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June 2018 - Equine Skin Tumors

Pose your questions concerning equine skin tumors for expert, Dr. Elizabeth Carr from Michigan State University, during the month of June.

Click here to read this month's questions and answers.

Preventative Care

  1. I have horses and donkeys that are only on my property and not exposed to other horses. I live on 20 acres in a rural area in Central California. What immunizations should I give? In the past, I typically administer west nile, tetanus and VEWT.

    (View Answer)

    I’d say you’re mostly on the right track so far. When you have a “closed herd,” meaning no horses enter or leave your property, you only need to worry about the diseases that “come to you.” The viral encephalitis diseases (eastern, western and Venezuelan equine encephalitis, as well as West Nile virus) are transmitted by mosquitoes, so vaccines for these diseases must be given to all horses (and donkeys). You should also have rabies vaccines administered to all animals yearly, since rabies can come to your horses in the form of a bite from a rabid animal. In California, as in most states, rabies vaccines must be administered by a licensed veterinarian, so you’ll want to call your vet for a visit. That will also be a great opportunity to ask a vet familiar with your area if there are any other diseases against which you should be vaccinating. Examples of region-specific diseases include botulism and Potomac horse fever. Lisa Kivett, DVM, Southern Pines, NC

  2. I live in Ocala and wondered when I should administer vaccines (Eastern/Western/Tetanus + West Nile combo)and Rabies separately? Also, what size needle should I use for the rabies vaccine? 

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    In areas where Eastern Equine Encephalitis and other mosquito-transmitted diseases are common, we usually recommend vaccination with EWT-WN about 30 days prior to the onset of mosquito season. In many southern areas, mosquito season is pretty-much year-round, and we often recommend vaccination every six months. If you administer your vaccines every six months, it’s unlikely that you’ll ever need to worry about timing of vaccination, since the horse’s immunity will be kept high. The risk of disease from one of these awful viruses is much greater than the risks associated with vaccine administration. Rabies vaccination should be administered yearly, and since there’s no “rabies season” it doesn’t matter exactly when in the year it is given. For all vaccinations, you’ll want to use a 20 gauge or 22 gauge 1.5” needle for administration. Keep in mind that in Florida, as in most states, it is illegal for anyone other than a licensed veterinarian to administer the rabies vaccine. In the case of suspected neurological disease, your horse may not be considered to be vaccinated against rabies if a veterinarian didn’t give the shot. Lisa Kivett, DVM, Southern Pines, NC

  3. My horse has been diagnosed with DSLD. Are there any supplements that will help the ligament heal? Would collagen supplements make a difference? We are doing shockwave therapy, which has promoted some healing, but are there other therapies we can try?

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    I think DSLD is one of the most frustrating equine conditions that veterinarians currently treat. This is mainly because of the lack of effective treatments. There are no supplements that have been shown to have an effect on ligaments, so that’s unlikely to be of much benefit. There’s a lot of research currently looking into this condition, but to my knowledge, there’s still nothing that can slow or stop the progression of this disease. Bandaging the affected legs and administering anti-inflammatories (like bute, banamine or firocoxib) may help provide some pain relief. We often also recommend egg bar shoes that extend well behind the heel to help provide some support and pain relief to the fetlock joint. One study showed that exercise didn’t make the condition worse, and might improve the pain and lameness in mildly-to-moderately affected horses. Unfortunately, much more research is needed before we understand this condition enough to treat or prevent it. Lisa Kivett, DVM, Southern Pines, NC

  4. A friend has started boarding her 6-year-old Thoroughbred/Appaloosa gelding with me. He is lean but I have been putting weight on him. My question is this, he looks sunken in, like he has not had water at all. He has a trace mineral block if he wants it, he gets a good grass hay, COB with molasses and beet pulp. Is this just a quirk with him or could it be something else? 

