The Modern Equine Vet - April 2022 by The Modern Equine Vet

The Modern

Equine Vet www.modernequinevet.com

Is there a GutPerformance Connection? About 27% of Owners Buy Painkillers Without Consulting Veterinarians What's the evidence for CBD in Horses? Technician Update: The Importance of Whole-Horse Exams

ASK THE INFECTIOUS DISEASE EXPERT

Vol 12 Issue 4 2022

TABLE OF CONTENTS

COVER STORY

4 Gut-Performance Connection

Cover: Shutterstock/Kwadrat

IMAGING

Laying the Groundwork for Evidence-Based CBD in Horses ...............10 TECHNICIAN UPDATE

The Importance of Whole-Horse Examinations.......................................16 NEWS NOTES

About 27% of Owners Buy Painkillers Without Consulting Veterinarians.........................................................................................8 What Do You Call the Person Who Assists You?............................................14 SPONSORED EDITORIAL

“What’s the Infectious Disease Outlook this Foaling Season?”.........................3

ADVERTISERS Merck Sponsored Content..................................................................................3 Merck Animal Health..........................................................................................7 Shanks Veterinary Equipment..........................................................................9 Arenus Animal Health/Assure Gold...............................................................11

CareCredit............................................................................................................13 Arenus Animal Health/Aleira..........................................................................15 Arenus Animal Health/Assure Gold...............................................................17 Arenus Animal Health/Releira........................................................................19

The Modern

Equine Vet SALES: ModernEquineVet@gmail.com EDITOR: Marie Rosenthal ART DIRECTOR: Jennifer Barlow CONTRIBUTING WRITERS: Paul Basilio • Adam Marcus Cath Paulhamus COPY EDITOR: Patty Wall Published by PO Box 935 • Morrisville, PA 19067 Marie Rosenthal and Jennifer Barlow, Publishers PERCYBO media  publishing

Issue 4/2022 | ModernEquineVet.com

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ASK

THE

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

“What’s the infectious disease outlook this foaling season?”

hen working to protect foals, the infectious diseases to watch for fall into the 2 main categories of gastrointestinal and respiratory disease. Pay special attention to the following illnesses.

ROTAVIRUS A new strain of equine rotavirus became an issue in Central Kentucky last year and has appeared again this year. It is particularly challenging from a testing standpoint, because not all labs are currently able to identify it on standard PCR panels. While rotavirus doesn’t generally cause much mortality, it can cause a tremendous amount of morbidity in young foals. It is a highly contagious, hearty, non-enveloped virus that’s difficult to kill, so it can cause challenging, widespread outbreaks on farms.

LAWSONIA INTRACELLULARIS

As foals reach the weanling age, watch for Lawsonia. While it is not necessarily a new disease, it’s becoming an issue in areas where practitioners may not have seen many cases in the past. Geographic pockets are emerging here in New York, for example, and more cases are being identified on specific farms. Anecdotal trends point to Lawsonia being an environmental concern that varies from year to year, so it’s an important disease to monitor.

RHODOCOCCUS EQUI

On the respiratory disease front, the major concern is R. equi pneumonia, which can cause significant morbidity and, while mortality is not common, substantial economic loss. Many of our infected patients are about 1 month old. There are limited treatment modalities, and practitioners are encountering more cases of resistant R. equi infection. Prevention is difficult, but we are starting to administer higher volumes of hyperimmune plasma against Rhodococcus. One study recommends giving 2 liters very early in age instead of 1, indicating that may be beneficial to help prevent infection.1 Twice-daily temperature checks are the number one way to monitor for R. equi, as well as many other infectious diseases. To identify Rhodococcus early, rather than intensive ultrasound screening, I advocate monitoring for fever, as well as outward signs, such as a general quieting and lack of nursing. Ultrasound tends to lead to overtreatment with antibiotics, which promotes resistance of the R. equi bacteria. Many foals have subclinical R. equi infection that will resolve without treatment. Ultrasound results are most useful when combined with other factors, such as bloodwork, transtracheal wash results and temperature trends.

