The Modern Equine Vet - August 2018 by The Modern Equine Vet

The Modern

Equine Vet www.modernequinevet.com

Vol 8 Issue 8 2018

Sand Accumulations

All’s Well That Ends Well Technician Update: Stuck on a Fence High Prevalence of Inflammatory Disease Among Chronic Colics Mom’s Microbiome Key to Foal’s Gut Can Aromatherapy Help Stressed Horses? Insulin Weakens Integrity of Equine Lamellae

TABLE OF CONTENTS

COVER STORY

Well That Ends Well: 4 All’s Surgical and Medical Management of Sand Accumulations Cover photo: Shutterstock/Julie Marshall

COLIC

Histology Study Finds High Prevalence of Inflammatory Disease Among Chronic Colics...................................................................................................... 8 DERMATOLOGY

Experimental Vaccine Looks Promising for Insect-Bite Hypersensitivity..............................................................................................14 BEHAVIOR

Can Aromatherapy Help a Stressed-Out Horse?..............................................................19 TECHNICIAN UPDATE

Stuck on the Fence........................................................................................................................20 ADVERTISERS Shanks Veterinary Equipment..................................3 Purina Animal Nutrition.............................................5 Standlee Premium Western Forage......................... 7 Boehringer Ingelheim/Vetera.................................. 9 Boehringer Ingelheim/Equioxx..............................11

NEWS

I See What You Are Saying.........3 Mom’s Microbiome Key to Foal’s Gut........................16 Every Breath You Take: New Way to Monitor Airway Inflammation............................18 New Bolton Receives $300,000 Grant to Research Gene Doping, Improve Integrity of Horse Racing......................... 18 Insulin Weakens Integrity of Equine Lamellae................... 25

Boehringer Ingelheim/PPID....................................13 Merck Animal Health................................................15 Boehringer Ingelheim/Gastroguard.....................17 AAEVT............................................................................21

The Modern

Equine Vet SALES: Matthew Todd • ModernEquineVet@gmail.com Lillie Collett • ModernEquineVetSales@gmail.com EDITOR: Marie Rosenthal • mrosenthal@percybo.com ART DIRECTOR: Jennifer Barlow • jbarlow@percybo.com CONTRIBUTING WRITERS: Paul Basillo • Carol Jean Ellis Jason Mazda COPY EDITOR: Patty Wall Published by PO Box 935 • Morrisville, PA 19067 Marie Rosenthal and Jennifer Barlow, Publishers PERCYBO media  publishing

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NEWS NOTES

Horses integrate human facial expressions and voice tones to perceive human emotion, regardless of whether the person is familiar or not, according to a recent study. The herd-forming animal possesses high communication capabilities, and can read the emotions of their peers through facial expressions and contact calls, or whinnies. Horses have long been used as a working animal and also as a companion animal in sports and leisure, establishing close relationships with humans just like dogs do. Dogs are known to relate human facial expressions and voices to perceive human emotions, but little has been known as to whether horses can do the same. Associate Professor Ayaka Takimoto, PhD, of Hokkaido University, and colleagues used the expectancy violation method to investigate whether horses crossmodally perceive human emotion by integrating facial expression and voice tone. They also tested whether the familiarity between the horse and the person affected the horse’s perception. The expectancy violation method has been used to study infant cognitive development. Horses were shown a picture of a happy facial expression or an angry facial expression on a screen, and they then heard a prerecorded human voice—praising or scolding—from a speaker behind the screen. Horses received both the congruent condition, in which the emotional values of facial expression and voice tone were matched, and the incongruent condition, in which they were not. Results of the experiment showed that horses responded to voices 1.6 to 2 times faster in the incongruent condition than in the congruent condition regardless of familiarity of the person. In addition, the horses looked to the speaker 1.4 times longer in the incongruent condition than in the congruent condition when the person was familiar. These results suggest that horses integrate human facial expressions and voice tones to perceive human emotions, therefore, an expectancy violation occurred when horses heard a human voice whose emotional value was not congruent with the human facial expression. “Our study could contribute to the understanding of

Credit: Ayaka Takimoto

I See What You Are Saying

Several horses on a farm visited by Dr. Ayaka Takimoto.

how humans and companion animals send and receive emotional signals to deepen our relationships, which could help establish a better relationship that emphasizes the well-being of animals,” Dr. Takimoto said. MeV

Lifting Large Animals Since 1957

For more information: Nakamura K, Takimoto-Inose A, Hasegawa T. Cross-modal perception of human emotion in domestic horses (Equus caballus). Scientific Reports. 2018; 8 (1) DOI: 10.1038/s41598-018-26892-6. https://www.nature.com/articles/s41598-018-26892-6

www.shanksvet.com • info@shanksvet.com ModernEquineVet.com | Issue 8/2018

COLIC

ALL’S WELL THAT ENDS WELL Surgical and Medical Treatment for Sand Accumulations Likely to End Well

Shutterstock/Rrajji

A general rule states that the more of a bad thing you eat, the worse the outcome becomes. While that may hold true for pizza and cake in humans, it does not necessarily hold true for sand in horses. In regions that have naturally sandy soils, such as California, Texas and Florida, sand is inadvertently ingested while grazing, or intentionally ingested in horses with conditions such as pica. “The accumulation of sand may result in luminal obstruction, causing colic,” said Isabelle Kilcoyne, MVB, DACVS, of the William R. Pritchard Veterinary Medical Teaching Hospital at the University of California, Davis. “If they become completely obstructed you may see mucosal irritation or motility dysfunction.” Clinical signs vary. Some horses will have weight loss, while others will present with diarrhea or chronic or acute colic. Diagnosis

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Radiography is one of the only ways to objectively measure sand accumulation. involves auscultation of the ventral abdomen, typically behind the xiphoid process. In some cases, sand can be palpated on rectal examination or found on fecal sedimentation testing. Some reports have shown that ultrasonography is useful for diagnosis, but radiography is one of the only ways to objectively measure the accumulation of sand inside the horse. Medical treatment involves rehydrating the colon with IV fluids or enteral fluids mixed with laxa-

tives such as magnesium sulfate or psyllium. “Psyllium is somewhat controversial,” Dr. Kilcoyne said. “Some studies have shown that it fails to hasten the evacuation of sand in experimental models, but a study in 2014 showed that a combination of psyllium and magnesium sulfate was an effective treatment to eliminate sand from the GI tract.” Surgery is indicated in the presence of concurrent pathology, but the literature varies on the prognosis of these cases versus medical management. Some studies show a fair-to-good prognosis for surgical cases, while other reports show that the likelihood of survival of surgical patients is decreased when compared with those who receive medical management. Dr. Kilcoyne and her colleagues

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The size and number of accumulations were recorded, and the presence of an increased amount of gas was assessed subjectively and subject to the consensus of two observers: a board-certified radiologist and a board-certified surgeon.

Photo: Dr. Isabelle Kilcoyne

Findings

TOP: Taking a radiograph of a horse’s abdomen BOTTOM: Example of a Grade 3 horse with >1,000cm2 CSA of sand accumulation on radiographs.

recently conducted a study of 153 horses that presented for sand accumulation at the Pritchard Veterinary Medical Teaching Hospital from 2004 through 2014. They compared the short- and long-term complications of medical and surgical patients with sand accumulation in the large colon. They also determined whether objective radiographic measurements were associated with surgery. “Our hypothesis in the beginning was that larger accumulations of sand based on radiographic assessment would result in an increased likelihood of surgical intervention,” she said.

