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Published by the Florida Association of Equine Practitioners, an Equine-Exclusive Division of the Florida Veterinary Medical Association Issue 1 • 2015



and the Performance Mare


History of

Creeping Indigo Toxicity in Florida ROBERT MACKAY | BVSC, PHD, DACVIM






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The President's Line Corey Miller, DVM, MS, Diplomate ACT - FAEP President

On assuming the presidency of the FAEP Council, I’d like to commend Dr. Suzan Oakley for leading the Association through a very successful year, during which three world-class equine-exclusive continuing education conferences were planned and executed. With Dr. Oakley’s stewardship, the FAEP continued to support its members, veterinary students and other equine-care team members through member support programs, publications, legislative activities in Tallahassee, and other educational activities. I am looking forward to the coming months as we continue to work to fulfill the FAEP’s mission to support development within our profession and to educate our members on conditions affecting the industry, including the welfare of our patients. The year commenced at the end of January with a very successful conference in Ocala, with a broad range of disciplines and topics included in the lectures and wet labs. Conferences such as this would not be possible without the fantastic support of our educational partners from industry who sponsor wet labs and other conference activities, as well as the support from exhibitors who signed up early to join us, and added great dynamism to the 52nd Annual Ocala Equine Conference. The Council and staff are now fully engaged in the planning of the 11th Annual Promoting Excellence Symposium (PES), which will be held October 15-19, 2015, at the Naples Grande Beach Resort, in Naples, Florida. We hope you will join us in Naples for this conference which will offer valuable CE in clinical medicine, imaging, and rehabilitation for our athletic patients. Our featured speaker is Jean-Marie Denoix DVM, PhD, internationally-renowned Professor of Veterinary Anatomy and Equine Lamenesses at the École Nationale Vétérinaire d'Alfort, France. Professor Denoix is highly respected for his expertise in anatomy, imaging techniques, biomechanics and lamenesses. The PES is established as the pillar of excellence in the provision of equine veterinary medicine, and we aim to surpass the previous years’ achievements at this Naples conference. The FAEP is also closely monitoring legislative activity in Tallahassee. We have been working closely with our lobbyists to ensure that our members’ interests are properly represented. We held our Legislative Action Days in the capital on March 11-13, and I will share details about that, in the next issue of the Practitioner. Please feel free to contact any board member or FVMA staff members with your comments, questions, or suggestions. Corey


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TOXICITY IN HORSES AMANDA M. HOUSE | DVM, DACVIM Introduction The recent news of the death of several horses in Central Florida from an accidental additive to equine feed has raised awareness and questions surrounding this important issue. Monensin and lasalocid are known as ionophore antibiotics. They have been commonly used in poultry feed as an antiprotozoal agent that reduces the number of coccidia parasites. Monensin and lasalocid are also routinely added to ruminant feeds to improve feed efficiency in pasture and feedlot cattle. Improved feed efficiency results in improved weight gain/body mass with the same feed intake, compared to animals that are less feed efficient. For poultry and ruminants, these feed additives are common and safe to use. Horses however, are the most sensitive domestic animal to monensin toxicity. The lethal dose for most horses is 2-3 mg/kg (equivalent to about 1,000 mg (1 gram) for the average horse). Unfortunately, when these additives are accidently mixed with equine feed, the results can be deadly.

Clinical Signs Clinical signs of monensin and lasalocid toxicity are similar. Lasalocid appears to be less toxic to horses compared to monensin. Affected horses develop several clinical syndromes, which appear to be dose-related. Depression and abnormal gaits (incoordination, weakness and paresis or paralysis which can lead to inability to stand) are characteristic, in conjunction with a reduced appetite. Horses that eat only a small amount of monensin-containing (sublethal dose) feed may exhibit signs of poor performance, heart failure, and unthriftiness. Cardiac arrhythmias are often apparent, with high heart rates and overly prominent jugular vein distension and pulsation. Damage to the heart is often permanent in affected horses, and cardiac evaluation is recommended in horses that survive. Ingestion of a large dose at one time can result in death within a few hours of eating the contaminated feed. Most affected horses will develop signs that can last for several days, to even weeks, before death or euthanasia. These symptoms can include poor appetite, colic, diarrhea, intermittent sweating, and stiffness and muscle weakness that progress to an abnormal ataxic gait. Horses will have increased heart and respiratory rates, low blood pressure, and increased urination. It is important to note that although the clinical signs of affected horses are suggestive, a definitive diagnosis of monensin or lasalocid toxicity requires feed analysis.

Diagnosis Feed analysis or post-mortem examination is required to make a definitive diagnosis. Horses exhibiting symptoms of anorexia, 8  The Practitioner 

muscle weakness, and heart failure should be evaluated by a veterinarian to determine if possible exposure has occurred. Changes in blood work values are not specific for this toxicity, but typically reflect dehydration and electrolyte abnormalities soon after ingestion.

Treatment No specific antidote exists for monensin or lasalocid toxicity. Suspect feed sources should be immediately removed pending test results of feed analysis. Initial treatment typically involves supportive care with intravenous fluids and oral laxative therapy. Anti-inflammatory and pain medication may be utilized as well.

Prevention Education is critical for prevention of this intoxication. Feed companies that make equine, poultry, and ruminant feed need to ensure that steps are taken to prevent these additives from entering equine feed.

Amanda Martabano House, DVM, DACVIM Dr. Amanda M. House is a Clinical Associate Professor in the Department of Large Animal Clinical Sciences at the College of Veterinary Medicine of the University of Florida. She is a large animal medicine clinician in the equine hospital, and coordinates equine continuing education and outreach programs at the College. Dr. House is also the Director of the Practice-Based Equine Clerkship Program and the Equine Research Program. She completed her BS in Animal Science at Cornell University. After graduating from Tufts University School of Veterinary Medicine in 2001, Dr. House completed an internship and large animal internal medicine residency at the University of Georgia’s Veterinary Teaching Hospital. Dr. House became board certified in large animal internal medicine in 2005. Her professional interests include neonatology, infectious disease, and preventative health care. She is active on committees for the American Association of Equine Practitioners, the American College of Veterinary Internal Medicine, and the Florida Association of Equine Practitioners. She is a past president of the Florida Association of Equine Practitioners (FAEP), and is currently the FAEP’s representative on the Executive Board of the FVMA.

