The Modern Equine Vet - August 2020

The Modern

Equine Vet www.modernequinevet.com

Vol 10 Issue 8 2020

Key to Safer Nerve Blocks

Ask the Nutritionist Recommending joint supplements Ask the Infectious Disease Expert Explaining the importance of vaccination Predicting Colic Prognosis When the Patient is Your Horse

CHECK OUT: ASK THE INFECTIOUS DISEASE EXPERT

TABLE OF CONTENTS

COVER STORY

4 Sit, Feed, and Bleb:

Keys to Safer Nerve Blocks Cover: Shutterstock/Au_Cr

ASK THE NUTRITIONIST

How Do I Determine the Best Joint Supplements to Recommend?............................... 3 NEW COLUMN: ASK THE INFECTIOUS DISEASE EXPERT

How Can I Help Horse Owners Understand the Importance of Vaccination?.............. 7 COLIC

Predicting Prognosis For a Colic................................................................................................... 8 INFECTIOUS DISEASES

Parasitic Disease Affecting Donkeys Detected in the UK for the First Time...............10 MORE THAN A HITCHING POST

When the Patient is My Horse....................................................................................................12 NEWS

Chromosomal Defect Plays Key Role in Pregnancy Losses..............................................14 Role of Serium Amyloid in Infection Detection...................................................................15 ADVERTISERS Purina Sponsored Content.........................................3 Merck Animal Health..................................................5 Merck Animal Health Sponsored Content..............7 American Regent Animal Health/Adequan...........9

Shanks..........................................................................10 AVMA PLIT....................................................................11 AAEVT............................................................................13

The Modern

Equine Vet SALES: Matthew Todd • Matthew Gerald EDITOR: Marie Rosenthal ART DIRECTOR: Jennifer Barlow CONTRIBUTING WRITERS: Paul Basillo • Adam Marcus 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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Issue 8/2020 | ModernEquineVet.com

LEGAL DISCLAIMER: The content in this digital issue is for general informational purposes only. PercyBo Publishing Media LLC makes no representations or warranties of any kind about the completeness, accuracy, timeliness, reliability or suitability of any of the information, including content or advertisements, contained in any of its digital content and expressly disclaims liability of any errors or omissions that may be presented within its content. PercyBo Publishing Media LLC reserves the right to alter or correct any content without any obligations. Furthermore, PercyBo disclaims any and all liability for any direct, indirect, or other damages arising from the use or misuse of the information presented in its digital content. The views expressed in its digital content are those of sources and authors and do not necessarily reflect the opinion or policy of PercyBo. The content is for veterinary professionals. ALL RIGHTS RESERVED. Reproduction in whole or in part without permission is prohibited.

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Ask the

Nutritionist

MARY BETH GORDON, M.S., PH.D., EQUINE RESEARCH AND NEW PRODUCT DEVELOPMENT DIRECTOR, PURINA ANIMAL NUTRITION

Ask the Nutritionist is a monthly column featuring questions answered by PhD equine nutritionists and sponsored by Purina Animal Nutrition. Have a nutrition question you want to see featured? Email Marie Rosenthal.

For clinics looking for specific nutritional advice, visit purinamills.com/ask-an-expert.

My clients often ask about joint supplements for their horses.

How do I determine which ones to recommend? Help!

Joint supplement questions abound! A veterinarian survey conducted in 2017 by Purina Animal Nutrition determined joint supplements were the No. 1 supplement question veterinarians received from their clients. With upward of 500 joint supplements on the market, it’s no wonder horse owners have questions and want recommendations.

It’s helpful to have a methodology to determine which joint supplements work best for the situation and when to recommend a pharmaceutical intervention instead. Hence, we developed “Test RIDE” – an acronym to help you evaluate and recommend supplements. Like you would with a new horse, putting supplements through a Test RIDE will help determine if they are a good fit.

treat or ameliorate active symptoms.

When recommending a joint supplement, consider offering lameness exams along with a followup exam several weeks later to help the owner determine efficacy for individual horses. If the supplement does not appear to be helping the horse, then it may be time to try a different supplement, therapy or pharmaceutical intervention.

PASS OR FAIL – WHAT NEXT? Unfortunately, when many joint supplements are put through the Test RIDE, they fail quickly. But this is the point of the exercise. This rigorous evaluation process will help you determine which supplements can truly support joint health.

If an oral joint supplement is desired, we recommend selecting a reputable product with research behind it, a clear ingredient list, appropriate feeding amounts fed at the proper rate and signs it helps the horse. If there is no clear difference in the horse’s response within a few weeks, work with the horse owner on an alternative preventative or treatment plan.

TAKE SUPPLEMENTS FOR A TEST RIDE Test RIDE stands for: • Research • Ingredients • Dose • Efficacy When evaluating a joint supplement, first look for one with peer-reviewed, published research to support its efficacy in horses. Reputable companies with highquality products will invest in this research and have it available for review. If a company doesn’t have product research, we suggest passing and moving to another option.

Next, look at the ingredients. Does the supplement contain one or several key ingredients targeted for joints? Or does it contain myriad ingredients seemingly unrelated to joint health? If there are so many ingredients the amount of each will be very small and ineffective, keep looking for a better option.

This brings us to dose. The amount of each joint supportive ingredient should be included at a rate appropriate for the size and weight of the horse you’re working with.

And feeding instructions should allow a proper amount to be reasonably fed in a day.

