The Modern Equine Vet - July 2018 by The Modern Equine Vet

The Modern

Equine Vet www.modernequinevet.com

Vol 8 Issue 7 2018

Fierce Competition Competion

Equine Athletes Look to Humans for Competitive Edge

Endurance Sports: How to Spot Colic in a Horse on the Run I Snort, Therefore, I'm Happy

Technician Update: A case of Equine Multinodular Pulmonary Fibrosis Airway Disease Prevalent Among Racehorses

TABLE OF CONTENTS

COVER STORY

Competition 4 As Becomes Fiercer

Equine Trainers Look to Human Athletes Cover photo: Riley Brandt, University of Calgary

SPORTS MEDICINE

Endurance Rides: How To Spot Colic in a Horse on the Run........................................12 TECHNICIAN UPDATE

Equine Multinodular Pulmonary Fibrosis...........................................................................16 NEWS

Airway Disease Prevalent Among Racehorses..................................14 Changes in Artificial Breeding Techniques Improve Success.................................................................15 Riders: Find Old Four-Legged Friends..................................................15 I Snort, Therefore, I'm Happy................................................................21 FDA Investigates 6 Horse Deaths.........................................................21 ADVERTISERS Merck Animal Health..................................................3 Boehringer Ingelheim/Gastroguard....................... 5 Boehringer Ingelheim/Equioxx................................ 7

Vetquinol....................................................................... 9 AAEVT............................................................................17

The Modern

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

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The Science of Effective Unique Mode of Action is what makes Panacur® (fenbendazole) so effective against the most dangerous parasites of the horse.

LO O K IN SID E D E WO RMIN G:

science-of-effective.com 1:10

2:46

Panacur: The Science of Effective

Consult your veterinarian for assistance in the diagnosis, treatment and control of parasitism. Do not use in horses intended for human consumption. When using Panacur® (fenbendazole) Paste 10% concomitantly with trichlorfon, refer to the manufacturer’s label for use and cautions for trichlorfon.

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

ModernEquineVet.com | Issue 7/2018

SPORTS MEDICINE

As Competition Becomes Fiercer

Equine Trainers Look to Human Athletes

Treadmill Improves Rehabilitation and Conditioning

The water treadmill revolu-

tionized rehabilitation and conditioning of human athletes, and today those same principles are gaining recognition in the training and conditioning of equine athletes. “Numerous claims about the benefits of water treadmill exercise in horses have been made, but the evidence is mostly anecdotal,” explained

The Coulee Equine Horse Gym USA Water unit, along with the unique mask system that measures equine ventilation in the field. (l to r): Katie Imler, owner of Coulee Equine; Persephone Greco-Otto, BSc, and Stephanie Bond, both PhD candidates at University of Calgary Faculty of Veterinary Medicine.

Issue 7/2018 | ModernEquineVet.com

Persephone Greco-Otto, BSc, who is a PhD candidate studying equine water treadmills at the Faculty of Veterinary Medicine, University of Calgary in Canada. “But now new and exciting scientific data have revealed significant increases in maximal oxygen consumption [VO2max] and endurance during water treadmill exercise.”

Why does this information matter to equine clinicians? “It’s the first evidence-based data examining water treadmill conditioning in competition horses,” she noted during her presentation at the 63rd AAEP Annual Convention in San Antonio. “Using new technology, we were able to record elaborate data on VO2max, ventilation, run-

Photo: University of Calgary, Faculty of Veterinary Medicine

WI N N I NG d o es n’ t h a p p e n

B Y

A C C I D E N T.

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

Time for a gut check. TheStomachToWin.com

by Merial

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

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

ning speed, blood lactate and heart rate during water treadmill training in the field.”

Back to Basics

But before delving into the study, let’s briefly review some basics. What is a water treadmill, and how were study data captured and analyzed? Treadmills originally were designed for rehabilitation of musculoskeletal injuries in humans, but their use quickly moved on to conditioning training. Today, both rehabilitation and conditioning water treadmill protocols are gaining popularity in a wide variety of species. This dual-purpose modality reflects the unique properties of water: Viscosity coupled with bouyancy of water allow for very high-resistance, low-impact exercise, which is important when rehabilitating an injured animal but also when trying to prevent future injuries during conditioning. “As shown in the opening picture, the water treadmill used in this study is the Horse Gym USA Water unit from Coulee Equine,” Ms. Greco-Otto explained, adding that “the unit features a unique Plexiglas chamber, while most water treadmill chambers resemble a metal-type box.” Researchers also used a unique ergospirometry mask system that continuously measures VO2, respiratory frequency, tidal volume, minute ventilation and ratio of expiratory duration to inspiratory duration. “This new technology is one of the first to measure equine ventilation in the field—that is, outside of a lab. This [system] allows us to examine the fitness of horses while they’re being ridden in their respective discipline,” she said, noting that data are calculated using customized software, with breath-by-breath recordings analyzed after steady state has been reached. Environmental conditions are also factored into ventilation calculations as well. What is the focus of equine conditioning? Equine conditioning has traditionally focused on skills rather than fitness. The specific conditioning protocols naturally depend on the competitive discipline, but regardless, today’s focus should not only be on skills but also on the fitness required to 6

Issue 7/2018 | ModernEquineVet.com

complete those skills, she emphasized. “It’s difficult to identify or outline training protocols because each owner, trainer and rider has a slightly different approach.” Over the course of their careers, equine athletes endure endless hours of long-distance work, speed and skills training—all designed to ensure overall fitness as well as foster competitive success. “Conditioning horses involves a variety of systems, including respiratory, cardiovascular, muscular and general fitness [of tendons and ligaments],” Ms. Greco-Otto said, adding that traditional conditioning methods may include mechanical walkers, (dry) treadmills and standard ridden programs.

