The Modern Equine Vet - April 2024

For the Rhodococcus equi screening

In >1000 foals over 3 years, incorporating SAA into routine screening exams was shown to reduce antibiotic treatment by >45% without negatively impacting foal health.1

SAA >75 μg/dL + Thoracic ultrasound grade ≥4 + WBC > 13,000/μL =

allows prediction of which foals will progress to clinical R. equi and should be started on antimicrobial treatment.1

Diagnosing Chronic Muscle Pain That Affects Performance COVER STORY

SALES: ModernEquineVet@gmail.com

EDITOR: Marie Rosenthal

ART DIRECTOR: Jennifer Barlow

CONTRIBUTING WRITERS: Paul Basilio

Tom

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Diagnosing Chronic Muscle Pain

THAT AFFECTS PERFORMANCE

By Marie Rosenthal, MS

Chronic muscle pain can be a cause of lameness and exercise intolerance, so identifying its cause and treating quickly become important to help improve performance, according to Stephanie J. Valberg, DVM, PhD, DACVIM, DACVSMR, of the Valberg Neuromuscular Diagnostic Laboratory, in Michigan.

Muscle soreness can be secondary to an orthopedic problem, so the challenge is differentiating muscle pain, a primary muscle strain and a chronic myopathy. In addition, a horse can have a primary myopathy and an orthopedic lameness, further blurring the picture.

The history, including performance history, is the key to distinguishing among the various problems that could be causing poor performance, according to Dr. Valberg, who recently retired from the Michigan State University. The 2 primary clinical signs that point toward a muscle issue are the presence of muscle pain and presence of weakness, which manifests as loss of muscle mass and a decline in performance, according to Dr. Valberg.

During the physical evaluation look at the muscle mass from both sides of a horse. A performance horse that has been in training for a while will have good muscle mass and tone. “I think it's important to put your hands on every muscle that you can get your hands on, compare left and right, assess the tone.

Horses that are fit will have a firm tone. Horses that are unfit have little tone, and horses that are painful have increased muscle tone. Mapping all of that out is important in differentiating a secondary muscle pain from an orthopedic lameness from primary pain due to a strain or chronic myopathy.”

To provide a targeted treatment, it is important determine what form of myopathy a horse has, and this requires measurement of serum creatine kinase (CK) and aspartate transaminase (AST). Elevated CK and AST distinguishes forms of exertional rhabdomyolysis (ER), where muscle fibers are damaged, from exertional myopathies where the muscle is painful but not degenerating. “If you suspect chronic exertional rhabdomyolysis but the resting CK is normal, take a CK before exercise, then exercise the horse for 15 or 20 minutes, then reevaluate when CK peaks 4 to 6 hours later,” she suggested.

• Exertional rhabdomyolysis (ER) can be sporadic with no chronic underlying cause or chronic. Causes of sporadic ER include exercising beyond the level of conditioning and dietary imbalances.

• Causes of chronic ER include malignant hyperthermia in Quarter horse-related breeds, recurrent exertional rhabdomyolysis (RER), type 1 polysaccharide storage myopathy (PSSM1) and type 2 PSSM with exertional rhabdomyolysis (PSSM2-ER).

Horses that are fit, nervous, excitable and have re-

GENETIC TESTS FOR CHRONIC MUSCLE PAIN AND ELEVATED CK OR AST1

QUARTER HORSE BREEDS: PSSM1, myosin heavy chain myopathy and malignant hyperthermia

MOST BREEDS WITH EXERTIONAL RHABDOMYOLYSIS: PSSM12

peated episodes of pain with elevated CK often have recurrent ER (RER). Horses that are unfit, calm and have persistently high serum CK often have PSSM1. A genetic test is available for PSSM1, which is present in more than 20 different breeds but not Arabians, Thoroughbreds nor Standardbreds.

PSSM2 can be subdivided into 2 types: The first is characterized as having ER with elevations in serum CK and AST (PSSM2-ER); and the second form we now recognize as myofibrillar myopathy (MFM). Arabian horses have a form of MFM that can result in pain at the end of endurance rides or after several weeks of rest and high serum CK.

“This usually occurs in highly successful endurance horses at the end of long endurance rides, and we think it relates to oxidative stress from a high reliance on fat. They may look fine when they finish, but then they get stiff and crampy afterward. They may have myoglobinuria. Sometimes, it occurs about 5 miles into a 2-week period when they’re given some time off. They get stiff, and they get crampy,” she said.

MFM has a different form in Warmbloods. The classic sign of MFM in Warmblood horses is a reluctance to want to go forward and a reluctance to want to engage from muscle tension and pain. “This disorder is more difficult to diagnose because it doesn’t involve breakdown of the muscle cell membrane and leakage of CK out into the bloodstream,” Dr. Valberg said. There is no blood test for MFM in Warmbloods.

