The Modern Equine Vet September 2018

The Modern

Equine Vet www.modernequinevet.com

Vol 8 Issue 9 2018

3 TIPS

for Embryo Transfer Preventing and Treating Strangles S. equi Hardier than Thought

Technician Update: Double Trouble Equine Rabies Surveillance

TABLE OF CONTENTS

COVER STORY

Tips for Successful 4 3Embryo Transfer Cover photo: Shutterstock/Zhambulat Ashimov

INFECTIOUS DISEASE

New Guidelines Offer Vets the Latest on Preventing and Treating Strangles.......................................................10 TECHNICIAN UPDATE

Mare’s Pregnancy: Double the Trouble.............................................14 NEWS

S. Equi Hardier Than Previously Thought.............................................. 8 Cornell-Developed Bone Marrow Concentrate Gets Colt Back in the Saddle....................................................................13 Horses' Rabies Risk Higher Than Dogs' Risk...................................17 ADVERTISERS Purina Animal Nutrition.............................................3 Equine Diagnostic Solutions.....................................5 Boehringer Ingelheim/PPID......................................7

Boehringer Ingelheim/Vetera..................................9 Boehringer Ingelheim/Gastroguard.....................11 AAEVT............................................................................15

The Modern

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

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Issue 9/2018 | ModernEquineVet.com

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

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REPRODUCTION

Equine embryo

3 TIPS Photo courtesy of Dr. Ryan A. Ferris

Embryo transfers are becom-

4

can help restore some reductions in fertility and help them have the ability to generate offspring into their late teens and early 20s.

Additionally, embryo transfer can be a great tool for mares while showing to maintain that mare’s career—winning money to create a following and desire for that foal. With embryo transfer, “these horses can continue in athletic performance while continuing to have foals produced every year,” he explained: a win-win for everyone.

Although most embryo transfers are fairly routine, there can be some challenges. Dr. Ferris offered 3 tips for a successful embryo recovery and pregnancy that

ing more routine these days, and a variety of veterinarians in clinical practice are performing them.

There are several reasons why embryo transfer is popular among owners. The ability to obtain more than one pregnancy a year per mare is high on the list. “This is especially important for my clients. They want multiple foals coming out of these broodmares to look for various genetic crosses to optimize their sales in future years,” explained Ryan A. Ferris, DVM, MS, DACT, a therogenologist and owner of Summit Equine in Newberg, Ore. An additional reason to consider embryo transfer is for mares with subfertility; embryo transfer

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a

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for Successful Embryo Transfer

i

e

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may help solve some of them, he said. The tips came from research that was done while he was at the Equine Reproduction Laboratory at Colorado State University.

TIP #1

Clinicians have multiple options when selecting media for embryo recovery and should expect good outcomes in pregnancy rates.

“It’s quite common in the United States to use a commercially manufactured media that contains a buffer, an antibiotic to improve shelf life and a surfactant (bovine serum albumin or polyvinyl alcohol) to perform embryo recovery attempts,” he said.

Many veterinarians in other countries routinely use a crystal-

h

a

l

,

M

S

loid isotonic IV fluid, such as lactated Ringer’s solution with or without a surfactant, for embryo recovery.

Colorado State University performed a study to evaluate embryo recovery and pregnancy rates between Hartmann’s solution (similar to lactated Ringer’s solution) to complete flush media.

“The reason we selected Hartmann’s solution for the comparison was because we were having a lot of fluid shortages. We could not obtain lactated Ringer’s in a 5-L bag, but we could obtain Hartmann’s solution,” he said. The two are similar, but Hartmann’s contains a little more potassium.

During the 2016 breeding seasons, embryo recovery was performed with either complete flush media (n=78) or Hartmann’s solu-

Many vets in Europe use a fluid, such as lactated Ringer's for embryo recovery. tion (n=77) on an alternating basis. Every other mare throughout the year was flushed with one of those two products.

Each embryo recovery attempt was treated as positive or negative regardless of the number of ovu-

lations or embryos recovered, he explained.