Study Parameters in a Nutshell

Objective: The objective or goal of this study was to determine whether water treadmill training could improve the conditioning or fitness of horses, Ms. Greco-Otto explained. Specifically, they looked at VO2max, ventilation, running speed, blood lactate and heart rate to determine the effect of an 18day water treadmill conditioning protocol using a high level of water (stifle height) to improve equine fitness. Why stifle-height water? They conducted an earlier study that looked at water treadmill workload in unfit Quarter horses (barrel racing competitors). In the water treadmill, workload is a function of water height and treadmill speed. The effect of water height interacting with speed was significant on VO2, tidal volume and heart rate, all peaking at the highest water level and a fast walk (ie, stifle water height at a speed of 1.45 meters per second), so this was used as a benchmark. Hypothesis: Water treadmill training would improve the conditioning or fitness of experimental horses, as compared with a control group working on dry treadmill training (ie, no water) at the same speed and for the same duration. Study design: This randomized, controlled study was conducted on 9 unfit, client-owned Thor-

by Merial

in a p A O g in g a n a m e s u a c Be in. shouldn’t cause more pa

ty profile.

ceptional safe ex an ith w y ac fic ef s er liv EQUIOXX de

tis pain and oice for treating osteoarthri ch ht rig the is XX UIO EQ d you’ll fin When you do the research, . inflammation for your clients for horses – spares COX-1

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

D out to pasture. See how Time to put your old NSAI rence for your clients. ffe di a e ak m n ca X OX UI EQ

EQUIOXX.com

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

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

SPORTS MEDICINE

Methods: Overview Study design: Randomized controlled study CAUTION: Federal law restricts this drug to use by or on the order of a licensed veterinarian.

CONTRAINDICATIONS: Horses with hypersensitivity to firocoxib should not receive EQUIOXX.

Days

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

•  Nine unﬁt Thoroughbred horses •  6 experimental (water treadmill) •  3 control (dry treadmill)

FIGURE 1. Overview of study timeline.

oughbred horses that were used for polo but had finished their competitive season and been de-conditioned for 6 months over the winter. The horses were randomly assigned to 1 of 2 groups: experimental (6 horses), where they underwent water treadmill training, or control (3 horses), where they worked on the same treadmill, but without water (dry treadmill). Methods overview (Figure 1): First, they had to establish the horses’ baseline fitness testing (Day 0), which they did on a racetrack at Bar None Ranches in Alberta. They shipped the horses to Coulee Equine, a water treadmill facility (also in Alberta), where they became acclimated (Days 3 to 9) to the treadmill as well as to their new housing, as they stayed at the facility through the entire course of training. Actual treadmill training began on Day 10, with maximal treadmill training at Day 19 and all training ending at Day 28, for a total training time of 18 days. Post-training testing occurred on Day 31 at the same racetrack used for baseline testing. They did not start the experimental horses at a stifle water height but instead gradually increased the water height over the initial 9 days of training, reaching maximal stifle water height at Day 19. Let’s look a little bit closer: Both groups of horses worked for a to8

Issue 7/2018 | ModernEquineVet.com

tal of 20 minutes per day (not including filling or emptying the water treadmill chamber, which was used for warm-up or cool-down, respectively). Both groups worked at the same speed of 1.45 meters per second, which is a fast walk. The only difference, of course, was that experimental horses worked in water and control horses worked without water. Both groups of horses were tested (Figure 2) before and after treadmill training, completing first an incremental test and then a maximal intensity test with a jockey and a lighter version of the facemask system for recording data (Figure 3). An incremental test was used as a warm-up, followed by a maximal intensity test of 800 meters, where the jockey pushed the horses as fast and hard as they could go. Based on data gathered from the devices, they obtained a number of measured outcomes: • Maximum oxygen consumption (ie, VO2max) • Tidal volume • Breathing frequency • Blood lactate • Heart rate • Speed

And the Results Show. . .

So, what did they find? Let’s start with VO2 because that’s really the gold standard of athletic research in humans. “This part is very exciting,” Ms. Greco-Otto said, “as finally

Credit Line: University of Calgary, Faculty of Veterinary Medicine

EQUIOXX® (firocoxib) is indicated for the control of pain and inflammation associated with osteoarthritis in horses. Firocoxib belongs to the coxib class of non-narcotic, nonsteroidal anti-inflammatory drugs (NSAID).

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SPORTS MEDICINE Methods: Racetrack TesIng

ConInuous

5, 80 min post maximal test

FIGURE 2. Both baseline data and post-treadmill training data were gathered through racetrack testing (incremental and maximal intensity tests).

we can measure VO2 in horses in the field! This previously was possible only under laboratory conditions, so the new facemask technology will revolutionize field data collection for horses.” Maximum oxygen consumption: Figure 4 shows the VO2max is measured in mL/kg/min on the Y axis, with time point [pre and post] on the X axis. All horses started at the same point and had the same level of fitness, with no significant differences between the 2 groups. Clearly, in the experimental group there is significant difference between pre and post training—with a 16% increase. “This increase is huge,” she emphasized, “especially considering that our study only spanned 18 days and involved walking only [not a canter or gallop].” In contrast, the control horses showed a decreasing trend in oxygen consumption. Ventilation (respiratory frequency, tidal volume): When it came to respiratory frequency (breaths per minute) and tidal volume (liters), there were no significant differences between any of these measurements either 10