Results showed that the breed distribution in sand accumulation cases was significantly different than the hospital’s colic population during the study period. Quarter Horses and Draft Breeds were overrepresented in the sand-eating group, and Warmbloods were underrepresented. Positive auscultation of sand was apparent in only 21% of the horses, and fecal sedimentation was positive in only 22% when it was performed. “We had rectal examination records for 137 horses,” Dr. Kilcoyne said. “About 65% did not have significant findings on rectal examination; about 60% had evidence of gas distention, and about 20% had evidence of an impaction. We did find that horses with positive rectal findings were significantly more likely to require surgery.” Radiographic findings showed that the mean cross-sectional area (CSA) of sand accumulation was almost 700 cm2, with a range of 85 cm2 to 1,780 cm2. Horses with multiple accumulations were more likely to need surgery when compared with those with single accumulations. In addition, the radiographic presence of gas within the intestine was present in 64% of the horses, and surgery was more likely in that group. Surgical treatment was carried out in 38 horses, and 115 underwent medical management.

Counterintuitively, horses with a greater accumulation of sand were not more likely to undergo surgery after controlling for the weight and size of the horse. While the mean CSA was smaller in the medically managed group (648 cm2 vs 828 cm2), each group had a wide range. The medically managed horses had a range of 85 cm2 to 1,780 cm2, and the surgical group varied from 200 cm2 to 1,481 cm2. “The horse with the highest accumulation of sand was actually medically managed and did not require surgery,” Dr. Kilcoyne said.

Outcomes

Overall, both groups had favorable prognoses. About 95% of the horses in the study survived to discharge. Long-term follow-up ranging from a few months to 11 years showed that 85% of the horses were still alive and kicking. “One of the interesting results was that 50% of the medically treated horses were reported to have more than one episode of colic following discharge, compared with only 17% in those treated surgically,” she said. While the presence of a large accumulation of sand can be disconcerting, this study showed that even the biggest amounts can be managed medically if no other pathologies are present. “More attention should be paid to the presence of increased gas accumulation on both the rectal examination findings and on radiographic examination,” Dr. Kilcoyne said. “A good prognosis can be offered for both treatment types.” She spoke at the 63rd AAEP Annual Convention in San Antonio. MeV

For more information: Kilcoyne I, Dechant JE, Spier SJ, et al. Clinical findings and management of 153 horses with large colon sand accumulations. Vet Surg. 2017 Aug;46(6):860-867. doi: 10.1111/vsu.12679. Epub 2017 Jun 19. https://www.ncbi.nlm.nih.gov/pubmed/28626911 6

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COLIC

High Prevalence of Inflammatory Disease Ends Well A M O N G

C H R O N I C

Shutterstock/Bildagentur Zoonar GmbH

Although diagnostic and

associated lesions and underlying mechanisms.”

treatment methods have improved substantially over the past 20 years, recurrent (also called chronic) colic in horses continues to be a diagnostic challenge to clinicians and a source of frustration for horse owners. Diagnostic evaluation has traditionally included a range of procedures, such as rectal examination, fecal examination, ultrasonography, gastroscopy, serum chemistry, abdominal fluid evaluation, absorption studies, rectal biopsy and laparotomy. A recent study found a high prevalence of inflammatory disease (55%), as determined by histologic evidence collected during exploratory laparotomy, noted Julie B. Engiles, VMD, DACVP, associate professor, department of pathology at University of Pennsylvania’s New Bolton Center and one of the study authors. “This study is an important investigative starting point. Definitively diagnosing and treating chronic colic remains challenging, but by implementing a multidisciplined approach, we’ll be better able to characterize the

Issue 8/2018 | ModernEquineVet.com

C O L I C S

A bit of Background

Most published studies on recurrent colic have emphasized management practices (eg, diet, time at pasture, stereotypic behaviors). Few reports have focused on abnormal histology associated with the intestinal tract. Histologic findings have traditionally described single cases or small case series of chronic colic, Dr. Engiles said, which may not mirror the true larger population of horses. If horses with chronic colic go to surgery, surgeons often opt not to obtain a biopsy specimen during exploratory laparotomy because of potential risk for postoperative complications, such as surgical site contamination. “At the New Bolton Center’s George D. Widener Hospital for Large Animals,” Dr. Engiles continued, “surgeons have developed a rapid, simple, relatively clean method of obtaining small full-thickness biopsy specimens during exploratory

laparotomy in horses with a history of recurrent colic. The technique utilizes a punch biopsy typically used for skin samples.” Because prior reports and anecdotal clinical data suggested that inflammatory GI disease plays a role in horses with recurrent colic, the Penn researchers designed a retrospective study to further investigate this association by: • Developing a safe technique to collect intraoperative full-thickness intestinal biopsy specimens from sites of suspected intestinal disease based on preoperative ultrasonographic findings or intraoperative findings, in order of finding a histologic diagnosis; • Comparing the rate of finding a histologic diagnosis from intraoperative full-thickness intestinal biopsy specimens with other less-invasive techniques of obtaining intestinal biopsy specimens, including endoscopic duodenal or rectal mucosal biopsy specimens; and • Determining the percentage of horses with recurrent colic

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Choose VETERA for around-the-clock protection from infectious diseases. Your clients might not be thinking about vaccines, but as a veterinarian, you have to – because oftentimes the most important kind of protection is one you can’t see. When it’s the health of the horses you treat on the line, be sure the portfolio you choose offers comprehensive, convenient, flexible and proven protection. There’s a lot riding on your vaccines. Choose tried and trusted VETERA. Vetera® is a registered trademark of Boehringer Ingelheim Vetmedica GmBH. Ultrafil® and Carbimmune® are registered trademarks of Boehringer Ingelheim Vetmedica, Inc. ©2018 Boehringer Ingelheim Vetmedica, Inc. EQU-0826-VET0718-B

COLIC

Courtesy Julies B. Engiles, VMD, DACVP, University of Pennsylvania

High magnification image of framed area in A showing numerous eosinophils (arrows) migrating through the villus epithelium. This horse’s disease resolved with medial management, including corticosteroid therapy, and survived for over 5 years until succumbing to laminitis. Scale bar = 50 µm

having histologic evidence of inflammatory disease versus histologic lesions (eg, ischemia, neoplasia). The researchers reviewed records from the database at the Pennsylvania Animal Diagnostic Laboratory Service, including horses examined at the George D. Widener Hospital for Large Animals and tissue specimens from horses submitted for necropsy from other practices. All intestinal histologic specimens obtained from adults older than 1 year of age from December 2006 to December 2015 were examined to determine which horses had a confirmed history of chronic colic. Of note, the literature often characterizes recurrent colic as 3 or more episodes of prolonged colic over a period of months to even a year or more. However, the researchers in this case defined recurrent colic as ≥2 episodes of colic within a 6-month period, with at least 48 hours separating colic episodes. “Horses with a history of recurrent colic as defined were eligible for the study. Horses that did not have this history and horses without a detailed history were excluded,” Dr. Engiles explained. Also recorded in the history were weight loss, inappetence, anorexia 10

Issue 8/2018 | ModernEquineVet.com

or diarrhea at admission, along with results from other diagnostic tests, including peritoneal fluid analysis, nucleated cell count, cytologic analysis, abdominal ultrasonography and gastroduodenoscopy. Study horses were further divided by categories of histologic diagnoses obtained from GI specimens for biopsy or necropsy. Diagnoses included inflammatory, neoplastic, ischemic, other lesions (eg, muscular hypertrophy) and histologically normal (ie, no lesions identified within the sections submitted). They also noted the results of other testing and recorded GI location and type of tissue specimens submitted for histology. Notations included whether the sample was partial- or full-thickness (ie, mucosa only versus mucosa with muscular wall) and the method by which samples were obtained (eg, gastroduodenoscopy, rectal biopsy, laparoscopy, laparotomy, during necropsy). They evaluated the effect of corticosteroid therapy in the horses studied, Dr. Engiles noted, as some of the horses that had undergone the new biopsy procedure in the hospital had received follow-up treatment with dexamethasone, prednisolone—or both—and had responded favorably.