EIV, EHV-1 AND EHV-4 Foals are also susceptible to multiple respiratory viruses, such as equine influenza vi-

rus (EIV) and equine herpesvirus type-1 and type-4 (EHV-1 and EHV-4). These viruses can cause significant morbidity, especially in suckling and weanling aged foals. I recommend vaccinating foals as early as possible based on AAEP vaccination guidelines. Again, routine temperature monitoring, ideally twice a day, is crucial. If time only allows for once-daily temperature checks, measure in the afternoon or evening. Horses with an infection tend to have biphasic fevers, so farms that measure temperature only in the morning, such as before turnout, may miss a lot of fever. To support early disease identification, I’m excited about the BioThermo® microchips from Merck Animal Health that measure temperatures accurately and rapidly by scanning the implanted chip. In addition to daily temperature monitoring, farms would do well to step up their biosecurity plans to help limit the impact of infectious diseases. Being more mindful of new horses coming onto the farm is especially important during foaling season and on breeding farms with high traffic. If foals do become ill, I recommend screening for common infectious diseases to help guide treatment, implementing biosecurity measures and reviewing vaccination protocols. These diligent preventive measures and regular monitoring will help protect foals, one of the most vulnerable populations on the farm.

1. Flores-Ahlschwede, P., Kahn, S.K., Ahlschwede, S., Bordin, A.I. and Cohen, N.D. (2022), Transfusion with 2 litres of hyperimmune plasma is superior to transfusion of 1 litre for protecting foals against pneumonia attributed to Rhodococcus equi. Equine Vet Educ, 34: e67-e72. https://doi.org/10.1111/eve.13443.

ABOUT THE AUTHOR Laura H. Javsicas, VMD, DACVIM (large animal), practices internal medicine at Rhinebeck Equine, LLP, in Rhinebeck, NY. She has a special interest in neonatology, ultrasonography, cardiology, gastrointestinal diseases, and emergency/critical care medicine.

WANT TO ASK A QUESTION? EMAIL THE EDITOR. For more information, visit https://www.merckanimal-health-usa.com/species/equine.

GASTROENTROLOGY

Gut-Performance

CONNECTION Gastric Ulcers Can be a Reason for Poor Performance

Although many people immediately look at the limbs when a horse is not up to par, poor performance can be multifactorial, warned Frank M. Andrews, DVM, the clinical service chief of large animal medicine at Louisiana State University College of Veterinary Medicine. And 1 of those factors is the gut, particularly gastric ulcers, he said during a presentation at the 67th

Annual Convention of the AAEP, in Nashville, Tenn. “Horses are basically the GI tract on 4 legs,” joked Dr. Andrews, whose research area is the gastrointestinal tract. “So, they are hindgut fermenters. They eat a variety of feeds that we give them, which can contain a lot of carbohydrates. Horses weren't meant tp be in stalls and eat high-grain diets. They were meant basically to be out on the pasture grazing and

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“The more the horses travel, the higher prevalence of gastric ulcers and a lot of horses that travel to competitions are in the trailer for long periods of time and certainly fed high-grain diets before and after the exercise periods.” Human athletes can suffer gastroesophageal reflux, splashing of stomach acid up the esophagus. Horses also suffer from similar acid splashing while exercising, which is increased as the effort is expended. Unfortunately, there is no clear way to tell if an ulcer is present except by scoping the horse, he said. There are clinical signs that suggest a gastric ulcer might be present: reluctance to work, lack of energy

Shutterstock/dikkenss

continuously eating and then storing feed for that next pasture. “We've taken them out of that environment, and we need to look at the gastrointestinal tract when we're looking at poor performance,” he said, “paying attention to how they are fed, how they are housed, and whether they are stressed is important regarding performance. Because performance horses are fed high-carbohydrate diets, stabled and travel, instead of allowing them to graze, they are at risk for developing gastric ulcers,” he explained. “We know that there are a lot of risk factors that are associated with gastric ulcers in horses,” said Dr. Andrews, who is also a professor of equine medicine at LSU, “such as stabling, certainly exercise, fasting periods that occur. And then one thing that we really don't think about too much, frequent traveling.

ModernEquineVet.com | Issue 4/2022

GASTROENTROLOGY

WHO GETS GASTRIC ULCERS?

40% 60% 93%

in barrel racing Quarter horses

in jumpers

in racehorses

or dullness, poor performance—slowing near the end of the race, sudden stops, reluctance to gallop— and abdominal discomfort. In addition, horses tend to lose a little weight because they don’t eat as well. Laboratory findings are not useful, although a horse might be mildly anemic. The concern for owners, of course, is that a horse that is not performing is a horse that is not winning a purse. “Our owners are looking for earnings,” he said, so scoping the horse could be worthwhile if an ulcer is suspected. Management involves not only treatment but changing some habits. Reduce the days and level of training.