Issue 7/2018 | ModernEquineVet.com

Credit Line: Riley Brandt, University of Calgary

Credit Line: University of Calgary, Faculty of Veterinary Medicine

1.  Incremental test (4, 6, 8 m/s) 2.  Maximal test

FIGURE 3. During racetrack training (Bar None Ranches, Olds, Alberta), a lighter version of the facemask system was used to record data, and researchers had direct communication with the jockey, telling him when to speed up or slow down.

at time point or between groups. This finding isn’t surprising, as previous work has shown that, in horses, ventilation does not change with exercise, she explained. But how can one explain the obvious 16% change that occurred in the VO2max? In human athletes, increased VO2max during athletic training occurs in part because they change breathing strategy. Human athletes actually reduce their respiratory frequency and increase their tidal volume, taking fewer and deeper breaths to effectively reduce the work of breathing. Equine athletes can’t do this, so when people observe Thoroughbreds at high speeds, they see locomotor respiratory coupling, which basically puts horses in a 1:1 ratio of breaths to strides. Because of this coupling, horses cannot alter their breathing strategy. Instead, increased VO2max in horses largely reflects cardiac adaptations. Heart rate & blood lactate: There were no significant differences in maximal heart rate of horses during training in either the ex-

perimental or control group. Work has shown that, unlike in humans, a change in maximal heart rate does not occur in horses during training. Likewise, lactate values at 5 minutes post exercise and 80 minutes post exercise showed no changes in either study group. Our final indicator—speed: These results are dramatic, according to Ms. Greco-Otto. Figure 5 shows the average speed over the entire 800 meters, with the Y axis giving average speed in meters per second, along with the same setup of time point on the X axis. Although the horses increased their average speed, it wasn’t in terms of instantaneous maximal speed—the horses didn’t break their previous records. “Although they weren’t faster from that perspective,” Ms. GrecoOtto explained, “there was greater endurance, with an average of almost 17.5% increase from pre to post in the experimental group.” To give an idea of what this increase achieved, the horses beat their pretraining speed by 80 to 96 lengths. Thus, even though they did not go faster in terms of maximum speed,

Results: Maximum Oxygen ConsumpIon

st Po

Po s

100

Pr e

16.1% increase (p= 0.03)

Pr e

VO2max (ml/(kg.min))

100

FIGURE 4. Maximum oxygen (VO2max) consumption from baseline to post training increased by 16% in the experimental group, while consumption actually decreased in the control group.

150

Water treadmill (experimental horses)

Take-Home Messages

Dry treadmill (control horses)

Results: Speed (Average)

FIGURE 5. Speed measurements confirmed a dramatic increase in the endurance of the experimental horses, with an average increase of almost 17.5% from baseline to post-treadmill training.

Average speed over 800 m sprint 15

5 17.4% increase (p= 0.03)

Water treadmill (experimental horses)

tion of bone and tendon remodeling, but excessive overloading can lead to injury. Establishing the scientific evidence needed to develop sound conditioning protocols for equine athletes participating in all forms of competition is essential to success. Based on the results of this study, water treadmill conditioning may be beneficial when added to existing exercise protocols for competition horses. How can water treadmills fit into an existing exercise? Use of water

st Po

e Pr

0 Pr e

Average speed (m/s)

15 Credit line: University of Calgary, Faculty of Veterinary Medicine

A dramatic shift in thinking is definitely taking hold, Ms. Greco-Otto noted, with more trainers and owners regarding their horses as athletes. “When we start thinking of horses as athletes, we then compare how we train them to how we train ourselves. This line of thinking is leading owners and trainers to question whether they are conditioning their horses in the best ways possible and to consider which technology might improve performance.” In addition, competition is getting stiffer, where the difference between first place and second place is becoming very small. “When a win versus a loss is less than one second,” she explained, “trainers realize they need to have a wide variety of tools at their disposal to ensure that they have a competitive edge.” Trainers also are becoming more proactive regarding injury prevention. Any type of training that limits some of the harmful loading on the limb is becoming a more attractive choice, she said, adding that loading is normal and essential for stimula-

150

VO2max (ml/(kg.min))

they maintained higher speeds for much longer periods. In contrast, the control horses demonstrated no change. Likewise, the average speed over the final 30 seconds of sprint showed a 12% increase in experimental horses; whereas in control horses, they had a tendency to reduce their final speed.

Dry treadmill (control horses)

treadmills could supplement or replace some ridden work. “For example, if you normally ride 5 times per week, you could instead ride 3 or 4 times, with 1 or 2 water treadmill sessions,” Ms. Greco-Otto suggested. Meanwhile, she emphasized, veterinarians need to continue accumulating data through randomized, controlled research on the effects of water treadmill training and the athletic fitness of horses. The ultimate goal is to create more robust conditioning guidelines for each competitive discipline. MeV

For more information: Greco-Otto P, Bond S, Sides R, et al. Workload of horses on a water treadmill: effect of speed and water height on oxygen consumption and cardiorespiratory parameters. BMC Vet Res. 2017;13(1):360. Ms. Greco-Otto extended much thanks and appreciation to her coauthors of the VO2max study: • From the Equine Respiratory Lab, Faculty of Veterinary Medicine, University of Calgary: Renaud Léguillette, DVM, MSc, PhD, DACVIM, professor of Equine Internal Medicine; and Stephanie Bond, DVM, a PhD candidate. • From the Equine Exercise Lab, Washington State University: Warwick Bayly, BVSc (Hons), PhD, DACVIM (Large Animal), professor of Equine Medicine; and Raymond Sides, AAS, BMET. In addition, special thanks to Coulee Equine Conditioning, Rehabilitation and Wellness in Olds, Alberta, Canada (site of treadmill testing); and to Bar None Ranches in DeWinton, Alberta, Canada (site of baseline and post-training testing). ModernEquineVet.com | Issue 7/2018

SPORTS MEDICINE

Endurance Rides:

How To Spot Colic in a Horse on the Run

Traveling 100 miles in 24 hours with someone on your back is hard work.

