Ask the vet: Immunizations, Have you vaccinated your horses yet?

The weather is perfect, trail rides are beginning and so is the show season. Have you vaccinated your horse(s) yet? Pose your immunization/vaccine questions to our AAEP month's expert, Dr. Christina Dayton-Wall during the month of May.

1	Question: My current boarding barn requires vaccination for Strangles. My horse has been exposed to Strangles several years ago at a former boarding barn, but did not get sick. My veterinarian recommends using the killed virus vaccination if I absolutely must get it. What do you think? Answer:  This is an excellent question because you are certainly not alone in this situation. There are definitely some options and you may need to discuss your situation with the boarding barn management. Since the horse did not contract Strangles, but was possibly exposed, I would recommend to test your horse's titers or level of immunity to Strangles. If the titers or levels of antibodies are high, I would not vaccinate and show the proof of titer to your boarding barn manager. If he or she has low titers then I would consider vaccinating with a killed or modified live vaccine (MLV). The killed vaccine is intramuscular (IM) and can cause muscle soreness, swelling, or even abscesses. The MLV is an intranasal vaccine and protects the mucosa in the upper airway. The side effects I see to the MLV is occasionally a runny nose from the nostril it was administered in.
2	Question: My horse has had terrible reactions to his vaccinations, which began 3 years ago. He now is vaccinated only for the West Nile, Eastern, Western and Tetanus and I have been admitting him to the equine hospital so they can treat/pre-treat and monitor him for any reactions. The reactions have been severe hives and, to the rabies vaccination, terrible pain as well. He recently had another bout of hives - cause unknown. Would a supplemental antioxidant offer a boost to his immune system? I currently give him Platinum Performance - but since he is now hyper-sensitive, would you advise I add something else and, if so, what would you recommend. He is a 15-year-old, pink-skinned Palomino Morab. Answer: I am sorry to hear that your horse is so sensitive to the vaccinations, but it seems like you are managing the situation well. I think the Platinum Performance is a great product! I feed it to my horses and have for years! Another option that I would add in would be Vitamin E. I suggest that you supplement with 400-1200 IU daily based on how much exercise your horse gets. There are several supplements on the market that provide Vitamin E. Some are liquid and others are pelleted. Consult with your veterinarian to determine if you also need to supplement selenium based on your geographical location.
3	Question: In New England, I always did my vaccinations in March/April. Now I am advised to either do West Nile later such as the end of May so that it will last through the fall as our autumns are getting warmer. The other option is to vaccinate twice, Spring and Fall. My horse has COPD and navicular, which I am managing with medication, but I don't want to over vaccinate.  If I don't tend to board my horse off the farm, but do attend day shows, would you vaccinate FluRhino twice a year for a COPD horse? I was concerned after the last vaccination he coughed quite a bit. Answer:  Since your horse has some medical issues such as the COPD and he is already an immune stressed horse, I would recommend limiting the amount of immune system stress. This means that I would try to limit vaccinating your horse to once a year. Most horses I would recommend vaccinating semi-annually, especially in areas with lots of mosquitoes! I would probably try to vaccinate in early to mid-May, that way your horse is fully prepared and his immune system is protected from West Nile and the encephalitis'. For your second question, regarding the Flu/Rhino vaccinations and the stress that it caused your horse, I have a couple of recommendations. I would recommend maybe trying a different brand of vaccines. Your veterinarian may be able to order a vaccine from a different manufacturer and this may cause your horse less stress and less side effects, but still protect from the diseases just as effectively. Another option would be to pre-medicate your horse with a dose of an anti-inflammatory. Your veterinarian can help guide you with this. This may help prevent any increases in your horse's inflammatory state in relation to receiving the vaccine. If you are traveling a lot to day shows, I would still vaccinate twice a year. Another way to avoid risk when you go to shows is to limit your horse's exposure to strange horses. Do not allow nose to nose horse interactions. Don't share buckets, or rags used to wipe the horse's nose. Try to limit your horse's contact with items strange horses may have used. If you have to use a stall at a show, consider using a disinfectant prior to allowing your horse into the stall.
4	Question: Is it still recommended to vaccinate for all three (3) forms of equine encephalitis (Eastern, Western and Venezuelan)? I notice a lot of the combo shots but only include two out of three (Eastern and Western). Answer:  What a good question! I too have also noticed the change in the vaccine combinations that are available. At this point in time, the American Association of Equine Practitioners recommends the Eastern Equine Encephalitis, and Western Equine Encephalitis as part of the core vaccines. I would say that the Venezuelan Equine Encephalitis would be a risk based vaccine. If the area you keep your horse in has had an outbreak, then I would recommend to vaccinate. Fortunately in the US, VEE has not been diagnosed for more than 35 years. The last cases were most notable in Florida. At this point, I would not vaccinate for VEE, but definitely EEE and WEE.
5	Question: There is controversy about "over vaccinating" humans, pets and horses. What is your opinion on this topic? Answer:  This is a very timely question. I believe that over vaccination can be an issue, however if your horse is in an environment that increases his or her exposure to disease, I recommend that you vaccinate. I recommend vaccinations based on the AAEP's core vaccines, which include annual rabies, Eastern and Western encephalitis, West Nile Virus and Tetanus. If you travel with your horse or keep your horse at a barn where there is a lot of horse traffic, I would strongly recommend that you also vaccinate for Equine Influenza (flu) and Equine Herpesvirus (a.k.a. rhino). You may also consult with your veterinarian regarding vaccinating for Strangles. I recommend that you vaccinate your horse based on his or her risk. For example, I practice in Georgia where with our mild winters and wet springs, I recommend semi-annual vaccines for EEE (eastern equine encephalitis), WEE (Western equine encephalitis), and WNV (West Nile Virus). I would recommend that you discuss what vaccines are appropriate for your horse with your veterinarian.
6	Question: Why does my 15-year-old Arabian mare get hives locally on her neck and shoulder after receiving her spring vaccinations? What should I do now and in the future to treat/prevent this? Answer:  This is an excellent question. A horse that gets hives on her necks and shoulders is having a mild reaction to the vaccine. If the horse gets all the vaccines at once, I would recommend to break them up and separate giving them by at least a week. This helps to allow your veterinarian and yourself to figure out which vaccine your horse is reacting too. Another precautionary step would be to give a dose of an anti-inflammatory prior to the vaccines to help decrease the reaction that your horse has. Your veterinarian can help determine which anti-inflammatory is the most appropriate.

Ask the vet: The foot: Structure, Function, and Disease

AAEP expert, Dr. Karen Blake, answers questions concerning the equine foot, including its structure, function and disease.

