April 2018 - Amputations & Neurological Conditions
Join us this month as our expert, Dr. Barrie Grant, joins the forum to answer your questions concerning neurological conditions in the horse. Dr. Grant will also be available to answer any questions related to amputations.
Click here to read this month's questions and answers.
Where is the best area on a horse to administer a 5-way vaccination?(View Answer)
The act of administering vaccine to a horse is dependent on the product to be used. In your question, you asked about a 5 in 1 product. As you review the labeling on your vaccine, you should find the method to administer this vaccine. Most likely, your product will say intramuscular (IM).
There are 3 areas most commonly used to place an intramuscular vaccination in a horse.
- Lateral cervical (each side of the neck): I instruct clients to form a triangle on the side of the neck using three landmarks. On an adult horse, measure down from the top of the neck where the mane is located one ‘open’ hands width to form the top of the triangle. Find the scapula (shoulder blade) and go just in front of this landmark to form the back of the triangle. The last landmark is one ‘closed’ hands width above the cervical vertebrae (neck bones). Within in this area, is commonly muscle tissue in most adult horses with normal body condition.
- The caudal (back side) of the rear limb. This large muscle mass can be used on either side where the tail lays on the back of the horse. One must be careful to avoid the sciatic nerve which lies in a distinct groove in the rear limb.
- The pectoral muscle group between the front legs.
I have listed the suggested injection sites in the order of common use. The actual site used may vary depending on the vaccine, or other product to be injected. Foals or horses with light muscle pattern may affect your vaccination location.
Let’s address a couple more concerns prior to vaccine administration:
- What needle do I use? If you purchased your vaccine in a ready to use packet, you will find a needle suggested by the animal health manufacturer. Typically, this will be a 20 gauge x 1.5” or 22 gauge x 1.5” needle. You must securely attach the needle to the luer tip of the syringe. When administering the vaccine to the horse, carefully place the needle through the skin and advance the full length of the needle deep intramuscular. Before administration of the vaccine, withdraw the plunger of the syringe and be sure you are NOT in a blood vessel. If you are, relocate your needle to a new location. If no blood is noted, give the vaccine injection.
- What do I do before I administer the vaccine?
- Vaccine handling- Be sure to read the vaccine label ‘very closely’. Often you will see ‘shake well’. This is very important to suspend the adjuvant within in the vaccine. Settling may occur when the product in stored in refrigeration.
- Cleaning the skin? This is a much disputed question amongst health care providers. If you are going to clean the skin for vaccination, a 3 scrub technique alternating betadine scrub with alcohol would be the ideal. This may not be the most practical, especially in a large herd situation. Some DVM’s will perform a quick alcohol scrub, others will dust off the superficial dirt and do nothing more. The dispute seems to come more about dry vs. wet skin. Alcohol, to be most effective, should dry before vaccine is given. Wet seems to cause ‘wicking’ at the injection site leading to post injection reactions at injection sites.
- Do I rub the skin after vaccination? Many DVM’s believe gentle skin and muscle massage in the area of the vaccination will encourage vaccine dispersement in the deeper tissue and limit leakage of the vaccine out of the skin or into the subcutaneous space just below the skin. Secondarily, the horse will appreciate a soothing massage after vaccination reassuring a good human-animal bond.
If this is your first experience in administering vaccine, please seek your local veterinarian to assist in vaccination techniques. You can also find additional vaccination information at www.AAEP.org >> under owner’s tab >> select guidelines >> vaccination. Duane Chappell, DVM, Owingsville, KY
I have a 6-year-old Quarter horse gelding that is going to be receiving his vaccinations soon. Is waiting too long to administer vaccines a bad thing and can it cause them to colic easier? This is my first year owning him and I'm not sure what his reactions are to some shots.(View Answer)
Vaccinations do present an inherent risk that an unpredicted reaction may occur. This does not out weight the importance to preventive vaccination. An adverse reaction to vaccinations is not a common outcome in most horses. If a past history of vaccination reactions is known, one can take precautions to offset these in the future. In your scenario, you do not have access to this history. Here are some considerations:
- With the assistance of your local veterinarian, develop a list of vaccinations that are needed for your horse. These will include the American Association of Equine Practitioners (AAEP) recommended “Core” vaccinations. These include Tetanus, EEE, WEE, WNV, and Rabies.