Once the embryos were recovered, they were washed in a commercial holding area and then transferred by two experienced clinicians who used the same standardized protocol. Pregnancy exams were done at 14 and 25 days of embryonic age.

They found no statistically significant differences in embryo recovery rates at either examination, according to Dr. Ferris.

“I think what this tells us clinically is that a surfactant is not necessarily needed during embryo recovery. We are not having a significant number of embryos that are not sticking to the catheter or tubing during the embryo recovery process,” he said.

Streptococcus equi real-time PCR and SeM ELISA EDS lab provides rapid and reliable results that you can trust. Our lab has over 15 years experience with S. equi PCR testing and the SeM ELISA. The EDS 3rd generation PCR includes 2 gene targets so that long term carriers of organisms with gene deletions are not missed. The SeM ELISA (M protein ELISA) is a valuable test to reduce the chances of hyperimmune complications with vaccination.

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Photo courtesy of Dr. Ryan A. Ferris

REPRODUCTION

Pregnancy examination

This could be important for veterinarians who travel from farm to farm. “In an ambulatory setting, what this really means is that you don’t have to carry two kinds of media with you in your truck any longer. You can carry lactate Ringer’s or equivalent for IV administration, uterine lavages and embryo recoveries. You don’t have to carry fluids just for embryo recovery in your truck at this time.”

An added bonus: Crystalloid fluids are less expensive.

TIP #2

When recipient mares are in short supply, hormone therapy can be used in acyclic and cycling recipients to prepare the uterus for an embryo with good pregnancy rates.

Multiple studies have shown that optimal donor-recipient synchrony is an important factor in establishing a pregnancy after embryo transfer with the best chances when the recipient ovulates 1 day before or up to 3 days after the donor. Although this gives veterinarians a pretty wide window to synchronize a recipient with a donor, often a suitable recipient is not available, he admitted.

There are several periods where veterinarians might not have optimal cycling recipients: in late April–early Maywhen many cycling recipient mares have all had embryos transferred into them and 6

Issue 9/2018 | ModernEquineVet.com

are pregnant, or later in the season, say around July, when the recipient pool is smaller.

The researchers wanted to see if hormone therapy could help with overcoming these periods where there is a lack of cycling recipients.

In the 2016 breeding season, embryos were transferred into 3 classifications of recipients: 1. 65 embryos were transferred into recipients that had natural ovulations.

2. 40 embryos were transferred into acyclic mares that received 6.6 mg estradiol on 2 consecutive days followed by 5 to 7 days of 200 mg of shortacting progesterone. These were mares both in deep anestrus and that were transitional for this. The day the donor ovulated, they would start that receiving mare on estradiol, 6.6 mg for 2 consecutive days.

“What we are trying to do here is mimic estrus phase for that mare and then we would start her on short-acting progesterone for 5 to 7 days, which would mimic a diestrus phase to set her uterus up to receive that embryo,” he said.

3. 14 embryos were transferred in cycling mares in early estrus. These would typically be mares 2 to 5 days off of prostaglandins. They would have a

25 mm follicle, and maybe just a hint of edema in their uterus.

“The day the donor ovulated, we would start that [recipient mare] on estrogen for 2 consecutive days, followed by 5-to-7 days of short-acting progesterone. Often in this group, we gave the estrogen therapy about the time we were ready to start the short-acting progesterone; those mares would have a follicle 30 to 35 mm in size.

We would often give them a dose of gonadotropin to try to induce ovulation with the goal being that maybe we could stop some of the endogenous hormone therapy if this mare received an embryo, and she became pregnant,” Dr. Ferris explained.

All recipients were treated similarly. All recipients were started on altrenogest regardless of their classification at the time of transfer.

“Overall, our 14-day pregnancy rate was close to 80% in 2016,” he said, and there was no statistical difference in transfer rates among the natural, hormone treated and ovulation-plus-hormone mares.

“Our natural ovulation was about 75% pregnancy rates,” he said.

“With our ovulation plus therapy, we had a numerically higher pregnancy rate—around 85%.”

