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By Amanda Hedges, DVM, cVA, CVSMT What is Osteoarthritis? A healthy joint relies on the production of synovial (joint) fluid to lubricate structures, bring in nutrients and clear away cellular waste products, and to transmit forces through the leg. Healthy synovial fluid is produced by cells in the cartilage in response to movement. Some components of healthy joint fluid include hyaluronic acid (HA) and polyglycosaminoglycans (PGAGs). Inflammation due to an acute traumatic event, chronic low-grade trauma/wear and tear, or a joint infection impedes the production of healthy joint fluid. Specifically, pro-inflammatory molecules damage cartilage. In general, inflammation leads to pain, as the joint loses its ability to lubricate, bring in nutrients and remove waste, and transmit force. In response to this pain and instability, the body attempts to stabilize the joint, remodeling it to limit mobility. The joint capsule becomes thickened and bone proliferates around the joint in an attempt to immobilize the damaged area. What are the Signs of Osteoarthritis and How Do We Diagnose It? In its advanced stages, signs of arthritis are hard to miss. These include clear lameness and/or visible joint distortion by extensive bone proliferation. However, signs can start subtly and the horse may be able to compensate, depending on the level of performance. These milder signs may include uneven wear on the hoof/shoe, difficulty holding up a limb for the farrier, decreased performance abilities, difficulty standing square, difficulty laying down or getting up, or behavioral changes. When dealing with an infected joint, joint fluid is sampled and analyzed for markers of inflammation. If arthritis is secondary to “wear and tear,” diagnostic imaging (radiographs, ultrasound, CT) is the best way to confirm the diagnosis. Diagnostic nerve blocks may be used during workup to both hone in on a particular joint and to shed light on the clinical significance of the changes seen on imaging. Treatment Goals There are three objectives of treatment: 1) decrease inflammation, 2) prevent further damage, 3) relieve pain. It is immensely important to remember that there is no one-size-fits-all program for treating arthritis. If there was, everyone would do it and we wouldn’t have so many options! It is always critical to work with your veterinarian to determine the best plan based on your goals for your horse; making sure to discuss reasonable expectations for treatment and possible costs. Oral Supplements Oral supplements rely on research in horses and other species to make claims for effectiveness. Challenges of oral supplements include lack of FDA-regulated supply, mixed results from evidence-based-research, widespread anecdotal claims, and palatability. Oral supplements can be beneficial in that they can be less expensive than some treatments and are relatively easy to administer. It is important to weigh out the cost vs. possible benefit as compared to injectable joint therapies long-term. Learn more about assessing oral joint health supplements... Topical Therapies Diclofenac (Surpass®) is an anti-inflammatory drug formulated to penetrate the skin and provide local anti-inflammatory actions and pain relief. This drug is in the same class as oral non-steroidal anti-inflammatory drugs, so care should be used to minimize negative systemic side effects when both topical and oral products are used together. Occasionally a skin reaction can be seen, and owners should wear gloves when applying this product. Many other topical options are available on the market or through your veterinarian. As with any product, discuss the benefits and possible risks with your veterinarian. Oral Medications The staple of anti-inflammatory drugs in horses is a class of drugs called non-steroidal antiinflammatory drugs (NSAIDs). Most commonly used are phenylbutazone (Bute®), flunixin meglamine (Banamine®), firocoxib (Equioxx®), and naproxen. These drugs act by halting the systemic inflammatory cascade at different points. Unfortunately, non-specific blocking of the cascade can also decrease other necessary pathways, resulting in the risk of damage to the stomach in the form of gastric ulcers, risk of damage to the intestinal lining resulting in colitis, and risk of kidney disease. Equioxx® is the most pathway-specific option and is often preferable for prolonged use (up to two weeks) but still carries some degree of risk. Oral steroids can also decrease systemic inflammation. Unwanted side effects of prolonged steroid use in horses include immune suppression and laminitis. Injectable Options Legend® and Adequan® are injectable joint support supplements both labeled for the prevention and treatment of arthritis. They may provide systemic anti-inflammatory effects. No contraindications are listed for either drug, but the risk of a site reaction applies, as with any intramuscular injection or intravenous injection. Legend® is a synthetic hyaluronic acid (HA) that has been studied to treat carpal and fetlock arthritis secondary to non-infectious causes. It can also be used in the joint for local anti-inflammatory therapy. It can be used as a weekly intravenous injection for 3 weeks, monthly, or at your veterinarian’s discretion. Adequan® is a synthetic polyglycosaminoglycan (PGAG) that has been studied to treat carpal and hock arthritis secondary to non-infectious causes. It is injected into the muscle every 4 days for a total of 7 injections, or at your veterinarian’s discretion. Note that both of these products were studied in young adult healthy horses, and their effect on a horse outside of this age-range is only anecdotal. However, both are widely used in veterinary medicine. Similar to oral steroids, long-acting injectable steroids may improve your horse’s comfort. Most common is a long-acting steroid that can provide systemic anti-inflammatory relief. Notable risks include site-reaction, immune-suppression, and risk of laminitis. Joint Fusion The body’s goal with producing excess bone around the joint is to decrease motion in the joint. In some cases, such as pastern or hock arthritis, we can help the body achieve this goal by fusing the joint (aka arthrodesis). Fusion can be hastened by injecting the joint with chemical irritants. Surgical procedures can also hasten joint fusion. Screws, plates, and/or cartilage drilling can all be employed to immobilize the joint. While these options may involve a greater initial cost, the chance of long-term comfort may make joint fusion a good choice for your horse. Intra-articular Options Anti-inflammatory drugs, synthetic joint components, and biologically derived anti-inflammatory products can all be injected directly into an arthritic joint to improve comfort. Steroids such as betamethasone and triamcinolone, often in conjunction with synthetic joint fluid components such as hyaluronic acid, can be injected under standing sedation and can provide targeted relief. Methylprednisolone acetate may decrease inflammation and impair cartilage health, making it a good potential choice for joints that are easy to fuse (such as the hock joints or pastern joints). Polyacrylamide gel (PAAG) is a synthetic gel that can be injected into a joint to add physical stability to a joint, although more research is needed before equine use can be recommended. Regenerative medicines such as interleukin-1 receptor antagonist protein (IRAP), Prostride®, stem cells, and platelet-rich plasma (PRP) may decrease inflammation and improve comfort in an arthritic joint as well. Anti-inflammatory mediators are removed and processed from the horse’s own blood, bone marrow, or fat tissue (depending on which therapy), and injected into the joint. This option may be preferable in a patient for whom steroids are not a good choice or depending on