The Modern Equine Vet May 2016

The Modern

Equine Vet www.modernequinevet.com

Hoof boots for laminitis

Where’d You Get Those Shoes?

Vol 6 Issue 5 2016

Beating the fracture odds Surgery for pastern instability Encourage boosters for horse health

Table of Contents

Lameness:

Where'd you

4 get those shoes?

Hoof boots for chronic laminitis Cover photo: courtesy of Dr. Bryan Fraley Cover illustration: Shutterstock/ Vextok

Colic

Camera pill examines horse gut..........................................................................................3 Technician Update

Slim to none: Beating the fracture odds.......................................9 Infectious Diseases

Vaccination: Not a one-shot deal..................................................14 The 5 minute egg (count).................................................................18 News

Surgery for pastern instability....................................................16 Quantifying locomotor activity...................................................17 Merck welcomes Dr. Fairfield Bain............................................17

advertisers Avalon Medical............................................................. 3 Merck Animal Health.................................................. 5

Boehringer Ingelheim................................................ 7 AAEVT............................................................................13

The Modern

Equine Vet Sales: Matthew Todd • ModernEquineVet@gmail.com Editor: Marie Rosenthal • mrosenthal@percybo.com Art Director: Jennifer Barlow • jbarlow@percybo.com contributing writerS: Paul Basillo • Kathleen Ogle COPY EDITOR: Patty Wall Published by PO Box 935 • Morrisville, PA 19067 Marie Rosenthal and Jennifer Barlow, Publishers percybo media  publishing

2

Issue 5/2016 | ModernEquineVet.com

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

colic

'Camera Pill' to Examine Horses Researchers at the University of Saskatchewan (U of S) are harnessing human imaging technology to find out what goes on in a horse’s gut.

“Whenever I talk to students about the horse abdomen, I put up a picture of a horse and put a big question mark in the middle,” said Julia Montgomery, DVM, PHD, DACVIM, in the U of S Western College of Veterinary Medicine, who worked with equine surgeon Joe Bracamonte, DVM, DVSc, DACVS, DECVS and Khan Wahid, PhD, P.Eng, SMIEEE, a specialist in health informatics and imaging in the College of Engineering.

The team used an endoscopy capsule about the size and shape of a vitamin pill to have a look inside a horse, a better less invasive way than exploratory surgery, laparoscopy or endoscopy. The capsule endoscopy offers a powerful new way to diagnose diseases, such as inflammatory bowel disease and cancer, or to check surgical sites. Researchers could use it to see how well drugs to stimulate bowel action are working, or to answer basic questions such

as determining what “normal” small intestine function looks like.

Dr. Wahid, who has patented algorithms and data compression technology for the improved performance of human endoscopy capsules, said he believes this is the first time it has been applied in equine health.

They administered the capsule through a stomach tube directly into the horse’s stomach. For the next eight hours, the capsule and its camera made its way through the horse’s small intestine, offering a continuous picture of what was going on inside.

The team plans to run more tests on different horses to gather more data to pursue funding to further develop equine capsule endoscopy. “Once we know more about the requirements, we can make it really customizable, a pill specific to the horse,” Dr. Wahid said.

MeV

Dr. Khan Wahid holds the camera pill, which is the size of a vitamin.

ModernEquineVet.com | Issue 5/2016

3

lameness

Where’d you get those

shoes?

B y

M a r i e

R o s e n t h a l ,

Hoof boots are popular be-

Photos courtesy of Dr. Bryan Fraley

cause they are easy to use, and they can make a horse more comfortable.

That can be good or bad, according to Bryan Fraley, DVM, who spoke at the 61st Annual Convention & Trade Show of the American Association of Equine Practitioners.

If the horse has a serious problem like laminitis, the hoof boot might be masking the extent of the issue, he warned. “Hoof boots do make horses comfortable and that is what owners are using as a barometer of

Chronic severe laminitis

4

Issue 5/2016 | ModernEquineVet.com

Modifying hoof boots to treat chronic laminitis

M S

success or failure,” he said. “But the more time I’ve spent treating feet in those boots, I realize there are some limitations.

“The comfort is only a small part of a much bigger picture. I’ve become tired of seeing horses deteriorate slowly in hoof boots by being comfortable.”

If the veterinarian does not use the boot to address the biomechanical issues that are causing the problem, the boot “is acting more as a Band-Aid rather than helping this

foot get rehabilitated,” said Dr. Fraley, who is owner of Fraley Equine Podiatry in Lexington, Ky., and one of four inventors of a patent-pending convertible hoof boot called the Easy Boot Click System that has been licensed to Easy Care.

Hoof boots have come a long way since they were developed in the 1970s by Dr. Neel Glass, who developed the original Easy Boot, which is still available. Modern hoof boots offer a lot of different styles and choices.

Safety In Numbers Some dewormers claim just one dose of their product is the best way to deworm your horse, but that’s simply not true.

Demand Safety: You won’t find a laundry list of warnings and precautions on the PANACUR® (fenbendazole) POWERPAC label because fenbendazole has a unique mode of action that makes it safe for horses of all ages, sizes, and body conditions.

Demand Efficacy: PANACUR® POWERPAC is the only dewormer FDA approved to treat ALL STAGES of the encysted small strongyle.1 Other dewormers miss a critical stage, EL3, which can account for up to 75% of the encysted small strongyle burden. Plus, it’s the best choice for treating ascarids — which are not just a problem in young horses!