- Additionally, based upon risk assessment, you may vaccinate for other diseases like Herpes, Influenza and others if determined by your veterinarian.
- The season of the year that vaccine is administered does not correlate to a concern for an adverse reaction. An adverse reaction to a product, whether vaccine or something else, is an individual’s response based upon that individual’s biological make-up. An example, if you have peanut allergies, these do not only occur in the winter.
- Some veterinarians may recommend vaccinating for only a few diseases at one time and allowing an interval of time between each vaccine. For example, administering Tetanus toxoid and wait 1-2 weeks before the next vaccine and so on.
- In a broader sense, the most common adverse reactions noted post vaccination, would be local swelling and soreness associated with injection site, stiffness and difficulty in movement, transient decrease in appetite or fever, and farther down the list may be incidence of colic or other systemic (whole body) allergic reactions.
Though your concern is well warranted to provide the best care possible for your horse, your local veterinarian can assist you with these decisions. You may also find more information about equine vaccinations at www. AAEP.org >> owner’s tab >> guidelines >> vaccination guidelines. Duane Chappell, DVM, Owingsville, KY
At our barn we administer our own shots because we have no local veterinarian in the area. Our one cow horse mare has had a reaction to the West Nile vaccine as her legs became swollen mid-cannon and down. She also ran a temperature of 101.3 and could barely walk. As suggested by a veterinarian via phone, we cold hosed her legs, wrapped them and gave her Banamine. Should we be worried about founder? Any suggestions?(View Answer)
Here are a few considerations related to post vaccination adverse events:
- Did the adverse event occur due to vaccination or coincidental to vaccination? Sometimes, this can be very hard to determine.
- Did the vaccine administered contain multiple antigens (combination vaccine)? If so, reducing the number of antigens (diseases) vaccinated for at one time can reduce likelihood of future events. For example, administer a Tetanus toxoid product and wait 2 weeks before administering the next product.
- The adjuvants included in the vaccines can also be a source of concern related to vaccine adverse events. Different adjuvants are used by different Animal Health manufacturers.
- Future vaccination adverse events should be considered for this individual.
- Immediate care for the adverse event described, swollen legs and decrease in mobility may have dramatic effects on the outcome. Will this event produce laminitis (founder) with rotation or change to the position of the coffin bone in the foot? This can only be determined through radiographic examination of the feet by a veterinarian. Then an appropriate plan of care can be determined.
- Preventive vaccinations are extremely important to be performed on an annual basis. The American Association of Equine Practitioners (AAEP) has a recommended “Core” of diseases that all horse should be vaccinated for on an annual basis. These are Tetanus, EEE, WEE, WNV, and Rabies. You can find further information on these and other diseases at www.AAEP.org >> select owner’s tab >> guidelines >> vaccination guidelines.
As a final thought, please contact a veterinarian to have a complete examination performed. This should be done sooner, than later, to limit long term possible effects related to founder. Duane Chappell, DVM, Owingsville, KY
I have a 15-year-old gelding that is borderline IR and early Cushing's. He foundered three years ago and was doing much better until I gave him a West Nile vaccination and he had an episode of laminitis again. He has always been sensitive to vaccinations sometimes running a mild fever. We pretreated him with Bute. My veterinarian has recommended no vaccinations. I live in Florida and we have a terrible outbreak of of mosquitoes this summer, which has me very worried. Is there any chance he has some protection left for the(View Answer)
vaccination he was given over a year ago?
Your question reveals several concerns: West Nile Virus(WNV) vaccine vaccination side effects, WNV vaccination length of protection, Laminitis, IR and Cushings.
The WNV disease falls under the “Core” vaccinations recommended by American Association of Equine Practitioners (AAEP) to be performed each year. The other diseases include in the “Core” are Tetanus, EEE, WEE, and Rabies.
Depending upon the WNV vaccine that was administered, you may find that the Animal Health Manufacturer of that vaccine may have data to support protection beyond 12 months. You would need to contact that specific company to find out this information.