“Additionally, behavioral issues, saddle fit, lameness and gastric ulcers can also cause pain and reluctance to go forward so, it’s important to rule those issues out before thinking of MFM,” she said at the 69th AAEP Annual Convention, held in San Diego.

“The treatment for exertional myopathies with normal CK is almost the opposite of the treatment that we’re going to have for horses that have ER and elevations in CK,” Dr. Valberg said. “That is why it is so important to assess muscle enzymes.

Because some of these conditions are breed specific, genetic testing can be appropriate (see box). If genetic testing results are positive, there is no need for a muscle biopsy, according to Dr. Valberg. However, muscle biopsy could be appropriate to diagnose PSSM2-ER, MFM and to assess difficult to manage muscle cases, she said.

She now uses formalin fixed rather than frozen muscle sections in her new lab. Formalin-fixed sections are more forgiving than frozen sections in terms of developing artifacts during shipping and don’t require cold overnight shipping. These myopathies can now be diagnosed with several immuno-

histochemical stains, she explained. In addition, the veterinarian can use a specific needle biopsy technique of the gluteal muscle, and the horse can go back to work the next day.

Some clients may not want genetic testing or biopsy, so a treatment trial may be done. In addition to dietary and exercise management, dantrolene can help to get horses with ER back into training. Dantrolene slows the flux of calcium inside the cell that produces a muscle contraction. If calcium is released from intracellular storage sites in excess, muscle fiber damage occurs. It should be given 60 minutes prior to exercise, and it must be withdrawn before FEI shows, and racing she said.

“I like using it for a couple of weeks if we’re putting a horse back into training after ER or if it’s going to be experiencing a type of exercise, we know is going to induce rhabdomyolysis,” she said, but it won’t work if the horse doesn’t have rhabdomyolysis. So, again, it’s important to measure serum CK as part of the diagnostic approach.

For ER, a low-starch diet, fat supplementation, regular daily exercise are the best first approach. This works for PSSM1 and PSSM2-ER because they have excessive glycogen in their muscle and for RER by keeping horses calm. For Arabians and Warmbloods with MFM, “a low-starch, high-fat diet doesn’t seem to be the right approach because glycogen concentrations in their muscle are not high like they are with PSSM1 and PSSM2-ER,” she explained.

“Opposite to what I used to recommend for PSSM2/MFM, and opposite from what we recommend for ER, Warmblood MFM horses need days off to recover,” Dr. Valberg said.

“Most owners report the horses do well with 3 days of work in a row; after 2 days off, they’ll come back and work well again. MFM horses need to be turned out and moving around. We recommend a nice long, low warm-up and then when they are working, give them intermittent breaks,” Dr. Valberg said. Even once we’ve got them under control, they still have good days bad days,” she explained.

Many seem to lack energy and “push,” so Dr. Valberg recommends a moderate amount of nonstructural carbohydrate as long as they don’t have other underlying issues like metabolic syndrome, or don’t appear to have a lot of glycogen in their muscle on biopsy.

“Giving them more energy seems to be helpful in these cases, and we don’t feel like we need to push fat at them as it can cause oxidative stress,” she said.

Amino acids appear useful. Dr. Valberg and Joe Pagan, PhD, MS, at Kentucky Equine Research (KER) developed the KER MFM pellet, which contains essential amino acids including a highly absorbable form of cysteine that appears to be limiting with MFM. Seventeen of 50 owners responded to a survey of MFM horses, and when those horses were fed this supplement with coenzyme Q10, 92% said their horses improved.

“The primary things that seem to improve is the hind limb engagement, and the reluctance to work,” she said. In addition, 71% of those owners reported that the horses continue to improve and build strength after 4 weeks.

“About 65% of the owners of these horses say that their MFM horses are meeting their performance expectations. The horse should show improvement within 4 weeks. If not, it’s time to go back to the drawing board and see what else might be contributing to this horse’s level of poor performance,” she said. MeV

FOR MORE INFORMATION

Dr. Valberg has information and videos on her laboratory’s website that could be useful for taking biopsies. Visit www.valbergnmdl.com

Cross-section pf muscle fibers stained for the cytoskeletal protein desmin. A. normal horse. B. A horse with MF. Note the central fibers that contains dark aggregates of desmin typical of MFM. Images courtesey of Dr. Valberg

Cross-section of muscle fibers stained for glycogen (PAS). A. Normal horse. B. PSSM1 horses with many fibers contain dark abnormal polysaccharide. C. PSSM2-ER horse with a dark glycogen stain and a few fibers with abnormal polysaccharide.

There’s

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Reduce inflammation

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When you start with it early and stay with it as needed, horses may enjoy greater mobility over a lifetime.2, 4, 5 Discover if Adequan is the right choice. Visit adequan.com/Ordering-Information to find a distributor and place an order today.