Aizuddin Saad / Shutterstock.com

Globally, about half of all horses that begin endurance races of anywhere between 25 to 100 miles will be eliminated during the race following an unsatisfactory veterinary examination. For U.S.-based rides, that number is reportedly around 15%. Examination stations are situated

Issue 7/2018 | ModernEquineVet.com

at the end of each phase of the race— every 15 to 20 miles. Horses are evaluated for heart rate, hydration, presence of gut sounds and gait. An estimated 60% of eliminated horses are disqualified for reasons associated with lameness, and about 15% of the eliminated horses are pulled off the trail for metabolic disturbances.

o “That might be an underestimation of the number of horses that really developed metabolic disturbances,” explained Yvette Nout-Lomas, DVM, PhD, DACVIM, DACVECC, assistant professor of equine internal medicine Colorado State University. “Undoubtedly, electrolyte distur-

bances and muscle disorders can also result in unsoundness.” Approximately 12% of endurance horses require emergency medical treatment on site, but that number may be an underestimation as well. Some horses may complete the rides and then go on to require some treatment after leaving the race site. Data from the American Endurance Ride Conference (AERC) show a fatality rate of about 0.03% from 2002 and 2016, compared with a fatality rate of about 0.2% for horse racing, as reported by the American Jockey Club. While endurance rides are relatively safe for the horses overall, Dr. Nout-Lomas said that the outcomes for the horses could be even better with earlier recognition of horses in trouble, so that treatment could be initiated earlier.

Recognition of Signs

Typically, a horse presenting with signs of colic would undergo physical examination, receive an NSAID and have a nasogastric (NG) tube placed, depending on severity of disease. An examination per rectum would then be performed to fully assess the GI system. “Some [endurance] horses will display overt signs of impending colic that will be picked up at veterinary checkpoints, but there is a subset of horses that are discovered by the owners to not be recovering well or not acting normally [after the event],” Dr. Nout-Lomas said. “These horses are sometimes missed because they have relatively normal clinical examinations, but we should pay attention to them.” The examination of an endurance horse is different from a typical patient. For example, a heart rate of 50 to 65 beats/min is not uncommon in an endurance horse that is experiencing significant colic pain. In addition, there may not be any reflux after initial placement of

an NG tube; however, gastric filling may occur with ongoing disease. Dr. Nout-Lomas recommended that the NG tube should remain in place during transportation of the horse.

Drug of Choice

Nonsteroidal anti-inflammatory Drugs (NSAIDs) are not recommended at the initial onset of clinical signs in endurances, because the horses are likely to have marked dehydration, she said. “If NSAIDs are to be used,” she explained, “horses should first be administered a good volume of fluids. Preferably 20 to 30 L before the NSAID, and even then it’s probably better to give a lower dose initially.”

Fluids

Some research has shown that horses could be starting the race at a deficit. During transportation to the event, they can lose between 5 L and 10 L of fluid per hour, which can add up to a severe fluid loss. “Ideally, horses should be administered 30 L to 50 L of balanced electrolyte solutions if they develop problems,” Dr. Nout-Lomas said. “This should be continued until they have urinated.” Horses should be continued at a maintenance level until the urine is clear and the creatinine levels are normal, if the necessary monitoring equipment is on site. However, intragastric fluids should be avoided, since the GI system functionality is likely to be limited in a volume depletion setting. If a horse needs to be restrained or calmed down, appropriate doses of xylazine and detomidine can be used, she suggested.

Nothing Per Rectum

Examination per rectum is a valuable part of a GI examination, but it could put an endurance horse at more risk. Arabian horses tend to dominate the endurance circuit,

and these horses are already at an increased risk of developing rectal tears. A rectal examination in a dehydrated Arabian horse may just be compounding trouble. “Based on what we know of these horses and the types of colic they develop, a rectal examination is probably not going yield a lot of extra benefit in the overall assessment,” Dr. Nout-Lomas said. “If ultrasonography is available, that could be very useful in measuring stomach size, looking at small intestinal distention and assessing GI motility.”

Monitoring

Stall-side laboratory equipment is useful for horses as they’re receiving fluids to determine whether they have added-on metabolic or electrolyte disturbances. Packed cell volume, total protein, electrolytes, creatine kinase, creatinine and lactate levels should all be recorded. As the rides are often done under aerobic conditions, Dr. Nout-Lomas said that lactate levels should be <4 mmol/L after the ride. However, if the horse arrives to the event already dehydrated or develops metabolic problems during the ride, then the levels may be much higher. “If the horse needs to be transported somewhere else to continue treatment, consider another bolus of fluids or providing fluids during transportation to the referral center, especially if the referral center is far away, which is not uncommon during these rides,” Dr. Nout-Lomas said. “Check for reflux before they're shipped, and consider leaving the nasogastric tube in place.” Despite the physical toll that a 100-mile ride can exact, the prognosis in these types of horses for non-strangulating small intestinal lesions—the most common cause of colic on these rides—is favorable, she said. MeV ModernEquineVet.com | Issue 7/2018

