Wednesday, May 25, 2011

BIOSECURITY: Protect your horses against EHV-1 and more

The term “biosecurity” may bring to mind movie images of shadowy government types in white HAZMAT suits tracking down some lethal organism that threatens all of mankind. But though it might sound like something that would only concern those who spend their lives tracking terrorists and ebola, biosecurity actually has very real applications for those of us down home on the farm.  No, there have not been any reports of terrorists planning biological weapon attacks on horse farms, but our horses do face a number of threats every day -- as the recent EHV-1 outbreak has demonstrated -- and biosecurity is all about what we can do to protect them.

            Looking at your horse farm in terms of biosecurity is in some ways similar to a military operation: you must identify the threats against you, identify any weaknesses in your operation that make you vulnerable to those threats, determine strategies to counter the threats, then implement those strategies with order and determination. Dropping the ball in any of these areas can leave your horses open to infectious diseases.

IDENTIFYING THE THREATS

            Some pathogens are restricted to a certain geographical area, while others seem to be able to exist almost anywhere. Periodically, pathogens that have not been present in one location may suddenly appear, while others come and go regularly with the seasons. Your veterinarian is your best resource for helping you to determine what diseases are of concern in your area at any given time. Keeping in touch with your veterinarian and planning your vaccination schedule according to local needs will help you stay ahead of the curve as much as possible. However, if you are traveling with your horses, you need to find out what threats are present in the area you are going to. Contacting a vet or agricultural extension office in that area is a good way to get the facts – but make sure you do this as far in advance as possible, as your horse may need additional vaccinations that can take weeks or even months before full immunity is established.
           
IDENTIFYING WEAKNESSES

Understanding how various diseases are transmitted is the first step in determining how exposed your farm is to any specific threat. Some pathogens, like West Nile Virus, require a vector such as a mosquito to transmit the disease. Others, like tetanus, are caused by organisms commonly present in feces or the soil. Of particular concern are contagious diseases like strangles that can be passed from horse to horse, or by people and objects that have been in contact with an infected horse.

Once you know how different diseases are transmitted, you can assess how likely it is for your horses to come in contact with each threat. Some horses and some farms are more vulnerable to certain threats due to their location, the kind of operation the farm is, or the activities the horses are involved in. If your location has a large opossum population, for example, your horses will be more vulnerable to contracting Equine Protozoal Myeloencephalitis (EPM). If your barn has an ever-changing roster of horses, either because it is a boarding operation or because horses are coming and going from shows, you will have an increased risk of introducing contagious pathogens into your population. Those running breeding farms need to be vigilant about sexually transmitted diseases – even with the use of chilled or frozen semen – and those that can cause mares to abort. Farms with foals need to particularly aware of the diseases that can attack youngsters.

COUNTERING THE THREAT

            As we’ve already mentioned, appropriately timed vaccinations against known threats are an important part of any biosecurity plan. It may be tempting to buy cheap vaccines online and administer them yourself, but keep in mind that your veterinarian can provide valuable guidance to help you decide which horses need which vaccinations at what times. You may also want to ask about whether it is safe to give multiple vaccines at once, or if it is best to space them out.

            Another key to good biosecurity is to have a protocol and dedicated area to quarantine any new arrivals. This does not just mean horses that haven’t lived in your barn before – it also applies to any that have left your property and returned (e.g. from shows, breeding farms, hospitalization). It’s not safe to rely on the healthy appearance of the new arrival, because many diseases have an incubation period – some up to several weeks or more – meaning that they can be harboring an illness but not yet showing symptoms.  By the time a horse is symptomatic, that horse may have already exposed many other to an infectious disease. The Ontario Ministry of Agriculture, Food & Rural Affairs (OMAFRA) recommends quarantining new or returning horses for at least 30 days. – even those who are returning home.

However, quarantine does not mean that the horse is put into a dark dreary stall and isn’t shown the light of day. It does mean the horse is not in direct contact with resident horses on the farm. Ideally, the horse should be housed in a separate barn or pasture where no nose-to-nose contact can be made with resident horses. If a separate quarantine area is not possible, try to at least house new arrivals at one end of the barn and keep them separate from broodmares and young horses, who are at greater risk of contracting infectious diseases.

