Biosecurity

When it comes to your horse’s care, you are meticulous in every nutritional, veterinary and physical need. You keep his stabling tidy and hygienic, the tack clean and shiny. Yet, one factor often gets overlooked – biosecurity. It is common for horse owners to introduce new individuals into a stabling environment or a herd immediately and without concern. However, just as people can carry or incubate disease and pass it on to unsuspecting persons at a meeting, in the supermarket, or on an airplane, horses can do the same to other equids on the farm or while away at events.

The strategy to minimize this transmission risk is termed biosecurity: It is the compilation of management protocols that limit transmission and spread of infectious diseases like bacteria, viruses, or fungal infections wherever horses congregate. Recent, serious outbreaks of highly infectious and potentially fatal equine neurologic herpesvirus (equine herpes myelitis, or EHM) persistently pop up throughout the country; biosecurity is to be taken seriously. Anytime horses congregate at home or away, they are subject to exposure to any number of infectious diseases, such as strangles (Streptococcus equi), equine influenza virus, equine rhinopneumonitis (herpesvirus), vesicular stomatitis virus, and Salmonella, as just a few examples.

There are effective equine vaccines against two viral respiratory diseases – equine rhinopneumonitis and influenza – which is one method of helping to contain spread of these diseases. A vaccination exists for strangles, but is often used primarily only on at-risk horses. Besides vaccinations, there are innumerable methods to maximize biosecurity and keep your horse’s health as safe as possible.

Practical Biosecurity

Every facility has the ability to implement methods to keep horses safe from infectious disease. This starts by considering isolation techniques for new incoming horses, as well as for those that go out and about to training, events, and races.

Keep tabs on every horse on the property. Know what is normal for each individual and have barn personnel communicate if anything is amiss with a horse’s attitude, appetite, and manure and urine output. Anytime something seems out of the ordinary, take the horse’s rectal temperature. Temperatures exceeding 101o F in a horse that isn’t feeling himself is a good reason to isolate the horse until your veterinarian determines what is wrong. Many biosecurity recommendations suggest grouping horses by risk (age, breeding, use, health) and in small groups (mares and foals; or traveling horses) so there is efficient containment in the event of a disease outbreak.

Before admitting a new horse to a property, insist on a certificate of veterinary inspection (CVI, which is a health exam and veterinarian-signed certificate) within a few days of entry as well as a negative Coggins test for equine infectious anemia (EIA). It is also prudent to ask for a negative fecal exam prior to moving a horse to the facility and/or that it has been dewormed appropriately in the preceding week or two. A horse – whether as a carrier or one that is incubating illness – does not necessarily show overt signs of sickness while still being able to shed disease. Also, ask for the horse’s travel history to check if there have been any disease outbreaks at other venues the horse may have visited. This can be tracked through the Equine Disease Communication Center (http://www.equinediseasecc.org), which continually updates suspicion and confirmation of any infectious disease in horses throughout the country. 

Set up an isolation area a good distance away from resident horses. A minimum distance for controlling spread of equine herpesvirus is at least 30 feet. Other infectious diseases (like equine infectious anemia (EIA or Piroplasmosis) have a required distance of 200 yards between suspect or infected horses and other equids. The concept of isolation is not just about the distance. It is also about the concept and implementation of multiple biosecurity practices. 

Often there is pushback to setting up isolation strategies, especially in big training or boarding barns where horses often come and go to events. There should be no opportunity for nose-to-nose contact or shared watering vessels between resident horses and those traveling or newly entering the farm. Horses brought in only for training should have no contact with others on the farm. 

Stabling in the barn can also be a problem. Air ventilation systems within barns can blow pathogens (e.g. influenza and rhinopneumonitis viruses) through the air footprint. Ideally, a newcomer stays completely out of touch with other horses for 2-3 weeks to ensure that he isn’t incubating disease. The length of time for isolation is dependent on knowledge of the horse’s health status and the health management program at the previous stabling as well as incubation times known for various pathogens. 

All feeding and cleaning chores are provided to a newcomer (or sick horse) only after taking care of resident horses. Watering hoses shouldn’t touch buckets or water within the containers. Equipment like manure buckets, rakes, wheelbarrows, tractors, blankets, grooming tools and tack shouldn’t be shared between the isolation area and the resident horses. Label tools and implements used in an isolation area, so they aren’t inadvertently mixed in with the resident herd equipment. Color code buckets to designate what is used where; highest risk areas may use red, for example. Good signage also impresses people about the location and seriousness of keeping the isolation area isolated.

