Equine Wellness Program
Strasburg Veterinary Clinic's Equine Wellness Program is designed to focus on both wellness and preventative medical treatment for horses of all ages. Some of our services include, but are not limited to:
- Core Vaccines (see Infectious Disease Control info below)
- At-Risk Vaccines (see Infectious Disease Control info below)
- Floating and Extractions
- Reproduction, inlcuding insemination, prenatal care and delivery
- Radiology
- Elective Surgeries
- Mobile Services
- Hospitalization and Treatment
- Pre-Purchase Exams
Please call our offices if you have any questions about the services listed above or to inquire about services not listed.
Infectious Disease Control Program
Programs for the control of infectious diseases are important components of good managerial practices directed toward maximizing the health, productivity and performance of horses. Infectious disease in an individual horse, or outbreaks of infection within a group of horses , occurs when sufficient quantity of an infectious agent overcomes the resistance acquired through prior natural exposure to the disease agent or through vaccination.
An Infectious Disease Control Program should be directed toward:
-Reducing the exposure to infectious agents in the horses’ environment
-Minimizing factors that decrease resistance or increase susceptibility to disease
-Enhancing resistance to those diseases by vaccination
Consistent utilization of such management programs will, in time, lower the incidence and/or severity of infectious diseases.
Occurrence of infectious diseases in populations of horses tends to increase with:
-Increase population density of susceptible horses at a facility (High population density situations as found on breeding farms, in sales or boarding facilities, in barns of performance and show horses, or at racetracks are often ideal for introduction and transmission of infectious diseases, particularly infections of the respiratory tract.
-Movement of horses on and off the facility (The introduction of horses from various origins, commingling of horses of different ages, and the high proportion of susceptible horses pose special problems and demonstrate some important considerations in the practice of disease control).
-Environmental and managerial influences (examples of external factors that can contribute to increased risk include stress, over-crowding, parasitism, poor nutrition, inadequate sanitation, contaminated water supply, concurrent disease, inadequate rodent, bird and insect control, movement of people, vehicles and/or equipment on and off of facilities during outbreaks).
Copies of vaccination and health maintenance records should accompany the movement of horses. Also, owners of equine facilities should establish health entry prerequisites, including, but not limited to, vaccinal history. Horses should be appropriately vaccinated no later than one month prior to entering or leaving such a facility in order to produce adequate antibodies before the anticipated exposure.
Principles of Vaccination
A “standard” vaccination program for all horses does not exist. Each individual situation requires an evaluation based upon the following criteria:
-Risk of disease (anticipated exposure, environmental factors, geographic factors, age, breed, use and sex of the horse).
-Consequences of the disease (morbidity/mortality)
-Anticipated effectiveness of the selected products
-Potential for adverse reaction to vaccine
-Cost of immunization (time, labor and vaccine costs) versus potential cost of disease
Owners should have realistic expectations and understand that:
-Vaccination alone, in the absence of good management practices of infection control, is not sufficient for the prevention of infectious disease.
-Vaccination serves to minimize the risks of infection but cannot prevent disease in all circumstances.
-The primary series of vaccines and booster doses should be appropriately administered prior to any like exposure
-Each horse in a population is not protected to an equal degree nor duration following a vaccine.
-Protection is not immediate after the administration of a vaccine. In most cases, a series of doses must be administered for that vaccine to induce protective active immunity.
-All horses in a herd should be vaccinated at intervals based on the professional opinion of the attending veterinarian.
-A properly administered, licensed product should not be assumed to provide complete protection during any given field epidemi
-Although rare, there is potential for adverse reactions despite appropriate handling and administration of vaccines.
Core Vaccine Schedules
Core Vaccines are vaccines that all horses should have each year to prevent the contraction of the most common diseases. Please note that while these vaccines are available from the Strasburg Veterinary Clinic at any time, we do host an Annual Vaccine Clinic in April that provides these vaccines along with an exam at a reduced price.