Efficacy is the last step. You and the horse owner should see or feel a difference in the horse after feeding a joint supplement, especially if it’s being used to

Contact a Purina PhD nutritionist for a complimentary consultation through Purina Customer Service, 800-227-8941 or send us a message at www.purinamills.com/ask-an-expert.

UPCOMING TOPICS September: Cardiology October: Reproduction: Stallion needs November: Reproduction: Mare needs

Have a question you want to see featured?

Send them to modernequinevet@gmail.com.

ABOUT THE AUTHOR Dr. Mary Beth Gordon, Ph.D., is the equine research and new product development director at Purina Animal Nutrition. She studies the effect of nutrition on horse health, separating trends from true efficacy.

SPONSORED BY PURINA ANIMAL NUTRITION

ModernEquineVet.com | Issue 8/2020

3

ORTHOPEDICS

The Keys to Safer Nerve Blocks B y

4

P a u l

B a s i l l i o

Issue 8/2020 | ModernEquineVet.com

horses “tap dancing" on his head while trying perform blocks, he joked, but he was unhappy with the methods used to get them to stand still for the injections.

He was never happy with lip twitches, lip chains or gum chains and hated “getting into a fight with a horse,” he said.

“As a result of my experience in eventing, I spent a lot of time trying to convince horses to do things that a normal horse would never attempt to do," and he used that knowledge to make blocking easier for horse, owner and himself.

Dr. Kleider, owner of Kleider Veterinary Services in Langley City, British Columbia, Canada, set out to find a better way to control horses for needle injections—specifically for injections into their limbs. Lip and gum chains were fine for control, he found, but the horse was never happy and did not want to stand still for the entire procedure, from scrubbing to injection.

Stocks are problematic because they leave little room to work around the bars, and if the horse is not adequately sedated then it may injure itself trying to flee.

“Two things are needed for more control,” he explained: removing the fear and helping horses and owners relax. Sedation is the best way to control the horse and make it relax, which helps the owner relax, too.

By using sedation, smaller needles, skin blebs, injections of flexed limbs and forewarning the horse through pre-injection pressure, the blocking experience can go more smoothly for everyone involved.

He spoke about a retrospective study performed at his practice that evaluated safe needle insertion for diagnostic analgesia at the 65th Annual AAEP Convention in Denver.

In a typical lameness exam, Dr. Kleider will sedate the horse prior to diagnostic imaging—usually with up to 5 mg detomidine.

That amount of sedation will usually persist, which will allow for the piggybacking

Shutterstock/Au_Cr

Sit, Feed and Bleb:

Nick Kleider, DVM, DACVSMR, grew tired of

The Science of

CONVENIENT PROTAZIL® (1.56% diclazuril) Antiprotozoal Pellets is the only FDA-approved alfalfa-based top dress antiprotozoal pellet for the treatment of EPM. • Equine Protozoal Myeloencephalitis (EPM) is a serious neurological disease that can strike anytime, anywhere.

Make treatment easy with PROTAZIL® • Safe and accurate dosing with a calibrated scoop • Easier to use than paste, less stress for you and your horse • Rapid absorption — no loading dose required1 Now that’s convenient.

Ask your Merck Animal Health Equine representative about PROTAZIL® or call 800-521-5767.

IMPORTANT SAFETY INFORMATION: Use of PROTAZIL® (1.56% diclazuril) Antiprotozoal Pellets is contraindicated in horses with known hypersensitivity to diclazuril. Safe use in horses used for breeding purposes, during pregnancy, or in lactating mares has not been evaluated. The safety of PROTAZIL® (1.56% diclazuril) Antiprotozoal Pellets with concomitant therapies in horses has not been evaluated.

For use in horses only. Do not use in horses intended for human consumption.

Not for human use. Keep out of reach of children.

2 Giralda Farms • Madison, NJ 07940 • merck-animal-health-usa.com • 800-521-5767 Copyright © 2020 Intervet Inc., d/b/a/ Merck Animal Health, a subsidiary of Merck & Co., Inc. All rights reserved.

1

Hunyadi L, Papich MG, Pusterla N. Pharmacokinetics of a low‑dose and DA‑labeled dose of diclazuril administered orally as a pelleted top dressing in adult horses. J of Vet Pharmacology and Therapeutics (accepted) 2014, doi: 10.111/jvp.12176. The correlation between pharmacokinetic data and clinical effectiveness is unknown

ORTHOPEDICS FOR ORAL USE IN HORSES ONLY CAUTION Federal ( U.S.A.) law restricts this drug to use by or on the order of a licensed veterinarian.

NADA #141-268 Approved by FDA DESCRIPTION Diclazuril, (±)-2,6-dichloro-α- (4-chlorophenyl)-4- (4,5-dihydro-3,5-dioxo-1,2,4triazin-2(3H )-yl)benzeneacetonitrile, has a molecular formula of C 17 H 9 CI 3 N 4 O 2 , a molecular weight of 407.64, and a molecular structure as follows:

Take a load off Thanks to a back injury sustained while eventing, Nick Kleider, DVM, DACVSMR, owner of Kleider Veterinary Services in Langley City, British Columbia, Canada, was forced to develop a sitting strategy for distal limb blocking.

Turns out that blocking the palmar distal forelimb, stifle, and proximal suspensory ligament while sitting was easier to do than while standing.

“A wise man once told me, ‘Never stand if you can sit.’”

Sitting allows the veterinarian to rest the fetlock on one knee, allowing extension during a digital sheath injection. The limb is balanced, so that if the horse suddenly insists on dropping the foot, it would slide right off.