BRIEF SUMMARY: Prior to use please consult the product insert, a summary of which follows: CAUTION: Federal law restricts this drug to use by or on the order of a licensed veterinarian. INDICATIONS: Adequan® i.m. is recommended for the intramuscular treatment of non-infectious degenerative and/or traumatic joint dysfunction and associated lameness of the carpal and hock joints in horses. CONTRAINDICATIONS: There are no known contraindications to the use of intramuscular Polysulfated Glycosaminoglycan. WARNINGS: Do not use in horses intended for human consumption. Not for use in humans. Keep this and all medications out of the reach of children. PRECAUTIONS: The safe use of Adequan® i.m. in horses used for breeding purposes, during pregnancy, or in lactating mares has not been evaluated. For customer care, or to obtain product information, visit www.adequan.com. To report an adverse event please contact American Regent, Inc. at 1-888-354-4857 or email pv@americanregent.com.

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1 Data on file.

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

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

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

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

All trademarks are the property of American Regent, Inc.

© 2021, American Regent, Inc.

PP-AI-US-0629 05/2021

Pain Relief for

Donkeys

By Joy Curzio

Most pain-relief agents for horses are used off label for donkeys even though the pharmacokinetics and pharmacodynamics might be different. Donkeys often require higher doses and more frequent intervals of medications than horses. Donkeys also have shown greater resistance to swallowing oral medications than horses and can prove to be difficult patients for insertion of IV lines.

Recent research has shown, however, that transdermal administration of flunixin meglumine (Banamine Trans-

Transdermal Flunixin Meglumine Provides Durable, Safe Pain Relief

dermal solution, Merck Animal Health) may be safe and highly effective for donkeys, providing durable pain relief despite the pharmacokinetic challenges.

“From behavioral and physiological standpoints, pharmacologically, donkeys are not just horses with big ears,” said Amy K. McLean, PhD, an assistant professor in the Department of Animal Science at UC Davis. “The thicker cutaneous colli muscles that cover the jugular vein can be a challenge [for IV administration of pain-relief agents], and even oral applications of various medications can be challenging because you think they have absorbed the medication, but they spit it out when you walk away.”

Dr. McLean led and reported on a small pilot study that found that transdermal flunixin, currently only approved in cattle, was measurable

courtesey of Dr. Amy K. McLean

Break free

Help your equine patients by controlling the clinical signs associated with osteoarthritis

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• Convenient; only 4 intramuscular injections required

• Not limited to use for specific joints1

To learn more about Zycosan®, please scan the QR code or visit go.dechra-us.com/zycosan

24-hour Veterinary Technical Support available: (866) 933-2472

Nonurgent Technical Support available: support@dechra.com

Important Satefy Information

As with all drugs, side effects may occur. For intramuscular use in horses only. Not for use in humans. Pentosan polysulfate sodium is a weak anticoagulant. Caution should be used when administering Zycosan if you are taking an anticoagulant. In case of accidental self-injection, seek immediate medical attention. If product comes into contact with skin, rinse skin thoroughly with water and seek medical attention if needed. Horses with hypersensitivity to pentosan polysulfate sodium should not receive Zycosan. Do not use Zycosan concurrently with other anticoagulant drugs. Do not use in horses with clotting disorders or within 24 hours of surgical procedures. Caution should be used when administering this drug before or after strenuous activities. Caution should be used when NSAIDS are administered concurrently due to the anticoagulant effects of Zycosan. If Zycosan and NSAIDS are used concurrently, horses should be monitored for hemorrhage or other clinical signs of abnormal bleeding. The safe use of Zycosan has not been evaluated in breeding, pregnant, or lactating horses. The safety of long-term repeat use of Zycosan has not been evaluated. The most frequently reported adverse reactions are injection site reactions, prolongation of coagulation parameters (activated partial thromboplastin time (aPTT) and prothrombin time (PT). Refer to the prescribing information for complete details or visit www.dechra-us.com.

Signs of discomfort and pain in donkeys can be discreet.

up to 96 hours post-administration compared with 60 hours for the oral and 48 hours for the IV formulations. Previous studies of transdermal flunixin for horses found anti-inflammatory efficacy for 24 to 72 hours. In addition, administration of the transder-

Zycosan®

(pentosan polysulfate sodium injection)

250 mg/mL

For intramuscular use in horses only.

Brief Summary (For Full Prescribing Information, see package insert)

CAUTION: Federal law restricts this drug to use by or on the order of a licensed veterinarian.

DESCRIPTION: Zycosan contains pentosan polysulfate sodium, a semi-synthetic polysulfated xylan. It is a pale yellow to brownish yellow, clear, sterile solution.

INDICATION: For the control of clinical signs associated with osteoarthritis in horses.