Tetanus
Adult Horses Previously Vaccinated: Annual Revaccination
Adult Horses Previously Unvaccinated or History Unknown: 2 doses primary series within a 4-6 week period, then annually thereafter
Pregnant Mares Previously Vaccinated: Vaccinated 4-6 weeks prior to foaling
Pregnant Mares Previously Unvaccinated or History Unknown: 2 dose primary series within a 4-6 week period, then revaccinate 4-6 weeks prior to foaling
Foals of Mares Vaccinated in Pre-Partum Period: 3 dose series beginning at 4-6 months of age with 4-6 week intervals for first and second dose, and third dose at 10 to 12 months of age
Foals of Unvaccinated Mares or Unknown History: 3 dose series beginning at 1 to 4 months of age with 4 week intervals between doses
Horses Having Been Infected and Recovered: Revaccinate Annually
Eastern/Western Equine Encephalomyelitis
Adult Horses Previously Vaccinated: Annual Revaccination
Adult Horses Previously Unvaccinated: 2 does series within 4-6 week period, then annually.
Pregnant Mares Previously Vaccinated: Vaccinate 4-6 weeks prior to foaling
Pregnant Mares Unvaccinated or Unknown History: 2 dose series within 4-6 weeks, booster 4-6 weeks prior to foaling
Foals of Mares Vaccinated in Pre-Partum Period: 3 dose series beginning at 4-6 months of age with 4-6 week intervals for first and second dose, and third dose at 10 to 12 months of age
Foals of Unvaccinated Mares or Unknown History: 3 dose series beginning at 1 to 4 months of age with 4 week intervals between doses, and the third does given at 10-12 months of age
Horses Having Been Infected and Recovered: Recovered horses likely develop lifelong immunity. Consider revaccination only if the immune status of the animal changes the risk of susceptibility.
Adult Horses Previously Vaccinated: Vaccinate in spring prior to onset of insect season
Adult Horses Previously Unvaccinated or History Unknown: 2 dose series with 4-6 week intervals between doses
Pregnant Mares Previously Vaccinated: 4-6 weeks before foaling
Pregnant Mares Unvaccinated: 2 dose series with 4-6 week intervals between doses
Foals of Vaccinated Mares: 3 dose series beginning at 4-6 months with 4-6 week interevals between first and second dose. Third dose administered at 10-12 months of age
Foals of Unvaccinated Mares: 3 dose series beginning at age 3-4 months, and, when possible, completed before the onset of insect season.
Horses Having Been Infected and Recovered: : Recovered horses likely develop lifelong immunity. Consider revaccination only if the immune status of the animal changes the risk of susceptibility.
Rabies
Adult Horses Previously Vaccinated: Annual Revaccination
Adult Horses Previously Unvaccinated or Unknown History: Administer a single primary dose. Revaccinate annually
Pregnant Mares Previously Vaccinated: Vaccinate 4-6 weeks prior to foaling
Pregnant Mares Unvaccinated or Unknown History: Vaccinate 4-6 weeks before foaling
Foals of Mares Vaccinated: Administer primary series with first dose not administered earlier than 6 months of age. Second dose 4-6 weeks later.
Foals of Mares not Vaccinated: Administer first does at 3-4 months of age. Revaccinate annually thereafter.
Foals of Mares of Unknown Vaccinal History: Follow one of two rational options:
1. Assume mare to be antibody-positive and follow above recommendations for Foals From Mares know to be vaccinated-first dose at 6 months, then second 4-6 weeks later with annual revaccination.
2. Document the rabies antibody status of the foal by testing the serum collected from the foal at 24 hours of age or older, or from the dam during the peri-patrurient period. If the foal of mare is rabies antibody-negative, follow the above recommendations for foals of mares known not to be vaccinated against rabies. If foal is antibody-positive, follow recommendations for Foals of Mare Known to be Vaccinated Against Rabies.
Horses Exposed* to Confirmed Rabid Animal:
1. Horses currently vaccinated against rabies with USDA-approved vaccines: Immediate revaccination by a licensed veterinarian and observation for 45 days for the development of clinical signs of rabies.
2. Unvaccinated Horse: Euthanize Immediately.
*Rabies exposure and transmission occur only when the virus is introduced into bite wounds, into open cuts in the skin, or onto mucus membranes from saliva or other potentially infectious material such as neural tissue.
At-Risk Vaccines
At-Risk are vaccines that should be administered prior to exposure of animal to a situation where these diseases may pose a risk. Contact one of our doctors to see if you may need vaccination against any of the following diseases.
Anthrax
Adult Horses Previously Vaccinated Against Anthrax: Annual Vaccination
Adult Horses Previously Unvaccinated or History Unknown: Administer primary series of 2 doses within a 2-3 week period. Vaccinate annually thereafter
Pregnant Mares: Not recommended
Foals: No specific information available
Botulism
Previously Vaccinated Pregnant Mares: Vaccinate annually with single dose 4-6 weeks prior to foaling
Previously Unvaccinated Pregnant Mares: Vaccinate during gestation with primary series of 3 doses at 4 week intervals and scheduled so last does will be administered 4 to 6 weeks prior to foaling
Foals of Vaccinated Mares: Administer a primary series of 3 doses at 4 week intervals, starting at 2-3 months of age.
