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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.


  1. I have a two-year-old Quarter horse that was recently put into work with off and on lameness LH. I had a lameness work up done and blocked the left stifle, which presented 70% better. But, then blocked the left hind fetlock down with no change. Radiographs were taken of the LH stifle, which showed a large cyst on the left medial femoral condyle. I had him injected with Hylaronic acid and steriod both stifles. The prognosis was not good due to the size of the cyst (22mm) however, the joint looked good.

    What options do you suggest to investigate? Debribe the cyst and inject with stem cells? Inject the cyst only? Use another drug such as Tildren? Magnetic therapy? Laser? Shock wave? Is there a supplement that is excellent for bone regeneration? Best supplement for inflammation? I am trying to look into all options as this is a super nice horse.

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    I think these questions would best be answered by the surgeon treating the stifle as there really isn't a good 'best answer' for a stifle cyst. Although I would suggest also discuss having a transcondylar screw placed across the cyst, which is a new method, but shows a lot of promise. Karen Blake, DVM, Park City, Utah

  2. When it is safe to remove my pony's grazing muzzle? I live in northern Illinois, and the night time temps have been below freezing, but with warm, sunny days. There isn't much grass left in the pasture but it is green in some areas. My pony has insulin resistance but no history of laminitis. Her IR has been managed through diet, Prascend (she is negative for PPID), and a grazing muzzle for the past 8 years. Thank you in advance for your advice.

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    I usually have people keep the grazing muzzle on until there's no bright green grass or the grass has had 1-2 frosts (so it's not growing so fast when it warms up during the day). It sounds like it's probably ok to remove the muzzle on your horse unless you get a random warm spell where the grass starts growing again. Karen Blake, DVM, Park City, Utah

  3. Our 14-year-old gelding has recently been diagnosed with laminitis. Our veterinarian recommended wedge shoes and our farrier agreed. After the shoes were put on the horse, we questioned the method, because our farrier put the wedge on the front edge of the horse's hoof and not the "heel" edge of the hoof. We are novice horse owners, and we are in an area with few veterinarians that are horse experts, but even our vet is questioning what the farrier has done. Are we damaging our horse? Is this a recognized way of applying wedge shoes to a horse?

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    This does sound suspicious. Occasionally, some farriers will use a shoe and apply it the 'wrong' way, which helps relieve the toe from pressure on the ground and gives a better break over point for the foot. If your veterinarian decides to go with a wedge pad or shoe with a wedge, the wedge goes towards the heel portion of the foot. This is to help take some tension off the deep digital flexor tendon (DDFT). I would have your farrier remove the wedge/shoe combo as quickly as possible to prevent further issues from having the pad placed as you describe. One wedge may not be enough to give adequate relief to the DDFT however, so typically I recommend using an ultimate wedge shoe, which can be taped on with elastikon or can be casted/glued on by your vet or a farrier. Karen Blake, DVM, Park City, Utah

  4. We have an 8-year-old Thoroughbred that has been intermittently lame. We have had a veterinarian that specializes in lameness provide scans that have shown he has broken the knobbly bit off of his shoulder and the tendon is rubbing over the rough bit causing tendonitis. He currently has had three months of box rest and is now on restricted turn out. He continues to look lame and have been told that the tendon may have to be cut. We are located in England and I cannot find anyone who has had this done to ask about the outcome. Can you provide further information regarding this procedure?

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    It would be unusual to cut the tendon in this type of case, however without seeing the scans and X-rays I cannot comment specifically. If I am envisioning what you are talking about correctly, it would be recommended to either remove the fragment or to place screws to attach it back to the parent bone (depending on how long ago this injury occurred). Additionally, you could have them try an ultrasound-guided injection of the bicipital bursa firstas since this can improve comfort level and is less invasive. Karen Blake, DVM, Park City, Utah

  5. My 27-year-old mare was diagnosed with laminitis in August of this year. She was given bute and put on thyroid and pergolide. She was moving sound within a couple weeks. She is having trouble eating the grass hay she was put on, so lost a lot of weight. I started adding some alfalfa back in her diet (so she could/would eat). How much can she probably eat? And will I be able to let her out to graze next summer? Looking back on her history, I think she has probably had laminitic episodes for years that were never actually diagnosed.