the nature of the injury. Learn more about these regenerative medicine modalities... Risk of joint infection or joint flare is present anytime a joint is injected. These risks are decreased by the use of sedation to prevent mobility and sterile injection technique. Dose and frequency of treatment depends on response to treatment. Adjunctive Therapies Acupuncture, chiropractic medicine, massage, light/laser therapy (usually Class 2 or 3), pulsed electromagnetic field (PEMF) therapy, thermal therapy, vibration floor plates, and controlled exercise programs may also improve comfort. Acupuncture creates a systemic release of endorphins and improves blood flow to painful areas. Chiropractic medicine relies on a high-velocity, low-amplitude thrust to a restricted joint (usually in the spine) to theoretically improve blood flow and nerve function. Massage can improve circulation and interrupt pain receptors. Light/laser therapy transmits energy in the form of light to cells, stimulating healing and pain relief. PEMF therapy (Assisi Loop®) pulses energy to cells via an electromagnetic current to stimulate healing and pain relief. The vibration floor plate VitaFloor® has been shown to improve topline muscle mass and improve circulation throughout the body. Learn more about equine acupuncture and chiropractic medicine... Controlled Exercise Perhaps the tool that has the greatest potential benefit and least cost is controlled exercise. A regular low-impact exercise program, such as walking for 20 minutes daily, can improve joint health and mitigate the potential injury and inflammation that comes from weak postural muscles and stiff joints. Exercises that focus on postural strength and core stability, low-impact mobilization of joints, and mental stimulation can benefit the arthritic patient. Equine rehabilitation facilities offer exercise programs, hydro-treadmills, and swimming pools to achieve equine fitness goals. Talk to your vet for more details! Other resources to consider: “Equine Joint Therapies: What to Know” by Erica Larson, published by The Horse “Lameness & Joint Medications” by Benjamin Espy, DVM, DACT and Justin Harper, DVM, MS, DACVS, LA, published by the American Association of Equine Practitioners (AAEP) “Equine Osteoarthritis: Early Interventions” by Natalie DeFee Mendik, MA, published by The Horse “What You Need to Know about Equine Osteoarthritis” by Stacey Oke, DVM, MSc, published by The Horse “Alternatives for Managing Osteoarthritis in Horses: PAAG and Stanolozol” by Alexandra Beckstett, published by The Horse 10 Equine Osteoarthritis Resources on TheHorse.com

Oral joint health supplements (OJHSs) “are a group of nutritional supplements that contain one or more non-nutrient, non-drug ingredient,” according to John P. Caron, DVM, MVSc, Dipl. ACVS, a professor in the Department of Large Animal Clinical Sciences at Michigan State University. With scores of OJHSs on the market, it can be difficult for horse owners to decide which one to try. Below you'll find an outline of the seven-step “ACCLAIM” approach to assessing OJHSs — for more details, see “Oral Joint Supplements for Horses” by Stacey Oke, DVM, MSc, published by The Horse. Below is a list of some common OJHS ingredients and what they may do to benefit horses, with dosage recommendations from the American Association of Equine Practitioners (AAEP). Note that combination products seem to have the best results. Steinbeck Peninsula Equine Clinics veterinarian, Amanda Hedges, reminds us that “Oral supplements rely on research in horses and other species to make claims for effectiveness. Challenges of oral supplements include lack of FDA-regulated supply, mixed results from evidence-based-research, widespread anecdotal claims, and palatability. Oral supplements may be beneficial in that they can be less expensive than some treatments and are relatively easy to administer. It is important to weigh out the cost vs. possible benefit as compared to other therapies, in the long-term.” For more information, see “Options for Managing Osteoarthritis” by Dr. Amanda Hedges.

By Amanda Hedges, DVM, cVA, CVSMT “Is it inhumane to keep him alive? What would YOU do in this situation?” Making end-of-life decisions can be difficult and emotional. Veterinary medicine and preventative care means horses often survive conditions that would result in death in the wild. By providing quality care, we also prolong our horse’s natural life expectancy. For example, most housing situations lack predators that would eat a horse that cannot keep up with the herd. We provide our horses with regular access to feed and water so they do not starve or suffer from dehydration as their feral counterparts may. By taking a horse out of its “natural” environment, we also accept the responsibility of providing a humane end for our horses. Our hope is that the following considerations will help you navigate this situation and prepare, as best as possible, for when the time comes to facilitate a peaceful passing. Ambulation Can your horse lie down safely, and does he/she lie down regularly (at least once every 2-3 days)? Does he/she lie down so much that he has bed sores/pressure sores? Can your horse walk around? Does he/she safely and voluntarily walk around his/her enclosure? If your horse lives in pasture, can he/she keep up with the herd? Can your horse perform basic behaviors, such as picking up and holding all 4 feet for the farrier? Appetite Does your horse show interest in feed? Is he/she able to chew and swallow the feed you provide? Are you able to make any feed changes your horse may need? Are you able to medicate your horse as frequently as he/she may need? Is it safe for your horse to receive preventative dental care? Attitude What are your horse’s three favorite things? Can he/she still do them safely, and as regularly, as he/she would like? Does your horse have something that he/she looks forward to (besides eating) every day? Is your horse in pain? Refer to the Pain Scale developed by Colorado State University to better answer this question. Can your horse’s pain be managed? Consider writing down your horse’s behaviors in a notebook at each visit to look for changes over time. Consult with people you trust who know you and your horse. Has your trainer/farrier/barn friend noticed a difference in your horse’s attitude? Miscellaneous Can your horse’s condition(s) be cured? If they cannot be cured, can they be managed adequately? Can you afford the costs of medications, procedures, and/or recheck visits needed to manage the situation? Do the good days outweigh the bad? If there are more bad days than good, quality of life questions prevail. Emergencies: know as best as possible what you are able and willing to do for your aged horse. While it can be difficult and emotional to think about end-of-life decisions, it is far preferable to have considered how you will handle an emergency situation before it arises. It is much more challenging to have a clear and rational thought process during a veterinary crisis. Are you aware of the cost and process of euthanasia? How will the remains be handled? Be realistic with yourself and your situation. Honestly answer the question “What does my horse want?” with the knowledge that your emotions may make this question difficult to answer. And as always, discuss any questions or concerns that arise with your veterinarian. Except under extreme emergency exceptions, your veterinarian cannot make this decision for you. All he or she can do is do his/her best to answer your questions and support your decision. The veterinarian may be more or less involved in helping you make this decision depending on the relationship you have developed. This is also a good article about end-of-life considerations: “Being Prepared for Equine Euthanasia" by Holly Mason, MS, DVM, published in The Horse.