“By allowing extension of the fetlock and the distal joints, one can more easily palpate the neurovascular bundle,” he said. “You can pick up a small fold of skin over the nerve and inject through using a 27-gauge needle. The horse feels the pinching instead of the needle. Then, by elevating the skin, there’s less chance of entering the digital sheath.”

Diclazuril is an anticoccidial (antiprotozoal) compound with activity against several genera of the phylum Apicomplexa. PROTAZIL® (diclazuril) is supplied as oral pellets containing 1.56% diclazuril to be mixed as a top-dress in feed. Inert ingredients include dehydrated alfalfa meal, wheat middlings, cane molasses and propionic acid (preservative).

INDICATIONS PROTAZIL® (1.56% diclazuril) Antiprotozoal Pellets are indicated for the treatment of equine protozoal myeloencephalitis ( EPM) caused by Sarcocystis neurona in horses.

DOSAGE AND ADMINISTRATION Dosage: PROTAZIL® (1.56% diclazuril) is administered as a top dress in the horse’s daily grain ration at a rate of 1 mg diclazuril per kg (0.45 mg diclazuril/lb) of body weight for 28 days. The quantity of PROTAZIL® necessary to deliver this dose is 64 mg pellets per kg (29 mg pellets/lb) of body weight.

Administration: To achieve this dose, weigh the horse (or use a weigh tape)). Scoop up PROTAZIL® to the level (cup mark) corresponding to the dose for the horse’s body weight using the following chart: Weight Range mLs of Pellets of Horse (lb) 275 - 524 20 525 - 774 30 775 - 1024 40 1025 - 1274 50

Weight Range mLs of Pellets of Horse (lb) 1275 - 1524 60 1525 - 1774 70 1775 - 2074 80 -

One 2.4-lb bucket of PROTAZIL® will treat one 1274-lb horse for 28 days. One 10-lb bucket of PROTAZIL® will treat five 1100-lb horses for 28 days.

CONTRAINDICATIONS Use of PROTAZIL® (1.56% diclazuril) Antiprotozoal Pellets is contraindicated in horses with known hypersensitivity to diclazuril.

WARNINGS For use in horses only. Do not use in horses intended for human consumption. Not for human use. Keep out of reach of children.

PRECAUTIONS The safe use of PROTAZIL® (1.56% diclazuril) Antiprotozoal Pellets in horses used for breeding purposes, during pregnancy, or in lactating mares has not been evaluated. The safety of PROTAZIL® (1.56% diclazuril) Antiprotozoal Pellets with concomitant therapies in horses has not been evaluated.

ADVERSE REACTIONS There were no adverse effects noted in the field study which could be ascribed to diclazuril. To report suspected adverse reactions, to obtain a MSDS, or for technical assistance call 1-800-224-5318.

CLINICAL PHARMACOLOGY The effectiveness of diclazuril in inhibiting merozoite production of Sarcocystis neurona and S. falcatula in bovine turbinate cell cultures was studied by Lindsay and Dubey (2000).1 Diclazuril inhibited merozoite production by more than 80% in cultures of S. neurona or S. falcatula treated with 0.1 ng/mL diclazuril and greater than 95% inhibition of merozoite production (IC 95 ) was observed when infected cultures were treated with 1.0 ng/mL diclazuril.

The clinical relevance of the in vitro cell culture data has not been determined.

PHARMACOKINETICS IN THE HORSE The oral bioavailability of diclazuril from the PROTAZIL® (1.56% diclazuril) Antiprotozoal Pellets at a 5 mg/kg dose rate is approximately 5%. Related diclazuril concentrations in the cerebrospinal fluid (CSF) range between 1% and 5% of the concentrations observed in the plasma. Nevertheless, based upon equine pilot study data, CSF concentrations are expected to substantially exceed the in vitro IC 95 estimates for merozoite production (Dirikolu et al., 1999) 2. Due to its long terminal elimination half-life in horses (approximately 43-65 hours), diclazuril accumulation occurs with once-daily dosing.

Corresponding steady state blood levels are achieved by approximately Day 10 of administration.

EFFECTIVENESS Two hundred and fourteen mares, stallions, and geldings of various breeds, ranging in age from 9.6 months to 30 years, were enrolled in a multi-center field study. All horses were confirmed EPM-positive based on the results of clinical examinations and laboratory testing, including CSF Western Blot analyses. Horses were administered PROTAZIL® (1.56% diclazuril) Antiprotozoal Pellets at doses of 1, 5, or 10 mg diclazuril/kg body weight as a top-dress on their daily grain ration for 28 days. The horses were then evaluated for clinical changes via a modified Mayhew neurological scale on Day 48 as follows: 0. Normal, neurological deficits not detected.

1. Neurological deficits may be detectable at normal gaits; signs exacerbated with manipulative procedures (e.g., backing, turning in tight circles, walking with head elevation, truncal swaying, etc.).

2. Neurological deficit obvious at normal gaits or posture; signs exacerbated with manipulative procedures.

3. Neurological deficit very prominent at normal gaits: horses give the impression they may fall (but do not) and buckle or fall with manipulative procedures.

4. Neurological deficit is profound at normal gait: horse frequently stumbles or trips and may fall at normal gaits or when manipulative procedures were utilized.

5. Horse is recumbent, unable to rise.

Each horse’s response to treatment was compared to its pre-treatment values. Successful response to treatment was defined as clinical improvement of at least one grade by Day 48 ± conversion of CSF to Western Blot-negative status for S. neurona or achievement of Western Blot-negative CSF status without improvement of 1 ataxia grade.