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    It’s hard to know what you mean by “sunken-in.” Most of the time, people are referring to a depression in the abdomen, just in front of the hip bones when they describe this to me. If this is the case, it may simply be a continued effect of him being underweight. Signs of dehydration in horses include dry, sticky gums, increased heart rate, cold legs and ears, and delayed “skin-tent” (pinch the skin on the horse’s neck, and determine if it “snaps back” within about two seconds. There can be a lot of individual variation in the results of this test, but it may help give an idea). If you observe the horse drinking and urinating normally, he’s probably not dehydrated, and what you’re observing may just be his individual conformation or he may just need a little more weight. Lisa Kivett, DVM, Southern Pines, NC

  5. My 9-year-old mare was recovering from ligament tears when we noticed issues with the stifles. Radiographs and bone scan revealed moderate arthritic changes within the medial femorotibial joints- chronic. Every year, there is slight lameness (sore to pressure and has mild effusion) and we have to inject the stifles. Synovial fluid has been thin/watery and yellow. Is there anything I can do to help the stifle area for the long term? We added dressage work to help strength the hind muscles. We are hoping to show this summer 2’6. Recently, I have seen ice/heat wraps for the stifles. I was wondering if applying cold or heat would help after jumping with her issues? 

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    Cold therapy and thermal (heat) therapy are commonly recommended for various equine injuries, especially soft-tissue injuries like bowed tendons. The idea behind cold therapy is to decrease blood flow to the site of an injury, decreasing the pain, swelling and inflammation associated with the injury. Cold therapy is commonly recommended in the first few days of injury. After about three days, veterinarians often recommend a switch to thermal therapy with the idea that increasing blood flow and cellular activity will then increase the rate of healing. The biggest problem in applying these principles to equine stifles is the size of the joint and the overlying surface area. Applying heat and cold wraps in this area are likely only going to change the temperature of the skin and surface tissue. It’s questionable whether you can achieve a significant change in temperature to the actual joint. This being said, if the wraps do create a temperature change in or around the joint, it’s possible that they could at least temporarily provide some pain relief. It sounds like you’re on the right track with the joint injections, but it could be worth discussing some additional treatment with your veterinarian. There are many “joint therapy” options available today, and your mare might benefit from some well-timed treatments before show season. Also, keep in mind that a steady, low-intensity workout routine is beneficial for horses with arthritis, so keeping her moving year-round will help keep her performing at her best. Lisa Kivett, DVM, Southern Pines, NC 

  6. I recently bought a 7-year-old dun gelding. The previous owner said he had a two year old torn fetlock and tendon injury, which causes him to limp when he is ridden too long or too hard. I purchased for him some fetlock and tendon support boots that stated they absorb up to 26% of the hoof impact. I also purchased ice boots to wear after he is ridden to cool down his legs. Now I am so confused on the supplements as there are so many! I truly want to provide him with the best joint health supplement but not sure what that is! If I can purchase it via Internet or over-the-counter is fine. I would just like to know a supplement that will help his joints and maybe keep inflammation away as well. 

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    The supplement industry can certainly be confusing, especially with the huge variety of products, wide range of claims made by the supplement companies, and variety of testamonials by horse owners. It’s important to know that supplements have, at best, inconclusive scientific evidence to support their use and effectiveness. In fact, some scientific studies have shown a complete lack of any effect when horses receiving supplements were compared to horses not receiving any supplements. We all want to do what’s best for our horses, and anything that can benefit them should be considered. However, there are several joint therapies (like joint injections, stem cell injections and anti-inflammatories) have very good evidence to support their use. What I’m getting at is that supplements are expensive, and probably don’t work. Your horse has an actual injury, so I’d save the money you’d be spending on supplements, and talk to your vet about proven options that you could spend your hard-earned money on. You may want to talk about using an anti-inflammatory (like bute or firocoxib) or, if you know the exact injury, injections of some kind. Lisa Kivett, DVM, Southern Pines, NC

  7. We recently discovered my 24-year-old Dutch gelding with Cushing’s Disease had not been eating his Prascend pill in his nightly feeding at the farm where he is boarded. He showed an increase in stamina and his spunky personality returned, however, his ACTH levels were very high. His feet and glucose levels are fine. I returned him to half the recommended dose and he is dull again with very low energy despite good nutrition and supplements. What would happen with unmedicated Cushings at his age? He was started on Prascend in his late teens with his previous owner.