Gastrointestinal Parasites in Adult Horses By Nora Grenager, VMD, DACVIM Over the past ten to fifteen years, there has been a huge shift in the equine veterinary community’s thoughts on parasite prevention. It is difficult to pick up a horse magazine or browse an equine website these days without reading about parasite resistance. Resistance to dewormers is increasing throughout the world, which is particularly concerning given the lack of new types of dewormers available. While there are many brand names, there are really only three or four main types of dewormer drugs. Unfortunately diatomaceous earth is ineffective in killing gastrointestinal parasites in horses. Parasitologists say it is not a matter of when, but rather how rapidly, parasite resistance will develop in any given region. The silver lining of this impending resistance is that we are now focusing our attention on more strategic deworming programs, rather than rigid regimens that do not take into account an individual horse’s needs. Most horses do not need to be dewormed as frequently as previously thought. It makes much more sense, from both a horse and herd perspective, to tailor the deworming program to each horse. Why do we deworm at all? Horses have evolved with parasites over millions of years and it is okay for a horse to have some parasites; actually it probably keeps their immune system active. Our goal of deworming programs is not to completely eliminate parasites. While often small worm burdens (i.e., just a few worms) cause no clinical signs, when there is a large burden these parasites steal nutrition from the horse. Gastrointestinal parasites can cause weight loss or poor growth, rough hair coat, poor performance, tail rubbing, colic, diarrhea, and decreased ability to fight other infections or respond to treatment for illness. The main gastrointestinal parasites of concern in adult horses (over 18 months of age) include: small strongyles, large strongyles, tapeworms, bots, and pinworms. This article will focus on adult horses, as younger horses have deworming needs that are distinct from those of adult horses. Each type of parasite has its own life cycle, but there are some similarities among them. Generally speaking, grazing horses ingest parasitic larvae that then (sometimes after extensive migration or hibernation that can cause significant damage) develop into adult worms within the gastrointestinal tract. These adult worms reproduce and the horses pass eggs in the manure so the cycle can begin again. Pasture conditions, environmental temperature and humidity all affect how long this takes and parasites in our part of California typically prefer late winter/early spring conditions when it is wet and getting warmer. There are three main types of large strongyles: Strongylus vulgaris, Strongylus edentatus, and Strongylus equinus. These large strongyles, also called “blood worms,” used to be the primary targets of deworming programs, but for the most part have been well-eradicated by the frequent deworming protocols used for the last several decades. Large strongyle larvae penetrate the lining of the small intestine and migrate throughout the body along blood vessels, causing hemorrhage and inflammation in the liver, pancreas, or abdomen before eventually taking up residence and reproducing in the large intestine. The migration of these large strongyles can cause organ damage or blood vessel damage with subsequent intestinal infarction and necrosis, peritonitis, and severe colic signs; the only way to diagnose this condition is at surgery or after death. There are over forty different species of the small strongyles or cyathostomes. Small strongyle larvae invade the large intestine and encyst (form a capsule in the intestinal wall), where they can safely hibernate for up to 2.5 years, a process called “arrested development,” until it is time to mature and then emerge. The larvae will often remain encysted during the hot, dry summer months or cold winter months during which they would have a difficult time surviving on the pasture. They are able to detect when environmental conditions will be favorable for their propagation and emerge at that time. When they emerge they can cause a large amount of inflammation within the intestinal wall, causing diarrhea of variable severity or colic. Diagnosis of large or small strongyle infections is dependent on finding the eggs in manure. However, during migration or arrested development there may be few to no eggs in the manure because it is larvae, not egg-producing adults, that are present. Tapeworms, or Anoplocephala perfoliata, have a more complicated indirect life cycle involving an intermediate host. Some larval stages of the tapeworm’s development take place in oribatid mites, which are prevalent on many pastures. Horses are infected by eating the tiny infected mites while grazing. Once ingested, the tapeworms attach to the intestinal lining, preferentially at the ileocecal valve between the small and large intestine, and complete their life cycle there. This can cause colic due to spasm of the intestine, blockage of the intestine, or telescoping of the intestine at the ileocecal valve (called “intussusception”). Diagnosis is based on finding eggs on fecal examination (which is not very sensitive) or serum antibody testing (which is difficult to interpret). Tapeworms, or Anoplocephala perfoliata, have a more complicated indirect life cycle involving an intermediate host. Some larval stages of the tapeworm’s development take place in oribatid mites, which are prevalent on many pastures. Horses are infected by eating the tiny infected mites while grazing. Once ingested, the tapeworms attach to the region between the small and large intestine (the ileocecal valve) and complete their life cycle there. This causes inflammation at the site, with signs of colic due to spasm of the intestine, blockage of the intestine, or abnormal motility with telescoping of the intestine at the ileocecal valve (called an “intussusception”). Diagnosis is based on finding eggs on fecal examination (which is not very sensitive) or serum antibody testing (which has not yet been well validated). There are two main types of horse botflies: Gasterophilus nasalis and Gasterophilus intestinalis. The adult botflies lay eggs in a horse’s hair coat that the horse then ingests during routine grooming. The eggs develop into larvae as they migrate to the stomach, then attach to the horse’s stomach where they can cause gastric ulceration or colic. While these are very common, they rarely cause notable clinical signs. Pinworms, or