Issue 1 • 2015

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History of

Creeping Indigo Toxicity in Florida ROBERT MACKAY, BVSC, PHD, DACVIM In South Florida, a mysterious and often fatal condition of indigo has become a very common plant around Alachua and adult horses and livestock had begun to be recognized in the Seminole counties and can be found growing along the edges of 1970s.1 Affected horses were dull, apathetic and uncoordinated; many pathways, including many at the University of Florida. Even some had convulsions, ulcers of the tongue, and whitening or more threateningly, it has become the dominant herb in some streaking of the corneas of the eyes. Most of them died within pastures in the Ocala area. weeks. The problem was seen most commonly in the late summer or fall. Creeping Indigo Beginning in 1973, a University of Miami botanist, Julia The Indigofereae are a small tribe of often very attractive, Morton, began to walk the properties on which these deaths pink to red-flowered shrubs and herbs. The  largest genus were occurring. She noticed an abundance of wild indigo plants is Indigofera which is pantropical, with 75% of the ~750 species (Indigofera suffruticosa) and initially supposed that these were restricted to Africa–Madagascar, and the rest in the Sinothe culprits. By the 1980s, however, Dr. Morton had investigated Himalayan region, Australia, Mexico, and Brazil.4 Because of many more incidents and had become convinced that the their complex chemistry, Indigofera contain many toxic and condition was actually caused by a different indigo herb, creeping medicinally-used species. These toxic chemicals have evolved as indigo (also known as trailing indigo; Indigofera spicata), that a defensive response to predation by herbivores and pathogens.5 had widely invaded local pastures and was being enthusiastically Other Indigofera are economically important indigo dye-producing eaten by horses. In 1987, she decided to present her findings and pasture legume species that occupy an extremely wide range at a local meeting of concerned equine veterinarians and of different habitats. Indigofera spicata is native to East Africa horseowners. Dr. Morton explained that creeping indigo had first and Madagascar, Indonesia, and the Philippines. It was valued been imported into the United States in 1933, and established at as a cover crop in coffee estates in Africa and was introduced into (embarrassingly) the University of Florida in Gainesville, so that India, Java, Malaya, and the Philippines, both as ornamental its supposed utility as livestock forage and ground cover could be ground cover and a cover crop for tea, rubber, oil palm, and sisal studied. When it was found that rabbits died when they grazed plantations. It has also been introduced into Australia, several the experimental plots, the project was quickly abandoned!2 The Pacific islands, and the Caribbean. neglected but apparently hardy plants escaped containment, Surprisingly, there is still some confusion as to the identity of invaded locally, and supposedly spread inexorably southward over the creeping indigo plants originally described by Dr. Morton. At the subsequent decades; they now can be found growing along the time she published her work, I. spicata/I. hendecaphylla were the sidewalks of Key West. Dr. Morton also noted reports from considered by some to be synonymous and referred to as Queensland of Birdsville Indigo Poisoning, an almost identical I. spicata complex.6 By 2006, there was a school of thinking nervous system disease of horses grazing another Indigofera among Australian botanists that these were actually different species, I. linnae.3 species and Dr. Morton had in fact described I. hendecaphylla.7 The presentation was well attended but Dr. Morton’s creeping This seemingly obscure point has currently excited some debate indigo theory was not well accepted, with many attendees holding among local botanists and a definitive determination is surely at fast to the notion that toxic chemicals sprayed on trees in local hand; however, for now, multiple examples of the plant harvested fruit groves were the problem – thus the name “Grove poisoning.” around Gainesville have been identified by the University of By the early 1990s, even the doubters had acknowledged the Florida Herbarium as I. spicata on the basis of the latter’s relatively obvious and, although feeding trials have thankfully not been smaller leaves, flowers, and pods. If these identifications are performed in horses to formally establish cause and effect, it is correct, it suggests that there are two closely related species of now generally accepted that creeping indigo causes the neurologic creeping indigo in Florida with their respective origins somewhat syndrome previously known as Grove poisoning. obscure. Both I. hendecaphylla and I. spicata have been connected Over the last 10 years, we have seen similar small outbreaks of with equine and livestock deaths, although such an association the disease in horses and in donkeys in central and north-central remains to be confirmed for I. spicata in Florida. Thus it will be parts of the state, especially in areas north of Tampa and around important to collect plants from all future outbreaks and have Brooksville. This extension in geographic range of the syndrome them identified by the UF Herbarium. appears to correspond to increasing abundance of creeping indigo Both plants are prostrate to sub-erect with branched runners in the central and north-central parts of the state. The origins of fanning out in all directions from the crown of a white, slender, this recent wave of invasion by creeping indigo are unclear. It is tapering taproot firmly set in the earth and descending nearly a interesting to hypothesize possible roles for climate change or meter (Figures 1-3).7,8 The stems are pale-green to yellow, tough, for a separate introduction or emergence of a new, more invasive and thickly set with alternate, pinnate, clover-like leaves that are strain. This is explored more fully below. In any event, creeping 1-5 cm long. The slender, tubular flowers are brick-red to pink 10  The Practitioner 

Issue 1 • 2015

Table 1. Comparison of characteristics of two closely-related creeping indigo species, I. hendecaphylla and I. spicata. Feature

I. hendecaphylla

I. spicata

Posture Leaves

Prostrate spreading perennial Pinnate, 7-10 leaflets, 20-55 mm,

Prostrate spreading perennial Pinnate, 5-7 leaflets, alternate, 12-40 mm,

Leaflets Inflorescences Pods

Obovate to elliptical, 5-16 × 3-7 mm, dull green Red, 120-150 mm Descending, 22-27 mm, brown

Obovate, 4-11 × 3-8 mm, dull green Pink to orange-red, 30-65 mm Descending, 10-18 mm, yellow-brown

(mostly pink around Gainesville). The most characteristic and identifiable feature, the needle-like, stiff, sharp-tipped seed pods, 1-3 cm long, are borne profusely in dense, downward-pointing clusters. The plant, perennial in tropical and subtropical climates, is killed back in winter in central and north-central Florida but sprouts from the root in spring.

Figure 1. Indigo spicata specimens obtained at the University of Florida and authenticated at the UF Herbarium.

Figure 2. Indigo spicata showing typical pink flowers and clusters of pods (upper part of image) growing at University of Florida.

Non-neurologic signs. There may be weight loss, inappetence, high heart and respiratory rates, labored breathing, high temperature (a rare finding), hypersalivation (ptyalism) or foaming from the mouth, dehydration, pale mucous membranes, feed retention in the cheeks (quidding), halitosis, watery discharge from the eyes (epiphora; Figure 4) and squinting (blepharospasm), light sensitivity, corneal opacity, corneal ulceration and neovascularization, severe ulceration of the tongue and gums (Figure 5), and prominent digital pulses without other signs of laminitis. Figure 4. 11-year-old mixed breed gelding with creeping indigo toxicity from near Brooksville, Florida. Note the dull appearance, staining with ocular discharge below the eye, and flaccid lower lip. On close inspection, there was also marked edema of the right cornea and blepharospasm or the right eyelids. Figure 5. 5-year-old Paso Fino gelding with creeping indigo toxicity from near Homestead, Florida. Note the extensive ulcerations of the gums above the upper incisors. This horse’s tongue was also severely ulcerated.