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    This is a common history for older horses and horses whose owners express concern for intermittent foot soreness. Their forage intake should be between 1-2% of their body weight, which for an average horse is 10-20lbs of forage. Older horses, as you have discovered, can have difficulty processing forage and need an adjusted diet to help them maintain weight. I usually recommend hay pellets (usually Timothy pellets, which is a grass hay, but some horses can deal with a mixture of grass and alfalfa pellets) for older horses as it is relatively inexpensive and then combo that with a senior feed, which is readily available for absorption in the small intestine so the older horse can get its appropriate nutrients. If the horse can eat this much hay pellets per day, then I usually add 3.25 lb of Purina Active Senior to their diet. You can get a good scale to help you measure the proper weight of the pellets and grain. Additionally, it is important to soak the pellets (even if just slightly) because they swell a bit and soaking will help them swell so the horse doesn't choke. This would be a complete diet for your horse. 

    However, if your horse needs to gain weight, then I would supplement with some amplify pellets, ultium pellets or some kind of oil such as vegetable oil/corn oil since fat has more calories per weight than any carbohydrates. Karen Blake, DVM, Park City, Utah

  6. I have a 22-year-old mare that has been on long-term dexamethasone for about three years. She gets 20mg every other day to control COPD. I am concerned about Laminitis and Cushing's disease. I am thinking about going a holistic route and need a withdrawal schedule for Dexamethasone since I know it should not be withdrawn abrubtly. Have you any opinion of Heave-Ho?

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    You are correct that decreasing steroids is a delicate process. The best idea is to talk with your veterinarian who prescribed the dexamethasone to get a withdrawal schedule for your particular horse. Additionally, your veterinarian can test your horse for Cushing's, which would help prevent a laminitis episode from occurring as Cushing's is a treatable disease and would give you a little more piece of mind about the steroid use.

    The best way to control a horse with heaves is through proper management - living outside or in a place with excellent ventilation, use of a hay steamer or soaked hay pellets/cubes and not allowing your horse to be inside at the time of sweeping/leaf blowing the barn or moving/feeding hay. Karen Blake, DVM, Park City, Utah

  7. I have a 12-year-old draft horse that started out with an abscess in the hind foot. It  has been a long six months, but it has gotten better. My farrier was concerned so I had radiographs taken. My veterinarian now says the horse has a tumor and his coffin bone is deteriorated about an inch up. He said the tumor may be taken out but was not sure if the coffin bone will be at a level of use. Have you seen this and and would you think the horse would be able to be used, or at least be a pasture mate? He is currently getting around great as we use him for pleasure wagon driving. We do not show him and he is showing no signs of discomfort.

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    The tumor you have discussed with your veterinarian is called a keratoma. This is an odd formation of keratin tissue, which pushes on the coffin bone and causes some loss of bone due to the pressure within the hoof capsule. The tumor can be removed standing and the horse can be used once the defect in the hoof wall grows out (anywhere from 6-12 months). However, since you had such a difficult time healing an abscess, it is possible that the coffin bone was infected (usually abscesses heal quickly with proper treatment) and could also cause the defect your veterinarian sees in the coffin bone. Karen Blake, DVM, Park City, Utah

  8. Do horses survive when the tip of the pedal bone penetrates the sole?

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    The answer to this question is yes, they can. However, the bone must have blood supply, which can be elucidated from a venogram and the horse must be put in the proper mechanics to allow the deep digital flexor tendon to have less pull. This can be accomplished by applying a Nanric Ultimate shoe, which allows the veterinarian or farrier to remove the shoe periodically to clean the sole region where the bone has penetrated. Karen Blake, DVM, Park City, Utah

  9. Our 20-year-old Quarter horse mare had laminitis five years ago. We manage this easy keeper carefully. We soak her hay except when it's too cold and feed blue grass straw. We use slow feeders for all the horses. How do I know she is getting enough nutrients? She gets a multivitamin and is on 24/7 turnout with the herd. She is ridden 2-3X/wk. She is also on Prascend for PPID and doing well. Tested grass hay=13.5% protein ESC and starch= 8.8