In respect to vaccination side effects or adverse events, utilizing vaccines with fewer antigens may be beneficial. For example, administration of a Tetanus toxoid, wait 2 weeks, administer a EEE/WEE product, wait 2 weeks, administer a WNV vaccine, wait 2 weeks and finally administer an equine Rabies vaccine. Though it is not known if your horse is reacting to the antigen (the disease we are vaccinating to prevent) or the adjuvant (the product in the vaccine to enhance the immune response). You may consult your veterinarian and see if consideration would be to trying a different company’s product to offset the possibility of an adverse event.
The laminitis event may have an underlying predisposition due to the IR and Cushings. Your efforts to minimize a reaction with Phenylbutazone are commonly done. There is not current information to determine if NSAID’s (Non-Steroidal Anti-Inflammatory Drugs), which Bute is included, have detrimental effects to the immune response upon vaccination.
Finally, with your geographic location in Florida, please consider the importance of EEE vaccination.
Your veterinarian is still your best source of information specific to your horse’s needs. You may also find additional vaccination information at www.AAEP.org >> owner’s tab >> guidelines >> vaccinations guidelines. Duane Chappell, DVM, Owingsville, KY
I've always vaccinated my horses using the Innovator-4 and West Nile Innovator by Fort Dodge. It was recommended to me to use the Recombitek West Nile vaccine for west nile prevention. Is it OK to use the two different brands? Recombitek does not offer a 5-way vaccine.(View Answer)
This is a great question and occurs very commonly. If your horse is currently doing well with vaccines administered for the diseases of risk in your area and is being protected against the “core” recommended diseases (Tetanus, EEE, WEE, WNV, Rabies), you may not want to change.
Let’s break down your question into pieces.
1) Use of vaccines from one animal health manufacturer
- The products from one manufacturer may contain the same adjuvant. This is the portion of the vaccine that enhances the immune response.
- Typically, the vaccines from one manufacturer have been tested together. This may limit vaccine reactions through compatibility.
2) Use of vaccines from different animal health manufacturers
- Each killed vaccine used will typically contain an adjuvant. Use of vaccines from multiple manufacturers may increase the possibility to a vaccine reaction as compatibility to different adjuvants is not known.
- Some vaccines do not have adjuvants, so this concern may be reduced with incompatibility.
- Each animal health manufacturer’s product lines may not always have the vaccines available for the diseases of concern. This will result in choosing a vaccine from a different manufacturer to meet your horse’s disease prevention needs.
Please remember that all vaccines are produced to be safe and efficacious. As horses are vaccinated, there will always be an inherent risk that a vaccine reaction may occur. If this has happened in the past, precautions can be taken to offset future concerns.
As the old saying goes, “If ain’t broke, don’t fix it”, may apply here; if you are satisfied with your horse’s current protection. Though new products do come to the market place, you should be wise to seek your local veterinarian’s advice in the application and use of these products and how they will best meet you horse’s needs.
For further information on vaccinations in horses, please go to www.aaep.org and under the owner’s tab select guidelines >> vaccination guidelines.
Please note: Innovator is currently marketed by Zoetis Animal Health. Recombitek is currently marketed by Merial Animal Health. Duane Chappell, DVM, Owingsville, KY
Why is it deemed necessary to give horses every vaccine every year when humans can go years for most vaccines? Even canine vaccine protocols are beginning to back off yearly boosters.(View Answer)
This is a great question to explore. Let’s begin by looking at the complexity of the equine immune system; two paths must be looked upon. One is the humoral antibody response and the other is the cell-mediated response. Each response carries great value and responsibility to your horse’s disease protection. In a basic review of each, the humoral response has an end goal of producing antibodies to the presenting antigen (disease or vaccine). These antibody responses can be easily measured in the laboratory through serum titer evaluations. The cell-mediated response produces many complex factors like cytotoxins and interferon products. These values are not easily measured in the laboratory without the means of specialized collection tubes and very specialized equipment to measure these products.
With this basic overview, as a vaccine is administered to a horse, both reactions occur. If the vaccine is a killed product with an adjuvant, as most of our equine vaccines are, there will be an expectation to see a rise in the vaccine titer from the humoral antibody response. This is a measureable response but may not equilibrate to protection from disease. Current research is not available to correlate vaccine titers to disease protection beyond the bounds of the vaccine label claims. Animal health manufacturers have conducted research that has extended label claims on some vaccines from every 6 months administration to every 12-14 months depending on the vaccine product.