CONTRAINDICATIONS: Horses with hypersensitivity to pentosan polysulfate sodium or any of the inactive ingredients in Zycosan should not receive Zycosan. Do not use Zycosan concurrently with other anticoagulant drugs. Do not use in horses with clotting disorders or within 24 hours of surgical procedures (see Warnings and Precautions).

WARNINGS AND PRECAUTIONS:

User Safety Warnings: Not for use in humans. Keep out of reach of children. Pentosan polysulfate sodium is a weak anticoagulant. Caution should be used when administering Zycosan if you are taking an anticoagulant. In case of accidental self-injection, seek immediate medical attention. If product comes into contact with skin, rinse skin thoroughly with water and seek medical attention if needed. To obtain a Safety Data Sheet (SDS), contact Dechra at (866) 933-2472.

Animal Safety Warnings and Precautions: Zycosan has been shown to prolong coagulation parameters up to 24 hours after injection, therefore caution should be used when administering this drug before or after strenuous activities (see Target Animal Safety). Due to the anticoagulant effects, this drug may exacerbate Exercise Induced Pulmonary Hemorrhage (EIPH).

mal formulation—applied as a liquid from the donkeys’ withers backward toward the tail, until the full dose has been used—resulted in no adverse events.

Finding Cues, Collecting Data

Signs of discomfort and pain in donkeys are discreet. Based on visual cues observed post-castration, donkeys show subtle facial grimacing and orbital tightening, slightly lowered ears, eye blinking and tail swishing when in pain, which are all signs that are easy to miss in the field or go unnoticed in a clinical practice.

Dr. McLean noted that when pain and discomfort can be identified, the next step is to decrease antiinflammatory markers and improve the donkey’s experience. “We’re trying to increase our ability to provide take-home information for the owner so they can continue to actively and progressively treat their patient at home,” she said.

Dr. McLean and colleagues aimed to compare how long flunixin and its metabolite (5OH flunixin) were measurable post-administration for each of the 3 formulations, with a focus on transdermal, and how well each formulation suppressed inflammatory markers (eicosanoids) over time in 6 healthy donkeys.

Catheters were placed to collect urine samples within the first 48 hours post-administration, and then direct

The concurrent use of NSAIDs with Zycosan has not been evaluated. Due to the anticoagulant effects of Zycosan and known anticoagulant effects of some NSAIDs, caution should be used if NSAIDs are concurrently administered. Horses concurrently treated with Zycosan and NSAIDs should be monitored for hemorrhage or other clinical signs of abnormal bleeding (e.g., petechiae, ecchymosis, or epistaxis). The safety of long-term repeat use of Zycosan has not been evaluated. Pigmentary changes in the retina (pigmentary maculopathy) have been reported in human patients following long-term oral use of pentosan polysulfate sodium. It is not known if a similar finding occurs in horses. The safe use of Zycosan has not been evaluated in breeding, pregnant, or lactating horses.

Other Warnings:

Do not use in horses intended for human consumption.

ADVERSE REACTIONS:

Injection site reactions were the most frequently reported adverse reactions in the field study. Injection site reactions were associated with clinicopathology changes in some cases. Other adverse reactions reported in more than one horse were prolongation of coagulation parameters (activated partial thromboplastin time (aPTT) and prothrombin time (PT)), lethargy, behavior changes, and colic.

To report suspected adverse events, for technical assistance or to obtain a copy of the Safety Data Sheet (SDS), contact Dechra at (866) 933-2472 . For additional information about adverse drug experience reporting for animal drugs, contact FDA at 1-888-FDA-VETS or online at http://www.fda.gov/reportanimalae.

STORAGE CONDITIONS: Store at room temperature 68-77°F (20-25°C), with excursions to 59-86°F (15-30°C).

MANUFACTURED FOR:

Dechra Veterinary Products 7015 College Boulevard, Suite 525 Overland Park, KS 66211 USA

Approved by FDA under NADA # 141-559

Zycosan is a trademark of Dechra Limited.

R 01 2023

venipuncture was used. Twenty-two whole-blood samples were collected over 96 hours post-administration.

LC-MS/MS suppression and calcium ionophore testing determined eicosanoid suppression in a second smaller set of whole-blood samples.

A 3-way crossover design was used, with a 2-week washout period in between formulations. Doses were 1.1 mg/kg for bodyweight for both the oral and IV formulations, and 3.3 mL/kg for bodyweight for the transdermal, the latter being based on the label recommendation of approximately 1 mL/100 lbs of bodyweight. A noncompartmental analysis was used for statistical determinations (P< 0.05).

Donkeys often require higher and more frequent doses of pain medications than horses.

Building on Promising Results

In addition to the extremely long measurable duration for transdermal flunixin, similar results were seen for duration of its metabolite: 72 hours with IV and 96 hours with both the oral and transdermal formulations. Thromboxane B2 and prostaglandin F2 alpha served as the inflammatory markers for the study.