Sixty-six horses with a history of recurrent colic met the study’s inclusion criteria. The median age was 10 years (IQR, 6–15 years) and most were Thoroughbred or Thoroughbred crosses (29/66; 44%), while 14 horses (21%) were American breeds. They analyzed data, Dr. Engiles said, to test associations between histologic diagnosis (ie, inflammatory, neoplastic, ischemic, other lesions, histologically normal) and clinical presentation (eg, weight loss, inappetence, anorexia, diarrhea), as well as results from diagnostic tests (ie, ultrasonography, gastroscopy, biopsy method). “We also determined associations between histologic diagnosis and clinical outcome variables (ie, number of days alive at time of follow-up, number of recurrent colic episodes after discharge, whether the patient was alive 1 year after discharge) and investigated the relationship between corticosteroid treatment and outcome,” she said.

The results

• Of the 66 study horses, 53 had been admitted to New Bolton Center, while 13 horses treated at other area hospitals had tissue specimens submitted to the Pennsylvania Animal Diagnostic Laboratory Service. • Of the 66 horses, 56 had biopsy, 9 underwent necropsy and 1 had both necropsy and biopsy. Four of the horses that had necropsy were given a tentative diagnosis of inflammatory GI disease based on history, clinical signs and diagnostic testing.

Histologic diagnosis: • Inflammatory disease was the most common histologic diagnosis (36/66; 55%), followed by neoplastic (9/66; 14%), other (8/66; 12%) and ischemic (2/66; 3%). A diagnosis was not made in 11 (17%) of the 66 horses. The predominant inflamma-

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NSAID XX – the first and only coxib • First and Only – EQUIO 1 , including while inhibiting COX-2 * ective than phenylbutazone eff 2 re mo or ive ect eff as ed provement scores UIOXX was rat im l EQ ral dy, ove stu a and In e – enc cy fer ca um Effi • , joint circ nipulation, range of motion ;3,4 improvement in pain on ma studies than any other NSAID ety saf in ses hor re mo on n tested • Safety – EQUIOXX has bee ects most horses had no side eff e, dos ed at the recommend o aid in compliance up to 24 hours which can als n pai ls tro con e dos e On – • Convenient been determined. *Clinical relevance has not

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Available in three formulations to fit in and out of competition needs: Injection, Paste and Tablet. IMPORTANT SAFETY INFORMATION: As with any prescription medication, prior to use, a veterinarian should perform a physical examination and review the horse’s medical history. A veterinarian should advise horse owners to observe for signs of potential drug toxicity. As a class, nonsteroidal anti-inflammatory drugs may be associated with gastrointestinal, hepatic and renal toxicity. Use with other NSAIDs, corticosteroids or nephrotoxic medication should be avoided. EQUIOXX has not been tested in horses less than 1 year of age or in breeding horses, or pregnant or lactating mares. For additional information, please refer to the prescribing information or visit www.equioxx.com. Merial is now part of Boehringer Ingelheim. ®EQUIOXX is a registered trademark of Merial. ©2018 Merial, Inc., Duluth, GA. All rights reserved. EQU-0460-JH0218

Data on file at Merial, Safety Study, PR&D 0144901. Doucet MY, Bertone AL, et al. Comparison of efficacy and safety of paste formulations of firocoxib and phenylbutazone in horses with naturally occurring osteoarthritis. J Am Vet Med Assoc. 2008;232(1):91-97. 3 EQUIOXX product labels and FOI summaries and supplements. 4 Data on file at Merial, Clinical Experience Report PHN 471, PR&D 0030701. 1 2

COLIC

tory infiltrate in 20 of 36 horses (56%) was lymphoplasmacytic, followed by eosinophilic (17%); neutrophilic (14%) and mixed-cell infiltrates (14%). • Neoplastic disease was the second most common histologic diagnosis (14%), with lymphoma being the most common neoplasm (44%). • Nonneoplastic abnormalities involving the wall of the intestine were diagnosed in 6 of the 66 horses (9%), and 6 of 8 horses (75%) histologically were categorized as other. • Ischemia was the least common diagnosis (3%). • No diagnosis could be made from GI biopsies in 11 of 66 horses (17%). Statistically, tissue specimens obtained by rectal biopsy alone were less likely to have a histologic diagnosis, as compared with specimens from laparotomy/laparoscopy, necropsy or gastroduodenal biopsy.

CAUTION: Federal law restricts this drug to use by or on the order of a licensed veterinarian. EQUIOXX® (firocoxib) is indicated for the control of pain and inflammation associated with osteoarthritis in horses. Firocoxib belongs to the coxib class of non-narcotic, nonsteroidal anti-inflammatory drugs (NSAID). CONTRAINDICATIONS: Horses with hypersensitivity to firocoxib should not receive EQUIOXX. WARNINGS: EQUIOXX is for use in horses only. Do not use in horses intended for human consumption. Do not use in humans. Store EQUIOXX Tablets out of the reach of dogs, children, and other pets in a secured location in order to prevent accidental ingestion or overdose. Consult a physician in case of accidental human exposure. Horses should undergo a thorough history and physical examination before initiation of NSAID therapy. Appropriate laboratory tests should be conducted to establish hematological and serum biochemical baseline data before and periodically during administration of any NSAID. NSAIDs may inhibit the prostaglandins that maintain normal homeostatic function. Such anti-prostaglandin effects may result in clinically significant disease in patients with underlying or pre-existing disease that has not been previously diagnosed. Treatment with EQUIOXX should be terminated if signs such as inappetance, colic, abnormal feces, or lethargy are observed. As a class, cyclooxygenase inhibitory NSAIDs may be associated with gastrointestinal, renal, and hepatic toxicity. Sensitivity to drug-associated adverse events varies with the individual patient. Horses that have experienced adverse reactions from one NSAID may experience adverse reactions from another NSAID. Patients at greatest risk for adverse events are those that are dehydrated, on diuretic therapy, or those with existing renal, cardiovascular, and/ or hepatic dysfunction. The majority of patients with drug-related adverse reactions recover when the signs are recognized, drug administration is stopped, and veterinary care is initiated. Concurrent administration of potentially nephrotoxic drugs should be carefully approached or avoided. Since many NSAIDs possess the potential to produce gastrointestinal ulcerations and/or gastrointestinal perforation, concomitant use of EQUIOXX with other anti-inflammatory drugs, such as NSAIDs or corticosteroids, should be avoided. The concomitant use of protein bound drugs with EQUIOXX has not been studied in horses. The influence of concomitant drugs that may inhibit the metabolism of EQUIOXX has not been evaluated. Drug compatibility should be monitored in patients requiring adjunctive therapy. The safe use of EQUIOXX in horses less than one year of age, horses used for breeding, or in pregnant or lactating mares has not been evaluated. Consider appropriate washout times when switching from one NSAID to another NSAID or corticosteroid. The Safety Data Sheet (SDS) contains more detailed occupational safety information. For technical assistance, to request an SDS, or to report suspected adverse events call 1-877-217-3543. For additional information about adverse event reporting for animal drugs, contact FDA at 1-888-FDA-VETS, or http://www.fda.gov/AnimalVeterinary. Rev 10/2016