Oxyuris equi, can live in the large intestine and small colon and cause colic or anal pruritis (an itchy hind end as evidenced by tail-rubbing). Most often these infections are not diagnosed on a fecal sample. Instead, a piece of tape is used to collect and then identify eggs from around the anus. One of the most important concepts about parasite control is that each horse has inherent (likely at least partially genetic) variable susceptibility to gastrointestinal parasites. It is said that 20% of horses shed most of the parasite eggs, and 80% of horses shed very few eggs. Therefore most horses do not need to be dewormed very frequently, while only a few horses need to be dewormed more often. This difference in an individual horse’s susceptibility to parasites underscores the fact that if we use one deworming protocol for all horses, we are deworming some horses too often and other horses not often enough. Therefore, it would be ideal to only deworm horses that have too many parasites. So how do we determine which horses have too many parasites? Currently, our best option is the fecal egg count (FEC), which is relatively inexpensive and easy to perform but unfortunately this method of detecting parasite numbers is not very sensitive. The procedure involves floating a manure sample and counting the number of eggs seen. Horses are then categorized as non-shedders (no eggs seen), low shedders (usually less than 150 eggs per gram), moderate shedders (usually 150-500 eggs per gram), or high shedders (usually greater than 500 eggs per gram). In adult horses, this technique mostly counts large or small strongyle eggs, and sometimes tapeworm eggs. This is the most reliable method we have to noninvasively determine parasite burdens, but it has several limitations. First, as discussed above, it is often the larval stage of the parasite that causes a problem, and larvae are not sexually mature and therefore not making eggs. Second, the number of eggs does not always correlate very well with the number of adult parasites. Third, if the sample is too old or sits too long before evaluation, the egg counts can be falsely low AND there can be variation in the amount of eggs passed between piles of manure. There are blood tests available to help diagnose tapeworm infections, but the results are difficult to interpret because the test does not distinguish well between active and previous infection so it is not particularly helpful in diagnosing tapeworms in a single horse (better at telling if there is an issue within a herd). So while the FEC is not very sensitive, it is the best test routinely available to us to determine a horse’s parasite burden. There’s a cool new smartphone app that should be available soon to do FECs stall-side for less cost and faster results. How do we determine each horse’s individual susceptibility to parasites? Our methods of detecting parasite numbers are unfortunately not very sensitive. Fecal egg counts (FEC) are most often used and are relatively inexpensive, certainly noninvasive, and are easy to perform. The procedure involves floating a manure sample and counting the number of eggs seen. Horses are then categorized as non-shedders (no eggs seen), low shedders (usually less than 200 eggs per gram), moderate shedders (usually 200-500 eggs per gram), or high shedders (usually greater than 500 eggs per gram). In adult horses, this technique mostly counts large or small strongyle eggs, and sometimes tapeworm eggs. This is the most reliable method we have to noninvasively determine parasite burdens, but it has several limitations. First, as discussed above, it is often the larval stage of the parasite that causes a problem, and larvae are not sexually mature and therefore not making eggs. Second, the number of eggs does not always correlate very well with the number of adult parasites. Third, if the sample is too old or sits too long before evaluation, the egg counts can be falsely low. There are blood tests available to help diagnose tapeworm infections, but the results are difficult to interpret because the test does not distinguish well between active and previous infection. So while the fecal egg count is not very sensitive, it is the best test routinely available to us to determine a horse’s parasite burden. Parasitologists and veterinarians have done extensive work to make it as useful as possible in creating an evidence-based parasite control program. The good news is that research has shown that if a FEC is performed long enough after the last dewormer was administered so that no more dewormer is present in the horse’s system (i.e., 4–5 weeks for pyrantel/fenbendazole/oxibendazole, 6–8 weeks for ivermectin, and 10–12 weeks for moxidectin) then the results stay consistent over time. Once a horse has shown itself to be a non- or low-shedder, this will remain true unless something change’s significantly in the horse’s health (such as the horse developing equine Cushing’s syndrome or recovering from serious systemic disease). Therefore, after one or two negative or low-shedder FEC, horses in these categories no longer need to have FEC performed unless there are suspicious clinical signs or something changes in their condition. This ideal single sample would also be taken in the late winter/early spring here in CA, when pastures are wet, because parasites here do not enjoy the hot, dry summers. The ideal deworming program then would focus on each individual horse’s parasite susceptibility and would determine if there is any parasite resistance to dewormers on a farm/facility. Resistance to dewormers can be determined by performing the Fecal Egg Count Reduction Test (FECRT). The FECRT involves doing a pre-treatment fecal egg count, administering a dewormer if the horse is a moderate or high shedder, and then rechecking the fecal egg count on those horses that were dewormed in 10–14 days. This provides information as to whether the horse is a low, moderate, or high shedder of eggs, and then also provides information as to whether the dewormer administered is efficacious. Once resistance to a dewormer has been documented at a facility, that resistance will remain. To slow the spread of resistance to dewormers, some parasites need to be kept “in refugia.” These parasite are those that are not exposed to a dewormer at the time of treatment, either because they are encysted, on the pasture, or in horses not dewormed. So, if non- or low-shedder horses are dewormed less frequently, they would then likely shed some eggs (of parasites that have not been exposed to dewormer) into the environment, thus