NEWS NOTES

Shutterstock.com/Mikhail Pogosov

Airway Disease Prevalent Among Racehorses Inflammatory airway disease (IAD) can rob a racehorse of its stamina, and a recent study in the Ontario Veterinary College at the University of Guelph in Canada, shows the disease is much more prevalent among racehorses than previously thought. “We looked microscopically at the lung tissue of horses that died during or just after races, and quantified the inflammatory cells within their airways,” said Luis Arroyo, LVM, DVSc, PhD, DACVIM (Large Animal), a professor in the Department of Clinical Studies. “We expected to find that the majority of the animals would have normal airways, with only a small number actually affected with the disease, but that was not the case.” Along with graduate student Federika ter Woort and Jeff Caswell, DVM, DVSc, PhD, DACVP, Dr. Arroyo discovered that most of the horses had some degree of IAD, with mild to severe airway changes. Previous research suggested the disease occurs in up to half of equine athletes. “The disease was known to be common in racehorses, but not as widespread as this study reveals," explained Dr. Caswell, who is a professor of pathology at the University. “The findings suggest that IAD does not result from unique exposure of an affected horse to the

stimulus that causes the disease. But rather the research suggests that all racehorses may be exposed, with inflammation of the airways experienced by many.” The researchers examined lung tissue from 95 deceased racehorses, including Thoroughbreds, Standardbreds and Quarter horses that had actively raced or trained before their deaths. They assessed inflammation by histology among horses not specifically selected for poor performance. “None of the deceased horses showed obvious signs of airway inflammation in their final three races,” Dr. Arroyo said. “The research shows that inflammation is always prevalent in racehorses, even those that may or may not have respiratory signs.” Unlike equine asthma in older horses, IAD causes no observable symptoms at rest but only during exercise. It most readily shows itself in poor race times, according to Dr. Caswell. Possible causes of IAD include: • recurrent pulmonary stress, • deep inhalation of dust, • airborne pollutants and • persistent respiratory viral infections. Young horses have a higher risk of exposure to these factors because of frequent transport, intense exercise and time spent in stables, the researchers said. Little is known about how IAD changes an affected horse's lungs, according to Dr. Arroyo “At this stage, the findings are mainly relevant to understanding the nature of the disease and how it develops. Until now, there was no knowledge about a potential correlation between the classification of the inflammatory cells in the airways and the lung tissues,” he said. The Ontario Racing Commission requires a mandatory autopsy when a horse dies in or soon after a race. That means experts know a lot about what causes racehorses to die. But since IAD is not fatal, it has not been closely examined until now, Dr. Arroyo said. “This project gives important information regarding the health status of the performing horse. Developing a better understanding of IAD could lead to better health in horses and a more competitive horse racing industry.” MeV

For more information: Fe ter Woort F, Caswell JL, Arroyo LG, et al. Histologic investigation of airway inflammation in postmortem lung samples from racehorses. Am J Vet Res. 2018; 79(3): 342 DOI: 10.2460/ajvr.79.3.342. https://avmajournals.avma.org/doi/abs/10.2460/ajvr.79.3.342?journalCode=ajvr 14

Issue 7/2018 | ModernEquineVet.com

Changes in Artificial Breeding Techniques Improves Success

Photo courtesy of The Equine Veterinary Journal

There have been significant adhorses. It concludes that placenvances in both natural breeding tal structure and gene expression and artificial breeding techniques are modified after embryo transfer in horses over the past 15 years, into a smaller or larger breed than according to a special issue of The that of the embryo, contributing to Equine Veterinary Journal. Not post-natal growth restriction or enonly have artificial insemination hancement. success rates improved but embryo Tullis Matson, founder and transfer has also become a commanaging director of Stallion AI mon procedure. Services works very closely with By transferring an embryo from the Rare Breed Survival Trust to a donor mare into the uterus of a help preserve the genes of rare recipient mare, a donor mare can equines. “It’s undeniable that new produce more than one foal in a reproduction techniques are a year and still remain in competilife raft for rare breeds. While we tion. It is a valuable technique for can preserve the male genetic line older mares that may not be able to through semen freezing, we don’t A 25 day conceptus showing the embryo and carry a foal to term. It is also behave this option with the female division between the developing allantois coming an important technique to line, but embryo transfer offers us (ventral) and regressing yolk sac (dorsal). Reproduced with permission from Equine support the survival of rare breeds. hope in widening the gene pool of Veterinary Journal from Allen, W.R. and Wilsher, Successful embryo transfer and our valuable female lines. We have S. (2018) Half a century of equine reproduction research and application: A veterinary tour de consequent pregnancy depends on already successfully produced a force. Equine Vet. J. 50, 10–21. many factors, including timing. One Suffolk Punch foal using embryo of the studies looked at the length of estrus on the liketransfer. Our next steps to help with rare breed preserlihood of pregnancy and early embryo loss in recipient vation are to set up a tissue bank and to look at options mares after embryo transfer, concluding that the prospect for sexing semen,” he said. MeV of pregnancy is reduced in those with a short preceding estrus. Vitrification success rates are currently low for immature equine oocytes. One of the papers compared two vitPurina launched www.FindYourOldFriend.com, which uses social media to help rification protocols and identified that the use of corona riders reconnect with former horses. Every horse rider or owner has that one horse radiata (CR oocytes), high concentrations of cryoprotecthey will never forget. Between sales, barn moves and life changes, it’s easy to tive agents (CPAs) and a short exposure time may be key lose track of a horse. In honor of the bonds that can’t be broken and the horses to uncompromised embryonic development. we won’t forget, Purina Animal Nutrition launched this new site. Find your old To date, few studies have been published about cryofour-legged friend. preservation and embryo assessment in horses and donkeys. A new Spanish paper disclosed that vitrified horse and donkey embryos did not show higher susceptibility to cell damage than those preserved by slow freezing. It is known that the size and breed of the recipient mare can affect fetal development and subsequent postnatal growth rate and insulin sensitivity in foals. The final study in the issue looks at placental alterations in structure and function in intra-uterine growth-retarded