Association of histologic diagnosis with clinical diagnostics: • In 47 of 66 horses with ultrasonographic evaluations, the proportion of horses with ultrasonographic evidence of thickened bowel was significantly lower in those with neoplastic disease than in horses with inflammatory disease (P=0.029), other histologic diagnoses (P=0.015), or no diagnosis (P=0.041). • In 32 of 66 horses with gastroduodenoscopies, gastric ulceration was found in 13 (41%). Gastric ulceration was observed in 9 of 20 horses (45%) with a histologic diagnosis of inflammatory disease. • There was significant (P <0.001) association between histologic diagnosis and lesion location, with lesions including

neoplastic, ischemic or other lesions not detected within less invasive biopsies obtained from the stomach, duodenum or rectum. Survival rate (outcome): • Of the 53 hourses admitted to Widner, 45 (85%) were alive at discharge including 29 with inflammatory disease; 3 with neoplastic disease; 2 with ischemic disease; 2 with other hsitologic lesions; and all 9 horses with no diagnosis. “The study found that 55% of horses with recurrent colic had evidence of inflammatory disease based on histologic evaluation of GI biopsy specimens,” Dr. Engiles said, adding that “although minimally invasive diagnostics may be preferred by owners and some clinicians, they may not provide a diagnosis in horses with recurrent colic, particularly if the biopsy site is not representative of disease that may involve other segments of the GI tract. However, transabdominal ultrasound may be worthwhile, particularly when paired with targeted fullthickness biopsies obtained during exploratory laparotomy.” Although this study serves as a starting point in the investigation of recurrent colic and lesions associated with the disease, a lot more work needs to be done to address clinical as well as diagnostic challenges as highlighted in this study, according to Dr. Engiles. “We were unable to address whether inflammatory lesions represented a primary or secondary process. We also were unable to address the potential association between diet or dietary supplements and histologic lesions,” she explained. MeV

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For more information: Stewart HL, Julie B. Engiles JB, Stefanovski D, Southwood L. Retrospective study: Clinical and intestinal histologic features of horses treated for recurrent colic: 66 cases (2006-2015). J Am Vet Med Assoc. 2018;252(10):1279-1288. https://avmajournals.avma.org/doi/abs/10.2460/javma.252.10.1279?journalCode=javma 12

Issue 8/2018 | ModernEquineVet.com

Like the constellations, the early clinical signs of PPID can be clear if you know what to look for.

Despite its importance in equine practice, pituitary pars intermedia dysfunction (PPID) can be easily overlooked. When you see these early clinical signs, no matter how subtle, it’s time to test. • Abnormal sweating (increased or decreased) • Change in attitude/lethargy

• Decreased athletic performance • Regional hypertrichosis

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DERMATOLOGY

Experimental Vaccine

Looks Promising for InsectBite Hypersensitivity An experimental vaccine that uses interleuken 2 on optimized virus-like particles appears effective for treating insect-bite hypersensitivity (IBH) in horses. The researchers are also working on a similar allergy vaccine for dogs with atopic dermatitis. 14

Issue 8/2018 | ModernEquineVet.com

Vaccine against IBH in Horses

Allergic skin reactions caused by insect bites are the most common type of allergies in horses. One important form of such a skin allergy, insect-bite hypersensitivity (IBH)â&#x20AC;&#x201D; also called sweet itch or summer eczemaâ&#x20AC;&#x201D;manifests in weeping and bleeding lesions, including crust formation, scales, swelling and lichenification of the skin. Thirty-four IBH-affected Icelandic horses participated in a placebo-controlled, double-blinded, clinical study. Nineteen horses received vaccine and 15 horses received placebo. The vaccine consisted of two

Credit: Antonia Fettelschoss-Gabriel / USZ

Typical summer eczema in the head of a horse.

Scientists from the Universities of Bern, Zurich and Oxford as well as the Latvian Biomedical Research & Study Centre led by Prof. Martin F. Bachmann have developed a new therapeutic vaccine technology based on enhanced, virus-like nanoparticle conjugates. The new enhanced vaccine platform has been engineered to incorporate a universal T-cell epitope for adaptive immune activation, a stimulator of innate immunity and repetitive antigen presentation in a nanoparticle. This optimizes the vaccine to produce a strong immunity and a high responder rate. The team of scientists developed breakthrough therapies for insect-bite hypersensitivity in horses and atopic dermatitis in dogs by displaying either equine IL-5 or canine IL-31 on the immunologically optimized, virus-like particles (NPJ Vaccines. 2017 Oct 23;2:30.). The researchers were able to generate vaccines that induced clinically effective levels of neutralizing target-specific anticytokine antibodies, which resulted in dramatically improved disease symptoms in immunized animals. This has previously only been achieved by passive immunization with high amounts of monoclonal antibodies. These vaccines are now being developed as firstin-class, breakthrough medicines for treating chronic allergic diseases in the respective target species.

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2 Giralda Farms • Madison, NJ 07940 • merck-animal-health-usa.com • 800-521-5767 Copyright © 2018 Intervet Inc., d/b/a/ Merck Animal Health, a subsidiary of Merck & Co., Inc. All rights reserved. 3531-FBZ-MODE-OF-ACTION-CAMPAIGN-PP

DERMATOLOGY

components coupled together. The first component is a general immune activation, partly based on the above-mentioned, enhanced, virus-like nanoparticle, the second component is IL-5, a cytokine and the master-regulator of eosinophil development and activation—a major effector cell type in allergy. Immunization with this conjugate vaccine was well tolerated and resulted in IL-5 specific autoantibodies, which neutralized its target. This limited the number of eosinophils localized to the skin and reduced tissue damage, resulting in strongly reduced skin lesion scores in vaccinated animals compared with the previous season, as well as placebo. In classical desensitization, one

tries to make the immune system tolerant to the allergens. The researchers here targeted the key effector cell in insect bite hypersensitivity, the eosinophil. This cell type also plays a key role in allergic human asthma and moncolonal antibodies against IL-5 have recently become an important new weapon for the treatment of the human disease. The new insights gained in horses may help to develop a similar new treatment in humans.