1	Question: I have a 9-year-old miniature horse that has developed chronic laminitis. At this point, he doesn't have significant sinking or rotation, but he is very lame. He is currently on banamine and a supplement from Smartpak called Smartflex Recovery. His feet have been trimmed and there were no problems with his sole or white line. He is receiving probiotics and timothy hay, and a very small amount of Safechoice feed. We don't really have any pasture right now, so that isn't a worry. He walks around, and he seems to lay down when he needs to. He's not stressed, no teeth grinding or grimacing. He actually seems pretty perky for as lame as he is. Is there anything else recommended for the daily management of this condition? I was told that this could take several weeks to months for him to improve. I just want to make him as comfortable as possible.  What about vaccines for him? I'm hesitant to vaccinate him right now since I do not want to cause a huge immune reaction while he has all of this inflammation going on. There seems to be a huge difference in clinical opinions about risk vs. benefit. We have a lot of mosquitoes that should be emerging any day now. I feel like we should wait until there is some improvement in his lameness to vaccinate, but I don't want to start the process all over again if we can get him to improve. Answer:  Poor guy! The most important part of managing laminitis is getting the inflammation down, getting his feet supported (they make miniature-sized Soft Ride boots for minis), keeping him slightly confined (so he doesn't walk all over the place when he is feeling better) and keeping the weight off, which can be especially difficult in these guys.  Remember that horses (and minis) should be fed 1-2 % of their body weight in hay. For a weight loss program, which almost all minis I see need and especially minis with laminitis, I use a 1% body weight amount. Therefore, a 150 lb mini would get 1.5 lb of hay broken into 2-3 feedings and add in Natures Essentials Enrich 32 to keep their Vit/Min balanced and keep giving them some protein, which is only used for muscle mass. I use this regime until I see significant weight loss. Then they can get bumped up a little to 1.5-2% bwt of hay. Generally, I also recommend soaking the hay for 30-60 minutes (no longer) to rid the hay of sugars (grass hay especially has significant variation of sugar and can be as high as 30%, which is terrible for horses sensitive to sugar in their diet).  Additionally, if the new grass is coming up, I restrict their grazing by using a grazing muzzle - I know they don't like it, but it is really important in keeping their weight down! All these recommendations should help stop the process of laminitis for your miniature horse. I would try to hold off on the vaccinations as long as you can, however you may also separate out the vaccination so that there's not so much reaction at one time.
2	Question: My 6-year-old mare is part draft and Paint horse. Her hooves flare out, typically to the back. Are there any good products for this? My farrier has never suggested shoeing as I mostly trail ride. Answer:  That is a common occurrence with draft feet - the pancake, as I like to call it. Keeping the feet trimmed with appropriate rounding of the exterior hoof wall will help keep the foot from chipping when it starts to pancake. It is possible that his bone alignment is slightly off, which will make the hoof wall less healthy to stand up to his weight. You could have some radiographs done to determine whether that is happening.  Shoes will also help to some extent as they 'tether' the hoof wall to an immobile object, but the nails only go to mid-way back on the hoof and will not help if the rear portion of the hoof is the one flaring out. The biotin product I recommend is either the Nanric 100 mg biotin powder or the double strength Farrier's Formula (approx 74 mg biotin). Biotin can help with horn growth of the hoof as well as health of the horn.
3	Question: We rescued a 11/2 year old Quarter horse filly whose growth plate had been injured on her left front ankle due to the previous owner trying to ride her. She has arthritis starting in it and radiographs show a small piece of bone missing from the ankle. Would a Glucosamine and Chondroitin supplement help with that? We have a farrier also working on her feet. Answer:  Yikes! Yes, there is more evidence that oral supplementation is helping horses with joint disease. My personal favorite is the Cosequin ASU plus; it has the typical joint supplements plus avocado and soybean extracts proven to help decrease inflammation/improve joint health as well as HA (Hyaluronic Acid), which is anti-inflammatory as well. Smart Pak makes a similar, as does Grand Meadows. At this point, her fetlock physis (growth plate) has closed and the farrier work, I would recommend, is allowing her easy break over from whatever side is lower towards the ground/fetlock angles away from; this will decrease the stress on the joint.
4	Question: I know that a normal landing of the hoof should be heel first or flat. However my 14-year-old gelding has one front hoof where the leg itself actually rotates slightly and he lands heel first, but slightly on the outside of the hoof. He has been trimmed and shod normally with both sides of the hoof even and has never had any lameness or other issues. He is used strictly as a trail horse. However, it is something that bothers me and I would like to know if there is a way or a need to trim and shoe him to land normally, or not. Is this an anatomical defect that can not be or should not be messed with since he is sound with the way he lands as is? Answer:  It sounds like your horse does have an anatomical reason to land on the outside of the hoof as he walks. This is common in horses that toe in or have slight rotations of their limb higher up. As long as your horse is sound and the farrier is cognizant of keeping the foot trimmed evenly, I would not change your program. Often times, trying to alter the horse's landing pattern actually causes lameness. It should be kept in mind that the horse may develop lameness over the long-term due to the landing pattern as it is bearing more stress on the lateral (outside) aspect of the limb, but that will have to be dealt with when it comes up (and it may never be an issue too!).
5	Question: I trail ride my horses on mountain trails that have a lot of rock as well as gravel. Is it better to keep horses shod for rocky trail conditions or can the foot harden to non-painfully allow the horse to travel barefoot? Would barefoot abrade the hoof down too much with many miles of trail riding? Answer:  It really depends on the horse and how hard the footing is on the mountain. Some rugged horses can handle mountain riding without problems. For the most part, I believe that our domestic horses can't handle the mountain riding without some type of protective foot-ware. Shoeing is usually the easiest and least labor-intensive, but some people have success with Easy Boot Trail shoes, which they apply for the ride. These boots can have rubbing issues on the heels and pastern regions though and should not be worn at all times as the foot needs some fresh air to keep it thrush-free.
6	Question: We took in an Appendix Quarter horse last summer. He now has, what appears to be, cracks from his frog up the heel to his hairline. He now has thrush. What is the best way to treat this, without further damaging more tissue? Answer:  I assume the crack you are talking about is in the middle of the frog and up between the heel bulbs. This is usually caused by sore heels and a decrease in use of the frog. As the heels get sucked upwards, the crevice/crack gets very deep. Your veterinarian can treat these horses by paring away excess frog, even using a scalpel blade to be more precise as the frog gets deeper, then using either a kopertox or sugardyne mixture to dry out that area. Also important is changing the shoeing so that the heel and frog come back down from their sucked up position as the foot gets more comfortable.