“What [we noticed] with the transdermal [formulation], there was a slower more gradual reduction in the suppression of thromboxane, starting around 1 hour … and it remained for a longer period, up to 24 hours. There were similar findings regarding prostaglandin F2 alpha, especially for both the oral and IV [formulations], suppressed at 1 hour and stay suppressed until about 8 hours,” she said.

The transdermal formulation also was shown to have a higher half-life compared with the IV formulation.

Although no hair loss or skin redness was seen, Dr. McLean noted that this pilot study only administered 1 dose so further study of multiple dosages and at various dose levels is needed. She also questioned what effect the transdermal formulation could have on the gastrointestinal system and gut microbiome. Dr. McLean encouraged veterinarians who are treating donkeys for pain management to share their experiences in community forums to help obtain more information about this group of patients. MeV

For more, see related story on page 16.

For more information:

McLean A, Falt T, Abdelfattah E, et al. Transdermal flunixin meglumine as a pain relief in donkeys: A pharmacokinetics pilot study. Metabolites. 2023;13(7):776. doi: 10.3390/ metabo13070776. https://www.ncbi.nlm.nih.gov/pmc/ articles/PMC10383245/

Knych HK, Arthur RM, Gretler SR, et al. Pharmacokinetics of transdermal flunixin meglumine and effects on biomarkers of inflammation in horses. J Vet Pharmacol Ther. 2021;44(5):745753. https://onlinelibrary.wiley.com/doi/abs/10.1111/ jvp.12993

Orth E, Navas GF, Pastrana CI, et al. Development of a donkey grimace scale to recognize pain in donkeys (Equus asnius) post castration. Animals. 2020;10:1411. https://www.mdpi. com/2076-2615/10/8/1411

CHECK OUT

IV Flunixin Meglumine May Be Good Choice for Lengthy Donkey Surgery

Intravenous flunixin meglumine may be a good choice over phenylbutazone (PBZ) for donkey longer surgeries, according to a recent study that compared the 2 treatments.

When treating visceral and musculoskeletal pain in horses, flunixin meglumine and PBZ are typically selected. However, there is little information to support their use in donkeys. The researchers wanted to better understand the postoperative outcomes in a group of jennies treated with either IV flunixin meglumine or oral PBZ following unilateral ovariectomies by standing left flank laparotomy.

Data from the medical records of 14 ovariectomised jennies were collected. They looked at case details, weight, nonsteroidal anti-inflammatory drug (NSAID) protocol, surgery duration, operative sequence, anaesthesia protocol, physical examination findings and outcomes. Postoperative adverse events (AEs) were defined as fever, tachycardia, tachypnoea, inappetence, altered mentation, abnormal oral mucous membranes,

For more information:

bruxism, colic, incisional complications, such as drainage and edema, as well as mortality.

They then stratified the AEs by occurring early (≤24 h) or late (>24 h) in the postoperative period.

The 14 donkeys either received either PBZ, 2.2 mg/ kg IV pre-op, then 2.2 mg/kg oral twice daily (BID) for 3 days postop or flunixin, 1.1 mg/kg IV pre-op and 1.1 mg/kg IV BID for 3 days postop.

In 8 out of 14 donkeys, PBZ treatment was associated with significantly more total early and late AEs than flunixin (odds ratio [OR] 3.01, confidence interval [CI] 1.87–4.84 and OR 2.69, CI 1.28–5.63). The most frequently reported AEs were tachycardia, tachypnoea, altered mentation, altered mucous membranes, incisional edema and incisional pain. Although rare, 2 donkeys in the PBZ group had colic and 1 died.

Donkeys were more likely to show abnormal physiologic parameters, changes in behavior and incisional discomfort when receiving PBZ than flunixin-treated jennies. MeV

Equid Owner Survey Looks at Restrictive Grazing Practices

The University of Kentucky is sponsoring a survey about the restrictive grazing methods equid owners and managers use.

“It’s that time of year. The grass is starting to grow, and many owners will start to think about using restrictive grazing practices, including grazing muzzles, dry lots, strip grazing

and other methods of management,” said Amanda Adams, PhD, an associate professor at the Gluck Equine Research Center and MARS Equestrian Fellow, in Kentucky.

“Understanding the uses of restrictive grazing practices helps us put science-supported answers behind practical questions and challenges. Our goal is to help people help horses. We look forward to sharing the results,” Dr. Adams said.

Morgan Askins, a graduate student working in Dr. Adams’ laboratory, is conducting the survey. As part of Ms. Askins’ doctoral program, she is researching the effect of various forages and management practices of equids, specifically in aged and insulin-dysregulated horses. Better understanding of how to manage body and condition in horses with metabolic diseases, along with dietary management, is critical to helping lower the risk of these equids to develop laminitis. MeV

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PRACTICE MANAGEMENT

Support Staff Can Help Maximize Veterinarian Effectiveness and Profits

By Tom Rosenthal

The more equine veterinary practices expand the roles of their support staff, the more effective and profitable the practice can become, according to a presentation at the 69th AAEP Convention, held in San Diego, CA.