Vaccine against Atopic Dermatitis in Dogs

Atopic dermatitis (AD) is the most common allergic skin disease in dogs. Extensive itching causes scratching which results in loss of fur and secondary infections of the

skin, accelerating the symptoms. AD not only affects the well being of dogs but also impacts the quality of life of their owners. IL-31 is a key cytokine—driving itching, and a monoclonal antibody against IL-31 has been licensed for use in dogs for the treatment of AD. The teams of Prof. Bachmann and Prof. Claude Favrot describe the development of a virus-like particlebased vaccine against canine IL-31, and demonstrate that immunized dogs mount a robust IgG response, which essentially abrogates symptoms of itching in house-dust-mitesensitized and challenged dogs. These vaccines are being developed by joint efforts of academic labs and commercial pharmaceutical companies MeV

For more information: Fettelschoss-Gabriel et al. Treating insect-bite hypersensitivity in horses with active vaccination against IL-5. J Allergy Clin Immunol. 2018 April 4 DOI: 10.1016/j.jaci.2018.01.041 Bachmann et al. Vaccination against IL-31 for the treatment of atopic dermatitis in dogs. J Allergy Clin Immunol. 2018 April 4 DOI: 10.1016/j. jaci.2017.12.994

Mom’s Microbiome Key to Foal’s Gut The mare’s microbiome may be a key factor in the establishment of her foal’s gut microbial ecosystem, according to a recent study out of Italy. The researchers from the Department of Veterinary Medical Sciences, University of Bologna, aimed to explore the perinatal colonization process of the foal gut microbiota. Thirteen mares that foaled at term (333–355 days gestation) and their healthy foals were included in the longitudinal study. At delivery, samples were collected from the mare’s amniotic fluid, feces and colostrum, and the foal’s meconium. Milk and feces samples from both mare and foal were also taken longitudinally, until day 10 postpartum. All samples were analyzed using bacterial DNA

extraction and 16S rDNA sequencing. Operational taxonomic units (OTUs) were compared among samples to determine the bacterial isolates present in each sample. The foals’ meconium shared 32 bacterial OTUs with the amniotic fluid and 75 with the mares’ feces, but no OTUs were shared between the mares’ feces and amniotic fluid. The foal gut microbiota gradually changed from the meconium sample about three days after birth, acquiring microorganisms found in milk. Later, the foal gut microbiota began to resemble that of the mare more closely. The mares’ hindgut bacteria were relatively consistent with a very low rate of inter-individual diversity throughout the sampling period. MeV

For more information: Quercia S, Freccero F, Castagnetti C, et al. Early colonisation and temporal dynamics of the gut microbial ecosystem in Standardbred foals. Equine Vet J. 2018 June 28 (Epub ahead of print). https://onlinelibrary.wiley.com/doi/full/10.1111/evj.12983 16

Issue 8/2018 | ModernEquineVet.com

WI N N I NG d o es n’ t h a p p e n

B Y

A C C I D E N T.

A nose. That’s all you need to see your number on top. To pay off on all those early morning workouts. The late nights planning strategy. You don’t do this to place or show. So ask yourself, does your horse have the stomach to win?

Time for a gut check. TheStomachToWin.com

by Merial

IMPORTANT SAFETY INFORMATION: CAUTION: Safety of GASTROGARD in pregnant or lactating mares has not been determined.

NEWS NOTES Caution Federal (USA) law restricts this drug to use by or on the order of a licensed veterinarian. Storage Conditions Store at 68°F – 77°F (20-25°C). Excursions between 59°F – 86°F (15-30°C) are permitted. Indications For treatment and prevention of recurrence of gastric ulcers in horses and foals 4 weeks of age and older. Dosage Regimen For treatment of gastric ulcers, GastroGard Paste should be administered orally once-a-day for 4 weeks at the recommended dosage of 1.8 mg omeprazole/lb body weight (4 mg/kg). For the prevention of recurrence of gastric ulcers, continue treatment for at least an additional 4 weeks by administering GastroGard Paste at the recommended daily maintenance dose of 0.9 mg/lb (2 mg/kg). Directions For Use • GastroGard Paste for horses is recommended for use in horses and foals 4 weeks of age and older. The contents of one syringe will dose a 1250 lb (568 kg) horse at the rate of 1.8 mg omeprazole/lb body weight (4 mg/kg). For treatment of gastric ulcers, each weight marking on the syringe plunger will deliver sufficient omeprazole to treat 250 lb (114 kg) body weight. For prevention of recurrence of gastric ulcers, each weight marking will deliver sufficient omeprazole to dose 500 lb (227 kg) body weight. • To deliver GastroGard Paste at the treatment dose rate of 1.8 mg omeprazole/ lb body weight (4 mg/kg), set the syringe plunger to the appropriate weight marking according to the horse’s weight in pounds. • To deliver GastroGard Paste at the dose rate of 0.9 mg/lb (2 mg/kg) to prevent recurrence of ulcers, set the syringe plunger to the weight marking corresponding to half of the horse’s weight in pounds. • To set the syringe plunger, unlock the knurled ring by rotating it 1/4 turn. Slide the knurled ring along the plunger shaft so that the side nearest the barrel is at the appropriate notch. Rotate the plunger ring 1/4 turn to lock it in place and ensure it is locked. Make sure the horse’s mouth contains no feed. Remove the cover from the tip of the syringe, and insert the syringe into the horse’s mouth at the interdental space. Depress the plunger until stopped by the knurled ring. The dose should be deposited on the back of the tongue or deep into the cheek pouch. Care should be taken to ensure that the horse consumes the complete dose. Treated animals should be observed briefly after administration to ensure that part of the dose is not lost or rejected. If any of the dose is lost, redosing is recommended. • If, after dosing, the syringe is not completely empty, it may be reused on following days until emptied. Replace the cap after each use. Warning Do not use in horses intended for human consumption. Keep this and all drugs out of the reach of children. In case of ingestion, contact a physician. Physicians may contact a poison control center for advice concerning accidental ingestion. Adverse Reactions In efficacy trials, when the drug was administered at 1.8 mg omeprazole/lb (4 mg/kg) body weight daily for 28 days and 0.9 mg omeprazole/lb (2 mg/kg) body weight daily for 30 additional days, no adverse reactions were observed. Precautions The safety of GastroGard Paste has not been determined in pregnant or lactating mares. Efficacy • Dose Confirmation: GastroGard ® (omeprazole) Paste, administered to provide omeprazole at 1.8 mg/lb (4 mg/kg) daily for 28 days, effectively healed or reduced the severity of gastric ulcers in 92% of omeprazole-treated horses. In comparison, 32% of controls exhibited healed or less severe ulcers. Horses enrolled in this study were healthy animals confirmed to have gastric ulcers by gastroscopy. Subsequent daily administration of GastroGard Paste to provide omeprazole at 0.9 mg/lb (2 mg/kg) for 30 days prevented recurrence of gastric ulcers in 84% of treated horses, whereas ulcers recurred or became more severe in horses removed from omeprazole treatment. • Clinical Field Trials: GastroGard Paste administered at 1.8 mg/lb (4 mg/kg) daily for 28 days healed or reduced the severity of gastric ulcers in 99% of omeprazole-treated horses. In comparison, 32.4% of control horses had healed ulcers or ulcers which were reduced in severity. These trials included horses of various breeds and under different management conditions, and included horses in race or show training, pleasure horses, and foals as young as one month. Horses enrolled in the efficacy trials were healthy animals confirmed to have gastric ulcers by gastroscopy. In these field trials, horses readily accepted GastroGard Paste. There were no drug related adverse reactions. In the clinical trials, GastroGard Paste was used concomitantly with other therapies, which included: anthelmintics, antibiotics, non-steroidal and steroidal anti-inflammatory agents, diuretics, tranquilizers and vaccines. • Diagnostic and Management Considerations: The following clinical signs may be associated with gastric ulceration in adult horses:inappetence or decreased appetite, recurrent colic, intermittent loose stools or chronic diarrhea, poor hair coat, poor body condition, or poor performance. Clinical signs in foals may include: bruxism (grinding of teeth), excessive salivation, colic, cranial abdominal tenderness, anorexia, diarrhea, sternal recumbency or weakness. A more accurate diagnosis of gastric ulceration in horses and foals may be made if ulcers are visualized directly by endoscopic examination of the gastric mucosa Gastric ulcers may recur in horses if therapy to prevent recurrence is not administered after the initial treatment is completed. Use GastroGard Paste at 0.9 mg omeprazole/lb body weight (2 mg/kg) for control of gastric ulcers following treatment. The safety of administration of GastroGard Paste for longer than 91 days has not been determined. Maximal acid suppression occurs after three to five days of treatment with omeprazole. Safety • GastroGard Paste was well tolerated in the following controlled efficacy and safety studies. • In field trials involving 139 horses, including foals as young as one month of age, no adverse reactions attributable to omeprazole treatment were noted. • In a placebo controlled adult horse safety study, horses received 20 mg/kg/ day omeprazole (5x the recommended dose) for 90 days. No treatment related adverse effects were observed. • In a placebo controlled tolerance study, adult horses were treated with GastroGard Paste at a dosage of 40 mg/kg/day (10x the recommended dose) for 21 days. No treatment related adverse effects were observed. • A placebo controlled foal safety study evaluated the safety of omeprazole at doses of 4, 12 or 20 mg/kg (1, 3 or 5x) once daily for 91 days. Foals ranged in age from 66 to 110 days at study initiation. Gamma glutamyltransferase (GGT) levels were significantly elevated in horses treated at exaggerated doses of 20 mg/kg (5x the recommended dose). Mean stomach to body weight ratio was higher for foals in the 3x and 5x groups than for controls; however, no abnormalities of the stomach were evident on histological examination. Reproductive Safety In a male reproductive safety study, 10 stallions received GastroGard Paste at 12 mg/kg/day (3x the recommended dose) for 70 days. No treatment related adverse effects on semen quality or breeding behavior were observed. A safety study in breeding mares has not been conducted. For More Information Please call 1-888-637-4251 Marketed by: Merial, Inc., Duluth, GA 30096-4640, U.S.A. Made in Brazil ®GastroGard is a registered trademark of Merial, Inc. ©2016 Merial, Inc. All rights reserved. Rev. 05-2011