So when it comes to which dewormer to trust, don’t forget there’s safety in numbers.

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 manufacturers labels for use and cautions for trichlorfon.

1

PANACUR® (fenbendazole) POWERPAC Equine Dewormer product label.

The Science of Healthier Animals 2 Giralda Farms • Madison, NJ 07940 • merck-animal-health-usa.com • 800-521-5767 Copyright © 2016 Intervet Inc., d/b/a/ Merck Animal Health, a subsidiary of Merck & Co., Inc. All rights reserved. 3290 EQ-PC-FP AD

lameness

There are many different uses for hoof boots. Owners are using hoof boots to minimize fatigue in shipping and to protect the heal bulb, or for providing some protection for a barefoot horse, and many are using them in endurance events now, he said.

Photos courtesy of Dr. Bryan Fraley

Shoeing approachs for chronic laminitis.

Aluminum shoe rolled and rockered toe boot modification

6

Issue 5/2016 | ModernEquineVet.com

But veterinarians can use them to improve the biomechanics of the foot. There are a few pitfalls for therapeutic use by a veterinarian. They require a large inventory. Much like a human shoe store, they come in all different sizes to accommodate the many different size horses that one

treats. So, there is an initial investment in hoof boots.

They also require some maintenance, which owners might not realize. “They often just want to set it and forget it, but they must be maintained. You have to change them at least every other day,” he said.

Hoof boots wear out and need to be replaced, and because a therapeutic hoof boot alters the function of the foot, they might need adjusting.

A hoof boot with altered mechanics means that the veterinarian or farrier has done something with the hoof boot to alter the function of the foot. It could be a wedge, rolled toe etc., he explained. Acute and chronic laminitis are probably the most common therapeutic reasons to use a hoof boot, although the evidence of the approach is anecdotal, he warned.

However, he said, adjusting the biomechanics of the laminitic foot makes sense to him and helps make the horse more comfortable as the veterinarian works medically to address the laminitis.

The most important issue is fit, he said. If the veterinarian alters the hoof boot—for instance, adds a 10° wedge—and the boot does not fit properly, it might spin, providing the opposite mechanics that were desired. “That can be devastating for the horse,” he said.

“Make sure the boots fit snuggly, but make sure to minimize rubs, sores and dermatitis. Talcum powder and socks can help,” he said. He uses a human sock that flips down over the boot and helps keep the straps intact and the horse off the straps. One can also use duct tape or put elastic on it if the horse bothers the straps a lot.

The weather can affect boot comfort. “Every horse is different.

Just from experience with my own horse—she will go through stages with hoof boots. They will get too

purified to remove unnecessary proteins. diversified to remove unnecessary hassles.

VeteraÂŽ vaccines are designed for ease of use and administration, and are updated to include the diseases most likely to infect horses today. Our exclusive Ultrafil ÂŽ Purification Technology removes unnecessary proteins that may contribute to injection site reactions. Protection has never gone this smoothly.

Visit vetera-vaccines.com to see the complete line of products.

pure & simple.

Vetera is a registered trademark of Boehringer Ingelheim Vetmedica, Inc. Š 2015 Boehringer Ingelheim Vetmedica, Inc.

lameness

Photos courtesy of Dr. Bryan Fraley

moist, they will get too hard—especially in a laminitic horse. I think that sometimes their feet can get so hard that the soft tissue inside the foot compresses against that outer

Prototype for Dr. Fraley's Easy Boot Click System

8

Issue 5/2016 | ModernEquineVet.com

hard sole and that can make them sore,” he said. Hot, muggy weather might need a hoof hardener. Cold weather might need a sole softener.

Icy weather might need some type of traction on the bottom.

And remember, “Boots are not for every case, nor are shoes,” he said.

Choose the appropriate sole support. There is no one-size-fitsall approach. Materials that work for him include ethylene vinyl acetate (EVA) foam pad material, which can be purchased in bulk; felt padding for carpet; orthopedic felt, and two-part dental impression material. The choice would depend on the horse’s comfort level and the amount of support the veterinarian is trying to provide. Some horses prefer felt over the impression materials because they apply less pressure to the frog.

The veterinarian might also want to apply hoof emollients, hardeners and medications, which can be done on a felt-like material.

Common approachs that he uses to improve the mechanics are the heart bar, the ultimate clog, and the rail shoe with a rocker toe.

Although a clinical examination of the hoof morphology can provide a lot of insight, Dr. Fraley said that the changes in a laminitic foot can take weeks-to-months to manifest. Therefore, he takes radiographs before using therapeutic hoof boots to decide the best approach—as well as after—to make sure the boot fits properly.

It is important to individualize therapy, he said. “We must tailor our approach to what the horse is telling us,” Dr. Fraley said.

“Aside from modifying the hoof boot, they offer the advantage of being able to alter the sole support and mechanics independently of each other. I think that this is important to really stress. We can make changes to the support material without changing the shoeing strategy or we

use the shoeing strategy for the mechanics without changing the support,” he added.

One of the first times he used hoof boots therapeutically was on a mare that was two months from foaling with chronic laminitis. She was in so much pain that she was reluctant to move. She had a pretty good trim, so he did very little trimming. He shortened her toe a little and put her in a boot with a 5° wedge and a rolled toe. He used an EVA foam pad.