diluting out any possibly resistant parasites. Parasites in refugia are not under selection pressure to develop resistance, and therefore are maintained as a relatively “resistance-free” population.This concept of keeping some parasites around that have not ever been exposed to dewormer is key in the prevention of resistance. Additional strategies should be considered to help minimize parasite exposure. Larvae can live for weeks in a pile of manure, and are easily disseminated when the manure gets spread out, thus increasing pasture contamination. For this reason it is also important not to drag or harrow a pasture while horses are grazing on it. It is important to not put horses on a pasture for 2–3 weeks after harrowing, and pastures should never been harrowed in the winter or wet months. Manure should also only be spread on a pasture if it’s been appropriately composted first to kill parasites. Daily manure removal from pastures may be easier said than done, but is the most effective way to prevent pasture contamination. Horses who live in stalls or dry paddocks are therefore at lower risk for parasite exposure. Manure should not be spread in a pasture unless it has been composted for at least two weeks, or unless the pasture will be ungrazed for at least two weeks in the hot, dry summer. Sharing pastures with livestock (cattle, sheep, goats, camelids) is another highly effective way to minimize parasite contamination, but this is not often practical. Lastly, using feeders in pastures/paddocks so horses are not eating off the ground and ingesting parasites (also good for sand control!). In Denmark dewormers can only be purchased from veterinarians, and are only prescribed if a horse has evidence of a significant parasitic infection. This was implemented in 1996 and is the most dramatic example of developing a dewormer program with your veterinarian’s advice. As we are slowly starting to incorporate more of these ideas into deworming practices here in the United States, each owner and veterinarian will need to work together to determine what is the best program for his/her horse. Some may opt to only deworm those horses with higher egg counts, some may opt to use a particular dewormer once or twice a year to kill any migrating large strongyles, then the rest of the year only deworm those horses with higher egg counts. The FECRT should be performed as needed to evaluate for any emerging resistance. Regardless of the program chosen, it is clear that the time has come to think differently about deworming. If we do not, the resistant parasites will eventually force our hand as resistance is being documented with increasing frequency around the country and world. In general, at Steinbeck Peninsula Equine Clinics we still recommend twice yearly deworming at the time of spring/fall vaccines. In the fall we usually recommend ivermectin or pyrantel or fenbendazole, while in the spring we recommend using a product that will kill tapeworms such as Quest Plus, Zimectrin Gold, or Equimax Plus. Each horse should have a FEC done at least once, ideally in the spring and long enough after the last dewormer. Those horses that are non- or low-shedders do not need to have FEC done again, and can be dewormed just twice a year at spring/fall. Horses who are moderate- or high-shedders should have FEC done summer and winter (so 3 months after the spring and fall deworming times) to see if they have developed worm burdens that would necessitate deworming. Additional FEC can be done at spring/fall to see “where they are” but these horses should be dewormed at those times regardless of the results. Lastly, facilities need to consider doing FECRT on a handful of horses that have parasite burdens in order to start to look for resistance to dewormers in our area. Incorporating these newer strategies into your deworming program will help create a bespoke deworming protocol for each horse leading to decreased administration of dewormer in most horses (80%) and therefore financial savings in the long run. Most horses will require less deworming treatments each year while those that would benefit from additional treatments (approximately 20% of horses) will be identified, leading to their improved health.

By Nora Grenager, VMD, DACVIM Timing of Manure Collection It is important to take a sample when the efficacy of any previous dewormer is out of the system. Dewormer drugs have different durations of efficacy. So, if the last dewormer used was: ivermectin: wait 12 weeks moxidectin: wait 16 weeks pyrantel salts: wait 8 weeks fenbendazole or oxibendazole: wait 8 weeks If this is the first time a FEC has been performed on the horse, discuss with your veterinarian about whether to do a FEC Reduction Test to evaluate if your horse has any parasite resistance to each type of dewormer. The FECRT involves: a FEC at day 0 (an appropriate amount of time after the last dewormer*), administering a dewormer per package recommendations, then a second FEC at day 10-14. This would need to be done for each type of dewormer, if necessary. The first FEC is best done in the spring or fall, not in the heat of summer when there are typically fewer parasites. How to Get the Best Manure Sample Fresh manure is important, as eggs deteriorate with time and temperature. Ideally, collect the sample immediately after your horse has passed it. If you are not sure, but a pile looks fresh, collect sample from the middle of the pile where it is still moist. Collect a large handful of manure in a ziplock bag then push as much air out of the bag as possible before sealing it. Bring the sample to the clinic as soon as possible, certainly within 24 hours. Keep the sample refrigerated until you drop it off at the clinic. Room temperature is fine if you are bringing the sample right away. Do not put it in direct sunlight or store it in a hot car. Drop manure off during regular business hour Monday through Friday; earlier in the day is better so the sample is sure to be run the same day.

By Lindsay Berreth Published in Chronicle of the Horse March 2020 "Whether it’s severe or mild, it’s useful to know how to deal with a horse that’s showing signs of colic and how to prevent it in the first place." Lindsay Berreth of Chronicle of the Horse magazine asked Nora Grenager, VMD, DACVIM, formerly Director of Internal Medicine at Steinbeck Peninsula Equine Clinic – Menlo Park, and Diana Hassel, DVM, Ph.D., DACVS, DACVECC, associate professor of equine emergency surgery and critical care at Colorado State University, some common colic questions from COTH readers. Read the full article...