Many individual horse factors must be taken into account, when vaccination responses are being evaluated. These may include the horse’s age, use, disease exposure and general health status including reproductive to name a few. Each horse’s response to a vaccine may vary widely. We must remember that administration of a vaccine does not always equal a response or complete disease protection.
The American Association of Equine Practitioners (AAEP) has divided equine diseases into 2 groups. The “core” vaccine recommendations are for Tetanus, Eastern and Western Equine Encephalomyelitis, West Nile Virus and Rabies. All horses should receive these vaccinations on an annual basis. All other equine diseases are in the “risk-based” disease category. The vaccinations for these diseases will vary based upon many different criteria that can be evaluated by your local veterinarian.
For further information of individual disease and age classification recommendations, seek your local veterinarian’s advice. You may also go to www.aaep.org and search vaccination guidelines under the horse owner tab. Duane Chappell, DVM, Owingsville, KY
My 14-year-old Paint mare developed headshaking syndrome three days post spring vaccinations that included a Rhino vaccine. My veterinarian acknowledged there have been reported side effects of this vaccine. Internet research also suggested anectodal reports of horses developing HS syndrome following the Rhino vaccine. What are your thoughts?(View Answer)
As we travel to Dr. Google’s office to inquire about a problem, a thought of caution should be at the forefront of our response to what we read. Is the source reliable? Is the correlation scientifically based? Is this an objective study vs. and subjective thought?
Through my background study for a response to your question, I exercised a couple queries. One was to look at all the Herpes virus products available by an animal health manufacturer and see if there had been any similar reported adverse events. In our US study, none were found with Herpes virus products.
Additional question would be to confirm that the Herpes virus vaccine in question is only for EHV 1 & 4, not a combination product with other antigens like Influenza. If so, which product would be the causative agent?
Further exploration for your answer yielded information from an article by Dr.John Madigan et al titled “Lack of evidence for a relationship between equine headshaking and EHV 1 antigenic sequences in the trigeminal ganglia”. This article summarizes by saying: “Therefore, this study does not support a role for EHV-1 infection and presumed postherpetic pain in the etiopathogenesis of equine headshaking.”
Dr. Madigan and associates have been investigating causes of head shaking for several years. There website is: http://www.headshakerinfo.org/ . This is a very reputable website that may help in answering some of your questions. Duane Chappell, DVM, Owingsville, KY
I have a 2-year-old colt that has been diagnosed with EPM. He was doing fine in training and then started having trouble staying on the correct lead, especially when being bridled up. It looked so strange when he would fall out ...it looked like his leg was going to dislocate at the hip and then he would lift his back leg really high, like he was marching and then he would be fine. I took him to be examined by the veterinarian and much to my dismay, the test was positive for EPM. He has been on Marquis for 3 weeks and we have not seen much improvement. He looked pretty bad today.
My question is, should we be doing anything else for his treatment? I’ve read that patients should be on Banamine or Bute to reduce inflammation. The vet we took him to specialized in lameness but didn’t explain much to us. He is a really nice colt and they seemed very optimistic about a full recovery but the more I read, the more concerned I become.(View Answer)
Currently available licensed treatments for Equine Protozoal Myeloencephalitis (EPM) include:
- Protazil- alfalfa pellet, active ingredient is Diclazuril, marketed by Merck Animal Health
- Marquis- oral past, active ingredient is Ponazuril, marketed by Bayer Animal Health
- Rebalance- oral liquid, active ingredients are Sulfadiazine and Pyrimethamine, marketed by PRN Pharmaceutical
Though a Non-Steroidal Anti-Inflammatory drug (NSAID) may be used initially in the EPM treatment regime, this drug class is not typically included in long-term care. Phenylbutazone (Bute), Flunixine meglumine (Banamine), and Firocoxib (Equioxx) are examples of NSAID medications.
EPM is caused by Sarcocystis neurona most commonly and Neospora hughesi less commonly. Where the organism effects the neurologic system, will determine the expressed lameness and/or neurologic signs that are seen. Secondly, the point of recovery will be dependent on the severity of disease prior to treatment. For many years, the Mayhew neurologic grading system has been used to stage the initial disease and progression of treatment. Based upon the initial grade, improvement is estimated to improve 2 grade levels. For example, if your horse started as a Grade 3-4, improvement may reach Grade 1-2 after treatment. Less than 30% of EPM diagnosed horses will fully recover, although 60-70% will show clinically improvement with early treatment. Relapse rate is approximately 10% within 60-90 days following initial treatment cessation.