7	Question: How should laminitis be treated for a pregnant mare? She became mildly laminitic with no rotation and foaled just last week. Now without the hormones and the weight of the foal, how do I treat her to return her to soundness? She is currently on a low sugar diet and wearing padded boots that support the frog, and walks with no discomfort. Is there anything else I can do for her? Answer:  At this point, especially since she's doing well, it seems like there is nothing more I can suggest besides taking her slow upon your return to riding. However, if you think she is sensitive to insulin (Equine Metabolic Syndrome), then you can always test for those levels in her blood and monitor them so that if her insulin is rising in her blood, you can modify her diet and weight further.
8	Question: I just realized that my farrier cut the frog down to almost nothing on three of my horses feet. I fired him on the spot but wonder if there is anything I can do in the meantime? Answer:  Sometimes in the spring, with the wet weather and mud, it can be easy for a farrier to take a swipe of the frog or even sole too deep as they have been softened by the weather. One product I really enjoy is called Keratex - it's a sole hardener but can be used on the frog as well. It's a liquid, which can be painted on with a small paintbrush, already included with the product. I would apply it once a day for seven days, then go to 2-3 times a week. It's very useful for thin soles or soft soles too.
9	Question: What is the best, most accepted, correction for a horse with low heel problems? Do wedges only make matters worse? Answer:  Wow! That is a very difficult question to answer as many people have differing opinions on the best method to use to correct low heel problems. There are lots of combinations of flat or wedge shoes with wedge pads, which can elevate the low heel. Unfortunately, if the heel is collapsing or underrun, they can make the situation worse as the pad is placing pressure on the collapsed heel and that pressure adds leverage to the damaged heel and increases the crushing force, worsening the problem. However, some farriers are able to use wedge pads/shoes with great success. Alternatively, there is another method to help the low heel called a 'rocker' shoe which elevates the heel portion of the foot by using a round bottom shoe and allowing the horse to 'roll' to the area of most comfort which is usually the toe region and thereby unweights the heel region (which essentially elevates the heel). The goal with these shoes is the create a healthier, more comfortable foot so the heel will eventually grow out to a relatively normal angle (less low).
10	Question: My Thoroughbred gelding went on a "joy" run last summer, going through deep fields, on two roads, and ran upon railroad tracks for quite a distance, total of 3 miles or so! When I caught up to him, he could barely walk. He kept pulling up one hind leg, then the other. As the day went on, he couldn't hardly stand. His muscles would become rock hard at times. The vet and I both did research to determine what was going on. (His labs were perfect, etc.) With and without the vet, I gave him bute and banamine, altering back and forth. I also started to give acepromozine for the relaxation of the muscles...(I told the vet and she agreed). After 7 weeks, he was better and just a walk under saddle was more than enough for him. I left out LOTS of detail, like uncertain if he should be hand walked vs. stall rest this whole time, etc. My husband wanted to put him down! The horse had good attitude during this entire process so I know he hurt but not to the point of euthanasia!  He finally abscessed in one hind hoof, then a week later, the other hind. My farrier said that happens even though trauma to the hoof (no nail holes, bruising, etc. present) can be unknown or just a guess. My questions, finally--what do you think caused the abscesses? Hard road? Deep soil in field? He recovered fine, except now he hates the field and WILL NOT agree to be ridden out there! Now he's scared and gets way upset! Any thoughts on this? Thank you! Answer:  It sounds like your horse developed rhabdomyolysis (ie: tying up) after his exciting get-away. Commonly, the lab values will not rise until 24 hours after the incident. I agree with your farrier in that the blunt trauma to the soles will cause inflammation within the foot, which can cause serum build-up or even bruising (blood pocket) within the foot - both of which are easily infected fluids. Once the fluid is infected, it becomes known as an abscess where it causes lameness and needs to be released from the foot so the infected fluid can drain out.
11	Question: I have been trying to research my concerns on-line, but have not come up with information pertaining to my gelding. Captain is a 12-year-old Paso Fino, used for trail riding (and not a lot at that). He's had a very easy life since I've had him (at 4 years of age) and he has not had any particular discipline stresses to his joints since I've had him, using arena work just for general warm-ups in which I use the rail and large 20 meter circles. This past year he has developed a "popping" movement in both front fetlocks, and I feel it when riding, obviously.  I've been observing other horses in their movements and have not seen this type of action. The popping happens during the full motion of strides. Last season, we applied an aluminum shoe with a very slight rear wedge, which helped and Captain traveled well over the trails, but there was still a slight visual of this popping. We removed shoes for the year, giving him time off to adjust, observing carefully for any discomfort (with concerns of tendon/ligament stress from angle change). Captain was sound and showed no stress. I don't ride much in the winter, here, but am starting to begin short warm-ups (straight line riding) and the popping has returned to be very noticeable. There has never been any heat or swelling at the fetlock/pastern areas, nor any sensitivity to palpation. My vet/farrier are scheduled next week for hoof x-rays (I want a baseline) to ensure proper shoeing, to get reading of sole depth, and coffin bone structure. My question to you: Have you ever seen anything like this? My farrier and vet, both, concur that this is an odd joint action and suspicion tendon/ligament stress.I appreciate your time in reading this and look forward to your response. Answer:  That is a difficult problem. I think your idea to get radiographs of the feet is an excellent idea. Sometimes, the foot angles will cause the suspensory to create an abnormal angle of the fetlock or pastern, which causes what I would call a pseudoluxation - a luxation of the joint, which is not a true or permanent luxation - and probably is the cause of the 'clicking'. Meaning, when you change the angles of the foot, as you experienced when you placed wedge shoes on your horse, the suspensory ligament drops and allows a more normal fetlock angle and 'corrects' the luxation. It is possible that there is some suspensory pain too which may cause the horse to not want to drop fully into the fetlock, the suspensory should be palpated by your veterinarian for discomfort or swellings. The hoof radiographs should help you to figure out these issues. Good luck!