Figure 3. Indigo sp. Dense thatch of creeping indigo comprising >40% of a bahiagrass pasture in Ocala, Florida. Note the abundant pods and evidence of grazing by horses in the pasture. 

Signs of Creeping Indigo Toxicity 1, 3, 6, 9, 10 Consumption of 10 pounds of I. linneae daily for 3 weeks is sufficient to cause the very similar Birdsville disease.3,9 Both neurologic and non-neurologic signs are seen.

Neurologic signs. Often, an early sign is a change in personality – affected horses at first seem quieter and less energetic than usual. Degrees of obtundation (depression) ranging from mild lethargy to recumbency and loss of consciousness may be seen as the condition progresses over days to weeks. Head carriage is low and there may be episodes of standing sleep-like activity (narcolepsy), head-pressing into corners, or compulsive walking around the inside of a stall or paddock. Some affected horses The Practitioner  11 

have been seen with their heads tilted to one side and their necks and bodies twisted in the same direction, indicating involvement of the balance centers (vestibular system) of the brain. These signs may be accompanied by rhythmic blinking and jerking eye movements (nystagmus). The blink response to hand gestures toward the eyes (menace response) is frequently absent or reduced, although constriction of the pupils to bright light is usually retained. The muzzle and lips may hang flaccidly. In retrospect, it is often clear that an abnormal gait has been seen developing over the preceding several days, characterized by incoordination and weakness in all limbs, with unpredictable crossing of pairs of limbs, interference between hooves, buckling of joints during weight-bearing, a “crab-like” gait and abnormal posturing at rest. Some affected horses develop a bizarre goose-stepping gait in their front legs. Most horses that continue to consume the plant eventually become cast on their sides and are unable to rise. They either become unconscious or develop convulsions which may become generalized and severe before death or euthanasia, after days in recumbency. Laboratory Findings. Abnormal findings on routine hemograms and plasma chemistry panels are mild, non-specific, and unhelpful in making the diagnosis. Typically, there is low-normal or low total white blood cell count with lymphopenia and mild electrolyte derangement that may include hyponatremia, hypophosphatemia, hypomagnesemia and metabolic acidosis.  Aspartate aminotransferase and creatine kinase activities often are slightly, to moderately above reference range.

commonly in a variety of settings, and the mechanism is well understood. The toxin is a potent and irreversible inhibitor of mitochondrial succinate dehydrogenase, a key enzyme in transforming glucose and oxygen into useable energy.12 Nerve cells are extremely vulnerable to energy deprivation, thus accounting for the early and prominent neurologic signs seen with all types of 3-NPA toxicity.  3-NPA accounts for 0.24 to 1.5% of the dry matter of creeping indigo. Because it is metabolized quickly, it is unlikely to be found in the serum of affected animals. Indospicine. Indospicine13 is a non-protein amino acid. It is toxic to the liver because of antagonism to the essential amino acid arginine, with which it competes. One of its principal toxic actions is inhibition of nitric oxide synthase, an action likely associated with the development of corneal edema and ulceration of mucous membranes. Although horses are relatively resistant to the liverdamaging effects of this toxin, it persists in the tissues of horses dying or killed with the disease, and these tissues are potentially toxic if fed to dogs. Indospicine accounts for 0.1 to 0.5% of the dry matter of creeping indigo and it can be detected in the serum of affected animals.

Treatment and prevention Horses that are quickly removed from the offending plants may recover completely, but more often there are persistent gait abnormalities. There is no effective treatment.  Early investigations into the14 prevention and treatment of Birdsville disease in Australia proposed the use of arginine-rich protein sources such as peanut meal (4.3% arginine) and gelatin (8.0% Necropsy Findings. arginine).9 The lack of significant liver lesions in horses because Both gross and histologic examinations of horses poisoned of their relative resistance to indospicine, together with the by creeping indigo are most notable for the lack of diagnostic likelihood that the neurological disease results from 3-NPA findings. It has been shown in experimental animals that poisoning, suggests that arginine alone would have little benefit in subacute and chronic toxicity by 3-NPA, the creeping indigo toxin the treatment of nervous signs although nonneurologic signs may that causes neurologic signs, does not cause changes evident on respond. Thiamine was also suggested as an effective treatment light microscopy, although Brazilian investigators documented for nitro toxicity in ruminants, but others showed this treatment changes by electron microscopy of the mitochondria of horses to be ineffective.6 The fact that 3-NPA neurodegeneration is that had consumed I. lespedezioides.10 Horses may show mild used as an induction model for Huntington’s disease research is liver pathology, evident histologically as periacinar necrosis, testament to the current futility of all treatments.15 Management infiltration of lymphocytes and haemosiderin-laden macrophages of affected horses should include their removal from the source, in periacinar regions, and vacuolation and swelling of surviving confinement to prevent any injuries and non-specific supportive hepatocytes. therapy. It was previously suggested that livestock poisonings by I. spicata can be prevented by keeping the proportion of this plant Toxins below 25% of the total forage available, but recent evidence does Over the last decade, there has been resolution of the not support this view.14 The best means for preventing poisoning previous confusion about the roles of the two putative is to stop access by horses to paddocks where creeping indigo toxins of creeping indigo, 3-nitropropionate (3-NPA) and is present or to remove plants by physical means or herbicide indospicine.  It is now clear that 3-NPA causes the largely application. irreversible neurologic signs described above while indospicine Although there is no herbicide commercially recommended causes the corneal edema, ulcerations, and other non- for eradication of creeping indigo, the University of Florida neurologic signs.6  Each of these toxins is described briefly: Pasture Weed Identification and Control page at the IFAS Extension EDIS website ( 3-nitropropionate. pasture_weeds), suggests spraying either of two herbicides 3-NPA is a highly toxic compound produced by the plant containing aminopyralid: Milestone (Dow AgroChemicals) at 5 primarily as defense against destruction by herbivores.11,12 This fl oz per acre or GrazonNext HL (Dow AgroChemical) at 24 fl oz nitrotoxin is by no means unique to Indigofera but is produced per acre. Retreatment the following year will likely be necessary. as anti-herbivore defense by a vast array of plants and Dead plants retain toxicity and must be removed and disposed fungi. Poisoning associated with 3-NPA therefore occurs quite of. Manure from animals that graze herbicide-treated pastures 12  The Practitioner 