Riders: Find Your Old Friend

The special focus is available free online at: https://onlinelibrary.wiley.com/toc/20423306/50/3

Click here to watch video

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For more information:

ModernEquineVet.com | Issue 7/2018

TECHNICIAN UPDATE

Equine Multinodular Pulmonary Fibrosis A 22-year-old Quarter horse mare presented to the Texas A&M (TAMU) Veterinary Teaching Hospital Equine Internal Medicine Service for a complaint of ongoing tachypnea and mild, intermittent signs of colic. The mare had been evaluated at the farm a week prior for a one-week history of bilateral nasal discharge and possible colic. The owner had administered 500 mg of Banamine (route unknown) prior to arrival of the TAMU Field Service clinicians. The mare was initially in sternal recumbency and colic was suspected. Abnormal vital parameters included mild tachycardia, tachypnea and a temperature of 98.8Â° F. The mare was sedated with IV xylazine to facilitate nasogastric intubation. No net reflux was obtained and 1 L of mineral oil and 4 L of electrolyte water were administered through a nasogastric tube. A rectal palpation revealed mild-to-moderate gas distention of the right dorsal colon and hard fecal balls in the small colon. Over the next several days, the mare had intermittent tachycardia, tachypnea, inappetence and remained in sternal recumbency for prolonged periods. Upon presentation to the hospital, the mare appeared bright, alert and responsive. I observed tachypnea of approximately 40 breathes/min; however, she did not appear to be in respiratory distress. Her mucous membranes were pale pink and tacky, and capillary refill time was 2 seconds. No abdominal effort or

nostril flare were appreciated. Once in the exam room, the veterinarian performed a more complete physical examination. Vital parameters included a rectal temperature of 101.6Â° F, mild tachycardia (52 beats/min) with normal sinus rhythm and no murmurs. Persistent tachypnea (40 breathes/ min) with crackles and wheezes auscultated bilaterally in the cranial, caudal and ventral lung fields was noted. A rebreathing bag was not needed to exacerbate the findings. Mucopurulent discharge was present in both nares. Gastrointestinal sounds were present in all abdominal quadrants. Digital pulses were within normal limits, except for the left hind which were increased. The mare weighed 495.5 kgs. Blood was submitted for a complete blood count, serum biochemistry panel and triglycerides (due to inappetence). Due to a history of presumed colic, a rectal palpation was also performed, with no abnormal findings. Time alone in an exam room with a patient is an opportune time for a veterinary technician to do a personal assessment to anticipate the needs of the clinicians for future diagnostics, and get a baseline for monitoring. Findings from the physical exam alone suggested lower airway disease such as pneumonia, recurrent airway obstruction (RAO) or neoplasia. A concurrent upper airway disease was also a consideration, and the historic signs of colic suggested that another unresolved issue could exist. Diagnostic tools that would be useful in a systematic process would be an arterial blood gas, thoracic radiographs and/or a thoracic sonogram, and an upper/ lower airway endoscopy. A tracheal wash (TW) and/ or a bronchoalveolar lavage (BAL) would also provide

FIGURE 1: Thoracic radiograph (EMPF), this mare

FIGURE 2: 60x TW neutrophils and macrophages, this mare

Photo courtesy of Stephanie Wertman

By Stephanie L. Wertman, LVT

Issue 7/2018 | ModernEquineVet.com

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

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

AAEVT Online Equine Certification Program

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

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

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

*American Association of Equine Veterinary Technicians and Assistants

TECHNICIAN UPDATE

FIGURE 4: Ultrasound guided lung biopsy, this mare

FIGURE 5: Lung biopsy intranuclear inclusion body, this mare

FIGURE 6: Fibrotic lung tissue (biopsy), this mare

valuable information to determine whether an infectious or inflammatory process was occurring. Both procedures may be performed transendoscopically and are minimally invasive. The clinicians returned after speaking to the owner. A plan was made to proceed, beginning with thoracic radiographs. The mare was moved to the TAMU Large Animal Radiology Service. Six images of the thorax were presented to the radiologist for review. Numerous, poorly defined, grouped nodules were noted throughout the lung fields. Equine multinodular pulmonary fibrosis (EMPF) was suspected, other, less likely differentials included fungal infection and metastatic neoplasia. Further diagnostics were recommended, to include quantitative polymerase chain reaction (qPCR) testing for equine herpesvirus-5 (EHV-5), a diagnostic test that detects the presence of DNA—in this case the viral nucleic acid for EHVs-5 that is associated with development of EMPF. The PCR can be run on bronchoalveolar or lung biopsy samples. The biopsy is a superior test for the PCR and has the advantage of providing other information about the lung pathology.

A bronchoalveolar sample is less invasive and the cytology also provides additional information. The owner was contacted. A decision to continue with further diagnostics, confirm diagnosis and formulate a treatment plan was pursued. Bloodwork results included: anemia, indicated by a red blood cell count of 6.08 M/uL, a packed-cell volume of 27%; hyperproteinemia of 8.6 g /dL (5.3–7.3 g /dL), with hyper-globulinemia of 5.5 g /dL (2.2–3.8 g / dL); hyperfibrinogenemia of 800 mg /dL (100–400 mg /dL), indicative of chronic inflammation; neutrophilia of 89% (30–65%), and a lymphocytopenia of 8% (25– 70%). These results were supportive of lower airway inflammation and EMPF remained the top differential. While the results were being reviewed, I set up for the following procedures: an upper and lower airway endoscopic exam, a TW, a BAL, and an ultrasound guided lung biopsy. Although a percutaneous transtracheal wash (TTW) and a BAL can be performed without the aid of an endoscope, the clinicians wanted to view the airway of this mare. The 1 m and 3 m endoscopes were disinfected in glutaraldehyde for 20