Foals of Unvaccinated Mares: Administer primary series of 3 doses at 4 week intervals, beginning at 1 to 3 months of age.
All Other Horses: Administer a primary series of 3 doses at 4 week intervals, followed by annual vaccination.
Horses Having Been Naturally Infected and Recovered: Duration of immunity following natural infections if highly probable. May give a primary 3 dose series after fully recovered from disease.
Equine Herpesvirus (Rhinopneumonitis)
Adult, non-breeding, horses previously vaccinated against EHV : Frequent vaccination of non-pregnant mature horses with EHV vaccines is generally not indicated as clinical respiratory disease is infrequent in horses over 4 years of age. In younger/juvenile horses, immunity following vaccination appears to be short-lived. It is recommended that the following horses be revaccinated at 6-month intervals:
- Horses less than 5 years of age.
- Horses on breeding farms or in contact with pregnant mares.
- Horses housed at facilities with frequent equine movement on and off the premises, thus resulting in an increased risk of exposure.
- Performance or show horses in high-risk areas, such as racetracks, more frequent vaccination may be required as a criterion for entry to the facility.
Adult, non-breeding horses unvaccinated or having unknown vaccinal history: Administer a primary series of 3 doses of inactivated EHV-1/EHV-4 vaccine or modified-live EHV-1 vaccine. A 4- to 6-week interval between doses is recommended.
Pregnant mares: Vaccinate during the fifth, seventh, and ninth months of gestation using an inactivated EHV-1 vaccine licensed for prevention of abortion. Many veterinarians also recommend a dose during the third month of gestation and some recommend a dose at the time of breeding.
Vaccination of mares with an inactivated EHV-1/EHV-4 vaccine 4 to 6 weeks before foaling is commonly practiced to enhance concentrations of colostral immunoglobulins for transfer to the foal. Maternal antibody passively transferred to foals from vaccinated mares may decrease the incidence of respiratory disease in foals, but disease can still occur in those foals and infection is common.
Barren mares at breeding facilities: Vaccinate before the start of the breeding season and thereafter based on risk of exposure.
Stallions and teasers: Vaccinate before the start of the breeding season and thereafter based on risk of exposure.
Foals: Administer a primary series of 3 doses of inactivated EHV-1/EHV-4 vaccine or modified-live EHV-1 vaccine, beginning at 4 to 6 months of age and with a 4- to 6-week interval between the first and second doses. Administer the third dose at 10 to 12 months of age.
Immunity following vaccination appears to be short-lived and it is recommended that foals and young horses be revaccinated at 6-month intervals.
The benefit of intensive vaccination programs directed against EHV-1 and EHV-4 in foals and young horses is not clearly defined because, despite frequent vaccination, infection and clinical disease continue to occur.
Outbreak mitigation: In the face of an outbreak, horses at high risk of exposure, and consequent transmission of infection, may be revaccinated. Administration of a booster vaccination is likely to be of some value if there is a history of vaccination. The simplest approach is to vaccinate all horses in the exposure area—independent of their vaccination history. If horses are known to be unvaccinated, the single dose may still produce some protection.
There remain concerns that heavily vaccinated horses may be more susceptible to developing neurological disease caused by EHV-1. This possibility is unsubstantiated and a subject of active investigation. To date, the use of a single vaccine immediately before exposure has not shown any association with an increased incidence of neurological disease.
Horses having been naturally infected and recovered: Horses with a history of EHV infection and disease, including neurological disease, are likely to have immunity consequent to the infection that can be expected to last for 3 to 6 months (longer in older horses). Booster vaccination can be resumed 6 months after the disease occurrence.
Equine Viral Arteritis
In planning a vaccination program against EVA, it is important to consult with state and/or federal animal health officials to ensure that any such program is in compliance with the state's control program for EVA, if one exists.
The indications for vaccination against EVA have been:
1) To protect stallions against infection and subsequent development of the carrier state.
2) To immunize seronegative mares before being bred with EAV-infective semen.
3) To curtail outbreaks in non-breeding populations.