By Jacquelyn Dietrich, BVSc Coronavirus is an RNA virus that can cause respiratory and gastrointestinal problems in many species. In horses, Equine Coronavirus can result in gastrointestinal problems. Horses can be carriers of coronavirus showing no signs (subclinical), but have been found to shed the virus in feces. Horses that become infected and develop clinical signs can also shed the virus. Thankfully mortality (death) is rare in uncomplicated cases. Seroprevalence of equine coronavirus in the Unites States has been estimated at 9.3% (Kooijman et al., 2017). This means that Equine Coronavirus it ubiquitous within the horse population, many of which never show clinical signs. How can my horse get Equine Coronavirus? Transmission is through fecal-oral route, meaning that your horse becomes infected by ingesting infected fecal material. How long does Equine Coronavirus survive in the environment? Unfortunately, this is unknown. It’s important to practice good biosecurity, including disposing of shedding horses' manure  in an area where no other horses can ingest it. What is the seasonality? Equine Coronavirus can occur anytime of year, however it is commonly seen in the colder months (December –May). How soon will my horse show signs? Every horse reacts different, but typically the incubation period is 2-4 days. How long will my horse be shedding the virus? The exact period a horse will shed the virus is still under investigation; however, horses have been found to shed the virus 5 – 21 days after being infected. Horses with no clinical signs and horses with clinical signs can both shed virus. What are some signs to watch for? Fever >101.5F Lack of appetite Depression Colic signs Laying down frequently Diarrhea (not always present in every case) Low white blood cells How can I confirm (diagnose) Equine Coronavirus? Your veterinarian can confirm Equine Coronavirus by submitting a fresh fecal sample to a lab for testing (PCR test). What is the treatment for Equine Coronavirus? Supportive care based on clinical signs is the best treatment. For more severe cases, hospitalization for IV fluid therapy and treatment for any secondary infections may be required. How likely is it that my horse will get better? Very likely with supportive care and monitoring for secondary infections. How can I prevent my horse from getting Equine Coronavirus? The best method for prevention is good sanitation of facilities, disposing of manure in areas horses can’t be infected, and other good biosecurity practices. Make sure manure cannot contaminate pasture, paddocks, stalls, and drinking water. What about other animals? Equine Coronavirus is a species-specific virus, meaning that is passed from horse to horse only. What do you mean by “good biosecurity”? Wash hands frequently, especially before and after handling each horse. Don’t share equipment and grooming supplies, especially with infected or potentially infected horses. Isolate horses that start to show clinical signs. Do not walk horses around facilities that have been showing clinical signs or that was in close proximity to infected horses. When cleaning stalls, clean infected and potentially infected stall last. Always handle infected or potentially infected horses last. This way stalls of healthy animals cannot come into contact with any fecal material from horses shedding the virus. Manure should be disposed in an area where horses can not reach (ingest). Reduce movement of horses in and out of facilities with horses positive for virus. Horses that are moved from a facility with horses positive for virus should be isolated for 3 weeks. A fecal sample should be taken to confirm no virus is present before removing horse from isolation. Disinfect anything that comes into contact with an infected horse. Remember, you must remove any organic mater (dirt, feces, etc) before using a disinfectant. This is because disinfectant becomes inactive when in contact with organic matter. Talk to your vet about the appropriate disinfectant to use for different outbreaks. For coronavirus, bleach, povidone iodine, and chlorhexidine gluconate are common disinfectants that have been shown to be effective against coronavirus. Chlorhexidine (Nolvasan) is a common product that can be purchased in many stores (feed stores, Target, drug stores, etc) can is effective against the virus even if organic matter is not completely removed. Equine Coronavirus is not a reportable disease in the state of California, as it is much less of a concern due to its high prevalence with low morbiditiy and mortality rates (meaning many horses show no signs of disease and few horses thankfully have furthering clinical signs/secondary disease/issues leading to death) compared to other contagious diseases horses have the potential for acquiring. Our state veterinarian says, "Currently, coronavirus is not a reportable disease in the state of California. Therefore, the state lacks authority to take regulatory action such as quarantine for confirmed cases of coronavirus. As always biosecurity measures, such as isolating horses with clinical signs and avoiding sharing of equipment, should be immediately implemented when there is any evidence of disease on the premises." Call Steinbeck Peninsula Equine Clinics with any concerns or questions. Equine coronavirus is NOT the same as the strain of coronavirus referred to as COVID-19 that is currently in the news (2020) associated with a world-wide outbreak, and is NOT considered as having a risk of transmission to humans. For more information, check out an article called "Can Pets Contract Coronavirus from Humans or Vice Versa" written by Dr. Niels Pedersen at UC, Davis, School of Veterinary Medicine and What is Equine Coronavirus? from thehorse.com. Below are some excellent resources for more information on Equine Coronavirus and biosecurity practices: Equine Disease Communication Center (EDCC): Disease Factsheet on Equine Coronavirus Cornell University College of Veterinary Medicine: Equine Enteric Coronavirus Equus: Coronavirus: An Emerging Threat? California Department of Food and Agriculture: Biosecurity Toolkit for Equine Events Equine Disease Communication Center (EDCC): What is Biosecurity? References: Pusterla, N., Mapes, S., Wademan, C., White, A., Ball, R., Sapp, K., . . . Magdesian, K. (2012). Emerging outbreaks associated with equine coronavirus in adult horses. Journal of Equine Veterinary Science, 32(10). doi:10.1016/j.jevs.2012.08.088 Pusterla, N., Vin, R., Leutenegger, C., Mittel, L., & Divers, T. (2018). Enteric coronavirus infection in adult horses. The Veterinary Journal, 231, 13-18. doi:10.1016/j.tvjl.2017.11.004 (2017). Prevalence of Fecal Shedding of Equine Coronavirus in Hospitalized Horses. Equine Veterinary Education, 29, 8-9.