Forty-two horses were initially evaluated for effectiveness and 214 horses were evaluated for safety. Clinical condition was evaluated by the clinical investigator’s subjective scoring and then corroborated by evaluation of the neurological examination videotapes by a masked panel of three equine veterinarians. Although 42 horses were evaluated for clinical effectiveness, corroboration of clinical effectiveness via videotape evaluation was not possible for one horse due to missing neurologic examination videotapes. Therefore, this horse was not included in the success rate calculation.

Based on the numbers of horses that seroconverted to negative Western Blot status, and the numbers of horses classified as successes by the clinical investigators, 28 of 42 horses (67%) at 1 mg/ kg were considered successes. With regard to independent expert masked videotape assessments,

10 of 24 horses (42%) at 1 mg/kg were considered successes. There was no clinical difference in effectiveness among the 1, 5, and 10 mg/kg treatment group results.

Adverse events were reported for two of the 214 horses evaluated for safety. In the first case, a horse was enrolled showing severe neurologic signs. Within 24 hours of dosing, the horse was recumbent, biting, and exhibiting signs of dementia. The horse died, and no cause of death was determined. In the second case, the horse began walking stiffly approximately 13 days after the start of dosing. The referring veterinarian reported that the horse had been fed grass clippings and possibly had laminitis.

ANIMAL SAFETY PROTAZIL® (1.56% diclazuril) Antiprotozoal Pellets were administered to 30 horses (15 males and 15 females, ranging from 5 to 9 months of age) in a target animal safety study. Five groups of 6 horses each (3 males and 3 females) received 0, 5 (5X), 15 (15X), 25 (25X) or 50 (50X) mg diclazuril/kg (2.27mg/lb) body weight/day for 42 consecutive days as a top-dress on the grain ration of the horse. The variables measured during the study included: clinical and physical observations, body weights, food and water consumption, hematology, serum chemistry, urinalysis, fecal analysis, necropsy, organ weights, gross and histopathologic examinations.

The safety of diclazuril top-dress administered to horses at 1 mg/kg once daily cannot be determined based solely on this study because of the lack of an adequate control group (control horses tested positive for the test drug in plasma and CSF). However, possible findings associated with the drug were limited to elevations in BUN, creatinine, and SDH and less than anticipated weight gain.

Definitive test article-related effects were decreased grain/top-dress consumption in horses in the 50 mg/kg group. In a second target animal safety study, PROTAZIL® (1.56% diclazuril) Antiprotozoal Pellets were administered to 24 horses (12 males and 12 females, ranging from 2 to 8 years of age). Three groups of 4 horses/sex/group received 0, 1, or 5 mg diclazuril/kg body weight/day for 42 days as a top-dress on the grain ration of the horse. The variables measured during the study included physical examinations, body weights, food and water consumption, hematology, and serum chemistry. There were no test article-related findings seen during the study.

STORAGE INFORMATION Store between 15°C to 30°C (59°F to 86°F).

HOW SUPPLIED PROTAZIL® (1.56 % diclazuril) Antiprotozoal Pellets are supplied in 2.4-lb (1.1 kg) and 10-lb (4.5 kg) buckets.

REFERENCES 1. Lindsay, D. S., and Dubey, J. P. 2000. Determination of the activity of diclazuril against Sarcocystis neurona and Sarcocystis falcatula in cell cultures. J. Parasitology, 86(1):164–166.

2. Dirikolu, L., Lehner, F., Nattrass, C., Bentz, B. G., Woods, W. E., Carter, W. E., Karpiesiuk, W. G., Jacobs, J., Boyles, J., Harkins, J. D., Granstrom, D. E. and Tobin, T. 1999. Diclazuril in the horse: Its identification and detection and preliminary pharmacokinetics. J. Vet. Pharmacol. Therap. 22:374–379.

Intervet Inc d/b/a Merck Animal Health 2 Giralda Farms, Madison, NJ 07940 Copyright © 2020 Intervet Inc. a subsidiary of Merck & Co. Inc. All rights reserved.

07-2014 211.x.3.0.3

of blocking if needed.

Blocking forelimbs without the need for imaging guidance rarely requires sedation, but sedation for hindlimb blocking is fairly common.

“It’s important to not overdo it,” Dr. Kleider said. “Ataxic horses can fall on you if you try to lift the leg up while the horse is not properly placed.”

It also is important to pay attention to the horse’s behavior and check the eyes, ears and face as you proceed.

“Also, consider your own capabilities,” he said. “An owner will rarely take a veterinarian’s health into consideration. They care more for your availability. You are the maker of your own destiny, and you need to get out of the way when manure happens.

Take the time to maintain your fitness.”

Food and Fair Warning

“I'm very food motivated,” Dr. Kleider joked. “Give me a piece of chocolate, and you can do an epidural on me.”

“Feeding horses seems to relax both the horse,” he said, “and most owners relax when they see their horse relax.”

Horses under stress may not be quite as food motivated, but once the sedation kicks in they may be more amenable to a food distraction during the procedure. Just be careful not to feed too early in the procedure, or the horse may snap back to reality and take it out on the health care staff.

In his study, grain or horse treats were provided to all horses undergoing diagnostic limb anesthesia. A bucket of horse 6

Issue 8/2020 | ModernEquineVet.com

crunch, palatable grain or treats were placed under the horse’s nose by a veterinary assistant, a staff member, or an amenable owner.