12	Question: My horse is recovering from a lameness and abscess that my vet contributes to a retained sole. I've never heard of this before in 40 years of caring for horses. How common is this? What can I do to prevent this from reoccurring? Answer:  A retained sole (also known as false sole) is when a separation occurs between sole layers of the outer hard sole and the inner soft sole; they separate and form a pocket. It's actually more common than you would think. In my experience, it develops when the horse has a thin sole (<15-20 mm sole depth as seen on a lateral/side view of the hoof) and either a deep bruising/inflammation develops, which separates the outer and inner sole. It most likely occurs from stepping on something hard like a rock, ice-covered pasture or hard arena footing.  The pain can either come from the edges of the pocket, which press on the soft, new sole beneath or from direct pressure of the hard sole on the soft sole as the horse walks. The only way to rid the horse of pain is for your veterinarian to peel out the hard sole with a hoof knife. This gets rid of the pressure/pain from the hard sole and allows the soft sole underneath to become firm. It is imperative that the soft sole underneath be protected during the time it is getting harder so new new bruising occurs. Usually after it matures for 1-2 weeks, I then put a protective pad under the shoe for one shoeing cycle so that the sole cannot be bruised as its growing out.
13	Question: Is a "clubfoot" a heritable trait?  Answer:  This is a very good question and so far there is no proof that it is inherited. However, if you take a look at many young foals, you can see the clear difference in hoof angles, which leads me to believe it is heritable. That being said, if you know that the foot may be inherited, surgery can be attempted to correct the condition as it works much better at a younger age.
14	Question: I have a 5-year-old gelding with a club foot. He had check ligament surgery as a 2-year-old. We are still struggling to get a heel first landing or at least a flat footed landing. The farrier has tried wedge pads, which did not work. He is much better after letting his feet grow, but seems as though the toe was cut too short, causing his knees to buckle. His frog was atrophying so, at my suggestion, we had his shoes pulled. He was definitely headed in the right direction for the first two months as his frog was growing and he was landing flat footed part of the time. Now we have back slid and he is now walking on his toe again. Any thoughts? Answer: When the club foot does not respond to the check ligament surgery, it can be difficult to manage as an adult. The reasons for this can be several-fold. Firstly, it is possible that the foot, as you suggest, has been trimmed too short. Many farriers and owners want the foot to look normal after trimming. Unfortunately, the foot is anatomically abnormal at this point and should not have the heel trimmed short. Taking off heel to 'create a more normal angle' creates tension on the deep digital flexor tendon (DDFT). This creates pain within the foot as the deep is putting tension on the coffin bone, which creates pain in the laminae (attachment to the hoof wall) or small tearing of the laminae. Additionally, if the heel has been trimmed to short, the tension in the heel region decreases the blood supply to the foot, which slows sole growth. This means that, in addition to pain in the laminae and heel region, there is possibly a thin sole present which can be cut too short at trimming, causing solar pain and eventually change in the solar portion of the coffin bone. In addition, it is likely that your horse will not land heel first, he will most likely land flat footed, which is fine. If he is landing toe first, then he doesn't have enough heel present I would encourage you to have an x-ray taken of the foot to see how thin the sole is and if there is any bone change in the coffin bone. The x-ray will help to determine how to properly align the coffin bone, which will allow sole and hoof growth.  As to the question of the frog, it will always be abnormal as the foot structure is abnormal and a thin, sucked up frog is directly related to the angle of the hoof and coffin bone within the foot. Therefore, the frog changes with the shape of the hoof/angle of the hoof, which is different than an atrophied frog. This is a difficult case to manage, as you have already experienced. Hopefully we could answer some of your questions and help get you and your horse back on track.

Ask the vet: deworming

Tired of knowing which dewormer to use? Or when to deworm your horse(s)? Learn all of the answers by posing your questions on the topic of deworming during the month of February to our AAEP expert, Dr. Chanda Moxon.

1	Question: Are there any particular dewormers that will cause horses to have problems with recurrent uveitis? I have a grey mare that has recurrent uveitis, and I was told that certain dewormers can trigger an attack. Is there any truth to that?  Answer:  Equine Recurrent Uveitis (ERU) is one of the most common eye disorders in horses. It is an immune mediated disease with several hypersensitivities, and no specific cause. The hypersensitivities include, leptospirosis, brucellosis, Streptococcus equi (strangles), Onchocerciasis, and hoof abscesses just to name a few. The most common hypersensitivity can be linked to Leptospirosis. With this being said, ERU can be very frustrating to link back to a particular cause. Onchocerciasis is a parasite that is associated with connective tissue. They are not found in the intestinal tract of horses like most parasites. They produce microfilaria, which most often migrate to the dermis and/or to the eyes of horses. The clinical sign most often seen with Onchocerca is dermatitis. There may be areas of scaling, ulcerations, alopecia, and pruitis on the skin.  Onchocerca can be diagnosed by having your veterinarian perform skin and/or cornea biopsies .The treatment includes Ivomec or moxidectin, which are found in many of the intestinal dewormers. If your horse has a history of ERU and has been diagnosed with onchocerciasis, during treatment, the dying of microfilaria can incite ERU. This question had me researching in a number of places for an answer. Equine Recurrent Uveitis can have so many causes and treatment options. I recommend working closely with your veterinarian and perhaps even taking your horse to an equine ophthalmologist, especially if your horse is showing any signs of skin problems. There could also be other parasites that I am not aware of that could cause the flare ups after deworming.
2	Question: My mare has been rubbing her tail very aggressively, off and on for a year, against posts, walls, etc. One veterinarian told me it was pin worms. I have tried to use paste dewormers, including a dose two weeks apart of Panacur. It seems better, but not completely 100%. Do you have any suggestions?  Answer:  I agree with your veterinarian that the “tail rubbing” is likely due to Oxyuris Equi or Pin worms. We should also consider other causes of pruitis in horses, such as an allergic response to the insect Culicoides and/or the fungi, dermatophytes (ring worm). And for male horses, sometimes a simple sheath cleaning will help when they are rubbing their tails, while in females cleaning the udders will help. But, let's get back to assuming it is Pin worms, a tape test can be performed by your veterinarian to diagnose them. Since your horse seems to respond temporarily after deworming, I would expect we are dealing with either parasite resistance with your dewormers or an environmental contamination issue and your horse keeps re-infecting herself. Pin worms have become resistant to some of the deworming products available. I would recommend using a Pyrantel Pamoate paste every four weeks for at least two treatments. I would also decrease environmental contamination by wiping the rectal area with baby wipes and clean all water/feed buckets, as Pin worm eggs are very sticky and attach to objects in the stall allowing for your horse to be easily re-infected.