Every Breath You Take: New Way to Monitor Airway Inflammation Exhaled breath condensate pH and hydrogen peroxide (H2O2) concentrations are altered by inflammation and may offer a noninvasive way to diagnose and monitor lower airway inflammation in the future. Surita du Preez, BVSc, MANZCVS, of Charles Sturt University in Bathurst, Australia, and colleagues performed a prospective, cross-sectional study to characterize the associations between biomarkers in exhaled breath condensate (EBC) and the cytological and endoscopic findings in horses with lower airway inflammation. Forty-seven horses were included in the study, 27 of which presented with respiratory disease and/or poor performance and 20 of which were asymptomatic. All of the horses underwent lower air-

way endoscopy and EBC analysis. The researchers measured H2O2 concentration, pH and the proinflammatory eicosanoid leukotriene B4 (LTB4). During endoscopic examination, tracheal mucus was graded and a tracheal aspirate (TA) and bronchoalveolar lavage (BAL) performed. Multivariable linear regression was used to identify associations between biomarkers and lower airway disease. EBC pH and H2O2 concentrations were higher in horses with lower airway inflammation and were positively correlated positively with the percentage of neutrophils in the BAL fluid. Mast cell and eosinophil percentages in BAL fluid were negatively associated with EBC pH and positively associated with EBC LTB4, respectively. MeV

For more information: Du Preez S, Raidal SL, Doran GS, Et al. Exhaled breath condensate hydrogen peroxide, pH and leukotriene B4 are associated with lower airway inflammation and airway cytology in the horse. Equine Vet J. 2018 June 19 (Epub ahead of print). https://onlinelibrary.wiley.com/doi/10.1111/evj.12979

New Bolton Receives $300,000 Grant to Research Gene Doping, Improve Integrity of Horse Racing The Pennsylvania Horse Breeders Association donated $300,000 to Penn Vet New Bolton Center’s Equine Pharmacology Laboratory to fund research to detect gene doping in equine athletes. Gene doping involves the transfer or modification of genes or genetically modified cells of healthy equine athletes, for nontherapeutic purpose to enhance athletic performance. The $300,000 donation from the PHBA will provide funding for Penn Vet’s multitiered, multiyear project. Elements of the project include continued research into potential protein and RNA-based biomarkers that have been identified as showing promise for detecting gene doping. The project will also include continued expansion of a BioBank that will be used to evaluate baseline levels of these biomarkers in active and 18

Issue 8/2018 | ModernEquineVet.com

injured race horses, as well as physiological changes in their musculoskeletal structure using New Bolton Center’s robotics-controlled imaging system. Because the money is being allocated from the association’s share of the State Racing Fund, which is typically used for enhanced breeder awards and incentives, the PHBA had to seek approval of Pennsylvania’s State Horse Racing Commission. The commission approved the PHBA’s request to provide the funding by unanimous vote. New Bolton is seeking additional funding for this research program. Individuals or organizations who would like to support the program through a financial donation are encouraged to contact Margaret Leardi, Director of Development for New Bolton Center, at mleardi@vet.upenn.edu. MeV

BEHAVIOR

From veterinary visits to hoof trims, there are many ways to stress out a horse. Unfortunately, calming options are not. Researchers observed significant signs of stress reduction in horses that inhaled lavender from a diffuser. “Horses can be under a lot of stress, so I was interested in seeing if aromatherapy could help in reducing stress,” said Isabelle Chea, a then-undergraduate honors student at the University of Arizona, in Tucson, and Ann Baldwin, UA professor of physiology and psychology. Ms. Chea had never been around horses until taking a course by Ann Baldwin, PhD, a UA professor in physiology and psychology. During the class, Dr. Baldwin uses horses to teach students about heart rate and heart rate variability. Both are indicators of the level of stress a person or animal is experiencing, though heart rate variability is a much more sensitive measurement. Heart rate was the focus of a limited amount of prior research on the use of aromatherapy to calm horses in the presence of a stressor, such as trailering. In one study, horses were startled by an air horn and then provided with humidified lavender air. The horses’ heart rates increased in response to the air horn but returned to normal more quickly in those that inhaled lavender. None of the studies looked at a horse’s response to aromatherapy in the absence of an imposed stressor, though, and none measured heart rate variability. “We wanted to test regular horses that aren’t stressed out by external forces,” said Dr. Baldwin, who

There were significant signs of stress reduction when horses smelled lavender. rides dressage on her 18-year-old quarter horse, Major. “Some horses and some breeds, it’s just in their nature that they are more stressed. So, we wanted to use horses that were not being scared deliberately to see what effect, if any, the aromatherapy had on them.” Dr. Baldwin enlisted the help of other owners at her boarding stable to put together a group of nine dressage horses of varying breeds and ages. Each horse was led to a small paddock and held by a volunteer while a diffuser containing lavender essential oil was held near the horse’s nose. A monitor tracked heart rates and heart rate variability for 21 minutes total—seven minutes before the introduction of the diffuser, seven minutes with the diffuser in close proximity and seven minutes after it was removed. “The heart rate didn’t change; what changed is what’s called the parasympathetic component of heart rate variability,” Dr. Baldwin explained. “One of the parameters of heart rate variability is RMSSD, and that represents parasympathetic input, which is the relaxation part of the autonomic nervous system. If

