Disease Control Strategies
Control of disease in your horse
requires a combination of good
management, proper vaccination schemes, and a good working relationship with your veterinarian. There are three
factors that impact the development of a preventative health care program:
horse factors, location factors, and owner factors.
- Horse factors: number/population
density, age, type and use of horses, and value of horses.
- Location factors: facilities,
climate, endemic disease, and population fluxes.
- Owner factors: cost of prevention
vs. cost of disease, likelihood of disease, potential zoonoses (spread of
disease from animals to humans), and management style.
Management factors that may influence
disease on your farm include: nutrition, isolation of new arrivals (very
important). Stable and pasture design, stable and pasture hygiene, pasture
management, routine screening tests for some diseases.
The vaccination schedule that you
choose for your horses will depend on: age of horse(s), efficacy of available
vaccines, likelihood of disease exposure and cost of vaccine vs. cost of
Timely vaccination of your horse is
important for proper health and performance. In North Carolina, horses should
be vaccinated for the following:
a bacteria that lives in the soil. Horses should be vaccinated every year with
tetanus toxoid vaccine. Do not administer tetanus antitoxin to your horse
without first consulting your veterinarian. This vaccine may cause an allergic
reaction of the horse’s liver which can be fatal.
Influenza (Flu) is a virus that can cause fever, cough and nasal discharge.
It is easily transmitted to other horses. Horses at risk (especially young
horses) should be vaccinated twice a year.
Encephalomyelitis (EEE/WEE/VEE) is a neurological disease (sleeping sickness) that can cause
death and in transmitted by mosquitoes. The warm moist climate of North Carolina
makes an ideal breeding ground for mosquitoes. We recommend vaccination at
least twice a year.
West Nile Virus vaccination should be given to horses twice yearly. West
Nile Virus a viral disease that can cause encephalitis or meningitis, infection
of the brain and the spinal cord or their protective covering. It is spread via
Rhinopneumonitis (Rhino) is caused by a herpes virus that can cause fever, cough, and
nasal discharge. This virus may also cause abortion in pregnant mares, or may
cause neurological disease. Rhinopneumonitis is a contagious organism that can
spread through barns via nose-to-nose contact between horses, or on the hands
of people handling the horses. Vaccination of performance horses should be at
least twice a year.
Equine Viral Abortion (Rhino) is also caused by a herpes virus and infection may result in
abortion. Pregnant mares should be vaccinated at the beginning of the 5,
7, and 9 months of pregnancy.
Rabies is a virus that can affect humans,
horses, dogs and cats – actually, any mammal. With the increasing number of
rabies cases in North Carolina, we recommend vaccination annually to protect
your horse from this fatal disease. This vaccine must be administered by a
veterinarian or a state-approved veterinary technician.
Potomac Horse Fever(PHF) is a viral disease that can cause colic, diarrhea, fever and
other non-specific signs of illness. PHF has not been reported in our area, but
if your horse travels in endemic areas, vaccination is warranted. The horse
should receive its first shot and a booster 30 days later. Annual revaccination
Strangles is caused by the organism Streptococcus equi and can cause swollen lymph nodes that may
abscess. Rarely, the guttural pouches of the horse may become infected, or the
organism may cause abscesses in the thoracic or abdominal cavity. Some stables
may require strangles vaccination for horses coming onto the property. The
intramuscular vaccine may cause abscesses and soreness at the injection site.
The absolute efficacy of the vaccine is unclear. An intranasal vaccine is
available, but the efficacy (usefulness) of this vaccine is unproven.
Additionally, vaccination of some horses may result in swollen lymph nodes, and
possible lymph node abscessation.
Suggested vaccine schedule:
We suggest that the “spring”
vaccines be performed between February and April, and the “fall” vaccinations
be performed between August and October.
Broodmares should follow a regular
vaccination program, but be sure to always use only killed vaccine products.
Add Pneumabort K or other killed herpes product that is approved for use in pregnant
mares at the 5, 7, and 9 months of
gestation. Administer tetanus, sleeping sickness, West Nile, and intramuscular
influenza vaccines 30 days prior to foaling.
Botulism, strangles, rotavirus and
Potomac horse fever vaccinations are based on your horse’s needs. Please
consult with us about these vaccines.
Early Disease Recognition is very important! Owners and trainers should observe all
horses daily for changes in attitude, appetite, or behavior. Monitor feed and
water intake, and fecal production at least once a day. You should try to
maintain regular communication with a veterinarian familiar with your horses.
If you think a horse may be sick, isolate it immediately if you think you may
have an infectious problem. A major flaw in most horse operations is failure to
isolate or quarantine horses prior to integration into the herd. Newcomers to
your property should be isolated for at least 2 weeks, and monitored for signs
of disease, especially cough, nasal discharge and swollen lymph nodes.