Photo courtesy off Ms. Wetman

FIGURE 3: 100x TW Curschmanns spiral (chronic disease), this mare

Issue 7/2018 | ModernEquineVet.com

Unfortunately, EMPF is a progressive, fibrosing lung disease, and in advance stages, the prognosis is poor despite treatment.

minutes, then rinsed well inside and out with sterile water prior to performing the procedures. The mare was walked to the TAMU Large Animal Ultrasound Service. At this point, she was sedated with xylazine and butorphanol. The 1 m endoscope was used for the upper airway exam and tracheal wash. A sterile Mila 3 stage sampling aspiration endoscopic catheter was advanced through the endoscope chamber into the trachea. Once in the trachea, the guarded catheter was advanced further into the trachea away from the end of the scope (to prevent contamination), 35 mL of lactated ringer solution was administered aseptically into the trachea. The catheter was advanced further into the “pool” of fluid near the thoracic inlet, and a sample was aspirated out. The sample was placed into 3 EDTA tubes and two plain red top tubes. A lower airway exam and BAL were performed using a 3 m endoscope. Topical lidocaine was administered through the endoscope chamber (to decrease coughing) as it passed down the trachea, bronchi and eventually lodged into the terminal bronchioles. A larger portion of the lidocaine is applied in the larynx and tracheal carina as these are areas with larger number of receptors that trigger coughing. Mucopurulent material was observed in the bronchioles prior to the lavage. Once lodged, 0.9% NaCl (240 mL) was administered into the lung, and a sample was aspirated out. The sample was divided for cytology and qPCR testing. A BAL fluid sample obtained from a focal area of the lung is preferred in diffuse lung disease and displays a more accurate cytological representation of lower airways. Conversely, a TW is preferred when focal disease is present and a bacteriologic etiology is suspected. The TW cytology revealed intracellular bacterial rods, and the cellular value consisted of 94% mildly degenerate neutrophils and 6% macrophages, with no neoplastic cells observed. Septic neutrophilic inflammation was the final interpretation. The BAL cytology cell population was different. The greater number of cells consisted of 56% macrophages (including multinucleated giant cells). Giant cells form in response to chronic infection such as from herpes virus infection. The rest of the cell population consisted of 30% nondegenerative neutrophils (normal is less than 5%),

13% small mature lymphocytes, and 1% well-granulated mast cells, rare eosinophils, and macrophages with artifacts consistent with fungus or pollen granules. No signs of neoplasia were observed. Moderate histiocytic and neutrophilic inflammation were the interpretation, consistent with chronic inflammation. A thoracic sonogram was performed to localize a nodular area for a lung biopsy. Once identified, the site was prepared. A 6 in x 6 in area of the right lung at the level of the 12th intercostal space was clipped, then prepped with chlorhexidine and alcohol. The site was locally anesthetized with Carbocaine-V (2%), then prepped again. A Baird Monopty 14 ga x 16 cm Biopsy Core Instrument was used to obtain four lung tissue samples under ultrasound guidance. Two cooled, fresh tissue samples and the divided BAL sample were sent overnight to Cornell University for qPCR testing for EHV-5. Two other samples were placed in 10% formalin and sent along with the divided TW sample to the TAMU Histopathology laboratory. The mare was administered IV flunixin meglumine (1.1/mg/kg), then placed in a lightly bedded stall with free access to water. The mare was monitored for complications of a lung biopsy such as bleeding in the airway or thorax and pneumothorax. The clinical signs of these complications are blood in the nose or mouth, worsening of dyspnea or tachypnea, depression or pale mucous membranes. Vital parameters at 4 PM included a rectal temperature of 98° F, a heart rate of 44 beats/ min and a continued tachypnea (36 breathes/min). The mare was fed 1 flake each of coastal Bermuda and alfalfa hay, plus 1 lb of Strategy pellets. Treatment for EMPF was initiated. Minocycline (a bacteriostatic broad-spectrum tetracycline), PO BID, and prednisolone (a corticosteroid- that is less potent than dexamethasone) PO SID were initiated. The mare was monitored overnight with no signs of colic observed. The following day the mare was bright, alert and responsive. She had readily eaten both pellets and hay and two normal manure piles were present in the stall. Her vitals: rectal temperature was 98° F; heart rate was 44 beats/min, and slightly tachypneic (36 breaths/min. Crackles were auscultated bilaterally in the cranio/cauModernEquineVet.com | Issue 7/2018

TECHNICIAN UPDATE

This was an interesting case from the moment the mare arrived at the hospital. In this geographical area and season (September), it is common to see horses with respiratory disease (most commonly summer pasture associated obstructive disease/equine asthma). What made this case so different was the profound findings with each diagnostic tool and how each one solidified the findings of the previous. This points to an advantage of working at a large referral practice: the access to the availability of radiology, ultrasound, endoscopy, clinical pathology, clinical microbiology, and access to the experts in those fields to interpret results the same day. This was my second case of EMPF. The first case had a presumed diagnosis made from radiographs, and confirmed histopathological post mortem. The previous horse was in a serious state of respiratory distress on presentation, and further diagnostics or treatment were declined by the owner. Although the outcome was ultimately the same, I was able to learn so much more about this disease process, to differentiate some of the abnormal findings, and learned not to assume anything.