Issue 1 • 2015

the metabolic poison propionate 3-nitronate and its conjugate acid, 3-nitropropionate. IUBMB Life 2013;65:759-768. 13. Hegarty MP, Pound AW. Indospicine: A new hepatotoxic amino-acid from Indigofera spicata. Nature 1968;217:354-355. 14. Borer-Weir KE, Menzies-Gow NJ, Bailey SR, et al. Seasonal and annual influence on insulin and cortisol results from overnight References: 1. Morton JF. Creeping indigo (Indigofera-spicata Forsk) (Fabaceae) – a dexamethasone suppression tests in normal ponies and ponies predisposed to laminitis. Equine Vet J 2013;45:688-693. hazard to herbivore in Florida. Econ Bot 1989;43:314-327. 2. Emmel MW, Ritchey GE. The toxicity of Indigoferae endecaphylla Jacq. 15. Tunez I, Tasset I, Perez-De la Cruz V, et al. 3-Nitropropionic Acid as a Tool to Study the Mechanisms Involved in Huntington's Disease: Past, for rabbits. J Amer Soc Agron 1941;33:675-677  3. Carroll AG, Swain BJ. Birdsville disease in the central highlands area Present and Future. Molecules 2010;15:878-916. of Queensland. Aust Vet J 1983;60:316-317. 4. Schrire B. A review of tribe Indigofereae (LeguminosaeRobert MacKay, BVSc, PhD, DACVIM Papilionoideae) in Southern Africa (including South Africa, Lesotho, Dr. Robert MacKay is Professor of Swaziland & Namibia; excluding Botswana). S Afr J Bot 2013;89:281Large Animal Clinical Sciences and 283. Large Animal Internal Medicine at 5. Perez LB, Li J, Lantvit DD, et al. Bioactive Constituents of Indigofera the University of Florida College of spicata. J Nat Prod 2013;76:1498-1504. Veterinary Medicine. 6. Ossedryver SM, Baldwin GI, Stone BM, et al. Indigofera spicata (creeping indigo) poisoning of three ponies. Aust Vet J 2013;91:143He is a 1975 graduate of Massey 149. University, Palmerston, New Zealand. 7. Wilson PG, Rowe R. A revision of the Indigofereae (Fabaceae) in He earned board certification from the Australia. 2. Indigofera species with trifoliolate and alternately pinnate American College of Veterinary Internal leaves. Telopea 2008;12:293-307. Medicine in 1981, and received his PhD 8. Du Puy DJ, Labat JN, Schrire BD. The separation of two previously from the University of Florida in 1987. confused species in the Indigofera spicata complex (Leguminosae: Papilionoideae). Kew Bulletin 1993;48:727-733. Dr. MacKay’s expertise includes general internal medicine and a 9. Hopper PT, Hart B, Smith GW. Prevention and treatment of special interest in clinical neurology. His research interests also Birdsville disease of horse. Aust Vet J 1971;47:326-329. include the area of inflammation/endotoxemia, and the diagnosis 10. Lima EF, Riet-Correa F, Gardner DR, et al. Poisoning by Indigofera and biology of equine protozoal myeloencephalitis (EPM). Through lespedezioides in horses. Toxicon 2012;60:324-328. his work, the pathogenesis of endoxemia in horses has been clarified 11. Anderson RC, Majak W, Rassmussen MA, et al. Toxicity and and at least one new treatment developed and extensively used. In metabolism of the conjugates of 3-nitropropanol and 3-nitropropionic the field if EPM, Dr. MacKay has contributed to an understanding acid in forages poisonous to livestock. J Agric  Food  Chem of the life cycle of the parasite, and is actively involved in developing 2005;53:2344-2350. new and more satisfactory diagnostic tests. 12. Francis K, Smitherman C, Nishino SF, et al. The biochemistry of

should not be composted. Also, any grass clippings removed from these treated pastures should not be composted. Be sure to follow all label directions when using pesticides!

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~ Part 2~


CORNEAL STROMAL ABSCESSES Focal trauma to the cornea can inject microbes and debris into the corneal stroma through small epithelial ulcerative micropunctures. Some stromal abscesses may be secondary to systemic disease. A corneal abscess may develop after epithelial cells adjacent to the epithelial micropuncture divide and migrate over the small traumatic ulcer to encapsulate infectious agents or foreign bodies in the stroma. Epithelial cells are more likely to cover a fungal than a bacterial infection. Reepithelialization forms a barrier that protects the bacteria or fungi from topically administered antimicrobial medications. Reepithelialization of stromal abscesses interferes with both routine diagnostics and treatment. Corneal stromal abscesses can be a vision-threatening sequelae to apparently minor corneal ulceration in the horse. A painful, blinding chronic iridocyclitis may result. Most stromal abscesses involving Descemet's membrane are fungal infections (Figures 12-13). The fungi seem "attracted" to the type IV collagen of Descemet's membrane. Both superficial and deep stromal abscesses do not heal until they become vascularized. The patterns of corneal vascularization are often unique, suggesting that vasoactive factors are being released from the abscess that influences the vascular response. Medical therapy consists of aggressive use of topical and systemic antibiotics, topical atropine, and topical and systemic NSAIDs. Superficial stromal abscesses may initially respond positively to medical therapy. If reduced inflammation of the cornea and uvea are not found after two to three days of medical treatment, surgical removal of the abscess should be considered. Deep lamellar and penetrating keratoplasties (PK) are utilized in abscesses near Descemet's membrane, and in eyes with rupture of the abscess into the anterior chamber. PK eliminates sequestered microbial antigens, and removes necrotic debris, cyotokines and toxins from degenerating leukocytes in the abscess.

Figure 12

18  The Practitioner 

Figure 13

Penetrating Keratoplasty (PK) for Deep Corneal Stromal Abscesses Corneal transplantation is performed to restore vision, to control medically refractory corneal disease, and to re-establish the structural integrity of the eye. Penetrating keratoplasty is considered high-risk for rejection in infected, vascularized corneal tissue. Nearly all PKs in horses are in high-risk corneas. Fresh corneal grafts are preferred in horse PK, but frozen tissue can be utilized. Vascularization of the grafts, indicating rejection, begins at 5-10 days postoperatively. Few equine PK grafts remain clear following their vascularization. They form a therapeutic and tectonic function.

OTHER CORNEAL PROBLEMS Squamous Cell Carcinoma and Other Corneal Tumors Preneoplastic epithelia dysplasia, intraepithelial carcinoma in situ, and the invasive squamous cell carcinoma (SCC) (Figure 14) are common to the limbus and cornea of horses. Epithelial dysplasia can be treated with topical 5-fluorouracil. Keratectomy and adjunctive therapies are needed for carcinoma in situ and SCC. Rapidly progressive and invasive SCC may necessitate enucleation. Limbal melanomas and hemangiosarcomas have also been reported.