Equine Infectious Anemia (EIA) is caused by a retrovirus and once infected, the horse remains
infected for life. The clinical signs are fever, weight loss, ventral edema,
moderate anemia, depression, and thrombocytopenia (low platelet count). Or
there can be no clinical signs of the disease. Horses with no
clinical signs can serve as a source of infection for other horses near them. There is no vaccine or treatment for this
disease. The virus is spread form horse to horse by biting horseflies and
deerflies, but not mosquitoes. Using the same needle on multiple horses could
also spread the virus.
Coggins testing: Each horse should be tested annually for EIA. The test for
this extremely contagious disease is called the “Coggins” test. In NC, positive
horses must be quarantined, euthanized, or moved to a recognized research
facility. If a horse tests positive, the laboratory immediately notifies the
state veterinarian. The state veterinarian will repeat the Coggins test to
verify the results. Horses that test positive for EIA must be permanently
identified by a brand on the left side of the neck. A negative test is required
for any horse to cross state lines.
Prevention of EIA:
- Require a negative EIA test as part
of every prepurchase exam
- Require all new horses on a farm to
have an EIA test within 12 months of their arrival.
- Test all horses on the farm at
- Encourage rigorous fly control; do
not pile manure near areas where horses gather.
- Thoroughly disinfect any items
contacting equine blood prior to use on another horse.
- Never use the same needle for
multiple injections on different horses.
of all ages are subject to tooth abnormalities that can adversely affect their
ability to chew and maintain body weight. In addition, tooth problems may lead
to infections or may cause soreness resulting in performance problems. In
contrast to humans, the teeth of horses grow continuously during their lives.
The horse chews its food by grinding from side to side. Excessive tooth growth
is thus limited by slow, continuous grinding away by the opposing tooth, Many
horse owners think that a horse does not need dental care or dental
examinations until it is old or having problems. Not true! Annual examinations
during routine vaccination visits by your veterinarian allow for early
detection of dental problems. Older horses may benefit from twice-a-year
examinations. These regular examinations allow for correction of tooth problems
before the horse experiences pain or has trouble maintaining its weight.
Problems to watch out for include:
- Sharp edges on the outside edge of the upper molars
and premolars and the inside edge of the lower molars and premolars. These
sharp edges are caused by the side-to-side grinding of feed during chewing.
Over time, these sharp edges may cut into the cheek or tongue, making it
painful for the horse to chew. In less severe cases, the horse may experience
discomfort when ridden, resulting in head-shaking or problems with the bit.
- Hooks on the premolars and molars as a
result of overbite or underbite. When the teeth do not meet properly
(malocclusion), the teeth are not worn down uniformly by an opposing tooth.
This results in a hook, most commonly in the first upper cheek tooth (premolar
2). A hook on this tooth may cause problems with the bit. More importantly, the
presence of a hook on the first upper cheek tooth signals a potential problem
of the last lower cheek tooth. A hook on this last tooth may cause the horse
considerable pain leading to serious weight problems and even colic.
- Wave mouth is an abnormality where the teeth
have an undulating pattern from front to back. In this condition, some teeth may
be too long relative to the adjacent teeth, and other teeth may be worn down to
the gum line.
- Step mouth is when the front cheek teeth are
longer than the back cheek teeth. Both wave mouth and step mouth may interfere
- Broken or split teeth –
if broken off below the gum line, do not cause a problem. Care must be taken
that the opposing tooth does not become overgrown.
- Infected tooth roots may cause the horse pain and may
result in extension of infection into the maxillary sinus. The signs of an
infected tooth root and maxillary sinusitis include fetid-smelling nasal
discharge and foul breath, and possibly swelling over the side of the face.
This problem can be diagnosed by radiography and can be treated by removal of
Probably the most serious problem associated with tooth
problems in horses is an inability to maintain body weight. As the horse ages,
its digestive efficiency diminishes. This problem is compounded if the horse is
not able to chew the feed effectively. A sign that your horse is having
problems with teeth is excessive dropping of hay and grain when eating, a
problem known as quidding.
Horse owners often spend large amounts of money on
feed and supplements for horses that have undiagnosed tooth problems. With
advances in veterinary care, especially in parasite control, horses are living
longer. In extreme cases, older horses may actually grind their teeth down to
the gum line. Horses with severe dental problems may require special diets to
maintain their body weight. This may include feeding all-in-one pelleted feed
that can be softened, if necessary, by soaking.
dental care is essential to the health of the horses. Regular teeth filing,
known as floating, is tolerated well by most horses and can be done with
minimal restraint. In some cases, it may be necessary to sedate the horse to
facilitate floating. More severe cases, especially those involving hooks on the
back teeth, may require the horse to be deeply sedated or possibly
summary, horses with problems gaining weight and horses with performance
problems such as head-shaking or discomfort with the bit, benefit from dental
examination by your veterinarian. It is much easier on the horse to have dental
problems corrected before they become severe. All horses should have their
teeth examined annually by a veterinarian, and older horses will benefit from
twice-a-year examinations. And remember, dolook that gift horse in the mouth. A horse with severe dental problems may
require extensive work by a veterinarian or costly feed supplementation to
maintain body weight.