RMSSD goes up, that indicates the horse is relaxed. We found that when the horses were sniffing the lavender, RMSSD significantly increased compared to baseline.” The data were supported by the horses’ observed behavior, which often included relaxation signals such as neck lowering and licking and chewing while the lavender was being inhaled. The experiment was repeated with water vapor and chamomile, neither of which produced a similar calming effect or increase in RMSSD. “We did get a calming effect with the lavender, but when we measured afterward, we no longer had the effect,” Dr. Baldwin said. “So, it’s just during the sniffing of the lavender that we see this calming effect.” Traditional tranquilizers often have long-lasting effects, while lavender can be used precisely and exactly when needed and could be a way to relax an anxious horse for a particular action, such as an examination. “Some horses don’t like to be shod. So, when the farrier comes and starts banging around with their hooves, it would be good for that,” Dr. Baldwin said, giving a practical example of how lavender aromatherapy could be used in the barn. “You don’t need a diffuser, really. Just put a few drops of lavender essential oil on your hand and let your horse sniff.” Dr. Baldwin said future research projects could examine the effectiveness of aromatherapy for horses using other scents or doses. When it comes to lavender, though, the research is clear. A sniff is all it takes to calm an anxious equine. MeV

Shutterstock/Ulada

Can Aromatherapy Help a Stressed-Out Horse?

For more information: Baldwin AL, Chea I. Effect of aromatherapy on equine heart rate variability. J Equine Vet Sci. 2018; 68: 46 DOI: 10.1016/j.jevs.2018.05.213 https://www.j-evs.com/article/S0737-0806(18)30126-6/fulltext

ModernEquineVet.com | Issue 8/2018

TECHNICIAN UPDATE

Stuck on the Fence Lisa M. Leake, RVT

Photo courtesy of Lisa M. Leake, RVT

On May 31, 2017, a 4year-old American Quarter Horse presented to Iowa State University’s Lloyd Veterinary Medical Center (LVMC) for a penetrating wound of several hours duration. A 2-inch piece of round metal pipe, approximately 3 feet long, had pierced the mare caudomedial to the right mandible and exited rostromedial to the left eye. The piece of metal had become lodged in the horse during the early hours of May 31. Examination of the pipe revealed that while it was well seated in the horse, it could be turned with minimal effort. On presentation, the mare’s physical examination findings were a temperature of 99.7° F, a pulse of 80 beats per minute, respiration of 16 breaths per minute, normal borborygmi in all four quadrants, mucous membranes were pink and moist, and capillary refill time was less than 2 seconds. The mare’s weight was estimated at 500 kg. Auscultation of the heart and lungs were within normal limits. The Packed cell volume (PCV) was evaluated at 30% and the total protein was 4.7 g/dL. While airflow was detectable from the nostrils, it was decreased. Additionally, the mare had moder-

Above pictures- taken by the owners on the morning of the injury.

Issue 8/2018 | ModernEquineVet.com

ate respiratory stridor, so a temporary tracheostomy was performed. The mare remained bright, alert and responsive throughout the examination. The pipe was cut down using a hacksaw so that only about 8 inches protruded from each end beyond the entrance and exit wounds. The mare exhibited clinical signs of right side facial nerve damage including right eyelid paresis, muzzle deviation to the left and drooping of the right ear. Lateral, oblique and dorsoventral radiographs were acquired. Interpretation of the radiographs indicated multiple small fracture fragments dorsal to the frontal bone near the point of impalement, air within the soft tissues of the cranial neck and soft tissue opacity within the left maxillary sinuses, which were indicative of trauma to the frontal bone with an open wound. A sterile, 14-gauge Mila catheter was aseptically placed in the right jugular vein and 1,500 mLs of 7% hypertonic saline, followed by lactated Ringer’s solution, were administered. The mare was taken into surgery to remove the pipe. The wound was débrided and lavaged, and a computed tomography (CT) scan performed. Prior to anesthesia, the mare was sedated with butorphanol and xylazine. Anesthesia was induced with ketamine and midazolam. Induction of the mare was challenging due to the protruding pipe. Because of

AAEV T M E M b E r s h i p Membership in the AAEVT is open to all veterinary technicians, assistants, support staff and those employed in the veterinary health care industry worldwide. Student membership is open to those currently enrolled in an AVMA/CVMA accredited veterinary technology program.

AAEVT Membership • • • • • • • • • • •

Bi-Annual Newsletter Weekly “HoofBeats” Email Newsblast Full access to www.aaevt.org, including the Career Center and the Library Up-to-date information on the AAEVT Discounted registration for AAEVT Regional Meetings and the annual AAEP/AAEVT Convention NTRA, Working Advantage and Platinum Performance Benefits The opportunity to participate in the AAEVT Online Certification Program or to become a member of the AEVNT Academy-Specialty in Equine Veterinary Nursing Scholarship opportunities. AAEVT’s Equine Manual for Veterinary Technicians (Blackwell Publishing 20% discount on purchase price) Opportunity to attend Purina’s Annual Equine Veterinary Technician Conference - All Expenses paid!

AAEVT Objectives • • • •

Provide opportunities for CE, training, communication, and networking Educate the equine veterinary community and the public about our profession Inform Members of issues affecting our profession Assist in providing the best medical care to improve the health and welfare of the horse

AAEVT Online Equine Certification Program

• A three course, 10 module, equine-only online program offered through ACT • Geared toward Credentialed Veterinary Technicians, Assistants, Support staff, & Students • Areas of study include: equine medical terminology, anatomy and physiology, parasitology, laboratory, diagnostics, equine basics (breeds, wellness, husbandry,) diagnostic procedures, emergency medicine, restraint, pharmacology, surgical assistance and anesthesia, equine office procedures • A certificate of completion is awarded to those who: Successfully complete required courses Complete the list of required skills (per a supervising DVM who is an AAEP member) Attend an AAEVT regional CE symposium and participate in the we labs • Those individuals who successfully complete the programs will be recognized as AAEVT Certified Equine Veterinary Technicians / AAEVT Certified Equine Veterinary Assistants depending on their current designation. The certificate is recognized by the AAEVT and the AAEP but does not grant the credentialed status by the AVMA • For more information go to www.aaevt.4act.com or call 800-357-3182

AAEVT Mission Statement: To promote the health and welfare of the horse through the education and professional enrichment of the equine veterinary technician and assistant.

Fo r m o re i n f o r m a t ion vist w w w.a ae vt.or g

*American Association of Equine Veterinary Technicians and Assistants

Photo courtesy of Lisa M. Leake, RVT

TECHNICIAN UPDATE

ABOVE: Dr David Wong placing an IV catheter at time of presentation. TOP RIGHT: Radiographic image of metal pipe. BOTTOM RIGHT: Original endoscopic images of the guttural pouch image taken on June 16th.