Corneal Foreign Bodies Penetrating and perforating corneal foreign bodies cause varying degrees of keratitis (Figure 15) and uveitis, and are common in horses. Superficial foreign bodies can be removed under topical anesthesia and the subsequent ulcer treated medically. Deep corneal and penetrating foreign bodies may cause severe uveitis/endophthalmitis and require more aggressive care.

Figure 14

Issue 1 • 2015

Figure 15

Figure 16

Corneal Endothelial Detachment Following Blunt Trauma Profound and persistent corneal edema may be present following blunt trauma to the globe of the horse (Figure 16). Detachment of the endothelium is a proposed mechanism of this syndrome. The prognosis for a return to normal is good if Descemet's membrane is intact, and poor if it is detached. Ultrasound of the eye can aid in determining the prognosis. Hypertonic solutions (5% sodium chloride) may be beneficial in the early stages. Thermatokeratoplasty may be necessary to reduce the edema in severe cases. Endothelial cell reattachment and cellular hypertrophy may occur to resolve the condition in some horses.

Nonulcerative Interstitial Keratitis (NIK) or Immune Mediated Keratitis Several forms of NIK are found in the USA and Europe. The etiology is presumed to be altered corneal immune privilege from abnormal exposure or expression of corneal antigens, inducing autoimmune dysregulation. A stromal form (Figure 17) and an endotheliitis with corneal edema (Figure 18) is another form of NIK. These eyes may partially respond to topically administered corticosteroids, NSAIDs, tacrolimus or cyclosporine A, and may require parenteral antibiotics, corticosteroids, or NSAIDs. Endotheliitis may be found with lens subluxations.

Eosinophilic Keratoconjunctivitis Eosinophilic keratoconjunctivitis has an unknown etiology, but may be an immune-mediated disease. All ages and breeds of

Figure 18


Figure 19

Figure 17

horses can be affected with many cases reported in the spring. Clinical signs (Figure 19) include corneal granulation tissue, blepharospasm, chemosis, conjunctival hyperemia, mucoid discharge, and corneal ulcers covered by raised, white, necrotic plaques. Eosinophilic keratoconjunctivitis resembles a corneal tumor in appearance. KCS may develop in affected horses due to lacrimal gland inflammation. The lacrimal gland should be palpated to detect swelling. Corneal cytology typically contains numerous eosinophils and a few mast cells to rule out similar appearing infectious and neoplastic causes. Superficial lamellar keratectomy to remove plaques speeds corneal healing. Topical corticosteroids (1% prednisolone acetate or 0.1% dexamethasone) 4 to 6 times a day in the early stages (in spite of corneal ulcerations), antibiotics (e.g., bacitracinneomycin-polymyxin or chloramphenicol), 1% atropine, and 0.03% phospholine iodide (BID) in combination with systemic nonsteroidal antiinflammatory drugs are indicated. Topical cromolyn sodium (4.0% TID) or lodoxamide (0.1% TID), mast cell stabilizers, can also aid healing. Systemic corticosteroids may be necessary. Horses with EK should be dewormed twice with ivermectin 10 days apart. These lesions are typically slow to heal. Scarring of the cornea occurs.

Herpes Keratitis Multiple, superficial, white, punctate or linear opacities of the cornea, with or without fluorescein dye retention, are found associated with equine herpes virus 2. The focal punctate corneal opacities may be found at the end of superficial corneal vessels, and may retain rose bengal stain (Figure 20). Varying amounts of ocular pain, conjunctivitis, and iridocyclitis are present.

Figure 20

The Practitioner  19 

corticosteroids for ERU. CBK is rare in ERU horses that have not been treated medically! Treatment is topically-administered calcium chelaters (dipotassium ethylene diamine tetraacetate 1%) to decrease tear calcium levels and aid healing. Topical antibiotics, atropine, and systemic non-steroidal anti-inflammatory drugs are also beneficial for the ulcers. Superficial keratectomy and burring may be necessary to remove the painful calcium deposits. Healing of keratectomy sites can occur with severe scarring. Recurrence of calcium band keratopathy is possible with continued episodes of uveitis. The prognosis for vision is guarded because of subsequent corneal scarring and further uveitis episodes. Figure 21

Multiple foals in a herd may be affected. Topically administered idoxuridine and trifluorothymidine (TID) have been used with topical NSAIDs for treatment of equine herpes ulcers, but recurrence is common.

Calcific Band Keratopathy Calcific band keratopathy (CBK) is a complication of chronic uveitis and consists of deposition of dystrophic calcium in the superficial corneal epithelium and stroma. Dense, white bands of calcium are noted in the interpalpebral region of the central cornea (Figure 21). Scattered areas of fluorescein retention are present as the calcium disrupts the epithelium to result in painful superficial ulcers. Deep ulcers can develop. A gritty sensation is found during scraping for corneal cytology. It appears to develop in the eyes of horses most aggressively treated with topical


Gelatt KN: Veterinary Ophthalmology 5th Ed, Lippincott, Williams and Wilkins, Philadelphia, 2013. Brooks DE: Ophthalmology for the Equine Practitioner. Teton NewMedia, Jackson, WY, 2008. Gilger BC (ed): Equine Ophthalmology, Ed 2. Elsevier, Maryland Heights, MO, 2010. Clinical Techniques in Equine Practice: Equine Ophthalmology, 4(1); 2005.

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Dennis Brooks, DVM, PhD, DACVO Dr. Brooks has been Professor of Ophthalmology at the University Of Florida College Of Veterinary Medicine since 1990. He was the President of the American College of Veterinary Ophthalmologists from 1997-1998. Dr. Brooks has written over 150 refereed scientific publications, 76 book chapters, received $1.6 million in research grants, and has given over 260 lectures both nationally and internationally in comparative ophthalmology. His book, Equine Ophthalmology, was published in 2002 and 2008. He received the British Equine Veterinary Association’s Sir Frederick Smith Memorial Lecture and Medal Recipient in 2007, and received the Frank J. Milne State of the Art Award of the American Association of Equine Practitioners in 2010.

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Issue 1 • 2015

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WITH OSPHOS THE BENEFITS ARE CLEAR . . . As with all drugs, side effects may occur. In field studies, the most common side effects reported were signs of discomfort or nervousness, colic, and/or pawing. OSPHOS should not be used in pregnant or lactating mares, or mares intended for breeding. Use of OSPHOS in patients with conditions affecting renal function or mineral or electrolyte homeostasis is not recommended. Refer to the prescribing information for complete details or visit CAUTION: Federal law restricts this drug to use by or on the order of licensed veterinarian. * Freedom of Information Summary, Original New Animal Drug Application, NADA 141-427, for OSPHOS. April 28, 2014.