5 AM Exercise Omeprazole

6 AM Hay (alfalfa & grass) ad lib

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Allow ad lib forage and daily pasture turnout. “I would suggest that using alfalfa hay or adding alfalfa hay to the diet can be important,” Dr. Andrews said. “Horses that are out in the pasture have a lower prevalence of gastric ulcers, however, that's not necessarily true in all pastures, especially when the pastures are of really poor quality.” A course of omeprazole might be useful. Give the horse omeprazole for 2 weeks. “If you can rescope that horse in 2 weeks, you might find that the ulcers have healed, and you can save your clients 2 more weeks of omeprazole treatment at the normal dose, and then maybe taper the dose,” he said. To make sure that the dose of omeprazole was appropriate, a veterinarian can aspirate gastric juice and measure the pH after dosing the omeprazole, as omeprazole should increase pH and reduce stomach acid. Sometimes, medical management involves a multimedication regimen, which can be difficult for owners and trainers to do. Owners might balk a bit though. “You have all these treatments and owners are going, ‘gosh, darn, when do I give all this stuff? You got to have somebody at the barn all the time.” 8 AM He suggested this schedule, which would fit in Sucralfate with the training of a racehorse. At 5 a.m., give the omeprazole before he’s fed. Exercise and then around 6 or 6:30, give the animal some hay and 10 AM corn oil. At least 2 hours after the omepraMisoprostol zole, give the sucralfate, which is cytoprotective. At 10 a.m., give misoprostol. Both sucralfate and misoprostol must be given later, too. 4 PM Ulcer prevention using low dose Sucralfate omeprazole is effective so think about prevention. “Preventive treatment can make a difference and is effective in decreasing the number of 10 PM gastric ulcers in our horses,” Dr. Andrews added. A recent metaMisoprostol nalysis paper showed that prevention of ulcers using omeprazole is effective. MeV

TYPICAL TREATMENT SCHEDULE FOR HORSES IN TRAINING 6:30 AM Grain & corn oil

12 AM Sucralfate

Get the scoop on EPM RECOVERY

Effectively treating Equine Protozoal Myeloencephalitis (EPM) doesn’t have to be difficult. Reach for PROTAZIL® (1.56% diclazuril) Antiprotozoal Pellets • Goes to work fast (within 12 hours) — no loading dose required1 • The only FDA-approved alfalfa-based top dress treatment for EPM, proven safe and effective • No mess, no fuss - easy to administer and highly palatable 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 © 2022 Merck & Co., Inc., Rahway, NJ, USA and its affiliates. All rights reserved. US-PRA-210600001

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

NEWS NOTES

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:

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 of Horse (lb)

mLs of Pellets

Weight Range of Horse (lb)

mLs of Pellets

275 - 524

1275 - 1524

525 - 774 775 - 1024

30 40

1525 - 1774 1775 - 2074

70 80

1025 - 1274

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. 1.

2. 3. 4. 5.

Normal, neurological deficits not detected. 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.). Neurological deficit obvious at normal gaits or posture; signs exacerbated with manipulative procedures. Neurological deficit very prominent at normal gaits: horses give the impression they may fall (but do not) and buckle or fall with manipulative procedures. Neurological deficit is profound at normal gait: horse frequently stumbles or trips and may fall at normal gaits or when manipulative procedures were utilized. Horse is recumbent, unable to rise.

About 27% of Owners Buy Painkillers Without Consulting Veterinarians Many horse owners purchase painkilling and potentially dangerous drugs without having a veterinarian examine their horse first, a recent survey has found. The survey of 389 horse owners in the United States found that about 27% bought painkillers from noncompliant sources that would fall outside the veterinarianclient-patient relationship. As of November 2021, 47 states require some type of veterinarian-client-patient relationship to exist before a veterinarian may prescribe drugs for an animal, according to the most recent information from the American Veterinary Medical Association. Of all survey respondents: • Nearly 20% said they acquired pain relievers from a feed store; • Nearly 13% acquired drugs from on-

SURVEY OF 389 HORSE OWNERS IN THE UNITED STATES FOUND

20% Acquired pain relievers from a feed store

13%

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.