With some pain control and the hoof boots, she was able to carry the foal to term, he said.

“I can’t stress enough how important the environment is for these hoof boots,” he said. One of the mares who gave him the idea for his hoof boot system is on nice glass eyed sand for 12 hours. She is turned out with a friend on a paddock for another 12 hours.

She's been in hoof boots for well over two years now. The hoof boot is only on one foot and the others are shod.

“She’s had three foals,” he said.

“I am very happy. I know that this mare would not be alive if I did not use hoof boots in this manner on her."

He said that there were some keys to this approach. “You need a well-fit boot first, but foremost, we need to address the support of the horse and try to find what makes this horse comfortable. We then address the mechanics that we deem appropriate, bearing in mind that we can alter those two independently. If it is not working for one we can switch it up and try to help this horse out. We need to mitigate rubs or we will not be successful,” he said.

Keeping those issues in mind, “The sky is the limit,” he said. “If you can imagine it, you can put it on a hoof boot and use it successMeV fully.”

technician update

Slim to None: The Story of a Brave Mare Who Overcame the Odds of a Life Ending Injury We have all seen it, time and time again—careerending injuries that affect performance horses.

Some can be treated and repaired, but many cannot.

On the evening of April 12, 2015 the cutting horse industry in Fort Worth, Texas was alive with excitement during the annual National Cutting Horse Super Stakes competition with trainers, owners and their best horses—all hoping for a chance at victory. Countless hours of training had gone into these hopefuls, and it was no different for a 4-year-old sorrel mare whose life was changed that night.

It was her turn, her chance at becoming a champion, her chance to prove herself. Calm, cool and collected, she walked into the arena and headed for the herd of cattle ready to compete. She was off to a brilliant start; right, left, right, left, left and then it happened—crack!

Her owner immediately dismounted in the arena, knowing that something was seriously wrong with his fierce competitor. She stood there, shaking and wide eyed, not wanting to put any weight on the left forelimb.

The trainer and his team bandaged her leg with the supplies they had and headed for the veterinary clinic.

The emergency staff at the clinic prepared for the worst, following the phone call describing the injury.

After what seemed like an eternity, a trailer was seen on the horizon headed for the clinic. On arrival, the attending veterinarian opened the trailer door to find the horse with profuse diaphoresis, muscle fasciculations and showing signs of distress. The bandage that was applied at the competition had slid down during the trailer ride, exposing the severity of the injury. This brave competitor’s leg was clearly fractured—presented as a flail limb.

She was standing on the proximal portion of the fracture with the distal portion of limb off to the side.

A decision had to be made quickly to prevent further damage and injury. She was sedated, her fractured limb was manipulated carefully back into place, and a fiberglass cast was applied by the veterinary staff to move her into the clinic for more diagnostics and evaluation.

Once in the clinic, a physical examination was performed and found to be within normal limits, with the exception of mild tachycardia due to pain and stress.

Images courtesy of Ms. Larsen

By Brandi Larsen, CVT

A blood sample was obtained from her jugular vein and submitted for a complete blood count (CBC), a chemistry panel, as well as a packed cell volume (PCV) and total protein analysis. With these types of injuries, it is common to have excessive blood loss and dehydration, which must be managed quickly. Fortunately for her, the results of all lab work came back with mostly no deficits or abnormalities. It did indicate mild shock, but nothing that required treatment at that time.

Now that the veterinary staff had determined that no major systemic disturbances were present, it was time to examine the injury. The fiberglass cast that was applied in the trailer on arrival was not removed due to the instability of the limb and severity of the injury. The fracture site had been contaminated with manure, wet shavings, dirt and other debris while on the trailer, further lowering a chance at successful treatment. Feelings of hopelessness came over the veterinarians and staff, knowing that the chance of a comfortable life following an injury like this was slim to none.

Digital radiography was used to confirm the fracture and to determine the best way to proceed—if proceeding was possible. The radiographs showed an open, long, oblique comminuted fracture of the mid-diaph-

Radiographs showing an open, long, oblique comminuted fracture of the mid-diaphysis.

ModernEquineVet.com | Issue 5/2016

9

Images courtesy of Ms. Larsen

technician update

From Left: Radiographs of the fracture. During surgery, the injury was held in place using pointed AO bone reduction forceps.

ysis of the left third metacarpal bone. A butterfly fragment and several small, focal, pinpoint opacities were appreciated around the fracture, as well.

Several questions came up immediately after understanding the nature of this injury. What did this mean for this horse? Do we proceed or give up? Could she make it through the recovery phase of anesthesia without further incident? Would her body reject internal fixation devices? Would she develop laminitis in her feet in the unaffected limbs? Would she develop an infection?

This would be a risky repair. After careful consideration, explanation of all risks involved and an understanding that her recovery and rehabilitation would be long and complicated, it was decided to make an attempt to save her leg and her life. An IV catheter was placed in the jugular vein, antibiotics were administered, and she was as ready as she would ever be to get started. She was induced for general inhalant anesthesia and placed on the operating table in right lateral recumbency. The fiberglass cast was removed, allowing a full gross examination of the injury and the beginning of a life-saving plan.