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Pregnancy and the Performance Mare MARGO L. MACPHERSON | DVM, MS, DACT

Introduction Peak performance potential in most mares directly coincides with peak reproductive capability, yet these two events are frequently considered mutually exclusive. Many mare owners are unwilling to remove a valuable mare from training for the months required to carry, deliver and raise a foal. Yet, the genetic potential of a successful performance mare can infinitely increase the mare’s monetary value. Several solutions allow for continued performance in the mare athlete while also producing offspring. The best choice for the mare and her owner is dependent on convenience, risk and cost. However, factors such as exercise, heat, transport, and stress must be considered when selecting the ideal option for breeding the performance mare.

Factors Affecting Reproduction in the Performance Mare Effects of Heat and Exercise on Fertility

Recent work[1, 2] has focused on the impact of heat and exercise on embryo recovery and quality in mares. These studies used an embryo recovery model as an indirect measure of pregnancy for mares subjected to elevated internal body temperature after induced exercise. Mares were exercised at a long trot to canter in an exercise pen, daily, for 30 minutes. Exercise sessions occurred from 1pm to 3pm with ambient temperatures >30C (86F) and humidity >50%. Body temperatures were monitored before exercise, every 10 minutes, and immediately after exercise. During the study period, mares were bred to fertile stallions using artificial insemination. Uterine flushing for embryo recovery was performed on day 7 post-ovulation (a routine procedure for embryo recovery). Core body temperature averaged 39.9C (103.8F) after sustained exercise which was 2C higher than non-exercised mares. Mares developed smaller ovulatory follicles and the time between cycles was increased. Importantly, fewer embryos were recovered from exercised mares compared to mares at rest (11/32 = 34% vs 22/35 = 63%). Of embryos recovered from exercised mares, there were 50% fewer grade I embryos than those recovered from nonexercised mares (36% vs 72%). These findings showed an effect of exercise and/or heat on reproductive function in mares under moderate conditions. In a subsequent study[3], workers attempted to elucidate the effect of exercise, vs heat, on reproductive outcome in mares. Mares were subjected to a similar exercise regimen with a 2-week training period, followed by moderate exercise, daily, for 30 minutes. Ambient temperature was slightly lower on some days (25.3 – 30.8C or 77.5 – 87F) and humidity averaged 50%. Mares were assigned to 1. Control (no exercise), 2. Partial exercise (daily exercise through the day of ovulation), 3. Full exercise (exercise throughout the experiment). Mares were bred to fertile stallions 22  The Practitioner 

using artificial insemination. Uterine flushing for embryo recovery was performed on day 7 post-ovulation. Blood samples to measure serum cortisol were obtained immediately prior to exercise and 30 minutes after exercise completion. Vascular perfusion of the ovaries was assessed using Doppler ultrasonography. Similar to the previous studies, fewer embryos were recovered from exercised mares, vs control mares (44 and 43%, respectively, from partial and full exercised mares, vs 67% in control mares). Partial exercise mares produced fewer Grade I embryos than control or full exercise mares. Core body temperatures increased by 1C in both exercise groups when measured immediately after exercise. Heart rates were also increased in both exercise groups immediately following exercise periods (partial exercise 59.8 ± 1.6 bpm, full exercise 60.2 ± 1.4 bpm). Serum cortisol concentrations were higher in exercised mares vs control mares. Blood flow was greater in both exercise groups in the days prior to ovulation, but vascular perfusion of the ovarian wall was lower in follicles the day before ovulation in exercised mares. Exercised mares from which embryos were recovered had higher vascular perfusion than exercised mares that did not produce an embryo. Data from this study showed that cortisol was higher in exercised mares which may have contributed to lower embryo recovery rates. Interestingly, ovarian blood flow was increased in exercised mares, which presumably would improve ovarian function. Increased ovarian blood flow had a positive effect on embryo production in exercised mares, but did not increase embryo recovery rates when compared to mares at rest. A period of rest following ovulation did not improve embryo recovery rates.

Effects of Transport and Stress on Fertility

Very little information exists about the impact of stress on reproductive function in mares. This topic has been extensively studied in humans and other species with interesting results. The physiologic response to stress is activation of the hypothalamicpituitary-adrenal (HPA) axis and release of cortisol. Cortisol, in turn, has been shown to affect gonadotropins (follicle stimulating hormone or FSH and luteinizing hormone or LH) secretion in some species. However, the effects of stress on the HPA are varied with whether the stressor is acute or chronic in nature. In many species, it has been determined that acute stress and cortisol release has minimal effect on reproductive function[4, 5]. In some species, chronic elevation of cortisol is reflected in depressed concentrations of LH, which can affect ovulation. This phenomenon does not to hold true for mares. When mares were transported in estrous or early-pregnancy[6, 7], cortisol secretions were increased but changes were not noted in length of the estrous cycle, pre-ovulatory surges of LH, ovulation, pregnancy or incidence of early embryonic death. These data suggest that mares tolerate transportation (stress) well during the estrous cycle and while pregnant. Issue 1 • 2015

What can one conclude from these studies? Exercise and associated heat stress can negatively affect reproductive efficiency in mares. These findings do not preclude breeding the performance mare. Certainly, hundreds of mares undergo reproductive procedures, such as embryo transfer, with good success while in training. Rather, these studies provide information to allow for educated decision making. The average, physically-fit mare likely can become pregnant while training or performing. However, mare owners should be advised of the reduced reproductive efficiency in performing mares. Further, performance mares with a history of poor or irregular embryo production might benefit from breeding during “off” seasons such as early spring or late summer. One must consider the ramifications of seasonal changes in day length, and cyclicity, during these time periods.

Options for Offspring in the Performance Mare Pregnancy in the Performance Mare

Breeding the performance mare to carry a pregnancy is a viable option, but there are certainly pros and cons to this choice. Pregnancy rates for a young mare bred to a fertile stallion are often 80 to 90% depending on the type of semen used (fresh, cooled or frozen) and methods of breeding (natural mating or artificial insemination). The cost of breeding a mare is determined by the above factors in addition to time lost for training and performance. However, these costs will almost always be lower than those for mares enrolled in assisted reproductive programs (embryo transfer $4000-6000/foal; oocyte transfer $8000-10,000/foal). There are also physiological benefits to breeding a mare to carry a pregnancy. Younger mares have more viable oocytes than older mares.[8, 9] Furthermore, the mare that delivers a foal earlier in her life will likely have a more pliable cervix than a middle-aged to aged mare. This not only aids in the delivery process, but also facilitates uterine clearance during breeding. The obvious “cons” to breeding a performance mare are the time lost to training and showing, increased weight and loss of fitness, change in body structure after pregnancy and the (remote) possibility of an injury associated with pregnancy (ruptured prepubic tendon, colic, etc.) or foaling (dystocia, retained fetal membranes, metritis). Anecdotally, progesterone can affect the personality of any mare. For some more fractious or aggressive mares, long-term exposure to progesterone (pregnancy) can positively quiet unwanted behaviors. Some people even administer exogenous progestins (ie, Regumate™) to mares with undesirable behaviors in an effort to quiet the mare. Alternatively, some mares become significantly more aggressive once a foal is born, which may or may not be precipitated hormonally. These intrinsic maternal behaviors generally modify over time as the mare becomes accustomed to her new foal.