Note: It is not possible to differentiate vaccine-induced antibody response from that due to natural infection. It is strongly recommended that prior to vaccination, serum from all first-time intact male vaccinates be tested and confirmed negative for antibodies to EAV by a USDA-approved laboratory . Mares intended for export should be similarly tested.
Stallions
Breeding stallions, previously vaccinated: Should receive an annual booster vaccination against EVA every 12 months and no earlier than 4 weeks before the start of each breeding season.
Breeding stallions, first-time vaccinates: Prior to initial vaccination, all stallions undergo serologic testing and are confirmed to be negative for antibodies to EAV. Testing should be performed shortly prior to, or preferably at, the time of vaccination. Negative certification is of importance should a vaccinated stallion be considered for export at a later date. All first-time vaccinated stallions should be isolated for 4 weeks following vaccination before being used for breeding.
Teasers can play a role in the introduction and dissemination of EAV within a breeding population. Vaccination against EVA is recommended on an annual basis.
Mares to be bred to carrier stallions or to be bred with virus-infective semen should first be tested to determine their serological status for EAV antibodies.
Seronegative mares should be vaccinated against EVA and isolated from any other seronegative horses for 3 weeks. The purpose of the isolation period is twofold:
1) To enable the vaccinated mare adequate time to develop immunity against the disease before being exposed to EAV infection during breeding.
2) To afford ample opportunity for cessation of post-vaccinal viral shedding via the respiratory tract.
Following insemination, first-time vaccinated mares must be isolated for an additional 3-week period as they are likely to experience a limited re-infection cycle with the strain of EAV present in the semen. Should such mares fail to become pregnant, they can be bred back to a carrier stallion or with infective semen without the need for revaccination or an additional 3-week isolation period post-insemination.
Seropositive mares, having tested serologically positive for antibodies to EAV, can be bred to a carrier stallion or with infective semen for the first time without the need for prior vaccination against EVA. After breeding, such mares should be physically separated from unvaccinated or unprotected horses for 24 hours to avoid possible risk of mechanical transmission of virus from voided semen.
Pregnant mares: The manufacturer does not recommend use of this vaccine in pregnant mares, especially in the last two months of pregnancy. Under circumstances of high risk of natural exposure to infection, the vaccine has been administered to pregnant mares in order to control outbreaks of the disease. Based on early experimental studies and field experiences using this vaccine, the last 1-2 months of pregnancy represent the time of greatest risk for a possible adverse effect on pregnancy. This was most recently illustrated in the aftermath of the 2006 multi-state occurrence of EVA when a very limited number of abortions caused by the vaccine virus were confirmed in mares vaccinated within the final 2 months of gestation.
Nurse mares can play a role in the introduction and spread of EAV among resident equine populations and should be vaccinated annually according to recommended protocols.
Foals The manufacturer does not recommend use of this vaccine in foals less than 6 weeks of age unless under circumstances of high risk of natural exposure to infection.
Colt (male) foals Especially in EAV endemic breeds, colt foals should be vaccinated between 6 and 12 months of age to protect against the risk of their becoming carriers later in life. Colts should be confirmed seronegative for antibodies to EAV prior to vaccination as described above and kept isolated for 3 weeks following vaccination. As foals of EAV-seropositive mares can carry colostral derived antibodies for up to 6 months, testing and vaccination should not be performed prior to 6 months of age.
Outbreak Mitigation
Non-breeding population: Vaccination is an effective strategy in containing outbreaks, particularly in congregated groups of horses where isolation may be problematic. Serology testing, as described above, should be performed on intact males and females that may be intended for future breeding purposes and/or export.
Breeding population: Outbreaks of EVA can be complex and can have far reaching implications. Vaccination is a component of outbreak management but should be performed only under the direct supervision of a veterinarian. (Link to AAEP infectious disease guidelines)
Vaccination and Exporting of Horses
In instances where there is uncertainty or concern over whether vaccination against EVA could prevent the export of a horse to a particular country, it is advisable to consult the federal area veterinarian in charge in the state to determine the specific import requirements of that country. There are a number of countries which bar entry of any equid that is serologically positive for antibodies to EAV, regardless of vaccination history. Countries which do accept EVA vaccinated horses, regardless of gender, typically require stallions or colts to have a certified vaccination history and confirmation of pre-vaccination negative serological status.
Equine Influenza
Adult Horse, previously vaccinated: Mature performance, show, or pleasure horses constantly at risk of exposure should be revaccinated at 6-month intervals. Other adult horses could be vaccinated as infrequently as once a year.