3	Question: I just moved to Las Vegas, Nevada from Michigan and would like to know if I need to change my deworming schedule for my horses and deworm for different types of parasites since the weather is so much different in Michigan than here in Nevada. Answer:  This is a great question; however, many theories are changing in the way we think of managing equine parasites. The rule of thumb in histories past was to deworm as the seasons changed or every three months. There are many considerations involved when dealing with intestinal parasites such as the age of the horse, the size of pasture, the number of horses grazing a pasture, and if pasture rotation is available. We have not had any new antiparasitic agents developed since the mid 1990’s, the current deworming products we have, we need to make them last. With this being said, there has been a great deal of parasite resistance developing with our current dewormers. The recommendations we are now making for “when to deworm” is to perform fecal egg counts before deworming. This is a very simple test that your veterinarian can run in the clinic and at that time your veterinarian can detect what parasites are found and give you a better understanding as to what deworming product will best meet your horse’s needs, as well as offer other environmental management recommendations. Often times, I have found that we are deworming when there is not a need to deworm at all. In Nevada, I would recommend taking a fresh fecal sample to your veterinarian every 3 months. I would expect with the dry environment, you will be deworming less often than you were in Michigan. This new way of thinking is to act more as a preventative management and attempt to decrease your horse developing resistance, as well as keeping a chemical out of your horse’s body if there is no need to deworm.

Ask the vet: EPM

AAEP's Dr. Sandi Farris answers questions on the debilitating disease, EPM.

1	Question: On October 23, 2012 I witnessed my 18-year-old paint gelding slip in the mud. He then began to side pass to meet me at the gate. Our veterinarian recommended a week of stall rest, but my gelding had little to no improvement. The veterinarian said came to evaluate my gelding, which included a lameness exam and radiographs of the left stifle. His diagnosis was severe sprain of the interior stifle, heat and apparent inflammation. Treatment consisted of bute and work him lightly building on strength and duration and a one to two week normal turnout routine. This didn't feel right to me, but I complied. On day 2, my horse became extremely lame on his right as well as original left . I contacted the veterinarian once again to discussed the current situation and response to treatment. His response to me was to keep him moving. Over the next week, my gelding tried to comply but lameness worsened. I had a second veterinarian reevaluate my gelding. He disagreed with treatment and told me to rest him and continue on bute. Over the next four weeks, my gelding's lameness worsened and seemed to loose control of his hindend. He almost seemed to have no clue where his feet were and had a pronounced right hind hip drop when moving. He looked one step away from falling.  Enter my farrier, who watched him move and suggested a lameness specialist and/or chiropractor. That said, a specialist came and did an evaluation, which included digital radiographs of both the head and stifle. She felt the horse definitely was neurologic in symptoms progressive of original injury. She felt there were three possibles, which included THO, EPM or West Nile. Radiographs showed moderate swelling of the right hyoid bone, and slight on the left. She started him on a high doses of Dexamethasone and would reevaluate him in one week, which did include some improvement. She then drew blood to hold for future EPM testing. I went online and watched several videos of EPM cases and felt this was what I was seeing in his movement. She then begain him on EPM medication along with Dexamethasone. Five weeks later he had significantly improved. I began walking him daily which we graduated to small hills backing and stepping over ground poles. I now have two new problems. The first is that he has lost the hair over his left eye, and she thinks it is possible uveitis, which dex is used for. How do we know what drug is working on his ataxia, and dex is an immune supresser, could it be causing other problems? My specialist that took blood samples is currently out of the country as I would like her to run the bloods for EPM. But, what about the hyoid bones swelling? Is it possible this is and has been his normal all along and we are dealing with EPM? And the hair loss over his left eye; is this some kind of immune response to the drugs or the disease in question? My gelding has been good-natured and patient throughout all of this. However, I am confused and frustrated! Answer:  Oh my, you do have a number of issues in your horse right now. This case has a high number of variables between the early history of lameness and the response to EPM medications and finally a question about the hyoid bone and the hairloss. I can't comment on a diagnosis for your gelding but I can suggest either contacting your last veterinarian for guidance or if she is unable to re-examine him contacting a referral center that can take your gelding's symptoms one at a time. I don't know where you are located but most areas have fairly good access to a Veterinary Teaching Hospital or if you'd prefer, a local private referral clinic. Referral centers and Universities tend to see a number of unusual and/or complicated cases each year and may have more diagnostic tests available to pinpoint a diagnosis for you.
2	Question: Is there a test available to see if my barn cats are carriers? If so, what is the name of it? Do most small animal vets perform the test or will I need ask my Equine veterinarian? I own an 8-year-old Gypsy gelding that has been battling EPM since April of 2012. We first tried a course of the Sulfa suspension medication, and now he is running through a course of Marquis. I have been extra careful with keeping the wildlife carriers of EPM out of my barn, but would like to see if our barn cat is carrying it.  Answer:  Cats have been tested experimentally to determine if they carry serum antibodies to Sarcocystis neurona. Researchers determined the domestic cat is one of the natural intermediate hosts for the causative agent of EPM. Some studies report that 5% of all farm cats have been exposed to S neurona in areas with opposum. Your question about testing your own cats is a good one. Although research labs have used the tests it is not a common test in the private clinic setting. A Polymerase Chain Reaction (PCR) test is required to differentiate exposure of the cat to the parasite from actual infection with S neurona. Zoologix Lab, among others, does offer a feline S neurona PCR. It can be run on blood or nervous system tissue. Talk to your veterinarian about the practicality and use of this PCR in your barn!
3	Question: My 13-year-old Appendix Quarter horse mare developed EPM at the age of 7. The disease was very severe and I nearly lost her, but she recovered well. She is sure footed, rides well and even jumps. The only setback she had was one paralyzed vocal cord (per bronxhoscopy). She is now in foal and due March 12. She is exhibiting symptoms of EPM again. I know foaling is stressful, but wondered if Marquis would be safe to give her before foaling? If so, for how long? If not, can it be given after foaling with a foal at her side? Answer:  EPM is unfortunately a disease in which stress of the horse plays a large part in recurrence of symptoms. Pregnancy and lactation are arguably the most physiologically taxing periods in a mare's life. Sarcocystis neurona has a tendency to recur during these times. The resulting neurologic deficits cause concern about the health and safety of mare and foal.  Current medications available for treating EPM can have a variety of adverse effects on a pregnancy and should be used carefully and under the advisement of your veterinarian. Risks and benefits to treating your mare while she is in foal will need to be assessed. Most commonly these drugs are folate-synthesis inhibitors which, as we are aware in human pregnancies, when used long-term can lead to birth defects and bone marrow arrests in the fetus.  Medicating your mare with the foal-at-side may be safer than treating during the pregnancy, and again you will want to discuss the specific risks and benefits with your vet. The Marquis drug insert does contain the broad statement that risk of use in breeding horses is unclear.