The horses were feed 4 to 5 seconds before the procedure, during the procedure and for 4 to 5 seconds after it was completed. The person feeding the horse was instructed to direct the horse’s attention to the veterinarian in the beginning to avoid any surprises.

Desensitizing the skin over the injection site can also help with a smooth procedure. In his study, Dr. Kleider slightly elevated the skin over superficial nerves (eg, proper palmar digital nerve) by pinching, and then the needle was placed subcutaneously.

For ultrasound-guided injections, he provided a momentary increase in the pressure of the probe via light poke to gauge the horse’s response and prepare the horse for injection. The needle was then inserted simultaneously with another momentary increase in pressure on the probe.

For desensitization of the median nerve, Dr. Kleider urged caution. “If the needle touches the median nerve, the horse will strike out at supersonic speeds,” he said.

“It’s probably one of the most dangerous blocks that I do. Make sure no equipment or personnel are in front of the horse.”

Use a skin bleb and follow the needle tip with the ultrasound probe. Inject a bit of local anesthesia up ahead to make sure that if the horse moves, the needle will slide out and not in.

MeV

SPECIAL ADVERTISING SECTION

ASK

THE

Infectious Disease Expert This column, brought to you by Merck Animal Health, features insightful answers from leading minds.

How can I help horse owners understand why vaccines are important even when a disease hasn’t recently been seen locally?

I

f COVID-19 has a silver lining, it’s that it’s spurring a lot of discussion about vaccinations. This gives veterinarians a unique opportunity to talk with horse owners about disease prevention. Your clients may be more receptive now to learning about how vaccinations work, why they’re critical and why veterinarian involvement is important.

Start the conversation by explaining that vaccines help prime the immune system so, when a horse gets exposed to a disease, the immune system can respond, ideally before the horse shows any clinical signs. The immune response to vaccination and protection from disease may vary from horse to horse depending upon the vaccine used, the horse’s individual immune system response to vaccination, and the degree of exposure to the disease-causing agent. Sometimes vaccinated horses still show clinical signs, but they’re reduced, as is the degree of illness.

Clients should understand that priming the immune system takes some time, which means horses aren’t immediately protected after a vaccination is given. That’s why timing is key. Veterinarians play an important role in ensuring horses receive the right vaccines at the right time.

VITAL VETERINARY INVOLVEMENT With COVID-19, some horse owners may be hesitant to invite a veterinarian onto their property for fear of exposure. Unfortunately, diseases won’t wait, and mosquitos will still spread eastern equine encephalitis (EEE)

REAL-TIME DISEASE ALERTS Sometimes horse owners aren’t aware of which diseases are present locally.

To educate your clients and reinforce the importance of vaccinations, encourage them to sign up for disease alerts from the Equine Disease Communication Center website at equinediseasecc.org. and West Nile virus (WNV). If vaccinations are delayed, especially for EEE and WNV, some horses will die, particularly in areas where mosquito season is long and severe.

Increase your clients’ confidence by reminding them that veterinarians are trained in infection control, including biosecurity measures to reduce exposure. Perhaps more importantly, emphasize that vaccinations are considered an essential service because they’re a pillar of disease prevention. Explain that your involvement helps ensure proper administration to minimize vaccination reactions. What’s more, most pharmaceutical companies provide guarantees when their vaccines are given by a veterinarian. Finally, outline the need for partnership in creating

ABOUT THE AUTHOR Amanda M. House, DVM, DACVIM, is a clinical professor and interim associate dean of academic and student affairs at the University of Florida College of Veterinary Medicine. She’s also course director of the Practice Based Equine Clerkship program, which enables veterinary students to complete an ambulatory practice clinical rotation with private practitioners. Dr. House’s clinical interests include infectious disease, neonatology and camelid medicine. A member of the AAEP Board of Directors, Dr. House serves on the organization’s Infectious Disease Committee.

SPONSORED BY MERCK ANIMAL HEALTH

a booster vaccination schedule to help ensure horses, especially foals, are properly protected.

EVER-PRESENT NEED FOR PREVENTION The pandemic demonstrates that safe and effective vaccines are vital to preventing diseases even when they haven’t been seen locally. Take rabies. It’s the perfect example to use with clients. Some diseases, including rabies, are common in wildlife populations.

Just because you aren’t seeing rabies in the horse population, doesn’t mean it’s not there.

That’s why the American Association of Equine Practitioners (AAEP) Vaccination Guidelines classifies the rabies vaccine as core. Remind clients that when a vaccine is designated as ‘core’ every horse should receive it every year regardless of geography or the presence of diagnosed disease. As for risk-based vaccines, your involvement is critical because you understand that horse’s age, lifestyle and environment and, as such, are equipped to make the most appropriate recommendation.

Talking with clients about vaccinations is time well spent, especially now. Veterinarians, physicians and research scientists are working together to control a global infection and promote vaccines as vital health maintenance.

You and your clients play a role, too. By helping your clients understand that vaccination is a critical component of disease prevention, you’ll not only help them keep their horses healthy, but you’ll also help them do their part.

WANT TO ASK A QUESTION? EMAIL THE EDITOR. For more infectious disease-related information, visit merck-animal-health-equine.com/programs

ModernEquineVet.com | Issue 8/2020

7

COLIC

By Adam Marcus For horses with colic; fever, advanced age and discolored mucous membranes are “red flags” for critical illness and death.

That’s according to a new, retrospective study of nearly 1,000 horses treated for colic over a two-year period, which found that animals with 1 or more of the 2 indicators were at a significantly higher risk of death from the gastrointestinal condition.