What is ISELP? You may frequently hear the term “ISELP” used by veterinarians, especially in the sports medicine field. But do you know what it is? ISELP stands for International Society of Equine Locomotor Pathology and is an organization of elite veterinarians focused on lameness problems in the equine athlete. This organization was founded under the direction of Dr. Jean-Marie Denoix in 2006 and continues to rapidly grow, having members on all five continents. The goal of ISELP is to provide extensive knowledge, techniques, and diagnostic plus therapeutic information on the most current practices, which are continually evolving within the field of Equine Sports Medicine. Certified members teach ISELP continuing education modules all over the world. Steinbeck Peninsula Equine Director of Sports Medicine Dr. Russ Peterson was one of the founding members of ISELP, serves on the ISELP Board of Directors, and continues to instruct at ISELP meetings both nationally and internationally. ISELP Education At Steinbeck Peninsula Equine, we frequently express how important education is to us and our clients, which is why we are proud to host ISELP modules. ISELP modules are multiple day events offering a comprehensive program of advanced education in equine lameness issues, such as osteoarticular, musculotendinous, and nervous pathology. There are eight ISELP modules: Distal frontlimb: foot, pastern fetlock joint Middle frontlimb: palmar fetlock, metacarpus and tendons, carpus, carpal canal Proximal frontlimb: forearm, elbow and shoulder Distal hindlimb: foot, pastern, fetlock, metatarsus Middle hindlimb: hock, crus Proximal hindlimb: stifle, thigh Neck and thoracolumbar area Lumbosacral area and pelvis These modules each include advanced education on the descriptive and functional anatomy and biomechanics of each region of the horse. Modules offer training in the clinical (physical and dynamic) examination, including diagnostic blocks, which are the foundation for a thorough and comprehensive lameness examination. They offer education and discussion of diagnostic imaging (radiology, ultrasonography, nuclear scintigraphy, MRI), current treatment and management techniques, and revised information on prognosis and evolution of diseases. What Does it Mean to be ISELP Certified? Before becoming an ISELP-certified member, equine veterinarians must have completed multiple requirements to qualify to complete the certification examination. Veterinarians must have five years of equine practice experience and present a number of documented cases, submit multiple scientific papers for publishing, and have completed all eight modules and wet labs. This rigorous path allows you to complete an intense certification exam resulting in becoming an ISELP-Certified Practitioner. This means the ISELP-certified members have years of extensive advanced education and training compared to non-ISELP certified veterinarians. Members have higher knowledge and experience in equine sports medicine. Their active participation in the advancement of equine locomotor pathology is recognized by the science and academic community internationally. ISELP-certified members are highly qualified veterinarians specializing in advanced sports medicine. ISELP Sponsorship ISELP is an internationally recognized non-profit organization, gaining sponsorship from some of the largest companies in the equine industry. Sponsorship from these companies allow for the advanced continuing education of veterinary practitioners internationally.

Steinbeck Peninsula Equine Clinics are always proud to offer the latest in regenerative medicine, including Pro-Stride® APS joint therapy, which we've recently added to our extensive arsenal of therapeutic modalities along with regenerative medicine procedures such as IRAP, PRP, and stem cells therapy.. We are extremely happy with the success our patients have had with Pro-Stride. Following a single injection, Pro-Stride has clinically demonstrated pain relief in horses for up to 52-weeks. Pro-Stride is an Autologous Protein Solution (APS) containing a high concentration of cells, platelets, growth factors, and anti-inflammatory proteins to treat inflammatory processes in joints. This all-natural, drug-free option takes 20 minutes to process with no incubation time and treatment can be provided in a single visit. An additional benefit of Pro-Stride is that there is no withholding time for both FEI and USEF events. How It Works In degenerative joint diseases, such as arthritis, inflammatory cells bind to the cell receptors on the joint surface and starts breaking down the cartilage. Cartilage breakdown leads to joint damage and pain. Interleukin-1 (IL-1) and tumor necrosis factor alpha (TNF-alpha) are two major pro-inflammatory proteins, also known as cytokines, which lead to the degeneration of the joints. Pro-Stride works by blocking these pro-inflammatory cytokines from binding to the cartilage surface. APS is concentrated plasma with white blood cell proteins and enriched platelet growth factors derived from the horse’s own blood. Specifically, Pro-Stride APS is a high concentration of interleukin-1 receptor antagonist (IRAP) that is 5.8 times more concentrated than blood. These receptor antagonists promote natural joint healing processes. The Process The Pro-Stride processing unit is mobile and the entire process takes about 30 minutes. Blood is drawn from the horse then placed in a centrifuge to be spun down. Then plasma is removed and the remaining PRP suspension is extracted. This extraction is then added to an APS concentration device which undergoes mixing, then is spun down once more. The resulting product is Autologous Protein Solution (APS). This can then be injected into the joint by your veterinarian all at the same appointment. Talk to us to see if Pro-Stride is the best treatment choice for your horse! For more information on Pro-Stride, please see: Pro-Stride web page Publications showing clinical data supporting the effects of Pro-Stride APS Pro-Stride: How It Works (video)

Here are a few things to remember as you and your horse prepare to travel to competitions. Prevent Stress to Keep Your Horse Healthy It’s important to realize that transport to shows, even if your horse seems like a calm traveller, puts stress on their bodies and immune system. Stress can play a large role in the development of gastric ulcers, so prevention is ideal. An in-depth article with the newest ulcer information will be coming soon, but here are some general management guidelines you can follow if you’re concerned about gastric ulcers in your horse: Increase turnout and decrease stall time to minimize stress Increase the amount of time feed is available using a hay net or slow feeder system Feed smaller meals more frequently throughout the day and overnight (ideally 4-6 meals daily) Feed hay before feeding grain – this will create more saliva, which is a buffer of stomach acid Feed more forage and less high concentrate grain Include up to 25% alfalfa in the diet – this can act as a buffer in the stomach Do not exercise on an empty stomach Avoid use of non-specific non-steroidal anti-inflammatory medications such as phenylbutazone (bute) or flunixin meglumine (banamine) unless directed by your veterinarian The respiratory system is another area vulnerable to stress while traveling. Horses have to stay stationary with their heads elevated for abnormally long periods of time and air quality may not be ideal while trailering. Signs of respiratory disease that you can watch out for include the following: Increased respiratory rate Increased respiratory effort Cough Nasal discharge Fever (>101.5F) Pack an Equine Emergency Kit While Traveling One way to be prepared for unexpected situations should they arise is to have an emergency kit with you while traveling. Some of the things we recommend you keep in such a kit: Stethoscope Digital thermometer (sold for people) or equine thermometer Supplies for a pressure bandage – a combine, brown gauze, vetrap, elastikon, white kling, and a non-stick telfa pad – to apply while waiting for a veterinarian Chlorhexidine Saline solution 3x3 gauze Furazone Exam gloves Triple antibiotic ointment Electrolytes Dose syringe to administer oral medications Stall card with all pertinent horse information (see our main Resources page) We also recommend consulting with your regular veterinarian on any prescription needs to have on hand in an emergency – for example, we often recommend having a tube of Banamine paste on hand in case of a colic episode to administer if your veterinarian gives you instructions to do so. Other supplies can be added based on the individual horse and horse owner. Stay Up to Date on Rules, Regulations and Paperwork Some competition organizations like USEF and USHJA require that your horse be microchipped. Those of you traveling out of state or out of country are aware of the paperwork that you should be carrying with your horse, but here is a reminder to keep an up-to-date Certificate of Veterinary Inspection or CVI (commonly known as a ‘health certificate’) and a negative Equine Infectious Anemia test (commonly known as a Coggins) on hand when you cross borders. CVIs must be issued by an accredited veterinarian within 30 days before crossing state lines, while an up-to-date EIA test done by a USDA-approved laboratory is required within six (6) or twelve (12) months dependent on the individual state. If you have any questions regarding your horse’s health prior to showing, please contact the clinic. Happy travels!