4	Question: I live in north central Virginia and have an 11-year-old Irish Draft gelding. Can/should I vaccinate him against EPM? Can this vaccine be given with other vaccines or should it be done at a separate time?  Answer:  In the past, EPM vaccines were available on the market for use in horses. Protection in those horses was, unfortunately, poor, and the vaccines were removed from manufacture. As of now, there is no USDA-approved vaccine against EPM. What a help it will be when there is one with a high level of protection! The best horse owners can do now to protect against the protozoal disease is to minimize the intermediate hosts (opposum, cats, raccoon, and skunk are most likely culprits) by keeping grain and water sources secured, decrease host access to horse pastures, and keep your horses as healthy and stress-free as possible. I am sure the ongoing research will one day lead to a useful vaccine.
5	Question: My 27-year-old mare presented the following symptoms on the evening of 11/8/12: barely able to walk; could not cross the threshold to stall without help, fell down in stall, which resulted in an emergency call to the veterinarian. They submitted blood drawn from my mare to MI State University for testing (S. neurona IFA Titer test), which was 320 suggesting + for antibodies against S.neurona. The clinical picture was consistent with EPM as well. She was then administered on a 28 day treatment with Marquis, which has shown improvement with her gait/balance, etc. I question that specific test as to what it is testing and have read that while the IFA test is believed to be an improvement over the Western blot relative to predictive ability; newer ELISAs are more quantitative. If the appropriate tests are used (whatever that would be) would a decreased antibody titer after treatment be useful? And, if symptoms re-appear, would it help to have this information and then re-test if I suspect a relapse? Answer: Such a good question...this is one of the toughest pieces in the EPM puzzle right now. Serum (blood) tests for EPM have improved over the past decade but still are not altogether definitive in diagnosing clinical disease caused by the EPM agent Sarcocystis neurona. The first test used was known as a Western blot, a procedure which was revolutionary in the 1990's but had limitations with a high number of false positives. Since then, polymerase chain reaction (PCR) and immunofluorescent antibody (IFAT) testing has improved the value of the results. Each test has individual limitations; a negative PCR does not rule out the presence of S neurona, IFAT may be more subjective than quantitative. Research is ongoing and new methods are being developed. It is possible that enzyme linked immunoabsorbent assay (ELISA) tests may currently be an ideal choice for accurate test results. That said, an elevated S. neurona serum titer is evidence of infection (exposure) than of actual disease. Titer levels can vary based on the number of organisms found in the horse, the immune system status, and the presence of concurrent or previous medical treatment.   Many cases of EPM are treated based on historical clinical signs in the presence of a strong serum titer. Presumptive treatment with an anti-protozoal with improvement in signs can be considered a diagnostic tool in itself. The most exciting new research Dr. Dan Howe, of the University of Kentucky Gluck Equine Research Center, has found proteins on the surface of the S. neurona parasite, which have the ability to create a strong immune response in the horse. The proteins, labeled snSAGs, elevate in ELISA titers on serum and cerebrospinal fluid (CSF). CSF is sampled via a spinal tap. Similar to previous testing methods serum snSAGs titers alone are not completely foolproof. CSF titers coupled with serum titers for snSAGs remain a more credible positive for EPM diagnosis. Check with your veterinarian for more information on using the newest snSAGs ELISA titers.
6	Question: My 13-year-old mare came up with a low positive on the EPM test when she returned to upstate NY from Va.as a 3 yr old. She was testy (wringing tail) about weight on her back and even tripped and fell once when being ridden but otherwise was perfectly fine. I treated her for one month with a medication that is now off the market. She never got wobbly but since I couldn't really make any progress with her dressage work, I stopped riding her. She is in foal now. Is there any way to know if the EPM was causing this behavior? Answer:  You don't specify which test was used in your mare; there are some differences in interpretation depending on the method used. Low positives on any serum (blood) test may indicate an early response of the horse to the Sarcocystis neurona protozoa, a low dose of S. neurona in the body, or may be a a cross-reaction to another type of sarcocystis and actually be a false positive. Because of the length of time that has elapsed it would be difficult to attribute your mares signs to EPM.  Many other variables can play a part in the difficulty of bringing a sport horse up the levels. Behavior, training, nutrition, and other musculoskeletal and orthopedic processes can lead to a wringing tail and gait deficits. Equine polysaccharide storage myopathy (EPSM or PSSM) and vitamin E deficiency are two specific disease syndromes that can cause some of the same signs as EPM. It sounds like she is no longer exhibiting these signs as she is currently in foal and hopefully healthy and well-fed. It is possible that EPM signs can return in horses that were previously infected, regardless of treatment history. Stress of pregnancy and lactation could provide an opportunity for pre-existing  S. neurona to "take hold" and create damage to the central nervous system. Watch for neurologic or balance and weakness issues in your pregnant mare and advise your veterinarian of her past episode of tentative EPM.  A team approach would be ideal in determining if your mare should currently be assessed for EPM. A cerebrospinal fluid test exists that can be more definitive in making an EPM diagnosis, but it is not without risk to the horse and may not be a good idea in a pregnant horse. Pregnant mares must be treated for EPM with caution: sulfadiazine/pyrimethamine combinations (Rebalance is a brand) have been shown to have toxic effect on foals. Marquis and Protazil are safe and have been used in pregnancies, though none are specifically FDA-approved for use in pregnant mares.
7	Question: I have a 20-year-old Tennessee Walking horse mare that was observed as having hind-end ataxia in Fall 2009. I am located in Santa Fe, NM where we have a lower population of the carrier mammals. She came from Tennessee a couple of years prior. Could she have acquired the organism and not exhibited symptoms until 2-3 years later? Two blood titers performed in 2009 and 2010 resulted in nearly the same probability: 70-something percent chance that she has the organism. I administered one round of Marquis in 2009, which seemed to help with some strengthening of the hind-end and reduced stumbling. Since then, her symptoms have not changed significantly. Is this EPM or is something else going on? She has foaled 13-14 times in her past life prior to my ownership. Answer:  There are a few possibilities with your mare. Changes in muscular strength from age and multiple pregnancies and a history of living in an area (TN) with the carrier opposum species could all contribute to the hind-limb ataxia (unsteady, unbalanced) you describe. Nutrition, exercise, and regional disease could also be variables in a diagnosis in your girl.  The organism of EPM, Sarcocystis neurona, can lie dormant in the horses central nervous system for years before a bout of illness, stress, or time alone results in disease symptoms. Stumbling, neurologic deficits, hindlimb weakness, and muscle atrophy, especially if asymmetric, are symptoms of EPM. The blood tests she received in 2009 and 2010 indicate that she has been exposed to and developed antibodies against S. neurona in her lifetime. This test is a useful tool to focus our suspicion on EPM, however the blood test alone is not definitive for a diagnosis of EPM. In some cases, owners and veterinarians decide to further identify the protozoa by collecting cerebrospinal fluid (CSF) from the horse. The spinal fluid is used as an aid in diagnosis in horses with active clinical signs such as those you describe in your mare. The collection of CSF is not without risk to the horse and contaminated samples can cause inconclusive or false results. The CSF testing is often reserved for horses in which the diagnosis would significantly change the treatment plan or affect the horses performance or quality of life. In many cases, diagnosis is achieved by administering a round of EPM treatments, such as the Marquis product that your mare received, and assessing changes in the patient. Subsequent improvement in EPM signs can lead to a presumptive diagnosis of EPM. Once successfully treated, EPM may remain in remission for months or years, but multiple reports of horses with recurring neurologic symptoms indicate that the protozoa is a difficult parasite to eradicate.