line or mail-order catalogs; and • 5% received drugs from a veterinarian who had never examined their animal. “By purchasing drugs online rather than from a veterinarian, owners miss many important aspects of a veterinary visit,” said Debra Sellon, DVM, PhD, DACVIM, a professor at Washington State University’s College of Veterinary Medicine. “When you see your veterinarian, you are going to get the best drugs, the best information, the best recommendation—and your veterinarian can help ensure you are confident in administering the drugs.” Dr. Sellon said as items become more available on the internet and people get more comfortable buying things online, the

Acquired drugs from online or mail-order catalogs

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.

received drugs from a veterinarian who had never examined their animal

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 © 2022 Merck & Co., Inc., Rahway, NJ, USA and its affiliates. All rights reserved. 07-2014 211.x.3.0.3

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number of drugs sold electronically is likely to increase. The survey found the most common drug horse owners had on hand was oral phenylbutazone, informally known as “bute,” a common pain reliever and antiinflammatory medication that was possessed by 87% of respondents. Dr. Sellon said some of the survey’s most interesting findings were the drugs some owners had, like injectable xylazine, a large animal sedative. The drug has toxic effects at high doses for horses. It can also harm humans if ingested or even spilled on broken skin. Nearly 8% of survey respondents said they had immediate access to injectable xylazine, and more than 12% said they administered the drug in the past 2 years. Dr. Sellon said veterinarians should have a conversation with owners who might not realize how dangerous some drugs can be, especially when those drugs are purchased online and without consulting a veterinarian. “They may have these drugs sitting out where they are available for kids to access or people who know nothing about them,” Dr. Sellon said.

Other common drugs like detomidine were also on-hand. Nearly 20% of owners said they had the gel form, which is dangerous to dogs and other animals. Nearly 27% said they administered the drug to their horses in the past 2 years. “I am not saying horse owners shouldn’t have these drugs. I am saying if you have them, know the risks and store them properly—I’d lock them up,” Dr. Sellon said. MeV

For more information: Dellon DC, Sanz M, Kopper JJ. Acquisition and use of analgesic drugs by horse owners in the United States. Equine Vet J. 2022 Feb 5. https://doi.org/10.1111/evj.13564. https://beva.onlinelibrary.wiley.com/doi/10.1111/ evj.13564

27 % 87 %

bought painkillers from noncompliant sources

Shutterstock/Rita_Kochmarjova

of respondents have oral “bute" on hand

Lifting Large Animals Since 1957 www.shanksvet.com

ModernEquineVet.com | Issue 4/2022

IMAGING

Laying the Groundwork for

Evidence-Based CBD in Horses As cannabidiol (CBD) continues its ubiquitous spread from pharmacies to gas stations to pet stores, it’s natural that owners are considering it for their horses. The products are marketed to reduce anxiety and pain, but human data about the safety, efficacy and pharmacokinetics of these treatments are limited, and there are even fewer data about its use in horses. CBD is also banned by most horse shows and equine governing bodies, but clients continue to use it in their horses. Alicia F. Yocom, DVM, and colleagues at the Colorado State University are helping the science catch up with the hype. “When we started, there were no published scientific studies looking at the use of CBD in the horse, except for a single case report of mechanical allodynB

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ia in a horse,” Dr. Yocom said during a presentation at the 67th Annual AAEP Convention in Nashville. “CBD is heavily marketed to our clients and to veterinarians at various doses and in various formulations, but we do not know what a clinically effective dose is at this point.” CBD and tetrahydrocannabinol (THC) are 2 of more than 120 compounds found in the Cannabis sativa plant. THC is the psychotropic compound responsible for marijuana’s well-known effects at getting people high, but CBD products must contain less than 0.3% THC—and it must be made from hemp. Currently, there is only 1 FDA-approved CBD product, which is indicated for epilepsy and seizure disorders in children 12 months of age or older. “Studies that have looked at behavior and arthritis are inconclusive at this point,” she added. “There are some

Shutterstock/BBstockimage

Trying to determine how it works in horses.

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IMAGING

CBD USE IN PET PRODUCTS

Although there are many companies selling CBD products for horses, there are no published surveys about how many people use the products in their horses. However, a survey about use in other pets can give a veterinarian a good idea about what their equine patients are getting at home.