dal/ventral lung fields and wheezes were auscultated over the left thorax. Nasal discharge was not observed. The remainder of physical exam was unremarkable. The diagnostic lab at Cornell University verified receiving the samples, with results possible by the end of the business day. Arrangements were made to send the mare home at the end of the day on the present treatment regimen and to reassess after receiving histopathology, culture, and qPCR EHV-5 results. At 3:30pm CST, I contacted the diagnostic lab at Cornell University. Results were finalized. The lung tissue sample and bronchoalveolar sample were both qPCR positive for EHV-5. With this diagnosis, valacyclovir was added to the regimen at 30mg/kg PO TID for the first 3 days, and reduced to 20mg/kg PO BID for 28 more days. The mare was discharged from TAMU Veterinary Teaching Hospital with treatments for EMPF. Current treatment and prolonged therapy were to be reassessed after further diagnostic results were obtained. A week after presentation the mare was evaluated by TAMU Field Services for foot pain and radiographs. The owner noted that the mare was stumbling on Sept. 19th and was lame at the walk. The mare was mildly positive to hoof testers over both front toes. Laminitis was suspected, and radiographs were recommended. Lateral and horizontal DP radiographic views of both front feet were taken. and did not indicate any coffin bone rotation associated with acute laminitis. The mare 20

Issue 7/2018 | ModernEquineVet.com

Shutterstock/nelelena

TEACHING POINTS

was tachycardic (52 beats/min) and tachypneic (48 breathes/min). Harsh bronchovesicular sounds were auscultated bilaterally with increased respiratory effort. Despite diligent and aggressive treatment, she did not respond favorably. After one month of therapy the mare was admitted to TAMU Veterinary Teaching Hospital for euthanasia due to persistent clinical signs (inappetence, continued tachypnea, increased respiratory effort), and with moderate ataxia in all four limbs. Unfortunately, EMPF is a progressive fibrosing lung disease and in advance stages, prognosis is poor despite treatment. This mare exhibited many of the abnormal physical findings of the disease: intermittent fever, tachycardia, persistent tachypnea, weight loss and inappetence. Abnormal lung sounds at rest, profound radiograph changes, chronic anemia, hyperfibrinogenemia, hyperglobulinemia and neutrophilia were all supportive of the diagnosis. Histopathological confirmation can be obtained with a lung biopsy, qPCR on lung tissue or bronchoalveolar fluid and blood combination results can also be used to support a clinical diagnosis. MeV

About the author

Stephanie L. Wertman, LVT, VTS-EVN, is the Equine Internal Medicine, Tech II at Texas A&M Veterinary Medical Teaching Hospital in College Station, Texas.

NEWS NOTES

A snorting horse is a happy horse, according to new research out of France that looked at how frequently horses snort and in what conditions. This new evidence that horses reliably produce more snorts in favorable situations could improve animal welfare practices, according to Mathilde Stomp, PhD, of the Université de Rennes, France, and colleagues. While assessing positive emotions is important for improving animal welfare, it has been difficult to identify reliable indicators. Physiological markers often give contradictory results, and many behavioral signals are ambiguous, the researchers said. Few studies have examined acoustic indicators of positive emotions, they said, although anecdotal reports have indicated that horses frequently produce snorts in positive situations. Following up on this observation, Dr. Stomp and her colleagues evaluated snort production by 48 horses that lived either in restricted conditions (i.e., riding school horses that spent much of their time in individual stalls) or natural conditions (i.e., stable groups of horses always in pasture). Snort production was significantly associated with positive situations and with a positive internal state, as indicated by ears positioned forward or sideways, they found.

For example, riding school horses produced twice as many snorts in pasture than when they were in stalls. In addition, pasture horses emitted significantly more snorts than riding school horses in comparable contexts. Taken together, the findings suggest that snorts are reliable indicators of positive emotions in horses, according to the researchers. “The snort, a non-vocal signal produced by the air expiration through the nostrils, is associated with more positive contexts (in pasture, while feeding) and states (with ears on forward position) in horses,” Dr. Stomp noted. “Moreover, it is less frequent in horses showing an altered welfare. These results provide a potential important tool as snorts appear as a possible reliable indicator of positive emotions, which could help identify situations appreciated by horses.” MeV

I Snort, Therefore, I am Happy

Horses snort in favorable situations.

For more information: Stomp M, Leroux M, Cellier M, e tal. An unexpected acoustic indicator of positive emotions in horses. PLoS One. 2018; 13 (7): e0197898 DOI: 10.1371/journal.pone.0197898

FDA Investigates 6 Horse Deaths From Contaminated Feed The FDA is Investigating 6 Horse Deaths, Which Appeared to have Died from Eating Feed Containing Monensin. The feed was a special order for the farm and not distributed to others. On June 9, a horse farm in Minnesota began feeding its horses with the feed. That evening, one horse became ill and was unable to stand. The horse was euthanized 2 days later. On June 12, the owner found 2 more horses that were unable to stand. One horse died that day and the other horse was found dead the next day. Over the course of the next month, 3 more horses died. Monensin is an ionophore animal drug approved for use in cattle and poultry feed to increase feed efficiency and prevent coccidial infections. It is highly toxic and potentially lethal to horses, even at relatively low levels, according to the FDA. A horse’s reac-

tion to monensin will vary depending on the amount of exposure and the horse’s breed, diet and metabolism. Symptoms including weakness, unsteady gait, inability to get up, diarrhea, abdominal pain, excessive urination, heart failure or death. Acute toxicity may progress rapidly enough that the horse doesn’t exhibit many symptoms prior to death. Monensin toxicity is rarely treatable, and most horses die or are euthanized to avoid pain and suffering. When inspecting the firm, the FDA found that on the date the batch of horse feed in question was manufactured, Gilman Co-Op Creamery first mixed cattle feed containing monensin, and then allegedly did not perform adequate cleanout to remove the monensin from its equipment before mixing the horse feed. MeV ModernEquineVet.com | Issue 7/2018

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