While the surgery technician was clipping the hair on the leg and using sterile technique to prepare it, the surgeons on the case were moving instruments, equipment and supplies into the operating room to be pre10

Issue 4/2016 | ModernEquineVet.com

pared for whatever was coming their way. The surgeons were scrubbed in, the patient was stable under anesthesia, and the support staff was quietly waiting for the next instruction. Everyone took a deep breath, said a prayer and the first surgical pack was opened. Her left limb was draped in a sterile manner with general surgical drapes and an Ioban antimicrobial drape was applied to the limb.

The fracture was reduced and manipulated back into its original location by open reduction and held in place using pointed AO bone reduction forcepsÍž digital radiography was then used to confirm reduction and placement intraoperatively. Two 5.5 mm cortical bone screws were placed in lag fashion across the fracture plane. A 4.5 mm, 9-hole, narrow low contact dynamic compression bone plate (LC-DCP) was placed on the dorsolateral aspect of the third metacarpal bone and (9) cortical bone screws ranging from 4.5 mm x 34 mm to 4.5 mm x 58 mm were placed in lag fashion when crossing the fracture to secure the plate. Placement of the bone plate and cortical bone screws was confirmed via intraoperative digital radiography.

A second LC-DCP 10-hole bone plate was placed on the dorsomedial aspect of the third metacarpal bone and 10 cortical bone screws ranging from 4.5 mm x 34 mm to 4.5 mm x 58 mm were placed in lag fashion when crossing the fracture to secure the second plate.

From left: 5.5 mm cortical bone screws were placed in lag fashion across the fracture plane. A 4.5 mm, 9-hole narrow low contact dynamic compression bone plate was placed on the dorsolateral aspect of the third metacarpal bone and cortical bone screws of various sizes were placed in lag fashion to secure it. A second 10-hole plate was placed on the dorsomedial bone.

Several different intraoperative digital radiographic views were taken to confirm appropriate reduction of the fracture as well as proper positioning and placement of the DCP plates and cortical bone screws. The incision was closed using absorbable, synthetic, polyglactin suture and skin staples.

A distal limb fiberglass cast was applied intraopera-

tively, and the patient was moved into recovery as everyone took a deep breath.

She was moved into a padded stall for recovery and administered romifidine IV to combat a premature attempt to stand. She was monitored in the recovery stall for about an hour and a half before she attempted to become sternal and stand. This was it, the part that was

Anesthesia Anesthesia was uneventful during the seven-hour procedure, and she remained stable throughout. Prior to induction, the patient was administered 2 L of hypertonic saline 7.2% IV as a bolus, her mouth was thoroughly rinsed and she was brushed to remove additional debris. Due to the ataxia secondary to the fracture, and the fiberglass cast, her hooves were not cleaned prior to surgery.

She was preanesthetically sedated with a combination of xylazine and butorphanol IV. After about 5 minutes and a determination of adequate sedation, she was induced with ketamine and diazepam IV and intubated with a size 26 mm endotracheal tube without incident.

She was moved into the OR and positioned in right lateral recumbency on the operating table with forward extension to her right forelimb and right hind limb to minimize the risk of post anesthetic myopathy and radial nerve paralysis. She was maintained on a Mallard rebreathing circle system with a mechanical ventilator on Sevoflurane in 100% oxygen. She was monitored using a Mindray Datascope ECG, invasive blood pressure, IRMA Blood Gas Analyzer and end tidal CO2. An arterial catheter was placed and maintained in her submandibular artery, and she was started on Lactated Ringer’s Solution IV to combat dehydration, hypotension, electrolyte imbalance and post anesthetic myopathy.

The patient became mildly hypotensive approximately 60 minutes into surgery and a dobutamine constant rate infusion was started IV to effect. An arterial blood sample was collected and analyzed every 60 minutes with no abnormal findings throughout. Due to the severity of the fracture, the total anesthesia time was 450 minutes, which greatly increased the risk of post anesthetic myopathy and the need to avoid any periods of intraoperative hypotension. Overall, the patient’s general inhalant anesthesia was uncomplicated and unremarkable.

ModernEquineVet.com | Issue 5/2016

11

technician update

She was standing on the proximal portion of the fracture with the distal portion of the limb off to the side.

crucial to allowing us to proceed to the next phase of recovery for her. The staff held their breaths as she made her first attempt. Success!

The patient recovered unassisted without incident and with minimal ataxia. She was allowed to remain in the recovery stall until she became steady and was able to return to a stall in the hospital.

The patient was carefully persuaded to attempt walking to her stall in the hospitalization unit and did remarkably well. About 12 hours postoperatively, she appeared mildly uncomfortable but still was willing to bear weight on the left forelimb. During her first week of hospitalization, she was managed on IV antibiotics including cefazolin and gentamicin as well as IV phenylbutazone.

To minimize the risk of gastric upset and delay of the healing process, she was also administered oral omeprazole paste and probiotics daily. Her distal limb fiberglass cast maintained well for approximately three weeks with the exception of minor edema proximal to the top of the cast and a minimal lameness.

On May 4, 2015, she was anesthetized under general anesthesia without incident and the fiberglass cast applied intraoperatively following the fracture repair was removed to allow evaluation of the surgical site.

The fracture repair was intact, and there was a moderate amount of granulation tissue present. The site was aseptically prepared with betadine and alcohol, a new bandage was placed as well as a new fiberglass cast to replace the original. She recovered without incident but displayed an increased lameness upon recovery. Following the placement of the new fiberglass cast, she became reluctant to bear full weight on the affected limb and was noticeably more uncomfortable, which made the entire staff nervous since she had already come so far.