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    Wow! You are doing very good management of your horse's diet. Congratulations, this is not an easy task. Your hay is relatively low in sugar content currently, but soaking for 30-60 minutes will get it even lower. Obviously, you test the hay, but a nutritionist can give you specifics about the nutrient content based on the hay analysis. However, there was a semi-recent study showing that soaking the hay between 30-60 minutes minimally changes the nutrient content of the hay (besides lowering the sugar); after 60 minutes your nutrients begin to lower. However, many times a balanced hay balancer (vitamin/mineral supplement) will meet the nutritional needs of your horse. I usually recommend Purina Enrich plus, but there are many feed companies out there that produce one. Karen Blake, DVM, Park City, Utah

  10. How and when should you introduce a laminitic horse back to grass, using a grazing muzzle?

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    It depends why the horse became laminitic. If it was associated with an illness or impact event, then grass restriction isn't usually an issue. If it is due to the horse having EMS, it really depends on what is going on in the horse's weight management. For example, if a horse gets severely laminitic each year with grass coming on, they should be restricted before heavy spring growth and should only get turned out overnight (brought in during the day). If they are overweight currently or they have fat deposits and a high insulin level, they need to be off grass until those deposits lessen and their insulin level has returned to normal. Karen Blake, DVM, Park City, Utah


  11. I have a horse that was diagnosed with laminitis after eating too much spring grass three years ago. He was 12 at the time. He recovered after nine months of special care by the farrier and diet restrictions. This year, as a 15-year-old, he came down with laminitis again the first week of January and was diagnosed with Cushings and Insulin Resistance. He is sound again with the farriers expertise, Prescend and special diet. Will he always need to be limited to short periods of grass before dawn & late afternoon? 

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    Yes, grass restriction is necessary for these horses that are sensitive to high sugar content. As you already know, the safest hours to turn an IR horse (EMS) out are late evening from 9-10pm to about 8 am when the sun is up. This is because the plants are starting to produce sugars; the time of highest sugar content is noon to 5-6pm. 

    You can also accomplish grass restriction with a muzzle with a small hole at the bottom. They may look mean, but the horse can get some grass through them and they are life-saving for horses with EMS, so worth the horse's annoyance. Karen Blake, DVM, Park City, Utah

  12. Are older horses at higher risk for suffering bouts of laminitis? 

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    Older horses have a reputation for laminitis, however most cases of aged laminitis are the result of a systemic condition in older horses. There are two conditions which can contribute to this - Equine Metabolic Syndrome (EMS) and Equine Cushing's Disease (CD). EMS commonly occurs in horses around 12-15+ years of age and it has similarities to Type II diabetes in humans. CD usually occurs in slightly older equids around 18+ years. Both conditions cause an inflammatory state in the horse which causes inflammatory mediators to be released in the lamina and create a laminitic condition. Both of these conditions can be tested for and controlled with management changes or medications, so it is important to speak with your veterinarian about your aging horse. Karen Blake, DVM, Park City, Utah

  13. I have an 8-year-old Halflinger mare that foaled, but had laminitis in her front hooves. Her feet were trimmed and is currently doing well, six months later. Do I need to worry about her on grass?

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    Many pregnant/perinatal mares can go through a laminitis bout. This is often a result of an underlying issue during pregnancy such as insulin resistance (EMS)/being overweight or a placentitis (infection of the placenta) or retained placenta. Figuring out why the mare foundered specifically would tell you whether grass would be an issue for her. Karen Blake, DVM, Park City, Utah

  14. For a 3rd year in a row, my horse goes lame in the fall. Recent x-rays were clear. At the vets suggestion, the farrier put pads on my horse. The next day I walked him on pavement and he ended up so sore that he was 3-legging it. The farrier came out and removed the shoes and pads. He checked with five other farriers and they felt that it was likely concussion laminitis.

    In the spring I was thinking of putting him in boots (Renegades). Do you think this could be concussion laminitis? Will boots enable me to ride from March - November?

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    Frequently termed 'concussive laminitis ' or 'road founder', this term gets its name because usually there is a history of riding hard on firm road/pavement. This condition is inflammation of the hoof from the repeated trauma of impact on the road/hard ground. This can affect the lamina (laminitis), the sole, the bones and the soft tissues of the foot. Any or all of these structures could be affected during this process. Frequently, with appropriate rest and anti-inflammatory therapy, the inflammation can go down with no longstanding issues. Frequently, shoes with pads are recommended to decrease the impact of working on hard ground, however it sounds like your horse was still in the inflammatory phase when they went on which is likely why the horse got worse instead of better. Protective boots can be useful as can appropriately applied shoes. Karen Blake, DVM, Park City, Utah