Assisted Reproductive Procedures

Assisted reproductive technologies offer alternative options to the horse owner wishing to use their mare for performances purposes while also producing valuable offspring. The most common reproductive procedure utilized in mares is embryo 

transfer. This technology is well accepted and can be performed on the farm or in a hospital setting. Less common procedures, such as oocyte transfer and intracytoplasmic sperm injection, require skilled personnel, equipment and special laboratory conditions. Oocyte retrieval and transfer is the rising technology in equine reproduction thus warranting discussion in this manuscript.

Embryo Transfer

Embryo transfer (ET) enables genetically desirable mares to produce more foals in a year. In the case of the performance animal, ET allows a mare to continue in training or work while also being reproductively functional. Breed registries may be restrictive on foals allowed per year, therefore it is important to know the regulations in a particular breed registration when using assisted technologies. It should also be noted that ET is not a cure for donor subfertility (or age), but a treatment. Embryo recovery rates are affected by the age and fertility of the donor mare, fertility of the stallion and type of semen used, the day of embryo recovery, number of ovulations and expertise of the veterinarians.[10] Recently reported data[10] clearly show that more embryos are recovered from mares <15 years of age than mares >15 years of age. These important factors should be discussed with an owner prior to embarking on an ET program. It is important to note that producing a foal using ET can be significantly more expensive than a traditional breeding program. An owner can expect to spend between $4000-6000 for a live foal following ET, depending on the program that they choose and whether they provide their own mares. Cooled-transported embryo programs have made embryo transfer available to horse owners that do not want to spend the time or money to synchronize multiple mares for breeding or transfer of embryos. Further, new holding media for cooled, transported embryos have been developed. These holding media are zwitterionic buffered solutions, with nutrients, growth factors, amino acids, and bovine serum albumin added to the solution. The composition of the media allows the embryo to survive for an extended time. These media, such as EquiPro™ Holding Media, EmCare™ Embryo Holding Solution or ViGro™ Holding Plus, may be used successfully for short-term storage and shipment of equine embryos.[11] Embryos are transported in a passive cooling system (Equitainer™, Hamilton-Thome Biosciences, Beverly, MA) using an overnight courier or counter-to-counter airline service. With increased airport security, most people opt for overnight shipment of embryo and morning delivery. If the embryo is recovered from the mare late in the day (afternoon), it can be transported and transferred into a synchronized recipient within 18 hours of recovery. This system works very well for horse owners and pregnancy results have been comparable to embryos that are recovered and transferred immediately, on the premises.

Oocyte Transfer and Gamete Intrafallopian Transfer (GIFT)

Oocyte transfer is a procedure where an oocyte is harvested from a preovulatory follicle of a donor mare, and placed in the oviduct of a recipient mare. Intrauterine artificial insemination (AI) may then be used in the recipient mare for fertilization of the transferred oocyte. Alternatively, sperm may be placed directly in the oviduct at the time of oocyte transfer. This procedure is called The Practitioner  23 

Gamete Intrafallopian Transfer (GIFT). GIFT may be selected over oocyte transfer in cases where the quantity of sperm available is limited, since much lower numbers of sperm are required for GIFT than for standard AI techniques (as low as 1x105 compared with 1x109). Oocyte transfer and GIFT techniques are useful in mares that are unable to carry a pregnancy or produce viable embryos for collection due to oviductal, uterine, or cervical pathologies. Common reasons for oocyte transfer include: • Ovulation failure • Oviductal blockages or adhesions • Severe degenerative changes of the uterus • Uterine infections • Urine pooling • Cervical lacerations Oocytes have also been successfully harvested from the ovaries of recently deceased mares and have produced live foals.[12] Recovery of oocytes is best achieved when ovaries are transported to a facility equipped to handle the sensitive oocytes. Ovaries are transported, at room temperature, in a traditional semen shipping device, such as an Equitainer ™. Time for ovarian harvest to procurement of the oocytes is critical to the viability of the oocytes. Generally, it is recommended that ovaries arrive within 7 hours of removal from the mare.[12] However, for practical purposes, the ovaries should be shipped as quickly as possible (using counter to counter airline delivery often works best) which may mean a longer time interval. Colorado State University (Dr. Elaine Carnevale) and Texas A&M University (Dr. Katrin Hinrichs) are the two facilities in the United States routinely performing oocyte transfer with good success. When collecting oocytes from the mare, the goal is generally to harvest the oocyte as close to ovulation as possible. This ensures that both nuclear and cytoplasmic maturation have occurred and that the oocyte is viable. In some domestic species, oocytes are harvested at an earlier time and matured in vitro; however, this technique has limited success in the horse. A variety of techniques exist for oocyte collection including follicular aspiration via transvaginal ultrasound guidance or surgical exposure of the ovary, either by flank approach, laparotomy or colpotomy. Today, flank puncture and trans-vaginal ultrasound guided puncture are the most commonly used techniques.[13] In standard oocyte transfer procedures, a recipient mare is inseminated as early as 12 hours prior to transfer; in some protocols they are inseminated up to 2 hours post-transfer (or both). Oocytes are then transferred to the recipient oviduct surgically. A standing f lank incision is used to locate the infundibular os, into which the oocytes are placed. If GIFT is selected as the method of choice, a small dose of semen (2-5 x 105) is pulled into the transfer pipette containing the oocyte and infused into the oviduct. The pregnancy rate for these procedures is highly variable with significant operator variation. Success of oocyte transfers is dependent on oocyte recovery rate and gamete viability, and can range from 7% to over 90% depending on these variables. In summary, alternative options for breeding in the performance mare can allow continued training while producing offspring. Providing owners with details regarding cost and expected outcomes can aid in making the best decision for their particular program. 24  The Practitioner 