8	Question: My Thoroughbred gelding is 24-years-old and has Cushing's Disease and now we suspect EPM. He is being treated for both. What are the odds of a full recovery from EPM - I mean will I ever be able to ride him again? Answer: According to current research information, around 70% of horses treated for EPM with appropriate medications and protocols will respond and return to their previous performance levels. Your horse is suffering from two separate diseases, however; so his return will depend on how readily each affected system (hormonal, or endocrine, and neurologic) is able to respond to treatments. There may be some overlap in symptoms from each disease. Hopefully the medications and management strategies will allow your guy to reach his full potential again. Your gelding is lucky to have you!
9	Question: My 11-year-old Appendix gelding was diagnosed/treated for EPM when he was 5 years old. He only showed very mild symptoms (easily pulled off balance with tail pull, stands "quirky" with legs crossed). I've ridden him moderately over the years, even doing some low hunter courses with him, but lately he seems to be getting weak. He slips and slides in our indoor arena, apparently not getting his hind feet firmly planted while cantering around. My question - can EPM return after a long "remission" and what can I do to strengthen my geldings' back and hindlegs so he doesn't slip so easily? Should we treat him again with medication? Answer:  Unfortunately, EPM is a disease process that can relapse after an apparently successful treatment regimine. The protozoal agent, Sarcocystis neurona, can lie dormant for many years before causing a horse to have any signs of neurologic instability. Weakness, balance deficits, lameness, and lack of coordination can all be symptoms of EPM. The same signs are found as well in a multitude of disease processes, including equine motor neuron disease, equine polysaccharide storage myopathy, and west nile virus syndrome. That said, I would strongly suggest having your veterinarian perform a full physical examination of your gelding to determine if an EPM relapse is happening. It is possible your vet will want to treat with another, longer-term course of medications. Traditionally sulfa drugs coupled with pyrimethamine were used to "paralyze" the protozoa. Newer drugs have come into use including ponazuril (Marquis) and nitazoxanide, or NTZ, (Navigator). Ponazuril is a form of a coccidiostat, a drug class that inhibits the replication of coccidia protozoa but may not effectively kill every organism in the central nervous system.  Nitazoxanide was originally developed for human AIDS patients and has also been found to kill the sarcocystis protozoa.  In the meantime, use caution working your gelding in order to prevent him from stumbling or falling and causing injury to himself or a rider/handler. Once he has been examined and a diagnosis made, exercises for restrengthening his topline and his hind limbs can include lots of walking, stretching his head, neck, and back long and low to activate his lumbar and gluteal muscles and lift his belly. Ensure that your arena footing is firm, not too deep, and not slippery. Walking up hills is an excellent strengthening routine once he is deemed safe to work.
10	Question: We seem to have a revolving door of opossums in our barn, despite trapping and relocating them. My concern is obviously EPM. Do we know what percentage of opossums carry the disease and how easily they can transfer it to horses? Answer:  Opossums are a tricky business in some barns! Like rodents, they are drawn to horse and cat feed, low-lying water sources and human garbage. Opossum prefer densely forested environments and riparian areas alongside rivers and streams along the West Coast and the southeastern coastal states. Horses become infected with S. neurona after ingesting the protozoa from the feces of opposum on pasture or in grain or hay, even in feeds shipped across country. EPM has been reported in nearly every region of the United States. It is difficult to say precisely what percentage of opossum carry the protozoa, but it has been found that an intermediate host is necessary to complete the sarcocystis life cycle and cause infection in the horse.    At this time, the natural intermediate host is not known definitively but is suspected to be raccoons, armadillo, birds, skunks, and/or cats. A study by Dr. Steven Reed et al found that 59% of tested raccoons were positive for S. neurona. Another study  reported in the Canadian Journal of Research that 7% of domestic cats carry the parasite. The good news for your barn is that although many horses are exposed to S. neurona by opossum, the majority are able to mount an immune response and prevent infection. Studies show that only 1% of horses will suffer neurologic disease after being exposed to sarcocystis. Unfortunately, young, old, ill, or stressed horses are much more at risk for clinical EPM disease. Because the horse is an aberrant, or dead-end host of S. neurona, positive horses can't infect other horses.   Management at your barn should include sealing feed containers and keeping cat food out of reach, using high-sided tubs for feeding, keeping your horses healthy and current on vaccinations and deworming, and feeding heat-treated pelleted feeds to minimize the infective sporocysts in the ingredients. Wire-mesh fencing may deter the opossum from entering the barnyard. Minimizing the presence of intermediate hosts will decrease the infected opossum population.
11	Question: I have a 23-year-old gelding that was diagnosed and treated for EPM, but not sure when....at least a couple of years ago. He has been having the hind leg spasms since I've had him (one year now), but over the last month or so, he's occasionally been suffering from narcolepsy. He catches himself before he falls. He has also been stretching out his stance when just standing around. Are these signs of progression and will it become worse? I have given him ABC's holistic supplement without folic acid, but will this help him? He is in good weight, has a good appetite but doesn't lay down to sleep very often. Anything I can do for him? ANY info you can give me about EPM and what to do for him will be greatly appreciated. Answer:  A horse with Equine Protozoal Myeloencephalitis (EPM) may exhibit a variety of neurologic symptoms, including poor balance, spastic leg movements, or the signs you describe with the appearance of narcolepsy. Sarcocystis neurona, the parasitic protozoal agent of the disease, is found most commonly in geographical areas inhabited by the opposum. Horses that graze pastures where opposum have defecated are most at risk for acquiring S neurona. Amazingly, a number of these exposed horses never show EPM symptoms though some horses will harbor the dormant parasite for years before becoming ill.    Given the history you mention, I suspect your horse is one of the 10-20% of patients that suffer a relapse of EPM after previous successful treatment. A veterinary examination of your horses neurologic system and physical condition would be ideal at this time. Your veterinarian can help rule out other causes of 'narcolepsy' such as sleep deprivation leading to the buckling you describe as well as determine if another round of EPM antiprotozoal treatment would be useful.