The researchers, led by Adelle Bowden, PhD, of the School of Veterinary Medicine and Science at the University of Nottingham in England, analyzed 941 horses treated on an emergency basis for colic at 2

veterinary practices in the United Kingdom between 2011 and 2013. Of those, 225 (23.9%) were considered “critical” cases, which the researchers defined as “requiring medical or surgical hospital treatment, or resulting in euthanasia or death.” (Non-critical cases were those that resolved with routine treatment.)

Discolored mucous membranes, which are easy for owners to assess by lifting up the animal’s gum, can be a sign of systemic inflammatory response syndrome, which itself is a sign of a gravely ill horse.

Older horses were more likely to experience a critical outcome, but why that was is not clear, according to the researchers.

“This requires further investigation to determine whether this is due to older horses being more likely to have critical conditions, or that owners are more likely to choose euthanasia instead of treatment in older horses,” the researchers wrote.

John Burford, BVetMed, PhD, DECVS, MRCV, an associate professor in equine surgery at the University of Nottingham, said the study differs from previous research because it looked at horses seen by general practitioners.

“Most other studies that have looked at survival of colic are often based on horses that have had surgery—this therefore doesn’t reflect the selection that has occurred previously—the most critically ill animals are likely to never be referred, especially in today’s economic climate,” Dr. Burford told Modern Equine Vet. Some evidence suggests that the incidence of surgery for horses with colic in the United States and United Kingdom has fallen recently. “Unless there has been a huge population decline, that means that more horses are being euthanized by referring vets,” he said.

“If any horses have these red flag signs they need immediate further examination as they suggest that the animal is critical, noting that horses that received urgent medical or surgical treatment may still need euthanasia or may die,” Dr. Burford said.

MeV

For more information: Bowden A, England GC, Brennan ML, et al. Indicators of ‘critical’ outcomes in 941 horses seen ‘out-of-hours’ for colic.

Vet Rec. 2020 Jul 27 [Epub ahead of print]. https://veterinaryrecord.bmj.com/content/early/2020/07/26/vr.105881 8

Issue 8/2020 | ModernEquineVet.com

Shutterstock/Elmari Viljoen

Predicting Prognosis for a Colic

There’s nothing else like it.

Over the past 30 years, Adequan® i.m. (polysulfated glycosaminoglycan) has been administered millions of times1 to treat degenerative joint disease, and with good reason. From day one, it’s been 2, 3 the only FDA-Approved equine PSGAG joint treatment available, and the only one proven to.

Reduce inflammation Restore synovial joint lubrication Repair joint cartilage Reverse the disease cycle When you start with it early and stay with it as needed, horses may enjoy greater mobility 2, 4, 5 over a lifetime. Discover if Adequan is the right choice. Talk to your American Regent Animal Health sales representative or call (800) 458-0163 to order.

BRIEF SUMMARY: Prior to use please consult the product insert, a summary of which follows: CAUTION: Federal law restricts this drug to use by or on the order of a licensed veterinarian. INDICATIONS: Adequan® i.m. is recommended for the intramuscular treatment of non-infectious degenerative and/or traumatic joint dysfunction and associated lameness of the carpal and hock joints in horses. CONTRAINDICATIONS: There are no known contraindications to the use of intramuscular Polysulfated Glycosaminoglycan. WARNINGS: 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. PRECAUTIONS: The safe use of Adequan® i.m. in horses used for breeding purposes, during pregnancy, or in lactating mares has not been evaluated. For customer care, or to obtain product information, visit www.adequan.com. To report an adverse event please contact American Regent, Inc. at (800) 734-9236 or email pv@americanregent.com.

Please see Full Prescribing Information at www.adequan.com.

www.adequan.com 1 Data on file.

2 Adequan® i.m. Package Insert, Rev 1/19.

3 Burba DJ, Collier MA, DeBault LE, Hanson-Painton O, Thompson HC, Holder CL: In vivo kinetic study on uptake and distribution of intramuscular tritium-labeled polysulfated glycosaminoglycan in equine body fluid compartments and articular cartilage in an osteochondral defect model. J Equine Vet Sci 1993; 13: 696-703.

4 Kim DY, Taylor HW, Moore RM, Paulsen DB, Cho DY. Articular chondrocyte apoptosis in equine osteoarthritis. The Veterinary Journal 2003; 166: 52-57.

5 McIlwraith CW, Frisbie DD, Kawcak CE, van Weeren PR. Joint Disease in the Horse.St. Louis, MO: Elsevier, 2016; 33-48.

All trademarks are the property of American Regent, Inc. © 2020, American Regent, Inc. PP-AI-US-0372 02/2020

INFECTIOUS DISEASES

Parasitic Disease Affecting Donkeys Detected in the UK for First Time A chronic and debilitating parasitic equine disease which causes lesions in the eyes and skin has been found in donkeys in the United Kingdom for the first time.

Equine besnoitiosis is a disease that occurs in donkeys, horses, zebras and mules. Donkeys with besnoitiosis develop multiple parasitic cysts on the skin, over the nostrils, and on the ears and face. One of the most unique features of the disease is the development of tiny cysts on the surface of the eye.

Some infected animals remain otherwise healthy, while others become thin and debilitated as a result of the disease.

Previously, the parasitic disease was rarely detect-

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ed in most countries, including in the United States, Spain, Belgium and Italy.