Normal anatomy was difficult to identify due to the amount of tissue damage.

this, she was anesthetized as the surgeons cradled her head. This approach was used to keep the pipe from causing any further trauma. She was maintained on isoflurane, ketamine, butorphanol, xylazine and lactated Ringerâ&#x20AC;&#x2122;s solution during the procedures. Once the pipe was removed, the mare was taken to radiology for the CT scan, which confirmed communicated fractures of the left frontal bones and body of the mandible. There was also severe soft tissue trauma to the left ethmoid turbinates and right guttural pouch. Following the CT scan, the wounds were dĂŠbrided and lavaged thoroughly. The periosteum and subcutaneous layer were closed with 2-0 poliglecaprone, while the skin was closed with 0 polydioxanone and staples. A Michele trephine was used to make a hole 22

Issue 8/2018 | ModernEquineVet.com

into the frontal sinus and a 22 Foley catheter was placed in the hole to flush the frontal sinus. Stents were sutured over the wounds using 0 polydiaxanone. An upper airway endoscopy was performed. Due to the amount of tissue damage, normal anatomy was difficult to identify. The right guttural pouch was visualized easily from the pharynx due to disruption of the pharyngeal wall of the guttural pouch; the larynx had sustained minimal damage. A grade 4 left laryngeal hemiplegia was observed. Much of the damage was to the soft palate and nasopharynx. The mare was taken to a recovery stall, where she recovered uneventfully. Prior to being moved into the ICU, the mare received procaine penicillin G, gentamicin, phenylbutazone, altrenogest and artificial tears every four hours.

Photos courtesy of Lisa M. Leake, RVT

Entrance wound caudal medial to the mandible June 2nd (left) and June 16th (right)

During her first night in the ICU, the mare was maintained on 1 L/hr of lactated Ringer’s solution and a 2% lidocaine continuous rate infusion. Feed was withheld, but the mare was allowed onequarter bucket of water every two hours. The tracheostomy site was monitored hourly to ensure that a patent airway was present. The wounds were monitored for any signs of infection or excessive bleeding. She had consistent drainage from her nares. The mare remained comfortable and stable throughout the night. During the mare’s first week in the hospital, she continued to improve and was moved out of the ICU. She remained on her standard doses of gentamicin and procaine penicillin G until she was transitioned to oral sulfadiazine-trimethoprim twice daily. Purulent discharge continued to drain from her nares and wounds and they developed a foul odor. The mare was confirmed to be carrying a viable 50-day fetus and was continued on altrenogest. Daily hand walks were discontinued because the mare was being turned out for most of the day. Once the sinus lavages were becoming non-productive, the Foley catheter was pulled and the lavages were discontinued. After re-evaluating her upper airway, it was decided to remove the tracheostomy tube. A moderate amount of drainage from the wounds and nares continued to be present. Even with decreasing inflammation, the neurologic deficits were still present with deviation of the muzzle, an ear drop and decreased ability to fully close her right eyelid. On the second week of the mare’s stay at the

June 2nd (left) deviation of the muzzle, laxity of the left ear, and wound post-op. June 16th (right) mild improvement of the muzzle deviation, ear laxity, and wound dehiscence of the exit wound.

LVMC it was noticed that there were fly larvae in the wound caudal to mandible. The fly larvae were only seen in the wound for three days but were very helpful in débriding necrotic tissue associated with the wound. This also allowed for healthy tissue to granulate in the wound quicker. During this time, phenylbutazone was decreased and the mare was removed from sulfadiazine-trimethoprim and artificial tears. The wound had a significant decrease in discharge and the odor was no longer present. The fetus was re-examined and sexed at approximately 60 days of pregnancy, and it was found to be a viable filly with a strong heartbeat. ModernEquineVet.com | Issue 8/2018

TECHNICIAN UPDATE

Anyone hauling an injured animal must make the ride from the farm to the university safe for the patient. She needed plenty of room to turn around in the trailer but also needed to be secure in the trailer. We didnâ&#x20AC;&#x2122;t want the mare to dislodge the pipe, which made it difficult to secure her in the trailer. We all took great care to move the mare off the trailer and throughout the building. While we did not intentionally introduce the maggots to the wounds, they made a huge positive influence on healing. The wounds were healing very slowly and after 36 hours with the maggots the wound healing time was faster and wounds lost their foul odor. It was important to remember that this was an embryo transfer recipient and the ultimate goal was a live foal. Keeping that in mind throughout this case was always a priority. We decided not to perform a blood transfusion of the mare because that could lead to neonatal isoerythrolysis in the foal. These are the most important things that I took away from this case. The initial presentation was a little chaotic but once the pipe was removed this was handled like any wound that would be admitted into the hospital.

Photo courtesy of Lisa M. Leake, RVT

was still extensive damage to the pharynx, the most significant being direct communication from the pharynx to the right guttural pouch. The mare was kept in the hospital until her owners were comfortable changing the stockinette bandage. On June 21st, the mare was discharged into the care of her owner. Because the mare was sent home with an open wound, it was strongly recommended to keep the head bandaged until more granulated tissue developed in the wound. Recommendations were made to monitor the mare for any increase in drainage, fever or any behavioral changes. They were advised to continue the mare on altrenogest but she no longer needed any nonsteroidal anti-inflammatory drugs or antibiotics. As long as the mare continued to improve, there was no need for rechecks by LVMC. The mare delivered a healthy foal in the Spring of 2018, and both are doing well. MeV 3D CT reconstruction of the skull. Note the wound rostal medial to the left eye and the bone fragments caudal to the mandible.

The head bandage was changed to stockinette with modified openings for the eyes and ears. This was easier to change and would be more cost efficient for the owners once the mare was discharged. A final endoscopic examination was performed and a left laryngeal hemiplegia was still present. While the tissue did appear to be healing well, there 24

Issue 8/2018 | ModernEquineVet.com

About the author

Lisa M Leake, RVT is an equine surgical technician at Iowa State Universityâ&#x20AC;&#x2122;s Lloyd Veterinary Medical Center in Ames Iowa. She has an interest in equine rehabilitation, orthopedics and equine theriogenology. She is pictured with her mare Banshee and her 2018 john mule, Ozarks Mountain Banshee.

Shutterstock/nelelena

TEACHING POINTS

NEWS NOTES

Source: Equine Vet J

Insulin Weakens Integrity of Equine Lamellae Insulin appears to weaken the structural integrity of equine lamellae, according to new research. This ex vivo study by Cole Sandow, DVM, an equine surgery resident at the Veterinary Clinical Sciences, School of Veterinary Medicine, Louisiana State University Baton Rouge in Louisiana, aimed to characterize the effects of insulin on the structural integrity of the hoof lamellae. Tissue was harvested from the dorsal aspect of the fore feet of four horses euthanized for reasons other than diseases of the digit. Multiple lamellar explants were harvested from each horse and then equilibrated and incubated for eight hours in cell culture medium alone or in a medium supplemented with 2.5 μg/mL insulin. After eight hours of incubation at 37° C, mechanical testing was performed by placing each explant into a clamp device and applying a mechanical load to cre-

ate tension parallel to the long axis of the distal phalanx until explant failure. The load, stress and elongation to failure were rerecorded. Selected explants also underwent histological evaluation after testing. A total of 89 explants were tested, 50 in the control group and 39 in the insulin group. Explant failure occurred in 90% (n = 35) of those incubated in insulin compared to 72% (n = 36) of those in the control group. Those incubated in insulin failed at a significantly lower load and stress. Histology of explants incubated in insulin showed separation of the epidermal‐dermal attachments at the basement membrane, whereas the controls better retained the basement membrane attachment, the researchers said. In this ex vivo model, insulin weakened the structural integrity of equine lamellae. MeV

For more information: Sandow C, Fugler LA, Leise B, et al. Ex vivo effects of insulin on the structural integrity of equine digital lamellae. Equine Vet J. 2018 May 28. (Epub ahead of print). https://onlinelibrary.wiley.com/doi/full/10.1111/evj.12964

Horse with hyperinsulinaemia

ModernEquineVet.com | Issue 8/2018

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