Ask the Vet: Orthopedic Surgery

Do you have concerns regarding orthopedic surgery on your horse? Pose your questions during the month of October to our AAEP expert, Dr. Chris Bell regarding orthopedic surgery, what to expect before and after.

1	Question: My horse recently had arthroscopic surgery. He was bleeding into the tibiotarsal joint in his right hock. The surgeon discovered a very large fibrous band of tissue in the joint that had a blood vessel in it. He felt it was so large that he could not resect it without significant risk, and it was too large to use a laser. He had never seen a case like this previously. Have you run across any cases like this? If so, were you able to resect the fibrous band of tissue? Are there other methods available to shrink the band of tissue? Could the bleeding into the hock cause the band of tissue to develop? If you have observed these types of cases, what was the outcome post surgery? I sincerely hope you will respond as this is so rare. I am trying to find any experts who have dealt with cases like this so I can help my horse make a full healthy recovery. Thank you for your time. Answer:  Thank you for your question. This does sound like an unusual case. I suspect the large fibrous band could have been due to the previous bleeding into the tibiotarsal joint. As the blood components reabsorb from the joint, they can sometimes leave behind a sticky fiber substance called fibrin. This fibrin will stick together and can form bands or webs. These bands then mature into a fibrous tissue. I have seen this before in different joints and tendon sheaths. Often these bands can be appreciated on ultrasound as well as during arthroscopic surgery.    In most cases, these fibrous bands can be resected but in this case, it sounds like the surgeon had seen a possible blood vessel within the band. That is very unusual and could limit the ability to resect.   As far as your options to remove the tissue, it will depend on how large the blood supply is to the tissue and where the tissue is located within the joint. It may be more web-like tissue than a distinct band of tissue - difficult to tell you the exact options without seeing this band. Potentially, the surgeon could ultrasound the joint and identify the size of the blood supply in the tissue. If there is no major blood supply then the surgeon will be able to go back into the joint and resect the tissue. If there is blood supply, then the surgeon may be able to apply hemostatic poly-L-lactate clips to the blood vessel and then resect the tissue. Another option for the surgeon would be to perform a arthrotomy (open the joint) and remove the tissue. This type of approach would allow good visualization for the surgeon during surgery if there was bleeding but does carry an increased risk of infection and is not as cosmetic as arthroscopy post-operatively.  This is a rare case and I wish you and Rex all the best. I am sure your surgeon will be happy to discuss your options from this point forward and I am hopeful that this does not limit his future athletic performance or comfort.
2	Question: This is follow up on the 2.5 year old Quarter horse with the patella luxation. Radiographs indicated no ligament, tendon, or knee cap damage as the ridges appear to be fine (Dr. Dunlap included the views you recommended). We are trying 6 to 8 weeks of rest in a 24 x 36 paddock, hoping the strain heals and patella will reseat. He is not experiencing any pain or lameness. In your experience, does this type of injury, correct itself? Thank you for your suggestions. Answer:  If the ridges appear normal, then the luxation is likely due to trauma and the patella needs to be reseated into the trochlear groove. In order for the patella to luxation, there was stretching of the collateral ligaments of the patella. If the patella is reseated and the horse is rested (as your veterinarian is recommending), then there is a potential that the collateral ligaments and collateral structures, which hold the patella in place, will scar and heal. In some cases, the patella will need to be surgically repaired and the surgeon will perform a procedure to strengthen the torn collateral ligament structures of the patella.   It is important that the patella is currently reseated during the rest phase of the recovery otherwise surgical correction will likely be required to keep the patella seated in the correct position. Best of luck!
3	Question: Is it recommended to do surgery by cutting the flexor ligament in a horse that has an 11 degree rotation of the coffin bone? Answer:  Cutting the deep digital flexor tendon (DDFT) is one option to help treat rotation of the coffin bone. The surgery is performed to relieve the tension of the DDFT on the back of the coffin bone and thereby, hopefully, prevent further rotation of the coffin bone within the hoof. There are no hard guidelines for when to cut the DDFT. Some soft guidelines include greater than 15 degrees of rotation, refractory to pain management, presence of the coffin bone through the sole. These are guidelines only.    There are several other options available to treat rotational laminitis. Depending on the severity and rapidity of the laminitis onset, other options may include, anti-inflammatories, cold therapy, padded frog support shoes, Styrofoam shoes, derotational shoeing treatments, etc.    You should discuss all the possible options with your veterinarian and farrier before making a final decision. Some horses can return to some form of athletic work after DDFT transection (cutting the flexor tendons) but the decision should be made once all other options have been weighed and considered.
4	Question: My 2 1/2-year-old Quarter horse gelding, has dislocated his knee cap. My veterinarian said it is from a possible slip/sudden twist that could have caused the problem. He is not lame or experiencing severe pain. The knee cap slips out of position when placed back in position. The course of action is 10cc benamine for five days and stall rest. His training has been ground manners and ponying with a reliable trail horse. He has carried a saddle, but never had weight on his back. Is surgery down the road for him? What are his chances of being more than a pasture ornament? I will keep him as that if that is what will keep him healthy. Answer:  Thanks for the interesting question. Luxation (dislocation) of the patella (knee cap) is fairly rare in Quarter Horses. It is seen more commonly in minature horses and ponies. The cause is often related to an anatomical abnormality in the end of the femur bone (part of the stifle joint). It is good that your horse is not in pain and able to move around normally. Once the five day prescribed course of anti-inflammatories is finished, your vet may want to take some radiographs (x-rays) of the stifle joint to confirm that the patella does indeed luxate and the position of the patella once luxated.    In addition to the standard views of the stifle, your vet should take a skyline or flexed skyline view of the stifle joint/patella. The vet will need to look at the end of the femur bone and see if the trochlear ridges are normal. These ridges help hold the patella in the proper position. In horses with a luxated patella (dislocated knee cap), one or both of these ridges will be malformed or missing. This will be important to know in order to determine if surgery is needed.    Once the radiographs are taken, your vet may refer your horse to a board certified equine surgeon for a consultation. In some cases, surgery will be required to correct the malformed femur and in other cases a more conservative approach may be available to help stabilize the patella and patellar ligaments.Once you have some more information about exactly what is going on, your vet will be able to give you a better idea of your horse's future athletic prospects. All the best!