Finally, other causes of lameness may be occurring. I would suggest contacting your veterinarian for re-evaluation. Your veterinarian may suggest a medication change based upon the results of the new examination.
Wish you the best with the care of your horse! Duane Chappell, DVM, Owingsville, KY
What part of the horse's body do you administer the strangles vaccine? Is intranasal better than the injection?(View Answer)
Strangles vaccine is referring to vaccination to prevent a highly contagious disease caused by Streptococcus equi infection. This bacterial disease is also referred to as ‘distemper’ and/or ‘shipping fever’. This is an upper respiratory disease with associated lymph node swelling and abscessation, high fevers, inappetance and very easily spread from one equid to another.
There are two products available for prevention of Strangles infection. One is an injectable product called Strepvax II marketed by Boehringer-Ingelheim. The other product is an intranasal product called Pinnacle marketed by Zoetis. These two products MUST be administered according to label directions. By interchanging the administration methods, serious adverse side effects may and have occurred.
*Strepvax II is a Streptococcus equi bacterial extract. Label directions are as follows:
Shake well. Using aseptic technique, inject 1 mL intramuscularly preferably in the hind quarters. For primary vaccination give 3 doses at intervals of 3 weeks. Foals vaccinated when less than 3 months of age should receive an additional dose at 6 months. Revaccinate annually and prior to anticipated exposure, using a single 1 mL dose. Use a separate needle for each injection.
*Pinnacle is Streptococcus equi vaccine, Live Culture. Label directions are as follows:
FOR INTRANASAL USE ONLY. DO NOT ADMINISTER BY ANY ROUTE OTHER THAN INTRANASAL.
DOSE: Aseptically rehydrate with the entire contents of the accompanying sterile diluent. Instill the entire rehydrated vaccine into one nostril using a syringe with applicator tip. Administer a second dose 2 to 3 weeks later. Annual revaccination is recommended.
As to the question which is a better product?
**Vaccination against S. equi is recommended on premises where strangles is a persistent endemic problem or for horses that are expected to be at high risk of exposure. Following natural infection, a carrier state of variable duration may develop and intermittent shedding may occur. The influence of vaccination on intermittent shedding of S. equi has not been adequately studied.
**Killed vaccines like Strepvax II are an adjunct to the prevention of strangles. Vaccination with these products should not be expected to prevent disease. However, appropriate pre-exposure vaccination with these products appears to attenuate the severity of clinical signs in affected horses, should disease occur, and has been shown to reduce the incidence of disease by as much as 50% during outbreaks.
**An intranasal product like Pinnacle has been shown to stimulate a high level of immunity against experimental challenge. The vaccine strain of Strangles may vary from the active field strain in circulation. This can account for reduction in vaccine effectiveness.
Strangles is a multi-factoral disease that vaccine alone will not address. There are many other cooperative decisions that need to be made by an active veterinarian-client-patient relationship. These include identifying best preventive methods, isolation and treatment and biosecurity measures prior to entry of this disease. Please contact your local veterinarian to identify the most appropriate product and plan for your horse’s needs.
Supporting documents used for this response include:
*Compendium of Veterinary Products
**AAEP website, vaccination guidelines for Strangles
ACVIM Consensus Statement: Streptococcus equi Infections in Horses: Guidelines for Treatment, Control, and Prevention of Strangles. Duane Chappell, DVM, Owingsville, KY
In a health maintenance program where horses are turned out individually or pairs in Potomac River Valley, what is the best vaccine program regarding Potomac Fever and rabies?(View Answer)
Let’s separate the two diseases in question and address each individually.
* Rabies is an infrequently encountered neurologic disease of equids. Though the incidence is low, the disease is often times fatal and considered of public health significance. Rabies vaccination is included in the “core” vaccinations for all equids. Wildlife is the typical vector of spread (raccoon, fox, skunk or bat) resulting in bite wounds to the equids. The virus migrates through the nerves to the brain producing a fatal encephalitis.