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    Changes in appetite and energy level are common when beginning treatment with pergolide (Prascend). We often recommend that horses who experience these difficulties be treated with a low dose (1/4 to ½ tab) at first, gradually increasing to the recommended 1mg per day. That being said, there is a very small percentage of horses that cannot tolerate pergolide at any dosage.

    Cushing’s, when left untreated, can result in laminitis, immune system compromise and the commonly-recognized excessive haircoat. Though these are recognized complications of Cushing’s, some horses don’t ever experience them. As with many things, you have to weigh the risks and benefits of treating your horse with this drug, and if he’s not happy or useful on the medication, it may be better to leave him off of it.

    One drug, cyproheptadine, was used to treat Cushing’s before the availability of pergolide. Its effects are variable, but some horses seem to have some response to it. It may be worth discussing this drug with your veterinarian. Lisa Kivett, DVM, Southern Pines, NC

  8. If a mare is 17 years-old and has had 15 foals (13 live) and currently in foal with number 16, approximately how many more foals could she safely have?

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    This 100% depends on the individual mare. As mares age (and have multiple foals) they can experience many changes in their uterus, including decreased lymphatic flow, cysts and cervical changes. Eventually, the mare’s fertility will decline due to one or several of these issues, but the age at which this occurs can be highly variable. If you continue to breed her, and she continues to become pregnant and maintain the pregnancy, there’s no arbitrary limit for number of foals! Lisa Kivett, DVM, Southern Pines, NC

  9. I have some hay that a Packrat had left droppings on. Will the hay hurt my horse?

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    It’s probably not worth the risk to feed the hay. Rat droppings can harbor diseases like salmonella and leptospirosis, which can affect horses. If it’s only a small quantity, it might be fine, but I think it’s better to be safe than sorry. Lisa Kivett, DVM, Southern Pines, NC

  10. I live in north west Iowa and am currently getting ready to purchase my yearly vaccines for the horses. I've done the same thing every year but I'm wondering if I need all of it anymore. I will still do rabies, tetanus, and eastern/western. But do I still need to vaccinate for west nile? I've noticed there aren't as many combo vaccinations with the WNV in it.

    (View Answer)

    Yes, you still need to vaccinate against West Nile virus. While cases are not as prevalent as they were during the height of the outbreak several years ago, equine West Nile cases continually occur throughout the US. According the USDA, five cases of West Nile virus were reported in Iowa horses in 2014.

    The changes to the vaccine combinations that you’ve observed are most likely due to increased demand for choices in the market. Horses that are sensitive to particular vaccines may benefit from “breaking up” the individual antigens (for example, administering EWT, rabies and west nile on different days). There is also concern that combination vaccines may be more likely to cause reactions (like local swelling), and in some cases, may not be as effective against individual diseases. In addition, some people may have preferences for different types of West Nile vaccines, such as the canary-pox vectored vaccine.

    You may also want to consider consulting your veterinarian on other vaccines that may be necessary for your farm or in your area. Examples of risk-based vaccines include flu/rhino (influenza and equine herpesvirus), strangles, botulism and Potomac horse fever.

    As a final thought, remember that vaccines are guaranteed by the manufacturer only when administered by a veterinarian. If a horse becomes ill from the disease that a vaccine is intended to prevent, or if a horse experiences a complication associated with vaccination, the manufacturer may be able to provide financial compensation. Again, this will only apply if your veterinarian administered the vaccine. Lisa Kivett, DVM, Southern Pines, NC

  11. I have a 7-year-old gelding I just purchased. His previous owner said he hurt his fetlock and tore his tendon about 2 years ago. He only limps when he is ridden hard with trotting and loping. He is ridable for light riding. Is there a boot that can support his fetlock and tendon while being ridden? Not protect it per say but actually support some of the impact while riding and perhaps keep some of the pressure off his fetlock and tendon?