Shutterstock/acceptphoto

ACCORDING TO A 2020 SURVEY BY NIELSON AND HEADSET* • Hemp-based CBD pet products will represent 3% to 5% of • To date, 24% of pet owners use hemp-CBD either for all hemp CBD sales within the U.S. by 2025. themselves, their pet(s), or for both. • 74% of CBD buyers have pets. • Nearly 26% of U.S. adults with dogs are using hemp-CBD products. Half already use hemp-CBD for their dog, while the • From the beginning of 2018 and to the third quarter of 2019, other half only use it for themselves. there was more than $9.4 million sales in pet products at regulated adult use cannabis retailers in California, • The average price per pound for CBD dog treats is 2x the Colorado, Nevada and Washington combined. average dog treat.

*Headset is a data and analytics service provider for the legal cannabis industry.

studies that have looked at dogs with osteoarthritis that have shown reduced subjective pain scores, but there was no improvement in objective lameness scores.” To gauge the plasma pharmacokinetics, shortterm safety and middle carpal joint synovial fluid levels of CBD, the team enrolled 12 adult horses— split evenly into 2 groups. The low-dose group received 1 mg/kg/day of CBD, and the high-dose group received 3 mg/kg/day for 6 weeks. The CBD used in the study was an oil product in a sunflower-lecithin oil base, and it was analyzed by a commercial lab before the study and again at 2, 4, and 6 weeks to test for purity. For 24-hour pharmacokinetics, the horses were given a full dose and blood was taken at 8 times in the first 24 hours. After that, the doses were divided into a twice-daily schedule. Each horse was fed 2% of its body weight in hay and was given 1 lb of grain approximately 30 minutes prior to CBD administration. “We gave the CBD in a fed state because there is a study in humans that showed an increase in oral bioavailability of 4- to 5-fold after humans were given a high-fat meal,” she explained. CBD plasma concentrations were found to be dose-dependent in both groups and time to maximum concentration was similar in both groups, with 12

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a mean of around 4-to-5 hours. There were no adverse effects noted on daily monitoring or physical exams in any of the horses after 6 weeks, but there were some abnormalities in the clinicopathological parameters. “We saw elevated liver enzymes in 8 of 12 horses, and hypocalcemia in all horses,” Dr. Yocom said. “Because of the hypocalcemia we checked the ionized calcium levels, which were normal in all horses.” There were some spikes in liver values in all horses, but they decreased or returned to normal by 10 days after the last dose. Two of the horses had elevated liver enzymes before the study, but they returned to normal levels after CBD was discontinued. After discontinuation of CBD, calcium levels improved or returned to normal in all horses. Elimination data showed that after discontinuation, CBD was still detectable in blood in both groups at 24 hours and in the higher dose group at 48 and 96 hours. CBD values were detectable in synovial fluid in 6 of 12 horses at 12 hours (1 in the low-dose group; 5 in the high-dose group). After 5 weeks of twice-daily administration, CBD was detectable in synovial fluid in 8 of the 12 horses. Plasma concentrations are markedly variable among individual horses, which is similar to results in dogs and humans. However, the total plasma concentrations of CBD for horses were significantly

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lower than in dogs and humans. “The low plasma concentrations found in horses is actually similar to guinea pigs,” Dr. Yocom added. “We don’t know if that’s because of the herbivore diet or that they’re both hindgut fermenters, but those are possible theories.” Average time to maximum concentration was also similar between groups, but the individual ranges were still quite large. It took anywhere from 30 minutes to 12 hours for horses to reach maximum plasma concentrations. “We would recommend dosing about 4 hours before your desired peak effect,” she said.

In the synovial fluid, CBD was only reliably detected in the high-dose group, and the plasma levels correlated with increases in synovial levels. “We don’t know if there may be a cumulative effect since we did see CBD in synovial fluid more frequently after 5 weeks when compared with 12 and 24 hours,” Dr. Yocom explained. While the study was the first step in evidencebased analysis of CBD in horses, the doses used in the study were much higher than are typically present in commercially available supplements so that the team could provide a measure of safety data for future studies. MeV

For more information: Yocom AF, O’Fallon ES, Gustafson DL, et al. Pharmacokinetics, safety, and synovial fluid concentrations of single- and multiple-dose oral administration of 1 and 3 mg/kg cannabidiol in horses. J Equine Vet Sci. 2022;(18)113:103933. https://www.sciencedirect.com/science/article/abs/pii/S0737080622000715?via%3Dihub