There was some concern that mares in deep anestrus would be primed for the receiving of an embryo but may have higher early embryonic loss rates. However, there was no difference in embryonic loss between 14 and 25 days among hormone therapy, natural ovulation and ovulation-plus-hormone therapy, Dr. Ferris explained.

“The use of hormone therapy in cycling and noncycling recipients is pretty common with similar pregnancy rates obtained as compared with mares with natural ovulations.

You can get similar pregnancy rates in mares that have been primed with exogenous hormones.

Like the constellations, the early clinical signs of PPID can be clear if you know what to look for.

Despite its importance in equine practice, pituitary pars intermedia dysfunction (PPID) can be easily overlooked.

When you see these early clinical signs, no matter how subtle, it’s time to test.

• Abnormal sweating (increased or decreased) • Change in attitude/lethargy

• Decreased athletic performance • Regional hypertrichosis

Find out more about our PPID diagnostic testing program and see the rest of the early clinical signs at PPIDTest.com

©2018 Boehringer Ingelheim Vetmedica, Inc. All rights reserved. EQU-0792-PRAS0818

REPRODUCTION

Dr. Ferris said that the estrogen phase was important to prime the uterus to receive that embryo, and that in the right hands, it could “result in very similar pregnancy rates in recipients with a natural ovulation,” he said.

The use of hormone therapy can be really important for owners who want a specific recipient matched to a specific donor mare, he explained. “With the use of endogenous hormones we were able to do that,” Dr. Ferris said.

secrete adequate progesterone.

“We all presume as clinicians that when the mare ovulates, the developing CL will produce adequate progesterone (>4 ng/mL) to maintain pregnancy,” Dr. Ferris said. Low progesterone values are associated with decreased uterine and cervical tone and pregnancy loss.

“We think the minimum value of progesterone required to maintain pregnancy is somewhere between 2.4 and 5 ng/mL,” he said.

In 2016 and 2017, the veterinarians at Colorado State evaluated 456 recipient cycles at 5 days after ovulation for progesterone production, using the mini VIDAS progesterone assay system.

TIP #3

Clinicians should be aware that even when an ovulation was detected, not every developing corpus luteum will

“As we expected, the mean progesterone value 5 days post ovulation was quite high—well above that 4 ng/mL range at 9.2 ng/mL But what we found of interest was that 5.5% (25 of 456) of mares had a progesterone value of <4 ng/mL,” he said, “And 0.9% (4 of 456) of mares had a progesterone value of <1 ng/mL even though an ovulation was detected, indicating a complete lack of CL formation.”

“While we’ve all assumed that after ovulation a normal corpus luteum will form and produce adequate progesterone, we should recognize that at least in a small percentage of mares, normal CL function does not occur,” he said.

MeV

S. Equi Hardier Than Previously Thought

Credit: Courtesy of the Equine Veterinary Journal

A recent study found that Streptococcus equi is a hardier organism than previously thought, able to survive for longer periods in wet, humid and cold conditions.

Researchers from the United Kingdom performed the study because they thought that environmental contamination with bacteria shed from an infected horse could represent a significant source of contagion to other animals. The researchers inoculated S. equi onto various objects found in a horse’s stall or used in the Strangles care of a horse: wood, the rubber sole of a shoe, cotton overalls, inside a nasogastric tube, a dental rasp, a wet plastic bucket and onto an outdoor fence post.

Samples were taken from all surfaces at 24-hour intervals for the first 5 days, then every 48 hours until day 23.

After day 23, they took samples at by biweekly intervals until no viable bacteria could be cultured from two consecutive samplings. The sample selection was carried out during both summer and winter months.

They measured both the time to the first negative culture as well as the vigor of the bacterial growth by looking at the growth score over the first 3 days of culture.

The researchers found that bacterial growth and vigor were higher in wet conditions and during the winter. In winter, the longest period over which successful cultures of S. equi were obtained was 30 days from the wet bucket.

In contrast, the longest period over which successful cultures were obtained in summer was 7 days, from the nasogastric tube.

