer notes. She adds, “The costs of a veterinary physical examination, vaccinations and deworming are money well spent to ward off potentially deadly diseases.”

How to Disinfect

When the quarantine is finished, stalls, buckets and feed tubs should be completely cleaned and disinfected before use by another horse. Even if the newbie showed no signs of illness, he may have shed small amounts of dangerous pathogens such as Salmonella and rotavirus. “These can build up in the environment, posing a larger threat to the next horse that occupies the stall,” Dwyer says.

First, strip the stall. Take out the bedding, feed tubs and water buckets. Sweep out and then wash the walls and floor with a detergent solution. Spray with a hose to rinse, working from the top of the walls down and from the corners to the drain.

When the stall is clean, you’re ready to disinfect. Don’t use chlorine bleach—it’s rendered inactive when it meets up with manure and other organic matter that’s everywhere in barns. Dwyer recommends a phenolic disinfectant, which will work against most equine pathogens even when some organic matter is present.

Wear protective gloves, clothing, and goggles for this job. Mix the disinfectant according to the label directions, and spray the solution on the walls and floor, again working from the top down. Don’t rinse—just let the stall dry.

Use the same type of disinfectant to clean buckets, feed tubs, pitchforks and grooming equipment. Clean the item with detergent, rinse it, and then soak it in disinfectant solution for ten minutes. Pitchforks and muck tubs can be left to dry, but feed and water buckets must be thoroughly rinsed. Rinse natural bristle brushes and leather items, too, because the disinfectant can damage them.

While it may seem like a lot of work for just one horse, imagine the consequences of infecting an entire barnful. That’s when the work really begins.