What Do You Call the Person Who Assists You? Only 10 states have a clear definition for the title “veterinary technician” and restrict its use to people with formal credentials in that state, according to a new report by the National Association of Veterinary Technicians in America (NAVTA). Veterinary practice acts in 29 states, the District of Columbia and Puerto Rico lack restrictions on use of the title “veterinary technician.” Another 10 states limit who can use titles of “certified veterinary technician,” “licensed veterinary technician,” “licensed veterinary medical technician” or “registered veterinary technician,” but do not restrict use of the more general title of “veterinary technician.” Ashli R. Selke, NAVTA president and a credentialed veterinary technician, said NAVTA data indicate that title protection and pay are among the top concerns of veterinary technicians, many of whom think improved title protection will lead to better pay. “Protecting the title of ‘veterinary technician’ is the right thing to do from a legal perspective, helps the consumer better understand who they are working with, and gives the title value,” Ms. Selke said. “That, in turn, enhances the profession and creates an incentive for indi-

viduals to go to school and earn the right to use that title.” The NAVTA report offers detailed recommendations for legislatures and regulatory agencies, academic institutions, veterinary medical and technician associations, veterinary practices, and others. “We commend our colleagues at NAVTA on this important study,” said Jose Arce, DVM, the president of the American Veterinary Medical Association. “Veterinary technicians—graduates of an AVMA Committee on Veterinary Technician Education and Activities® [CVTEA]- or Canadian Veterinary Medical Association [CVMA]-accredited program—are an integral part of veterinary medicine and care teams. The AVMA encourages schools, organizations and regulatory authorities to use the appropriate terminology for veterinary technicians, who are integral parts of veterinary medicine and care teams.” There are 216 veterinary technician programs in the United States accredited by the AVMA’s CVTEA, which graduate about 5,500 students per year.

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For more information: Protection for ‘Veterinary Technicians’ is Needed and Desired, But Absent and Misunderstood in Most States. https://d2vjg8vjbfxfu1.cloudfront.net/app/uploads/20220222135054/NAVTA_Title-Protection_Whitepaper_final-1.pdf.

Issue 4/2022 | ModernEquineVet.com

IN A WORLD OF ITS OWN

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TECHNICIAN UPDATE

The Importance of Whole-Horse Examinations

Image courtesy of Jessica Cook. Image courtesy of Platinum Performance®

By Jessica Cook

A whole horse examination is just as it sounds. It is a baseline evaluation of the horse’s entire body rather than focusing on just 1 area. Palpating, manipulating and mobilizing the neck, back, pelvis and limbs can help determine the causes of poor performance—not just lameness—identifying, treating and managing these issues for the future. With advances in sports medicine for the equine athlete, we are moving away from “scheduled injections” and focusing on what the patient needs now. It’s understood that if there is a significant pathologic or physical reason to treat a specific area on a regular schedule then you do that, but for the most part, we want to keep our equine partners at their absolute best. This is where the whole-horse examination comes in. Every veterinary practice is likely to have a different approach to the exam, but the following describes how we approach it. First, a patient history is obtained and if it is a new patient, a physical exam—including listening to the heart and lungs—is performed. An oral exam will look for any abnormality that may cause discomfort with bitting or be affecting eating and body condition. Every patient on every visit is given a body-condition score. Breed, fitness and occupation is considered to discuss how this may directly affect overall performance. The horse stands on a level surface with the limbs as square as possible. The symmetry of the forehand and

Issue 4/2022 | ModernEquineVet.com

hind-end bony structures and muscles are compared. The symmetry of the body depends not just on conformation, but the repetitive use or disuse/misuse of muscle groups over time. A horse that has more development on one side may be favoring a limb without any evidence of being lame. Structural asymmetry can be due to conformation, trauma, or asymmetric movement over time. Starting with the neck, back and pelvic region; each area is palpated repeatedly to evaluate for heat, sensitivity or structural abnormality. These areas are then put through a series of mobility tests to look for suppleness and/or reactivity to movement as well the range of motion. The range of motion of some of these tests may have variations due to breed and age. All 4 limbs are palpated in the standing and flexed positions. Notes are made regarding any joint effusion (inflammation of a joint notable by palpating the joint’s recesses), bony irregularities (ie. splint) any angular limb deformation (ie. toes in/out). In the flexed position we evaluate for range of motion of each joint, palpate all the soft tissues (when the limb is not weight-bearing, the tendons and ligaments between the knee and ankle can be palpated individually). Health and symmetry of the feet are also evaluated. A grading scale is used for all findings to allow a reference for changes over time. From there we begin the movement phase of the evaluation. Horses are walked and jogged on a flat, firm surface to see baseline soundness and symmetry of movement, also noting how each foot lands. Ideally, a horse moves symmetrically and lands with each foot level on the ground. Common abnormalities include feet landing asymmetrically inside or outside, a hind