Maximizing the work of licensed veterinary technicians (LVTs), veterinary assistants (VAs) and other staff can help a practice retain its talent by letting veterinarians focus primarily on patient care while providing professional development to support staff members so they have a more meaningful career, said Mike Pownall, DVM, MBA, partner of McKeePownall Equine Services, in Ontario, Canada.

Additionally, that can improve the work-life balance and the quality of life for both the veterinarians and the support staff members, he said.

Dr. Pownall cited a 2018 AAEP/AVMA Economic Survey that found single veterinary practices without support staff reported annual gross sales of $205,000, while those with support staff grossed $330,000— $125,000 more.

This made them 1.6 times more productive than practices without support staff, according to Dr. Pownall.

With a shortage of equine veterinarians entering and staying in clinical practice, veterinary practices everywhere are suffering, he added. As a result, veterinarians are caring for more patients, increasing the chances for burnout. The best way to stop this is to become more efficient, he explained.

Dr. Pownall and his wife Melissa McKee, DVM, started their practice in 2002 in the Toronto area. Their practice has grown to 16 veterinarians in 3 locations, he said. “The reason why the practice grew was the use of support staff and really having an emphasis on letting the vets do what vets do and training and nurturing support staff.”

By empowering support staff to have more responsibilities, veterinarians can see more patients during a workday and have fewer post-patient responsibilities like maintaining medical records, client communications and preparing submissions to

For more information:

the laboratory for testing, he explained.

Additionally, veterinarians are using LVTs and VAs for such responsibilities as removing sutures, changing bandages and laser therapy.

He noted there is value in having an LVT or VA accompany the veterinarian on a patient visit because they help provide additional safety in dealing with a physically challenging client or discussing the case after the visit.

Putting Tasks Off Costs Money

Bridget Heilsberg, DVM, the owner of Crown 3 Equine, in Whitesboro, Texas, who also spoke at the conference, noted that front-office staff can take over the vital role of ensuring that activities are properly billed.

She suggested practice owners make a list of the things that they don’t like about practice ownership or management. These chores can range from clerical and administrative duties, such as scheduling appointments and ensuring bills are paid, to carrying out specific procedures in the field.

“Those are the things that you put off doing, and they’re costing you money,” she said. “Now find someone or multiple ‘someones’ to do those things and [who] enjoys doing the things that you don’t like doing. Make sure you can afford the people and then hire the people to do those things.”

She said an important step in effective team building is to determine what is permitted under your state’s or province’s practice act.

Dr. Heilsberg cited the website of the American Association of Veterinary State Boards (aavsb.org) as an invaluable resource in determining what functions support staff can perform under the laws in each jurisdiction.

“Find out what your practice act says,” Dr. Heilsberg advised, and then use the information as guidelines to maximize the practice. “Staff utilization turns into higher profit margins,” she said.

Another vital step in team building is taking the time to determine what needs are not being met at the practice and filling those gaps. MeV

American Association of Equine Practitioners. Economic Report (April 1, 2019).

https://aaep.org/sites/default/files/Documents/2019%20FINAL_AMVA_AAEP_Equine_Report.pdf

Equine Vet

PUBLIC/CORPORATE EMPLOYMENT:

14,488

Academia: 6453

Government: 3,236

Industry/commercial: 3,083

Other: 1,716

PRACTICE MANAGEMENT

U.S. Veterinarians

TOTAL: 127,131*

CLINICAL PRACTICE:

Cervical Injuries Due to Rotational Falls

By Jessica Cook

These 2 cases come from the realm of timber racing and involve rotational falls incurred at speed. With the horse’s best interests at heart, and an increasing awareness of safety protocols, I think horses who incur rotational falls should be required to have their cervical spine cleared by diagnostic imaging prior to returning to work.

This can be applied in all disciplines for the safety of both horse and rider. One case represents cervical injuries diagnosed by radiographs taken at the horse’s primary stable. The final case is an example of potentially undiagnosed injury from rotational fall approximately 2 years prior to development of clinical signs.

Case 1

Inciting Rotational Fall: A 6-year-old timber racehorse sustained a rotational fall, regained his footing and jumped off course before being caught. The horse was evaluated briefly at the racing venue and deemed safe to ship 3 hours home.

Clinical Evaluation: At the trainer’s request the horse was evaluated the following Monday. Upon examination the horse had significant stiffness and was unable to graze comfortably. There was visible deformation in the cranial cervical region with sensitivity to palpation. He was observed in hand at a walk in a straight line and figure 8. A bilateral hind limb toe drag was seen, but no other neurologic signs were evident. Placement tests of all 4 limbs were within normal limits.