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    It would be interesting to have more information about this horse’s particular injury. Since there are several tendons and ligaments that involve the fetlock joint, it’s nearly impossible to make an all-encompassing recommendation. Studies on the effect of different boots on the fetlock joint have produced some conflicting and not-too-exciting results. One study did show that boots (regardless of the type) decreased the extension of the fetlock joint by about 1 degree. Whether this 1 degree reduction in angle translates to any real benefit is unknown! You could also question whether reducing the angle and “supporting” the joint might delay healing. Sorry to be wishy-washy on your question, but the reality is that there is no simple answer! In your situation, I would certainly consider having a veterinarian evaluate the horse to determine whether there are any therapies that may help the horse (he’s still so young!), or whether an anti-inflammatory (like phenylbutazone or firocoxib) may be beneficial when you know he’ll be going on a longer ride. Lisa Kivett, DVM, Southern Pines, NC

  12. Is it recommended to regularly clean a gelding's sheath? I had a veterinarian clean their sheaths about four years ago and there were not any "beans" or other detritus. They were both about 20 years old at the time and this was probably the first time their sheaths were inspected. They are always kept in a pasture and not in stalls. They seem to easily have a regular stream when urinating. 

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    We do recommend occasional sheath-cleanings for geldings. Horses have a “pouch-like” structure adjacent to the urethra called the urethral fossa. Accumulation of dirt and cellular debris in this pouch forms little stones, which we commonly refer to as “beans.” Though very large beans that disrupt urine flow are uncommon, it is worth inspecting the horse yearly for presence of a bean. We often find that owners may be cleaning the sheath, but fail to fully explore the urethral fossa (horses generally resent this procedure)! In addition, the penis and sheath can be a site for cancer and tumors, so yearly inspection may reveal a problem before it progresses. Since most horses are sedated for a complete dental examination at least once yearly, we find that a sheath exam and cleaning is conveniently performed at the same time! Lisa Kivett, DVM, Southern Pines, NC

  13. I have a 3-year-old Quarter horse mare that has just been started lightly under saddle. The issue I am having is that she seems to "sprain her ankles". We've had our veterinarian examine her and he said stall rest, wraps and bute. What would be a good supplement to give her that could help with her ligaments?

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    It’s tough to know exactly what you mean by “sprained ankles,” since there are a range of issues with the fetlock joints that may be causing the problem. Some of these issues include early arthritis, suspensory ligament problems, fetlock “chips,” OCD lesions, problems with the sesamoid bones, and more. Regardless of the problem, I doubt a supplement will help. It’s important to remember that the supplement industry is not regulated, and these products can make a range of unsubstantiated claims. To my knowledge, no supplement has been proven to have any beneficial effect on treating or preventing soft-tissue injuries in horses. Supplements are also rather expensive. If I were you, I’d save the money that would be spent on supplements, and put that money toward a set of x-rays or an ultrasound! Lisa Kivett, DVM, Southern Pines, NC

  14. What are the causes of a bloody nose in horses? My 21-year-old Appendix mare had a right side sinus flap procedure to remove an abcessed tooth 4 years ago. At that time, a sinus cyst was discovered and also removed. The mare has had several short one nostril nose bleeds in the last year, bright red blood, from the left and right nostrils (never both nostrils at the same time).

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    We typically divide the cause of bloody noses (“epistaxis” in veterinary terminology) into two categories: unilateral (one nostril) and bilateral (two nostrils). Your horse is interesting, since you notice bleeding from both nostrils, but not at the same time! Structures in and around the nasal cavities (like the nasal passages and sinuses) are usually responsible for one-sided bleeding. Structures in the lower respiratory tract (like the lungs) and elsewhere in the body tend to be responsible for simultaneous bleeding from both nostrils.