Observe an incoming horse closely and keep a daily log kept of rectal temperature, attitude, appetite, manure and urine output. Educate yourself on normal vital signs so you know when a horse isn’t quite right. Have your veterinarian immediately investigate any signs of malaise, fever, diarrhea, cough, ocular or nasal discharge, or neurologic instability.

Another important consideration is personnel who come into contact with horses: Barn help who feed and muck, trainers, farriers, veterinarians, alternative therapists, bedding suppliers, hay delivery people, fence repair persons, to name a few. These people come across many horses in their daily rounds with the potential to bring disease along with them on their hands and clothes, and even within their nose. Hand washing with liquid soap in between handling different horses is a simple good hygiene practice for everyone to follow. A general rule is to sing “Happy Birthday” twice while scrubbing. Hand sanitizers with a minimum of 61% alcohol can also be used if hand washing isn’t available and if there is only minimal contamination on the hands. An appropriate amount (2-3 cm diameter, i.e. about an inch) of hand sanitizing gel must be applied, rubbed in well and then allowed to dry for 15-20 seconds. 

Some farms require that every visitor sign in to a visitor log – this ensures a trace back should an outbreak occur. When possible, all visitors should park away from barns, paddocks and pastures. If anyone has visited other farms where they have encountered sick or not-quite-right horses, then request that they come back another day once cleaned up, in fresh clothing and footwear. Use of bactericidal and viricidal footbaths is important for disinfection of footwear under all circumstances.

Throughout the farm, dedicate implements like shovels, rakes and pitchforks with separate uses for either manure cleanup or application of bedding, but not both. Consider direction of water drainage so there is no chance of contamination of any part of the farm with any other part. Manure management and elimination of standing water are important, too, to minimize flies and mosquito vectors that can carry disease around the property. The United States Department of Agriculture’s Animal and Plant Health Inspection Service (USDA-APHIS) notes a sobering fact of just one example: “Each fly acting as a mechanical vector can carry 6,000 Salmonella organisms at one time.”

Children and small animals (cats and dogs) as well as wild animals (rodents, raccoons, opossums, etc.) also can carry disease around a farm. Cats, dogs, and children are manageable to some extent, although wild animals are not. Remove wild animal attractants and store feed supplies within animal-proof containers, rooms or buildings. Clean up spilled or leftover feed and remove trash regularly.

It is often difficult to figure out what to do with horses that travel regularly off the farm and back again. Do you isolate them into separate areas altogether, or reintegrate them back into the herd or barn? It helps to segregate traveling horses into their own group and with as much distance as possible from others on the farm. Many horse owners are fairly lackadaisical about following biosecurity protocols in these situations, especially during a busy training and competition season. If no special measures are taken on the farm, then at the very least, caution should be taken when away. 

Horse trailers also move on and off the property, with horses and horse secretions abundant on the interior surfaces. For example, influenza virus remains infective in this kind of dark, cool, moist environment for 7-10 days; herpesvirus can remain infective in manure for up to 35 days. Remove all soiled feed, water, and manure; dispose of these away from the resident herd in dumpsters or well-tended compost piles. Trailers are best parked away from resident horses and cleaned and disinfected as often as possible, especially after returning from an off-site location. Spray trailers both inside and outside with pesticides to limit infection brought in by insect vectors. Clean floor mats in the vehicle and don’t forget to wipe down the vehicle’s steering wheel with antiseptic or baby wipes to remove accumulated microbes.

Preparation is Key

Have a plan at the ready in the event that something falls through the cracks and an outbreak occurs on your farm. Know in advance where to move sick horses away from the others, how to monitor every horse on the property, and the logistics of caring for both well and sick animals during an outbreak. Consult with your veterinarian for details on how best to accommodate this situation.

Biosecurity strategies are part of waging a war on equine infectious disease not just on your farm, but also around the country. While this multitude of efforts may at first glance seem labor intensive, keeping your herd’s health paramount through simple biosecurity steps can save you from great difficulty, expense, and intensive labor. The objective is to prevent an infectious disease outbreak in the first place and to keep your horse “healthy as a horse.”