In addition, horses in quarantine should not share water, feed bins, tack or grooming equipment with other horses. Manure from their paddocks and stalls should be taken to an isolated area and not come into contact with other farm animals. Ideally, you would not take a wheelbarrow or other tools from the quarantine area into a non-quarantine area.

All new arrivals should also have the following updated records prior to stepping off the trailer at your facility:

·        A current health certificate/exam
·        Up-to-date health records including health history, current vaccinations and deworming information
·        Current negative Coggins test (EIA)

While even fully vaccinated horses can contract and spread even the diseases they are vaccinated against, your risks are lower if you insist on such records.

While we can’t require health certificates for the humans on our farms, it is important to recognize that people can also spread disease to horses through their hands, clothing and shoes. According to the OMAFRA website, “The horse industry is very lax when it comes to personal hygiene as a means of preventing the spread of disease. To prevent the spread of disease, the swine and poultry industries require that their employees "shower in and shower out" of their facilities. Horse people, however, commonly go from barn to barn and from a show to home without any concern for disease spread.” Horse farms would be less vulnerable to infectious diseases if we followed similar protocols.

It is therefore best to put one person in charge of handling sick or quarantined animals on a farm. It is easiest to accomplish this if these duties are conducted at the end of the work day to reduce exposure to other horses. If the caretaker must work with sick or quarantined animals prior to caring for other animals then he/she should shower and change both clothes and shoes before working with other horses.

Visitors present another avenue to transmit infectious disease.  Visitors that have not had any contact with other livestock are at a low risk for bringing infectious organisms to the farm. However, they could still spread disease from barn to barn on the farm. Therefore, when giving farm tours, you should always start the tour with the young horses and broodmares and then move to the rest of the farm. This limits exposure of your most susceptible stock.

All visitors should wash their hands and dip their feet in a foot bath prior to touring the farm. It is a good practice to have hand cleaning stations and foot baths between barns.  If a person is coming from another horse farm and handles horses, they are at a high risk of spreading infectious diseases. This includes your veterinarian and farrier. If there is concern about a potential outbreak, you can ask them to shower and change shoes and clothing prior to coming onto your farm.  It is also a good precaution to ask visitors not to pet or feed horses.

Vehicles are another potential source of infection for your farm. Trailers that have hauled sick or new livestock should be thoroughly cleaned before hauling other farm stock. In addition, tires can spread infectious organisms from one location to another. Therefore the underside of the truck and trailers should be cleaned as well. Similar precautions should be taken with standard farm equipment like wheelbarrows, tractors, and manure spreaders.

Keep in mind that vehicles driven by veterinarians, farriers, feed dealers, and trainers may also be carrying potential pathogens on their tires and undercarriage. It is best to have all off-farm vehicles park in an area away from where horses are housed. On large farms, it is worthwhile to have an area outside of the general farm activities where farriers and veterinarians can work with horses and still have access to their equipment from their truck.

Other measures you can implement to beef up your farm’s biosecurity include:

·      Having separate brushes, tack and feed buckets for each horse, with clear labels and color coding if possible
·      Disinfecting stalls regularly (ask your vet about which disinfectants are most effective yet safe around horses)
·      Disinfecting any rented stall at a show or other temporary housing prior to putting your horse in it
·      Not letting your horse touch or sniff noses with new horses. This applies at home, on the trail and at shows
·      Minimizing the traffic of wildlife through your farm
·      Storing all feeds in rodent-proof bins, and doing your best to keep vermin out of your hay
·      Keeping manure piles well away from your horses, and not spreading fresh manure on fields where horses graze
·      Protecting your horses from flying insects.

IMPLEMENTING STRATEGIES

            Having a good biosecurity plan means nothing if it is not carried out. Though it may seem onerous and difficult at first, these measures soon become habitual if you incorporate them into your daily routine. Barn staff and visitors may scowl a bit initially, but when your horses remain healthy during the next outbreak sweeping the neighborhood, those same folk will be knocking on your door (after dipping their feet and washing their hands, of course), to ask for advice on how they can improve their own farm’s biosecurity.

            For additional information on biosecurity for horse farms, see the OMAFRA website pages:
And check out this great Equine Biosecurity Risk Calculator from the University of Guelph: http://www.equineguelph.ca/education/biosecurity.php