Adult horses, unvaccinated or having an unknown vaccination history: Either one dose of the MLV intranasal vaccine or a primary series of 3 doses of the inactivated-virus vaccines is recommended. The ideal intervals between these vaccinations are three to four weeks between the first and the second vaccination, followed by an interval ideally as long as three to six months before the third vaccination. This regimen generally induces higher and more persistent antibody titers than those induced by use of the previously recommended 2-dose initial series. Subsequent revaccination should be at intervals of 6 to 12 months, depending on the age of the horse as well as the degree and duration of risk of acquiring infection. If using a canary pox vector vaccine, use a 2-dose series with the second dose given 4 to 6 weeks after the first dose. Revaccinate semi-annually.
Pregnant broodmares, previously vaccinated: Vaccinate 4 to 6 weeks before foaling using the inactivated-virus vaccine or the canary pox vectored vaccine.
Pregnant broodmares, unvaccinated or having an unknown vaccination history: Use a 3-dose series of the inactivated-virus vaccines, with the second dose administered 4 to 6 weeks after the first dose and the third dose administered 4 to 6 weeks pre-partum. With a canary pox vector vaccine, a 2-dose series is recommended with the second dose administered 4 to 6 weeks after the first dose but no later than 4 weeks pre-partum.
Foals of vaccinated mares: Administer either a single dose of the MLV intranasal vaccine or a primary series of 3 doses of inactivated-virus vaccine beginning at 6 months of age. The recommended intervals between these vaccinations are 4 to 6 weeks between the first and the second vaccinations. The third dose should be administered between 10 and 12 months of age.
Foals of nonvaccinated mares: Administer either a single dose of the MLV intranasal vaccine or a primary series of 3 doses of inactivated virus vaccine at 6 months of age (see above), unless there is an unusual threat that recommends earlier vaccination. Because some maternal anti-influenza antibody is still likely to be present, a complete series of primary vaccinations should still be given after 6 months of age.
Due to the seasonal incidence of disease, vaccination should be timed to precede the anticipated peak challenge during the summer months or fall.
Adult horses, previously vaccinated: Manufacturers recommend revaccination at 6- to 12-month intervals. However, veterinarians may consider an interval of 3 to 4 months for horses in endemic areas because protection following vaccination can be incomplete and short-lived.
Adult horses, previously unvaccinated or with unknown vaccinal history: Administer a primary series of 2 doses, at a 3- to 4-week interval. Peak protection occurs 3 to 4 weeks after the second dose.
Pregnant mares previously vaccinated against PHF: Vaccinate semi-annually to annually. Schedule 1 dose to be administered 4 to 6 weeks before foaling. To date no studies have been published that examine the efficacy of PHF vaccines to prevent N. risticii induced abortion.
Pregnant mares unvaccinated or with unknown vaccinal history: Administer a primary series of 2 doses, at a 3- to 4-week interval. Schedule so that 2nd dose is administered 4 to 6 weeks before foaling.
Foals: Due to the low risk of clinical disease in young foals and the possible maternal antibody interference, primary immunization for most foals can begin after 5 months of age. The manufacturer’s recommendation is for a 2-dose series administered at a 3- to 4-week interval. However, as with other killed products, a third dose at 12 months of age is recommended. If the primary series is initiated when foals are less than 5 months of age, additional doses should be administered at monthly intervals up to 6 months of age to ensure that an immunologic response is achieved.
Horses having been naturally infected and recovered: Administer a primary series (as described above) or booster vaccine (if previously vaccinated) 12 months following recovery from natural infection.
Rotaviral Diarrhea
Pregnant mares (regardless of vaccination history): Should receive a 3 dose series of intramuscular vaccinations at 8, 9, 10 months of gestation.
Concentrated horse breeding areas in the
**It is essential that the newborn foal receives an adequate amount of colostrum and absorbs sufficient anti-rotavirus antibodies from rotavirus-vaccinated mares.
Newborn foals: There are no data to suggest that vaccination of the newborn foal with inactivated rotavirus A vaccine has any benefit for preventing or reducing the severity of infection.
As colostral-derived antibody titers wane at approximately 60 days of age, foals may develop rotaviral diarrhea. However, the severity of diarrhea is generally milder and of shorter duration than foals that become ill within the first 30 days of life.
Other adult horses: Vaccination is unnecessary