As her right distal limb became slightly edematous, it was decided to place a standing wrap and soft ride boot on her for additional comfort and support.

Antibiotic, NSAID and gastrointestinal support were continued over the next week, as well as repeated treatments in the hyperbaric oxygen therapy chamber as her injury became increasingly more painful.

On May 12, 2015 her digital pulses were bounding and she was reluctant to stand. The owners were updated on the patient frequently and, with the surgeon, decided to continue treatment, hoping she 12

Issue 5/2016 | ModernEquineVet.com

would soon show improvement.

During treatment, an acupuncturist performed an evaluation and acupuncture as complementary medicine—to aid with comfort as well as to promote healing.

On May 26, 2015, the patient was again anesthetized and maintained under general inhalant anesthesia for a cast change.

The previous cast was removed and the surgical site and distal left forelimb were evaluated. The condition of the limb appeared to be progressing and additional granulation tissue was present.

The limb was prepared aseptically with betadine and alcohol, bandaged and casted. She recovered without incident and was returned to her stall. Supportive therapy was continued with antibiotics, NSAIDS and GI support as the fracture continued to heal.

The final fiberglass cast was removed on June 16, 2015 without general anesthesia and a bandage was applied for additional support. Following the final cast removal, the patient became increasingly more comfortable and continued to progress daily.

It was truly a miracle to see this brave mare overcome an injury that most would not survive. Digital radiographs were taken routinely throughout her hospitalization to confirm stability, assess progress and ensure proper positioning of all bone screws and plates. She spent nearly three months at the clinic and quickly became a favorite due to her quiet nature.

She was discharged and placed on strict stall rest to allow continued healing. The bone plate was removed under standing sedation after several more months of rest and rehabilitation. This brave mare is now sound and comfortable at home. The possibility of a positive outcome for an injury such as this is slim-to-none. Her tale of bravery and recovery will stay with me forever.

MeV

About the author randi Larsen, CVT, is an independent consulB tant in Weatherford, Texas. She has piloted and implemented custom veterinary training programs in large animal practices in Texas as well as lent her knowledge as a speaker at veterinary conferences nationwide.

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

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

Bi-Annual Newsletter Weekly “HoofBeats” Email Newsblast Full access to www.aaevt.org, including the Career Center and the Library Up-to-date information on the AAEVT Discounted registration for AAEVT Regional Meetings and the annual AAEP/AAEVT Convention NTRA, Working Advantage and Platinum Performance Benefits The opportunity to participate in the AAEVT Online Certification Program or to become a member of the AEVNT Academy-Specialty in Equine Veterinary Nursing Scholarship opportunities.

AAEVT’s Equine Manual for Veterinary Technicians (Blackwell Publishing 20% discount on purchase price) Opportunity to attend Purina’s Annual Equine Veterinary Technician Conference - All Expenses paid!

AAEVT Objectives • • • •

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

AAEVT Online Equine Certification Program

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

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

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

*American Association of Equine Veterinary Technicians and Assistants

infectious diseases

Vaccination: Not Typically a One-Shot Deal B y

T o m

Now is a good time to remind owners that horses need booster vaccinations to protect them from infectious diseases—especially if they travel domestically and internationally to shows and events, such as the upcoming Olympics this summer in Brazil, according to Robert Keene, DVM, Equine Technical Manager with Boehringer Ingelheim Vetmedica (BIVI).

“And the entire herd should be vaccinated similarly, not just the traveling horse especially if there are not good quarantine facilities,” he said.

“Horses are incredibly mobile,” said Dr. Keene.

“And that mobility makes them more susceptible to infection in two ways: first the stress of transportation weakens their immune system and second, co-mingling with other horses during the competition increases their e x p o s u r e .”

14

Issue 5/2016 | ModernEquineVet.com

R o s e n t h a l

Photos courtesy of Boehringer Ingelheim Vetmedica, Inc.

He said the entire traveling experience is “the perfect environment” for the spread of infectious diseases.

That is why veterinarians need to recommend an aggressive program of booster vaccinations, which help protect horses yearround, Dr. Keene said. “Whether they are the ones giving vaccinations or not, they need to strongly advise their clients that their animals need boosters.” (To read about how two veterinarians took back the vaccine business, click here.)

Dr. Keene said that, unfortunately, only a small percentage of horses actually receive boosters.

He particularly recommends a booster vaccination program for older horses. “As horses get older, they still need to be vaccinated,” he said. “Their immune system doesn’t function as well as they did when they were young.”

The American Association of Equine Practitioners (AAEP) Vaccination Guidelines (http://www. aaep.org/info/vaccination-guidelines) states that there is no “standard” vaccination program for all horses. While each individual situation requires evaluation based on a series of criteria, the AAEP Vaccination Guidelines do recommend that all horses in a herd be vaccinated at intervals based on the opinion of the attending veterinarian regarding the risk of specific diseases.

The AAEP noted that increased population density and moving horses on and off their facility raises the risk of introducing or transmitting infectious diseases. The vaccination guidelines cited examples of external factors that contribute to increased risk of infectious disease, and include, among others, stress, over-crowding, and movement of people, vehicles and/or equipment on and off facilities during

AAEP Core Vaccination Guidelines: The core equine vaccines include tetanus, Eastern equine encephalitis/Western equine encephalitis (EEE/ WEE), West Nile virus (WNV) and rabies, and according to the AAEP, they have demonstrated their efficacy and safety.