1. Kelley, D.E., et al., Exercise lengthens the interovulatory interval in mares. Journal of Equine Veterinary Science, 2009. 29(5): p. 337-338. 2. Mortensen, C.J., et al., Embryo recovery from exercised mares. Animal Reproduction Science, 2009. 110(3-4): p. 237-244. 3. Smith, R.L., et al., Impact of moderate exercise on ovarian blood flow and early embryonic outcomes in mares. Journal of Animal Science, 2012. 90(11): p. 3770-3777. 4. Tilbrook, A.J., A.I. Turner, and I.J. Clarke, Effects of stress on reproduction in non-rodent mammals: the role of glucocorticoids and sex differences. Rev Reprod, 2000. 5(2): p. 105-13. 5. Wagenmaker, E.R., et al., The estrous cycle of the ewe is resistant to disruption by repeated, acute psychosocial stress. Biol Reprod, 2010. 82(6): p. 1206-15. 6. Baucus, K.L., et al., Effect of transportation on the estrous cycle and concentrations of hormones in mares. J.Anim Sci., 1990. 68(2): p. 419-426. 7. Baucus, K.L., et al., Effects of transportation on early embryonic death in mares. J.Anim Sci., 1990. 68(2): p. 345-351. 8. Carnevale, E.M., D.R. Bergfelt, and O.J. Ginther, Aging Effects on Follicular Activity and Concentrations of Fsh, Lh, and Progesterone in Mares. Animal Reproduction Science, 1993. 31(34): p. 287-299. 9. Carnevale, E.M., et al., Comparison of oocytes from young and old mares with light and electron microscopy. Theriogenology, 1999. 51(1): p. 299-299. 10. McCue, P.M., et al., Embryo recovery procedures and collection success: results of 492 embryo-flush attempts. Proceedings American Association of Equine Practitioners, 2010. 56: p. 318 - 321. 11. Moussa, M., et al., Comparison of pregnancy rates for equine embryos cooled for 24 h in Ham's F-10 and emcare holding solutions. Theriogenology, 2002. 58(2-4): p. 755-757. 12. Ribeiro, B.I., et al., Transport of equine ovaries for assisted reproduction. Animal Reproduction Science, 2008. 108(1-2): p. 171-179. 13. Hinrichs, K., Assisted reproduction techniques in the horse. Reproduction, Fertility and Development, 2012. 25(1): p. 80-93.

Margo L. Macpherson, DVM, MS, DACT Dr. Margo Macpherson is Professor and Chief, Reproduction Department of Large Animal Clinical Sciences, at the College of Veterinary Medicine, University of Florida. Dr. Macpherson received her DVM degree in 1990, from Michigan State University. She completed a residency and Master’s degree in Equine Theriogenology at Texas A&M University. She spent time at the University of Pennsylvania and in private practice in central Kentucky after leaving Texas. She is interested in all aspects of equine reproduction, but has a special interest in problems affecting late pregnancy in the mare. For more than a decade, Dr. Macpherson has been unraveling strategies for treating mares with bacterial placentitis. Dr. Macpherson is a past president of the American College of Theriogenologists, and she is currently on the Board of Directors of the American Association of Equine Practitioners.

Issue 1 • 2015

We’ve got you covered. Give your patients the added advantage of Flu Avert® I.N.: • Just ONE dose required • Proven safe and effective in numerous challenge studies • Rapid onset of immunity Give your patients exceptional protection against clinically relevant influenza strains infecting the U.S. horse population. Ask your Merck Animal Health or distributor representative about Flu Avert I.N.

556 Morris Avenue • Summit, NJ 07901 • • 800-521-5767 Horse Care for Life and We’re for the Horse are trademarks of Intervet Inc. Copyright © 2014 Intervet Inc., d/b/a Merck Animal Health, a subsidiary of Merck & Co., Inc. All rights reserved. Photography: Vince Cook. 2/14 51358

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NO GENERIC ® ADEQUAN Get the facts at BRIEF SUMMARY : Adequan® i.m.: For the intramuscular treatment of non-infectious degenerative and/or traumatic joint dysfunction and associated lameness of the carpal and hock joints in horses. There are no known contraindications to the use of intramuscular Adequan® i.m. brand Polysulfated Glycosaminoglycan in horses. Studies have not been conducted to establish safety in breeding horses. Each 5 mL contains 500 mg Polysulfated Glycosaminoglycan. WARNING: Do not use in horses intended for human consumption. Not for use in humans. Keep this and all medications out of the reach of children. Caution: Federal law restricts this drug to use by or on the order of a licensed veterinarian. Adequan® I.A.: For the intra-articular treatment of non-infectious degenerative and/or traumatic joint dysfunction and associated lameness of the carpal joint in horses. Inflammatory joint reactions and septic arthritis have been reported following administration of Adequan® I.A. Joint sepsis, a rare but potentially life threatening complication, can occur after intra-articular injection. Use only in the carpal joint of horses. Each 1 mL contains 250 mg Polysulfated Glycosaminoglycan. WARNING: Do not use in horses intended for human consumption. Keep this and all medications out of the reach of children. Caution: Federal law restricts this drug to use by or on the order of a licensed veterinarian. SEE PRODUCT PACKAGE INSERTS FOR FULL PRESCRIBING INFORMATION. Adequan® is a registered trademark of Luitpold Pharmaceuticals, Inc. ©LUITPOLD PHARMACEUTICALS, INC., Animal Health Division, Shirley, NY 11967. AHD 010, Rev. 2/2014

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Equine POTOMAVAC is a trusted vaccine for aiding in the prevention of PHF — even in foals as young as three months. Early and regular vaccination helps protect horses in your care against the effects of PHF, including fever, dehydration, colic, late-term abortions and laminitis. The benefits of POTOMAVAC also are available in Equine POTOMAVAC + IMRAB®, a combination vaccine that helps protect against rabies and Potomac horse fever. Best of all, both are backed by Merial, a trusted leader in equine health.

• If Potomac horse fever has been confirmed on a farm or in a particular geographic area, it is likely that additional cases will occur in future years.5

Based on Market Dynamics, Inc. AHS study data for period from Q12004 through Q42013. Ranking represents cumulative dollar sales volume over the period. Madigan J and Pusterla N. Life Cycle of Potomac Horse Fever – Implications for Diagnosis, Treatment, and Control: A Review. AAEP Proceedings. 2005;51:158-162. Hamende V. Potomac horse fever cases confirmed in northern Wyoming. University of Wyoming Cooperative Extension Service. Press Release, September 13, 2002. Available at Accessed May 15, 2014. 4 Williams, N. Potomac Horse Fever. Eq Dis Quart. 2012;21(1):4-5. 5 Potomac Horse Fever. Available at Accessed May 15, 2014. 1

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Mary Walker WPRA World Champion Barrel Racer, Platinum Performance® Client since 2010

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Practitioner Issue1 2015  

Published by the Florida Association of Equine Practitioners, an Equine-Exclusive Division of the Florida Veterinary Medical Assoication

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