Diagnostic Approach and Diagnosis: Radiographs were performed with standing sedation in a rope halter to avoid metallic interference with images. Fracture and ventral displacement of the atlantoaxial articulation with associated distortion of the vertebral canal was elucidated with the first radiograph. A cervical spine survey was completed with no other significant findings on lateral or ventrodorsal views.

Rehabilitation: The horse was placed on strict stall rest for 90 days with feed, forage and water at chest height. He was maintained on phenylbutazone for 5 days administered at a dosage of 1 g twice daily for 5 days, 1/2 g twice daily for 3 days and then discontinued. The gelding also received gastroprotectant medication while on nonsteroidal medication and was closely monitored for any discomfort or deterioration in proprioception.

Following his initial confinement, case 1 was transitioned to a small paddock and then ultimately large field turn out for 5 months. He was not reported to have any negative change in condition or movement during the progression. Serial clinical and radiographic examination was performed at the 5-month mark. The ventral deviation was still visible but unchanged. Baseline movement in a straight line and figure 8 was repeated with no proprioceptive concerns revealed.

Radiographs were repeated and showed osteoarthritic changes because of the fracture and displacement. There was the development of enthesophyte on the caudal occiput in the enthesis of the ligamentum

images: Courtesy of Equine Sports Medicine of Maryland and used with the permission of Cooper Williams, VMD

Case 1: Visible deformation in the cranial cervical region, which was sensitive to palpation. Lateral radiograph of atlantoaxial joint – normal joint. Lateral radiograph of atlantoaxial joint – fracture and ventral displacement.

nuchae. The deviation in alignment was compared with the original radiographs and was unchanged.

Outcome: The patient in this case resumed work progressively increasing until returning to training as a timber horse. Following his injury he raced 8 times, including a win, before ultimately retiring to become a fox hunter. He was hunted successfully for several seasons.

Case 2

Inciting Rotational Fall: An 8year-old Thoroughbred racing in a timber race had a rotational fall and then regained his feet before being caught in the van area. Due to his fall during an unsanctioned race, it was not required for him to be evaluated prior to shipping home. There were no reports of any movement concerns for nearly 2 years. Approximately 2 years after the fall the horse was found to be acutely ataxic in all 4 limbs, and the trainer requested an emergency visit after administering IV flunixin meglumine himself.

The horse was seen by an associate veterinarian who deemed him capable of shipping and referred him to the hospital after administration of IV dexamethasone and bolus fluids.

Diagnostic Approach and Diagnosis: Upon arrival at the referral hospital the horse presented with ataxia of all 4 limbs and muscle fasciculation around the head and neck. Nuclear scintigraphy of the region was deemed within normal limits and the equine protozoal myelitis (EPM) testing was negative. Neutral lateral radiographs were performed during a myelogram as well as in flexion.

In the neutral position there was compression of the spinal cord in the caudal portion of the vertebral canal of C6 with both dorsal and ventral impingement of the dye column, In the flexed position the C6 impingement persists as well as obliteration of the ventral dye column at C2/3, C4/5, and C5/6. However, the dorsal dye column was not diminished by more than 50%.

Rehabilitation: Due to the results of the myelogram and clinical picture the gelding was euthanized and submitted for postmortem examination.

Outcome: The postmortem images demonstrate the

Lateral radiograph of atlantoaxial joint at 5 months.

Case 2: Malalignment in flexion C6 and C7 and visible deformation of C6 vertebral head: Arrow directed at the C6 vetebral head abnormality.

Postmortem images demonstrate a significant lytic lesion found on the vertebral head of C6.

Postmortem image demonstrates associated cystic mass within the spinal canal at this location.

Teaching Points

1. Cervical injuries do not have to be accompanied by neurologic deficits, even in the most extreme cases.

2. Horses should be thoroughly evaluated by a physical examination and imaging in the event of a rotational fall whether there are any neurologic deficits.

3. Immediate diagnosis of cervical injuries can determine rehabilitation, prognosis and management for the safety of both horse and rider in future athletic endeavors or full return to previous levels of activity.

findings of a significant lytic lesion found on the vertebral head of C6 and associated cystic mass within the spinal canal at this location. It can be presumed that both are a result from the trauma he incurred, although congenital defect cannot be ruled out. MeV

ABOUT THE AUTHOR

Jessica began in Equine Sports Medicine of Maryland, in 2003 with Cooper Williams, VMD, when he was a single practitioner. 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 variety of patients they see. Being an assistant to Dr. Williams, Jess has relished the opportunity to learn and aid in diagnostic imaging. In 2018 and 2023, she submitted case studies 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 national convention. She has had articles published with modernequinevet.com online magazine in reference to the practice's "whole horse" philosophy and has continued submissions for future use. When not involved with horses, Jess enjoys gardening and hiking with her hound mix, Pilot, who often accompanies her and Dr. Williams on the road.