“Survival tended to be short in the summer (up to 9 days in wet sites and up to 2 days in dry sites) but much longer in the winter (up to 34 days in wet sites and up to 13 days in dry sites). Vigor of bacterial growth was also greater in the winter than in the summer as judged by 3-day-growth scores,” the researchers wrote.

MeV

For more information: Durham AE, Hall YS, Kulp L, et al. A study of the environmental survival of Streptococcus equi subspecies equi. Equine Vet J 2018 Apr 13 (Epub ahead of print). https://onlinelibrary.wiley.com/doi/abs/10.1111/evj.12840 8

Issue 9/2018 | ModernEquineVet.com

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INFECTIOUS DISEASES

W E N

S E N I L E D I U G Offer Vets the Latest on

Preventing and Treating Strangles The American College of Vet-

erinary Internal Medicine released a new consensus statement earlier this year to provide the most up-to-date recommendations for treating Streptococcus equi infections.

“From a practical standpoint, the consensus statement serves to advise all veterinarians on what we recommend as a way to treat and deal with the disease,” said Ashley Boyle,

DVM, DACVIM, an associate professor of medicine at the University of Pennsylvania’s School of Veterinary Medicine, who took the lead in writing the new statement.

“I’m an internist who sees this disease as a primary care doctor at the horse farms as well as being a field researcher. The authors of the consensus statement are a collection of experts in the field of

streptococcal diseases in horses including veterinary microbiologists, epidemiologists, and veterinarians who research this disease, as well as internists who encounter the disease frequently,” she said.

The last consensus statement was issued in 2005.

One of the key areas where the guidance has shifted in the new statement is how to determine when an animal is free of disease.

This is a critical component of strangles control, as 10% to 40% of animals who have had the disease can remain carriers—able to pass on disease to other animals even when they appear healthy.

The previous consensus statement indicated a throat wash should be tested 3 times to be sure the horse was free of disease.

“But it was hard to get owners and clients to do that 3 times,” Dr. Boyle said. “And multiple studies have shown that those 3 may not

By Katherine Unger Baillie • University of Pennsylvania 10

Issue 9/2018 | ModernEquineVet.com

WI N N I NG d o es n’ t h a p p e n

B Y

A C C I D E N T.

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

Time for a gut check. TheStomachToWin.com

Merial is now part of Boehringer Ingelheim. ®GASTROGARD is a registered trademark of Merial. ©2018 Merial, Inc., Duluth, GA. All rights reserved.

EQU-0445-EGUS0218

by Merial

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

Photo courtesy of Penn Vet.

Caution Federal (USA) law restricts this drug to use by or on the order of a licensed veterinarian.

Storage Conditions Store at 68°F – 77°F (20-25°C). Excursions between 59°F – 86°F (15-30°C) are permitted.

Indications For treatment and prevention of recurrence of gastric ulcers in horses and foals 4 weeks of age and older.

Dosage Regimen For treatment of gastric ulcers, GastroGard Paste should be administered orally once-a-day for 4 weeks at the recommended dosage of 1.8 mg omeprazole/lb body weight (4 mg/kg). For the prevention of recurrence of gastric ulcers, continue treatment for at least an additional 4 weeks by administering GastroGard Paste at the recommended daily maintenance dose of 0.9 mg/lb (2 mg/kg).

Directions For Use • GastroGard Paste for horses is recommended for use in horses and foals 4 weeks of age and older. The contents of one syringe will dose a 1250 lb (568 kg) horse at the rate of 1.8 mg omeprazole/lb body weight (4 mg/kg).

For treatment of gastric ulcers, each weight marking on the syringe plunger will deliver sufficient omeprazole to treat 250 lb (114 kg) body weight. For prevention of recurrence of gastric ulcers, each weight marking will deliver sufficient omeprazole to dose 500 lb (227 kg) body weight.

• To deliver GastroGard Paste at the treatment dose rate of 1.8 mg omeprazole/ lb body weight (4 mg/kg), set the syringe plunger to the appropriate weight marking according to the horse’s weight in pounds.