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TECHNICIAN UPDATE

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Teaching Points The value of the whole horse examination is to know what the horse’s body may be trying to tell you at a single point in time. Some owners elect to perform these once a year either before or during a competitive season. The findings are put in a detailed form that will allow for comparison with future examinations. Similar to people, our horse’s bodies change over time. It is valuable to know how to best support our equine partner’s needs. Although we can’t make them younger, we hope to keep them at their best each step along the way.

toe tapping the ground on 1 side or a limb cross-tracking. Normal movement would be a horse tracking each of the hind limbs toward the same-side forelimb, feet landing level on the ground and having a good arc of flight with the hind toes being lifted and placed. Flexions, or dynamic stress tests, are often performed but are an interpretive art. To separate upper and lower limb, they are stressed more directly individually. Proximal or upper-forelimb flexion, for example, stresses shoulder, elbow, and carpus—not just the carpus—and distal- or lower-limb flexion would stress the fetlock, pastern and coffin joints. We add in variations like cross-limb flexions (for hind end) or extension of limbs. Alterations in gait can be isolated further with these additional tests. Watching a horse on a lunge line allows the examiner to evaluate a horse without the rider, however, not every horse is amenable and if it is deemed unsafe or unlikely to provide valid information, it is not performed. The most common parameters evaluated on the lunge relate to limb movements, i.e., length of stride, arc of flight, tracking. Equally important is body position that can be evaluated regarding the natural suspension, curve, and movement of the axial skeleton (neck, back, pelvis). A normal horse should bend around the person and not be straight or reverse in its bend, as well as have a natural spring-like motion to its back and pelvis. Evaluation under tack allows the veterinarian to see how a horse uses themselves with their rider. Does weight on their back change movement? Are they un18

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able to maintain a lead at a canter? Even behavioral issues can be considered when putting everything together. A rider can directly influence movement— sometimes positively and sometimes negatively. When evaluating a horse for baseline and performance, there is never too much information. Starting with each gait in each direction on an approximately 20 m circle, we usually ask the rider to show us other movements that the horse is expected to perform. This will vary with discipline, but may include dressage movements, jumping over fences, or any other discipline-specific movements. The information-gathering portion is time consuming, but a thorough baseline is paramount to gauge changes over time. Now that you’ve spent the better part of 2 hours with your veterinarian, what’s next? Usually, at this time it’s best to allow a horse to return to its stall for a little break from us while we discuss the whole picture with all parties involved. The idea of “it takes a village” is true with horses and discussions often include not just an owner but trainers, farriers, bodywork people and more. The veterinarian will give a synopsis of findings and any recommendations. After localizing regions of interest/problems the information is used to create an appropriate plan for diagnostic analgesia (blocking), if appropriate, and diagnostic imaging. Then all the information is used to create a plan for treatment, rehabilitation (when needed), and management. Occasionally, nothing is recommended on the day of evaluation and instead, a plan is made for treatments to be performed in the future when they will most benefit a competition schedule. MeV

About the Author

This year marks 20 years of Jessica working with Cooper Williams, VMD, at Equine Sports Medicine of Maryland. After horse showing for several years in the hunter/jumpers, she was hired by the practice and trained by Dr. Williams. She has a special fondness for the racehorses within the practice but enjoys getting to know the wide variety of patients. Being a technician, Jess relishes the opportunity to learn and aid in diagnostic imaging. In 2018 she submitted a case study paper to the American Association of Equine Veterinary Technicians and was selected to have the paper printed in the proceedings, as well as present the case at the San Francisco meeting for the organization. When not keeping up with the doctors on the road, or working in the office, Jess enjoys spending as much time outside with her rescue dog, Pilot, as possible, hiking and gardening.

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The Modern Equine Vet - April 2022

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