Tetanus

Adult horses should receive 2 doses of tetanus toxoid 3 to 4 weeks apart followed by an annual booster. If a horse is wounded or undergoes surgery 6 or more months after a tetanus booster, it should receive tetanus toxoid immediately at the time of injury or surgery.

Foals of mares vaccinated against tetanus during the prepartum period should receive a 3-dose series beginning 4 to 6 months of age with a 4- to 6-week interval between the first and second doses. The third dose should be given at 10 to 12 months of age.

Foals of unvaccinated mares or mares with an unknown vaccination history: Administer a 3-dose series beginning 1 to 4 months of age with a 4-week interval between doses.

EEE/WEE

Adult horses should receive an initial 2-dose series at a 4- to 6-week interval, followed by a yearly booster prior to the vector season. In high-risk animals, and in areas with year-round vectors, more frequent vaccination is recommended (or twice yearly).

Foals of mares vaccinated against EEE/WEE in prepartum period should receive a 3-dose series beginning at 4 to 6 months of age with a 4- to 6-week interval between the first and second dose. The third dose is administered at 10 to 12 months of age.

Foals of unvaccinated mares or having an unknown vaccination history should be given a primary series of 3 doses beginning at 3 to 4 months of age, with a 30-day interval between the first and second doses and a 60-day interval between the second and third doses. If the primary series is initiated during the mosquito vector season, an interval of 3 to 4 weeks between the second and third doses is preferable to the above described interval of 8 weeks.

WNV

Adult horses should receive an initial 2-dose series at a 3- to 6-week interval with a yearly booster prior to the vector season. In high-risk animals, and in areas with year-round vectors, more frequent vaccination (with any of the currently licensed products) may be recommended to meet the vaccination needs of these horses.

Foals of vaccinated mares should be given a primary 3-dose series beginning at 4 to 6 months of age with a 4- to 6-week interval between the first and second dose. The third dose should be administered at 10 to 12 months of age prior to the onset of the next mosquito season.

Foals of unvaccinated mares or mares where the vaccination history is unknown should be given a primary series of 3 doses beginning at 3 to 4 months of age, with a 30-day interval between the first and second dose and a 60-day interval between the second and third dose. If the primary series is initiated during the mosquito vector season, an interval of 3 to 4 weeks between the second and third dose is preferable to the above described interval of 8 weeks.

Rabies

Rabies vaccines induce a strong immunologic response after a single dose. After the initial single-dose, adults should receive a yearly booster.

Foals of mares vaccinated against rabies should be given a primary 2-dose series beginning no earlier than 6 months of age. The second dose should be given 4 to 6 weeks later. Revaccinate annually thereafter.

Foals of mares not vaccinated against rabies should be vaccinated according to label directions. The first dose of vaccine should be administered at 3 to 4 months of age. Revaccinate annually thereafter.

For more information about the AAEP vaccination guidelines, go to http://www.aaep.org/info/vaccination-guidelines

ModernEquineVet.com | Issue 5/2016

15

infectious diseases

infectious disease outbreaks.

Dr. Keene said spring or early summer are when horses should be vaccinated against eastern and western equine encephalomyelitis (EEE/WEE) and West Nile virus (WNV).

The World Organization for Animal Health reported increased equine influenza activity in the United States in 2015 over 2014; there were outbreaks detected on 46 premises in 23 states in 2015 and confirmed cases on 28 premises in 19 states in the United States.

“As horses continue to travel and be shown, it might be wise to booster those horses with respiratory vaccines,” he said, adding that there are new United States Equestrian Federation documentation requirements for traveling horses.

“While some studies have shown that horses are not being vaccinated at the intervals they should be,” Dr. Keene said, “we are trying to get the message out. We are spending time educating owners and helping veterinarians educate their clients.”

MeV

Click here for a link to a Vaccine Chart that includes information about all currently approved vaccinations that you can download free.

Surgery for Pastern Instability Using a double fixation technique for injuries involving axial pastern instability results in a high survival rate and allows some horses to return to work.

Researchers from Texas A&M University used a retrospective case series to evaluate 30 cases (13 forelimbs and 18 hind limbs) of double-plate fixation in treating axial instability of the proximal interphalangeal joint.

The 11 geldings, 11 mares and eight colts ranged in age from 1 month to 15 years.

Trauma sustained during paddock turnout, cattle work and arena work were the most common causes of injury. One case developed gradual plantar luxation following intra-articular injection with alcohol to promote ankylosis. Pastern instability had been confirmed radiographically in each case.

Prior to surgery, the affected limb was stabilized in a bandage cast with a dorsal splint. Fracture repair was carried out 1 to 28 days following injury. The delay before surgery did not negatively affect outcome, according to Justin D. McCormick, DVM, lead author of the study.

Dr. McCormick and his colleague Jeffrey P. Watkins, DVM, MS, DACVS, a professor at Texas A&M, wanted to reconstruct the proximal articular surface and engage the palmar/plantar eminences to re-establish tensile strength. Two dynamic compression plates

or locking compression plates were applied to the dorsomedial and dorsolateral aspects of the proximal and middle phalanges. Abaxial plates with a single lag screw engaged the proximal aspect of the middle phalanx. A half-limb cast was left on until two to three weeks after surgery.