At Steinbeck Peninsula Equine Clinics, we have found that integrating complementary medicine techniques to our treatment plans has led to greater success when managing lameness cases, painful conditions, and various disease processes. It also helps us maintain the musculoskeletal health of all our patients from the athletic performer to the retired horse. Several Steinbeck Peninsula Equine veterinarians have attended specialized training programs to become certified in acupuncture. It’s important to be aware that you must be a veterinarian and complete a certified program to be a true equine acupuncturist. What is Acupuncture? Acupuncture is considered to be under the umbrella of Traditional Chinese Medicine (TCM) and involves the stimulation of predetermined spots, called “acupuncture points”. In TCM, acupuncture points are often associated with “meridians” to stimulate movement of qi (“chi”) energy. There are multiple free nerve endings at these acupuncture points, that when stimulated sends messages to the brain. As a result, the brain tells the body to produce different chemicals and hormones that help the body to heal. Some points are associated with different organs or useful when treating specific disease processes, such as laminitis, liver disease, and stomach ulcers. The effects of acupuncture are attributed to multiple mechanisms involving the nervous system, immune system, and endocrine system. In equine practice, we commonly use acupuncture to complement our treatments for lame horses and aid in pain relief. “Trigger points” are also known as acupuncture points, which can be described as reactive areas that are usually associated with muscle tension or knots. We can scan the horse as a diagnostic technique to observe the reactive regions associated with musculoskeletal problems. In addition, the World Health Organization (WHO) recognizes the effectiveness of acupuncture as a form of analgesia, or pain relief. Acupuncture can also be an effective way of treating chronic pain of the musculoskeletal system with restricted joint movements. It has been shown to not only treat pain, but also reduce muscle spasms, which result in abnormal loading of different joints causing the clinical signs associated with pain. Many of our geriatric (older, retired patients) benefit from routine acupuncture treatments to maintain their musculoskeletal health and alleviate pain commonly associated with many of the disease processes that are associated with age, such as arthritis. The Science of Acupuncture Stimulation of acupuncture points near the body surface produces effects carried out by the nervous, immune, endocrine, cardiovascular, and other systems that promote healing. The stimulation of the free nerve endings can result in local and distant effects within the body. Effects can be summarized by five mechanisms of action: local effects, segmental analgesia, extrasegmental analgesia, central regulatory effects, and myofascial trigger points. There are multiple ways for stimulating these nerve endings: Dry needling – the insertion of a needle into a predetermined spot Aquapuncture – injection of a fluid into an acupuncture point, often vitamin B12 Electroacupuncture – attachment of electrodes to acupuncture needles inserted into an acupuncture point. The intensity, frequency, and pulse type can be manipulated to provide appropriate treatment for individual patients Moxibustion – the burning of an herb, often “mugwort” (Artemisia vulgaris) on an acupuncture point or over the skin at am acupuncture point. This is often used for treatment of chronic muscular and arthritic pain. Hemoacupuncture – a procedure where a hypodermic needle causes bleeding at an acupuncture point Cold Laser/Infra-red (IR) Stimulator – the use of a laser to stimulate acupuncture points, often times at extremities. This is also useful with horses that are needle-shy who would benefit from acupuncture. For additional information: AAEP – Veterinary Acupuncture and Chiropractic: What, When, Who? AAEP Proceedings – Acupuncture and Pain Management The Horse – How Does Acupuncture Work? References: Boldt, E. (2016). Veterinary Acupuncture and Chiropractic: What, When, Who? Retrieved February 16, 2018, from https://aaep.org/horsehealth/veterinary-acupuncture-and-chiropractic-what-when-who Kenney, J. (2011). Acupuncture and Pain Management. AAEP Proceedings, 57, 121-137. Larson, E. (2016, June 10). How Does Acupuncture Work? The Horse.

While microchips are required for some competitors, we also want to remind you about the additional benefits of a microchip in your horse and answer some commonly asked questions. Microchipping for Competitors As many of you are aware, the United States Equestrian Federation (USEF) and United States Hunter Jumper Association (USHJA) have rules requiring a microchip for horses and ponies competing in classes that require horse registration. The microchip verifies the horse’s ID, which allows the horse to compete for points and prize money and to be eligible for certain US Equestrian and USHJA programs and awards. US Equestrian requires microchips to be ISO 11784/11785 compliant (see USEF Microchip FAQ). This microchip has a unique 15-digit number that will be assigned only to your horse. Why Microchipping is Important for All Horses Microchips are a great way keep your horse identifiable in many situations, even if you are not participating in competitions that require them. The recent fires in Northern and Southern California serve as a reminder that disaster preparedness is essential and a microchip can significantly increase the odds that you and your horse are reunited as soon as possible. While other means of identification certainly have their use in these situations, such as information taped onto the halter or animal-safe paint directly on the horse, these methods are not permanent – halters can come off and paint can fade. A common misconception is that microchips can be used for tracking purposes, but this is not the case. Microchips contain a small amount of information that is only accessible when scanned and read with specialized scanners. They are also very safe, as is the procedure to insert them – we have seen no adverse reactions in decades of use. Getting the microchip is a quick, easy process. If you do choose to have your veterinarian microchip your horse, please remember that you are responsible for registering the microchip number. The USEF provides an informative video on microchipping, as well