“It is absolutely essential—particularly now—that veterinarians in the UK learn more about besnoitiosis, so they can identify and protect donkeys potentially at risk. Knowledge obtained in this study should improve our response to this emerging parasitic disease in donkeys in the UK, especially with the few treatment options and the unknown routes of transmission,” said Dr Hany Elsheikha, lead author of the study and an associate professor of Parasitology at the University of Nottingham.

Besnoitiosis was initially discovered in the United Kingdom in 2013, when a donkey at the Donkey Sanctuary presented with skin lumps that were presumed to be sarcoid tumors. Microscopic examination of the affected skin tissue of the donkey revealed the presence of cysts similar to those caused by a protozoan parasite known as Besnoitia bennetti, alongside the finding of tissue changes associated with a sarcoid.

This case triggered a collaboration between a team of clinicians from the Donkey Sanctuary and a veterinary parasitologist from the School of Veterinary Medicine and Science at the University of Nottingham. Since then upward of 20 clinical cases have been identified and studied.

Although the classic clinical signs associated with besnoitiosis were not seen in the UK cases, this study has important clinical relevance, according to the researchers from the University of Nottingham and the Donkey Sanctuary in the United Kingdom.

“Given the relative proximity to other European countries, where clinical besnoitiosis is apparent, our findings will inform British vets of the potential for this emerging disease so that they can better recognize the pattern of clinical signs during clinical 3. examination,” said Dr Rebekah Sullivan, co-author of the report and a veterinarian at the Donkey Sanctuary.

Several serological methods and screening strategies have been developed to help guide veterinarians to earlier diagnosis and treatment of the disease.

Gereon Schares from the Friedrich-Loeffler-Institute, Federal Research Institute for Animal Health, Germany, and co-author of the report, added, “This study is particularly important because by using a suite of molecular methods we were able to confirm for the first time in Europe that the parasite agent involved in these cases is specifically Besnoitia bennetti

FIG 2.

FIG 3.

Images courtesy the University of Nottingham

FIG 1.

FIG 1. Donkeys from the Donkey Sanctuary FIG 2. A donkey with the characteristic lesions on the eye caused by this parasitic infection FIG 3. This micrograph shows the characteristic cystic structures of the parasite Besnoitia bennetti embedded within the skin of the donkeys

and infection can be shown by serological methods.”

The correct identification of Besnoitia cysts in skin biopsies taken from UK donkeys does have clinical advantage for veterinarians providing a more accurate prognosis where a skin mass has been identified.

“It can no longer be assumed that skin masses are either neoplastic in origin or inflammatory, such as eosinophilic granulomas, for example,” said George Paraschou, co-author and pathologist at the Donkey Sanctuary.

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For more information: Elsheikha HM Schares G, Paraschou G, et al. First record of besnoitiosis caused by Besnoitia bennetti in donkeys from the UK. Parasit Vectors 2020;13:79 [Epub ahead of print]. https://doi.org/10.1186/s13071-020-04145-8

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MORE TECHNICIAN THAN A HITCHING UPDATEPOST

When the Patient is My Horse

Image courtesy Lexie Conrow, LVT

By Lexie Conrow, LVT

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August 30th, 2019 will be a day I will never forget.

Something I hoped would never happen to me or my horse happened. My horse had colic surgery.

I have spent my life as a horse woman and my career as an equine veterinary technician—watching countless horses and owners, friends and strangers, go through this experience.

It starts with the confusion and panic of the “before.” The “is she colicking or is she not?” The “ok — now what?” phase. I’ve met them at the door of the hospital, given a somber welcome and gotten to work.

I’ve seen patients—the horses—show us how they feel. I've heard them speak as they tell us in any way they can, the amount of pain they are in. I’ve watched the anguish and confusion of the owners who have to wrap their heads around what’s going on, who blame themselves for something that no one can control. I’ve been an integral part of the veterinary team who does their best to relieve pain (horse and human) and to try to offer clarity in a world that is often blurry.

The place I feel most confident in my profession-

Issue 8/2020 | ModernEquineVet.com

al life is my ability to be a part of that team. When the horse has spoken loudly enough and the owner has made the decision that surgery is the next step, I know exactly what to do: the dosages for drugs, the fluid rate and additives, pain management, ventilation, perfusion, blood pressure—all the things.

Throw it at me. I love it, and I live for it.

I’ve seen horses who have had colon torsions, displacements, enteroliths, lipomas, diaphragmatic hernias, sand impactions, parasites, gastric impactions, ileus—the list could go on and on and on.

In recovery, I’ve seen horses stand up like nothing happened, and I’ve seen horses flop like fish and break their legs. I’ve seen horses not make it to the recovery stall at all.

I’ve seen horses go home after 3 days and I’ve seen horses be sick for weeks after surgery.

I’ve seen horses go home and back to work whether that be on a racetrack, the jumper ring, cutting cows, making babies, or eating sugar cubes from their (human) kid. Minis, Drafts, Arabians, Thoroughbreds, Quarter horses, Mustangs…it doesn’t matter. I’ve seen them live, and I’ve seen them die. I

MORE THAN A HITCHING POST

thought I had seen it all.

What I’ve never seen is it be my horse….my love… my life…hanging in the balance. I’ve never had to be the owner who gets handed that paperwork and had to make that call. That Thursday night, I didn’t know how to be that person. More specifically, I didn’t know how to be both people, especially when my horse needed both people. How does someone who has seen what I’ve seen, who knows what I know, reconcile all those thoughts and emotions?