    Causes for bleeding from both nostrils simultaneously include: pneumonia and other lung diseases, exercise-induced pulmonary hemorrhage (“bleeder” race horses), clotting disorders and a few other systemic diseases. Causes for bleeding from one nostril include sinus problems (like the cyst you mentioned), diseases of the guttural pouch, ethmoid hematoma, nasal polyps and other problems of the nasal cavity. Horses with guttural pouch problems may bleed from either one nostril or both.

    With your horse’s history, I would probably recommend upper airway endoscopy first. This involves the use of an endoscope, which is a long, flexible camera. With the endoscope, your horse’s nasal passages, throat and guttural pouches could be evaluated for any problems. If nothing significant is found, x-rays of the head can show problems with the sinus cavities and tooth roots.  It’s also never the “wrong” idea to have some bloodwork run! If nothing shows up on any of the tests, I might wonder whether the history of sinus surgery is a clue- perhaps she has some residual sensitive scar tissue in this area? Again, I would only make this assumption if all the tests results are clean. Lisa Kivett, DVM, Southern Pines, NC

  15. Is there a standard chart or guidelines book used to age horses based on their teeth? We have a gelding that has received 4 different ages from 4 different vets. We need to figure out how old he really is, to decide if he should retire to a sanctuary or be adopted by a private party. 

    (View Answer)


    You can purchase the AAEP's Official Guide for Determining the Age of the Horse via the following link:

    This booklet is easy to use and has great photos!
    It is important to remember that as horses get older, there can be tremendous variation in the wear patterns of their incisors. This means that it would not be unusual to have different ages reported by different veterinarians, particularly for a horse in his teens and above! Lisa Kivett, DVM, Southern Pines, NC

  16. I have a 15-year-old Appaloosa that had a gran mall seizure when he raised his head very high to avoid a supplement that I was trying to give him. This head raising produced another seizure when examined by my vet. I was financially unable to have an MRI performed. I did get an opthmologist to examine his eyes because he had supra orbital swelling. That vet thought she saw a tumor behind his left eye. Blood work came back IR only. I placed him on a low sugar diet and decided to let him live out his life. Not only did his eye swelling go down but he stopped having the head position seizures! His ACTH had been normal on exam. However, I always wondered could he have Cushings and the enlarged pituitary pressed against something when he lifted his head to cause the seizure? No vet can figure this out!

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    Seizures have been documented in horses with Cushings, and I think that your idea certainly makes sense. While there are many causes for seizures, an enlarged pituitary from Cushing’s (Pituitary Pars Intermedia Dysfunction or PPID) would certainly be on the list of differentials. Many horse owners do not wish to pursue CT or MRI due to expense and risks of general anesthesia, so it can be challenging to gain an accurate diagnosis. One thing I would suggest is to use a more accurate test for PPID. A baseline ACTH level is suitable for screening horses, but some horses can test negative even when they do have the disease. You may want to look into having a TRH-stimulation test performed, which is a more accurate test. Your veterinarian should be able to help with you with this test, and it would probably not be harmful to consider treating your horse with pergolide (Prascend) in an effort to help the seizures! Lisa Kivett, DVM, Southern Pines, NC

  17. I am just in the process of building a barn for my horses. We have well water that feeds our olive grove and now I need to find out if this well water is suitable for drinking water for the horses as it is now. I already have a well water test report with the results on various parameters.

    Would you be able to help me to find out who could take a look at those results? or, is there a website that I could consult? I live in Glen Ellen, Sonoma County in California.

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    Since your water has already been tested, I would consult your county cooperative extension office. Extension agents are trained in pasture management for horses and other livestock and are often an underutilized resource! Most extension offices can help you with soil testing, hay/forage analysis and will even make site visits to search for toxic plants. Lisa Kivett, DVM, Southern Pines, NC