The cast was then replaced, or a bandage cast used and bandaging was continued for three weeks following cast removal.

Horses were kept on box rest for two months followed by two months of hand walking. If no complications were apparent at this point, horses were reintroduced to paddock turnout for two months before returning to an exercise regime.

Following this repair, 29 of 30 (97%) horses were discharged (compared with 67–70% with other methods in previous reports), six returned to their intended use, nine were able to be ridden in less demanding activity, seven horses were sound for pasture and/or breeding, three were euthanized and five horses were unavailable for follow-up.

“Double-plate fixation for management of disruptive injuries causing pastern joint instability resulted in a short convalescence time and a high percentage of survival and allowed some horses to return to useful function,” the researchers wrote.

MeV

For more information: McCormick JD, Watkins JP Double plate fixation for the management of proximal interphalangeal joint instability in 30 horses (1987–2015).

Equine Vet J 2016. Apr. 29 [Epub ahead of print]). http://onlinelibrary.wiley.com/doi/10.1111/evj.12578/abstract 16

Issue 5/2016 | ModernEquineVet.com

news

An accelerometer was able to accurately differentiate between movement at different speeds and gaits, with positioning on the hind limb providing the most accurate results.

This study used an activity recording system (Animal ActiCal) to monitor locomotor activity in horses.

The system included an omnidirectional piezoelectric accelerometer, which detects body accelerations in all directions, providing data in the form of an activity count over five seconds and a step count/frequency over one minute.

Six riding horses were fitted with four accelerometers on the head, withers, left fore pastern and lateral metatarsal of left hind. A series of trials were then carried out with the horses in varying conditions: freely moving around a paddock, grazing on pasture, walking in hand, trotting on a lunge line, cantering on a lunge line and walking on a horse walker at different set speeds, randomized in order. To validate the device, manual measurements of step frequency were made from video recordings and the data compared over a period of one minute.

The hind limb device produced activity counts that were significantly different at all stages of movement— except grazing and moving freely in a paddock—and produced activity counts that were positively and linearly

correlated with walking speed. The head device detected the difference between free movement in a paddock and grazing, but not between grazing, walking or trotting. The data from the withers and forelimb devices did not alter significantly at different walking speeds.

At the walk, the accelerometer data on step frequency correlated exactly with video recording data, validating this method of measuring step frequency. At canter, the accelerometer device measured each step correctly. However, at walk and trot the accelerometer counted each step twice (for unknown reasons). When information from activity and step counts was combined, it was possible to accurately differentiate among the gaits and adjust the step count accordingly. After correcting for the doubling, it was shown that recordings from the device on the hind limb had the lowest margin of error at all gaits; however, the devices in the three other locations had an unacceptable percentage of errors.

MeV

Courtesy of Dr. Fries

Quantifying Locomotor Activity

A horse from the experiments with the four accelerometers mounted (left front foot, left hind leg, withers & head collar).

For more information: Fries M, Montavon S, Spadavecchia C, Levionnois OL. Evaluation of a wireless activity monitoring system to quantify locomotor activity in horses in experimental settings.

Equine Vet J. 2016. Mar 22. [Epub ahead of print]). http://onlinelibrary.wiley.com/doi/10.1111/evj.12568/epdf

Merck Animal Health Welcomes Dr. Fairfield Bain to Equine Vet Tech Services Team Merck Animal Health announced that Fairfield T. Bain, DVM, MBA, DACVIM, DACVP, DACVECC, has joined its equine veterinary technical services team. Previously, Dr. Bain was clinical professor of equine internal medicine and equine section head at the Washington State University College of Veterinary Medicine.

A graduate of Auburn University, School of Veterinary Medicine, Dr. Bain’s distinguished career includes extensive experience in practice, academia, and within the industry. He also is known for his work in perinatology and neonatal intensive care, cardiovascular disorders, pathology and hyperbaric oxygen therapy. “Dr. Bain’s personal and professional attributes and achievements are considerable, and he is well recognized and respected within the equine industry,” said D. Craig Barnett, D.V.M, Merck Animal Health director of equine veterinary technical services. “With his vast knowledge and expertise, he will be an incredible asset to our customers, as well as our own team.”

Dr. Bain holds specialty board certification from the American College of

Veterinary Internal Medicine, American College of Veterinary Pathologists, and the American College of Veterinary Emergency and Critical Care, and received his masters of business administration from the New York Institute of Technology.

Dr. Bain also has significant clinical experience at several equine referral hospitals, including Peterson & Smith Equine Hospital, Hagyard Equine Medical Institute, Littleton Equine Medical Center and Equine Sports Medicine and Surgery. Additionally, he spent 12 years as co-owner and vice president of a worldwide manufacturer and distributor of hyperbaric oxygen chambers for veterinary applications.

Dr. Bain will provide technical support to internal and external customers for Merck Animal Health equine products and programs, assistance with research and new product development, continuing education to equine practitioners, and equine health-related information to horse owners. He also will help develop, monitor and summarize MeV clinical trials specific to equine health.

ModernEquineVet.com | Issue 5/2016

17

Parasites

The

5-Minute

Egg (Count) P a u l

B a s i l i o

The fecal egg count has been

a mainstay of diagnostic testing in the veterinary field for decades, but it is also archaic, time consuming, difficult to perform in the field, and not terribly reliable. Combined with the advent of over-the-counter anthelmintic drugs, horse owners have reverted to a prophylactic mode of cyclic deworming protocols that is causing drug resistance.