What I tried my best to do, was to rely on my work family, the veterinarian team—specifically the veterinary technicians who I work so closely with every day—to give my horse the best care possible ... like we do every day ... for every horse.

Going through this journey with my horse reminded me of why I became a nurse in the first

place—to relieve suffering, both horse and human. It reminded me that all the long hours and long nights, the years of study, the literal blood, sweat and tears...

It’s all worth it, if we can bring that 1 owner, that 1 horse, a little relief. Veterinary technicians are good at what we do because we love what we do.

We are more than a hitching post.

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About the Author

Lexie Conrow, LVT, has been a licensed veterinary technician for 8 years. She worked for Comstock Equine Hospital, Reno, NV, for more than 10 years. This was where she worked when her horse got colic. She recently moved to Kreature Komforts Animal Hospital in Sparks, NV. She has been a Regional Contact for the AAEVT since 2019.

ABOUT THE SERIES: More Than a Hitching Post is a series being run in the AAEVT’s Newsletter Hoofbeats as well as Modern Equine Vet. Equine veterinary technicians share their stories and feelings about their profession.

Chromosomal Defect Plays Key Role in Pregnancy Losses A new study found that a chromosomal defect plays a key part in a significant number of equine pregnancy losses, according to researchers at the Royal Veterinary College in the United Kingdom.

This defect is a key reason why a significant number of equine pregnancies fail within the first 2 months of development, they said.

Because the underlying cause behind equine pregnancy loss is often unknown, it is notoriously difficult for veterinarians to manage. In this study, researchers determined “aneuploid pregnancies” as the major factor for the condition. Aneuploidy is a condition in which a cell has an incorrect number of chromosomes. A common aneuploidy among humans is Down Syndrome.

Researchers collaborated with 7 different veterinary practices to gain access to samples from across the United Kingdom and Ireland and found that around 20% of the pregnancies lost were aneuploid.

To confirm the results, RVC PhD student Charlotte Shilton applied 3 different genetic approaches.

Scientists are now investigating the underlying cause

of these aneuploid pregnancies, with early data suggesting it is most commonly introduced via the egg or sperm.

Until now, chromosomal defects such as aneuploidy have only been reported as rare in young horses with developmental disorders.

Researchers said the study shows why the condition is so rare in horses and highlights the need to reconsider this condition both in pregnancy loss but also for early developmental disorders.

The researchers said the discovery could lead to the development of new diagnostic tests, offering hope to the thousands of owners of breeding mares that suffer this condition.

“Early pregnancy loss remains a very frustrating condition for clinicians to treat as the underlying cause is unknown in around 80% of cases,” said Mandi de Mestre, PhD, a reader in reproductive immunology at the RVC. “A diagnostic test would allow them to make informed decisions on treatment strategies and to advise on whether they should invest in further attempts to breed their mare benefiting both horses and their breeders alike in the future.”

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For more information: Shilton CA, Kahler A, Davis BW, et al. Whole genome analysis reveals aneuploidies in early pregnancy loss in the horse. Scientific Reports 2020; 10 Article number: 13314 (2020) Published online Aug 7. https://www.nature.com/articles/s41598-020-69967-z 14

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NEWS NOTES

The Role Serum Amyloid Can Play in Detecting and Monitoring Equine Infections More veterinarians are turning to serum amyloid A (SAA) to help them diagnose and monitor conditions faster.

SAA is a major, acute-phase protein produced by the liver that can be a reliable biomarker for inflammation due to infection. SAA levels rapidly and dramatically increase in response to an infection. Stablelab by Zoetis, a hand-held stall-side diagnostic blood test, can detect inflammation due to possible infection in about 10 minutes—in some horses before they showed clinical signs, such as fever.

Holly Helbig, DVM, and owner of the Hawthorne Veterinary Clinic, found herself caring for horses at a show when fevers started to develop. She suspected equine influenza virus due to the signs presented, and knew she needed to act quickly to protect the other horses.

“At a show, I will have upward of 700 horses under my care, so the SAA testing provided crucial information to help guide me in determining what horses needed to be isolated,” Dr. Helbig said.

Dr. Helbig developed and quickly implemented a plan of action to isolate and care for possibly infected horses. SAA testing provided the results needed to successfully enforce the plan, which included: • Monitoring horses in different barns that potentially came into contact with an infected horse at the show.

• Conducting an SAA test on horses showing EIV signs and obtaining results without leaving the horse’s side.

• Isolating horses with SAA levels greater than 50 and then testing for EIV. •Q uarantining EIV-positive horses to minimize the risk of spreading the virus.

•C onducting follow-up SAA tests 3 days later to monitor treatment response.

“In my practice, I use

Stablelab primarily for a fever of unknown origin, cellulitis and respiratory issues when I am at horse shows.

In cases like this one, where I suspected EIV, Stablelab proved itself a valuable tool to help me to monitor, isolate and treat infected horses,” Dr. Helbig said.

“Once a case of EIV is confirmed, horse owners worry that their horses could have been exposed or possibly infected,” Dr. Helbig said. “Horse owners are looking for a quick response for peace of mind.”

In addition to a situation such as Dr. Helbig described, measuring SAA is becoming popular in primary and ambulatory care to determine the need for antibiotics; it can be used during pregnancy, parturition and the early neonatal period to identify inflammation and ward off potential health challenges; and is used by referral hospitals to screen for subclinical inflammation due to infection prior to surgery and monitor the response to treatment over their hospitalization.

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Serum amyloid

A is a biomarker

of inflammation

that can signal the onset of infection and hasten diagnosis.

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