What works for some horses doesn’t work for all. Developing a herd health program means taking each herd and individual horse into consideration.

Horses are extremely social animals, and naturally run in large herds. Keeping your horses in herds is an integral part of their holistic care. The herd environment comes with its own set of challenges, however – mainly, how to keep everyone happy, healthy and sound.

Herd Living

Many people choose not to let their horses live in a herd due to the risk of blemishes or injuries from herd mates. This is a real issue and often poses liability concerns when multiple owners are involved. The problem is commonly addressed by having all involved parties sign a waiver acknowledging that any horse could injure any other horse at any time in a herd, and that no one is held liable (“enter at your own risk” policy).

Injuries are most likely to occur when introducing new horses to a herd and very rarely happen when herds remain consistent. Temperament also plays a role in injury risk – horses that haven’t been properly socialized or are extremely dominant can pose additional risk. Herd mates should be chosen wisely and allowed to get to know each other over a fence for a few days before being introduced. Protective leg wraps or boots can be used for introductions to help decrease the risk of injury. Minor bite wounds and blemishes are common in most herds and are often a sign of a playful, active herd.

Once the ideal scenario of a balanced, consistent herd has been established, the next step is developing a herd health program. Such a program should not lose sight of individual health concerns – in fact, all individual needs should be addressed within the herd management plan.

Food for Thought

Nutrition is the first consideration.

• Hay should be spread in multiple piles throughout the pasture to simulate grazing. There should always be at least one more hay pile than there are horses, to avoid food aggression. • Water placement should also be carefully considered – keep it in a safe/accessible location where dominant horses are not able to trap submissive ones.

• Salt blocks and free choice minerals should also be in accessible locations for submissive horses.

When easy keepers and hard keepers are integrated into the same herd, feeding plans must be carefully managed. The two main solutions are:

a) Have separate paddocks for a few hours a day or overnight. Separating horses into individual paddocks a few hours a day works well for giving special feed or supplements – each horse can eat at his own pace and is guaranteed to get the ration he needs. It also makes it easier to check over each animal on a daily basis (i.e. appetite, water consumption, manure output, visual check).

b) Use grazing muzzles/feed bags. Grazing muzzles can be put on easy keepers at meal times and taken off after a few hours to limit their feed intake and allow others time to eat. Feed bag muzzles are also handy to feed each horse his supplements without having to separate the horses or have someone stand and police the feed bowls.

A Proper Environment

Next on the list of importance is shelter and footing.
Many mismanaged herds have horses with rain rot, scratches, thrush, abscesses and other illness because of overcrowding in shelters, mud in high traffic areas, or overgrazed pastures. The general rule is to have at least one 12’x12’ covered area for each horse. For example, a herd of three horses should have at least a 12’x36’ loafing shed. There should also be a large mud-free paddock/sacrifice area (or individual paddocks) that the herd can be enclosed in so the pasture gets a rest during the winter and wet weather. Pastures should be maintained with 3” or longer grass length in order to be healthy and weed free, so having an appropriately sized sacrifice area for the herd is essential.

Parasite Management

Herds can pose an increased risk of spreading parasites and contagious disease. New horses should be quarantined for two to four weeks before being introduced to a herd, and they should also be parasite free. De-worming programs need to be discussed with your veterinarian and tailored to each individual’s needs, as well as the herd’s. In general, horses in herds that graze on pasture have a higher parasite exposure than horses that are kept individually or who do not have pasture access.

The first line of defense in minimizing this exposure is manure management – pastures should be picked completely free from manure every day. A pasture rotation program can also be very helpful, and fecal floats on each individual horse are vitally important. Some horses tend to be parasite carriers and spreaders while others tend to be more resistant. Identifying which horses have heavy parasite loads allows you to only treat those that need to be chemically de-wormed. In general, alternating de-wormers and fecal floats at three-month intervals is ideal – so the horse is only de-wormed twice a year as long as the twice-yearly fecals are negative. The horses whose fecals come back positive are de-wormed according to what/how many parasites are found, and then a fecal fl oat is rechecked two to four weeks later before starting back into the alternating program.

Simply doing rotational de-worming every eight to 12 weeks is no longer appropriate or sufficient in some cases, as we are now seeing parasites that are resistant to multiple types of de-wormer. This problem is largely a result of years of excessive de-worming, and will continue to get worse on farms that manage parasites with this method.

Vaccination Protocol

Vaccination decisions should also be made on a case-by-case basis and discussed with your veterinarian. In Washington State, we are lucky to have never had a case of rabies in a horse, and to only have pockets of risk for eastern and western encephalitis virus and West Nile virus on the east side of the state. So unless these horses are traveling into problem regions, they do not need these vaccines. It is important to note that horses are dead end hosts for West Nile virus, which means a horse can’t spread it to another horse. So if you have herd mates traveling into a West Nile problem area, they could be vaccinated for it, but the rest of the herd back home wouldn’t need to be.

The other vaccines to consider are tetanus and flu/rhino (strangles is only considered in extreme risk situations since strangles vaccines can be dangerous for the horse).

• All horses are at risk for tetanus if they get an abscess or puncture wound, so it is generally not thought of as a herd health issue. Horses that are accident prone can be vaccinated yearly, while horses that are not can sometimes get away with vaccination every two to three years. The tetanus vaccine, however, is labeled as protective for one year, so consult your veterinarian before deciding to skip this one.

• Flu/rhino is the main vaccination to consider in herd situations. In most cases these viruses are similar to the common cold and resolve uneventfully with minimal care. They can, however, turn life-threatening with dehydration, colic or neurological problems. Since the vaccines are not very effective against all strains anyway, the choice is a personal one you should make based on risk of exposure. Herds that are static and don’t go to shows are at low risk for fl u and rhino, whereas herds in which one or all the horses travel to shows (or herds that are changing members frequently) are at high risk for these viruses.

Since vaccines are not without risk, a “less is better” approach should be taken. The horses should only be vaccinated for things they really need. Vaccination titers can be done to help assess the level of immunity the horse has, so that vaccines can be skipped if he already has a high level of immunity. Titers are expensive to run but well worthwhile, particularly for horses sensitive to vaccinations. Many boarding stables with vaccination requirements will accept titers in lieu of vaccination, so be sure to discuss this with the barn manager before assuming you are required to vaccinate for something you don’t want to.

The Holistic Lifestyle

In general, horses kept in a holistic fashion (in a balanced herd) are less stressed and healthier overall. Their immune systems are stronger than their stressed (individually housed) counterparts. Contagious disease is less likely to run through a large barn where horses are kept in herds versus a barn where horses are kept individually. Large barns with horses kept in separate stalls and runs tend to have a higher rate of disease transfer since the horses can still make nose-to-nose contact with their neighbors and their stress levels are considerably higher.

Keeping horses in herds does have some risk, but the benefits by far outweigh the risks when the herd is properly managed. If your horse does not have a buddy, consider adopting a non-rideable (“pasture pal”) horse from a rescue organization to keep your equine happy and healthy. This makes for happy horses and a win-win situation!

Dr. Hannah Evergreen is a graduate of Oregon State University College of Veterinary Medicine. She has loved, cared for, ridden and trained horses most of her life – they are her passion. She started her own mobile veterinary practice in Monroe, Washington in December of 2004 and offers full service equine veterinary care including acupuncture, chiropractic, advanced dentistry, sports medicine and more. Find out more at ehvcequine.com.