“It doesn’t look like we have learned our lesson from antibiotics,” said Paul Slusarewicz, PhD, adjunct associate professor at the University of Kentucky’s Maxwell H. Gluck Equine Research Center and co-founder of MEP Equine Solutions. “This is a growing concern in the United States and globally.

Organizations such as the AAEP have issued guidelines trying to encourage members to actually use egg counts and egg reduction tests and to treat only when needed.”

At the 61st Annual American Association of Equine Practitioners Convention in Las Vegas, Dr. Slu18

Issue 5/2016 | ModernEquineVet.com

sarewicz explained his attempt to drag the fecal egg count kicking and screaming into the 21st century.

Dr. Slusarewicz’s first obstacle was to identify what he calls a “universal egg marker” to distinguish the eggs from other organisms and miscellaneous fecal detritus.

“If you look at these shells under the microscope, they all have a translucent appearance,” he explained.

“My hope was that there would be a chemical similarity underlying the morphological similarity. I eventually narrowed my options to chitin.”

Chitin is a linear polysaccharide that is sometimes referred to as the animal version of cellulose.

It has been reported in a number of parasite eggs in the literature, and it has been localized to some adult worms, which shows that some of these creatures express the material.

It also has a structural role in the exoskeleton of arthropods, so it is not unreasonable to speculate that the substance may have a similar structural role in the shells.

Trial and Error

Dr. Slusarewicz created a simple filtration system consisting of one large-pore and one small-pore filter.

The fecal sample is driven through the filters using a syringe. The smaller porosity filter offers a place to trap and manipulate the eggs, as well as add any reagents that may be needed.

After filtering a sample of strongyle-positive feces, he stained it with a special chitin-binding protein coupled to fluorescein dye so that it glows green when exposed to blue light.

“As is the case 99% of the time in science, I was sorely disappointed when I looked through the microscope,” he joked. “I didn’t see anything.”

Fortunately Dr. Slusarewicz had read enough about egg morphology to know that most—if not all—eggs are covered with a vitelline membrane. The composition of this layer is largely unknown, but he postulated it was keeping the stain from

Shutterstock/Jojje

B y

contacting the chitin. After bleaching the sample and re-applying the stain, Dr. Slusarewicz was greeted with dozens of small green strongyle eggs staring back at him.

“That was great, but all I had done was show that equine strongyles contain chitin,” he said. “For a universal egg marker, I needed to find out if it stained anything else.”

And stain it did.

Figure 1.

Figure 2.

Images courtesy of Dr. Paul Slusarewicz

Ascarids in horses, trichostrongyles in goats and sheep, hookworms in dogs, and roundworm and Toxocara eggs in cats were all identified using this process. In a composite sample from a single cow, Dr. Slusarewicz was able to identify strongyles, Nematodirus, a trichurid and even protozoal oocysts, suggesting that chitin may be a marker for other internal parasites.

“That satisfied us enough that we could use this as a universal egg marker,” he said. “The trouble with that, however, is that there are other things in the world that contain chitin, such as insects, fungi and yeast.”

At this point, Dr. Slusarewicz determined that the image of the eggs was so clean and distinct that it would be possible to have a computer identify and count the eggs while ignoring irrelevant contaminants.

Using free software from the National Institutes of Health, his team gave the program parameters and had it count the eggs. The results were promising.

Following a few more rounds of experimentation, the team was able to take the process and shrink it down to the point where a smart phone with a macro lens function could be used to make the whole thing portable.

“This was an example of the 1% of time in science when things actually work the first time,” he said.

After analyzing eight strongyle-

Figure 4.

Figure 1. Microscopic images of a fecal sample stained using fluorescent chintin-binding domain. The picture on the left was taken using visible light and shows both ascarid (arrowheads) and strongyle (arrows) eggs amid the fecal debris. On the left is the same image but taken in fluorescence mode, and shows how the dye stains only the eggs and not the rest of the fecal matter. Note that the ascarids lack their characteristic “fuzzy coat” and brown color due to bleaching. Figure 2. An example of an image taken with an imaging unit and an iPhone followed by counting by the app. Ascarid eggs (red circles) are identified separately from strongyles (blue circles). Figure 4. Staining of a number of different eggs types from a single cow sample, showing that chitin is a UEM.

positive fecal samples and correlating the results, Dr. Slusarewicz determined that the computer-aided counting was potentially more sensitive than the McMaster method. The filtration process concentrates the feces, so more material can be counted at once than with McMaster.

This method can be conducted in less than 5 minutes. The staining takes 1–2 minutes, and the bleaching takes another 30 seconds. The remaining time is spent doing the washes and harvesting the sample.

MEP Equine Solutions is currently working on a device which will fully automate the liquid handling process to make it as simple as possible for the user.

Dr. Slusarewicz’s collaborator, Professor Martin Nielsen, also at the Gluck center and one of the world’s leading equine parasitologists, will conduct a full validation of the automated method. MEP Equine Solutions currently has a deal with Zoetis and is hoping to release it in the second half of 2016.

MeV ModernEquineVet.com | Issue 5/2016

19

The Modern

Equine Vet

Reach your veterinarians wherever they are, whenever they want.

FOR ADVERTISING RATES AND INFORMATION, EMAIL Matthew Todd