* Vaccination is the best method of prevention with one of the three licensed rabies prophylaxis products (Merck, Merial and Zoetis). The vaccine is administered deep intramuscular according to label directions and repeated annually.
*Potomac Horse Fever, also called Equine Monocytic Ehrlichiosis, is caused by a bacteria called Neorickettsia risticii. Though this disease is identified in other parts of the United States, the initial observation and identification occurred in the Potomac River Valley. The disease is seasonal, occurring primarily between late spring and early fall. Most cases are seen in July, August and September at the onset of hot weather. Clinical signs are variable but may include fever, mild to severe diarrhea, laminitis and mild colic.
* Vaccination is available through one manufacturer, Merial. Vaccination for this disease is based upon “risk-assessment” by your veterinarian. Vaccination against this disease has been questioned because of field evidence of benefit is lacking. Explanations may include lack of seroconversion after vaccination and multiple field strains and only one strain of bacteria in the available vaccine. Vaccination boosters are label recommended at 6-12 month intervals. Your veterinarian may suggest boosters at 3-4 month intervals in endemic (highly infected) areas. Vaccination timing may be beneficial by administration of the available vaccine 3-4 weeks prior to peak season occurrence.
A combination vaccine is available for Rabies and Potomac Horse Fever from Merial.
The following information has been paraphrased from the *(AAEP Vaccination Guidelines). You may access this information at http://www.aaep.org/info/guidelines, vaccination guidelines. Duane Chappell, DVM, Owingsville, KY
Small animal veterinary medicine is going to a more expanded vaccination schedule (3-5 years) after the initial puppy and kitten vaccines. They found that when they tested the titers, immunity was still conferred, even for rabies years later. Is this something equine medicine is looking towards?(View Answer)
As one reviews the complexity of the equine immune system, two paths must be looked upon. One is the humoral antibody response and the other is the cell-mediated response. Each response carries great value and responsibility to your horse’s disease protection. In a basic review of each, the humoral response has an end goal of producing antibodies to the presenting antigen (disease or vaccine). These antibody responses can be measured in the laboratory through titer evaluations. The cell-mediated response produces many complex factors like cytotoxins and interferon products. These values are not easily measured in the laboratory without the means of specialized collection tubes and very specialized equipment to measure these products.
With this basic overview, as a vaccine is administered to a horse, both reactions occur. If the vaccine is a killed product with an adjuvant, as most of our equine vaccines are, there will be an expectation to see a rise in the vaccine titer from the humoral antibody response. This is a measureable response but may not equilibrate to protection from disease. Current research is not available to correlate vaccine titers to disease protection beyond the bounds of the vaccine label claims.
Many individual horse factors must be taken into account when vaccination responses are being evaluated. These may include the horse’s age, use, disease exposure and general health status including reproductive to name a few. Each horse’s response to a vaccine may vary widely. We must remember that administration of a vaccine does not always equal a response or protection.
For further information of individual disease and age classification recommendations, seek your local veterinarian’s advice. You may also go to www.aaep.org and search vaccination guidelines under the horse owner tab. Duane Chappell, DVM, Owingsville, KY
Some owners of American Miniature horses believe that vaccination for equine influenza poses extra risks for the breed, so they avoid the shots altogether. Is there any scientific support for this belief?(View Answer)
The American Miniature horse population has been observed to have adverse responses to vaccinations. Often times, these vaccine reactions relate to the adjuvant products in the vaccine. The adjuvants are present to enhance the immune response to the vaccine antigen. In the case of the influenza vaccine, vaccination reactions can be minimized to eliminated by choosing a non-adjuvant product. The only non-adjuvant product available is FluAvert by Merck Animal Health. This is an intra-nasal administered modified-live product that requires administration once a year.
Initial vaccination evaluation should begin with recognition of the AAEP vaccination guidelines that separate diseases into core and non-core categories. These may be found at www.AAEP.org. The core vaccination category includes Tetanus, EEE, WEE, WNV and Rabies. The non-core category includes many other diseases like Influenza, Rhinopneumonitis (Herpes) and several others. As you see from this list, Influenza is categorized as a non-core disease. This category would indicate that Influenza vaccination should be based on a risk assessment by your veterinarian.
Please contact your local veterinarian to further evaluate your individual horse’s need for Influenza vaccination. Duane Chappell, DVM, Owingsville, KY