Does Inbreeding Increase Pregnancy Losses?

Breeding choices are critical for Thoroughbreds, according to a recent study that found inbreeding may predispose the mare to mid- and late-term pregnancy losses.

Excessive inbreeding increases the probability of homozygous recessive genotypes and has been associated with an increased risk for retained placenta and lower semen quality in horses, according to the researchers, but to their knowledge no genomic analysis has investigated the association between inbreeding and pregnancy loss.

They compared the genetic inbreeding coefficients (F) of naturally occurring early, mid- and late-term pregnancy losses of Thoroughbred mares with controls. They genotyped allantochorion and fetal DNA from early pregnancy loss (n = 37, gestation age 14–

65 days); mid- and late-term (n = 94, gestational age 70 days–24 hours post parturition) and controls (n = 58). Inbreeding coefficients using runs of homozygosity (FROH) were calculated. They split the ROHs into size categories to investigate the recency of inbreeding.

Mid- and late-term pregnancy losses had significantly higher median number of ROH, length of ROH and total number of ROH and FROH when compared with the controls and the early pregnancy losses (P<0.05). There was no significant difference in any of the inbreeding indices between the early pregnancy loss and controls. The mid- and late-term losses had a significantly higher proportion of long (>10 Mb) ROH than the Controls (P = 0.001). No unique ROHs were found among the mares with the early or midand late-term losses. MeV For more information:

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Photo Courtesy Platinum Performance

New Testing Approach Improves Detection of Rare but Emerging Powassan Virus Spread by Deer Ticks

Researchers at the New England Regional Center of Vector-Borne Diseases at the University of Massachusetts Amherst have come up with a new, more accurate method for detecting the emerging Powassan virus (POWV) in ticks.

This robust, real-time approach reduces the incidence of false-positive results, the NEWVEC researchers found because false-positives can confound surveillance efforts, according to Stephen Rich, MS, PhD, a professor of microbiology at UMass Amherst and the principal investigator and executive director of NEWVEC. “The development of sensitive detection methods for diagnostics and surveillance is critical,” he said.

minex xMap technology.

The new triplex method accomplishes a reduction in false negatives by using a clever quality control. Both tests seek to detect the presence of POWV RNA. “But we also had a paired search for the RNA from the tick, which is present in every tick regardless of whether it has the virus or not,” Dr. Rich said. “If we don’t detect the tick DNA, then we have no hope of being able to detect the virus RNA.

The incidence of Powassan virus is increasing in the United States.

Named after the town in Ontario, Canada, where it was first identified in 1958 in a 5-year-old boy who died from encephalitis, POWV is a flavivirus related to West Nile, which can affect humans and horses.

Although still rare, POWV is increasing in incidence in the United States, predominantly in the Northeast and Great Lakes region. More than 10% of the record 290 U.S. human cases reported in 2022 (compared with only 1 case per year from 2004 to 2006) resulted in death, and half of the survivors suffered long-term neurological damage.

The virus is transmitted to humans primarily by Ixodes scapularis, which also transmits Lyme disease, babesiosis and other tickborne illnesses.

The team at NEWVEC developed a triplex real-time polymerase chain reaction (PCR) test for the simultaneous and quantitative detection of the Powassan virus and Powassan virus lineage II in I. scapularis

The NEWVEC team conducted a tick survey in coastal and offshore Massachusetts, focusing on 13 sites from the highly endemic regions of tickborne diseases in Cape Cod and Martha’s Vineyard. They tested the ticks for POWV, comparing their new triplex PCR method to the standard, commercially available Lu-

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“And before we developed that method, people would be left to wonder whether a negative result meant that the virus wasn’t there or that the sample wasn’t testable. So, we’ve ruled out that latter possibility. And now we know with some assurance that when a tick tests negative, it’s a true negative. It’s not that the sample just isn’t good enough,” he said.

In the areas surveyed, “We found pockets of high incidence of this virus,” Dr. Rich said.

POWV was detected at 4 of 6 sites in Cape Cod and 2 of 7 sites in Martha’s Vineyard. Of 819 ticks collected, 33 (4.03%) tested positive for POWV and 752 tested as Powassan negative, using the new triplex method. Thirty-four ticks (4.15%) failed the quality control tick RNA test. That showed that the standard Luminex method underestimated the overall prevalence of POWV because those 34 ticks were found Powassan negative. And only 30 ticks tested positive using the Luminex method, demonstrating that the triplex technique has a higher sensitivity to detect the virus RNA.

Infection rates reached as high as 10.43% at 1 site in Truro on Cape Cod and were completely absent at 7 other sites. All the ticks that tested positive for the POWV also were positive for the lineage II deer tick virus.

The researchers said they hope this improved triplex PCR test will be useful in transmission studies and as a tool to monitor and prevent POWV infections in areas where the virus has been reported. MeV