• To deliver GastroGard Paste at the dose rate of 0.9 mg/lb (2 mg/kg) to prevent recurrence of ulcers, set the syringe plunger to the weight marking corresponding to half of the horse’s weight in pounds.

• To set the syringe plunger, unlock the knurled ring by rotating it 1/4 turn. Slide the knurled ring along the plunger shaft so that the side nearest the barrel is at the appropriate notch. Rotate the plunger ring 1/4 turn to lock it in place and ensure it is locked. Make sure the horse’s mouth contains no feed.

Remove the cover from the tip of the syringe, and insert the syringe into the horse’s mouth at the interdental space. Depress the plunger until stopped by the knurled ring. The dose should be deposited on the back of the tongue or deep into the cheek pouch. Care should be taken to ensure that the horse consumes the complete dose. Treated animals should be observed briefly after administration to ensure that part of the dose is not lost or rejected. If any of the dose is lost, redosing is recommended.

• If, after dosing, the syringe is not completely empty, it may be reused on following days until emptied. Replace the cap after each use.

Warning Do not use in horses intended for human consumption. Keep this and all drugs out of the reach of children. In case of ingestion, contact a physician. Physicians may contact a poison control center for advice concerning accidental ingestion.

Adverse Reactions In efficacy trials, when the drug was administered at 1.8 mg omeprazole/lb (4 mg/kg) body weight daily for 28 days and 0.9 mg omeprazole/lb (2 mg/kg) body weight daily for 30 additional days, no adverse reactions were observed.

Precautions The safety of GastroGard Paste has not been determined in pregnant or lactating mares.

Efficacy • Dose Confirmation: GastroGard ® (omeprazole) Paste, administered to provide omeprazole at 1.8 mg/lb (4 mg/kg) daily for 28 days, effectively healed or reduced the severity of gastric ulcers in 92% of omeprazole-treated horses. In comparison, 32% of controls exhibited healed or less severe ulcers. Horses enrolled in this study were healthy animals confirmed to have gastric ulcers by gastroscopy. Subsequent daily administration of GastroGard Paste to provide omeprazole at 0.9 mg/lb (2 mg/kg) for 30 days prevented recurrence of gastric ulcers in 84% of treated horses, whereas ulcers recurred or became more severe in horses removed from omeprazole treatment.

• Clinical Field Trials: GastroGard Paste administered at 1.8 mg/lb (4 mg/kg) daily for 28 days healed or reduced the severity of gastric ulcers in 99% of omeprazole-treated horses. In comparison, 32.4% of control horses had healed ulcers or ulcers which were reduced in severity. These trials included horses of various breeds and under different management conditions, and included horses in race or show training, pleasure horses, and foals as young as one month. Horses enrolled in the efficacy trials were healthy animals confirmed to have gastric ulcers by gastroscopy. In these field trials, horses readily accepted GastroGard Paste. There were no drug related adverse reactions. In the clinical trials, GastroGard Paste was used concomitantly with other therapies, which included: anthelmintics, antibiotics, non-steroidal and steroidal anti-inflammatory agents, diuretics, tranquilizers and vaccines.

• Diagnostic and Management Considerations: The following clinical signs may be associated with gastric ulceration in adult horses:inappetence or decreased appetite, recurrent colic, intermittent loose stools or chronic diarrhea, poor hair coat, poor body condition, or poor performance. Clinical signs in foals may include: bruxism (grinding of teeth), excessive salivation, colic, cranial abdominal tenderness, anorexia, diarrhea, sternal recumbency or weakness. A more accurate diagnosis of gastric ulceration in horses and foals may be made if ulcers are visualized directly by endoscopic examination of the gastric mucosa Gastric ulcers may recur in horses if therapy to prevent recurrence is not administered after the initial treatment is completed. Use GastroGard Paste at 0.9 mg omeprazole/lb body weight (2 mg/kg) for control of gastric ulcers following treatment. The safety of administration of GastroGard Paste for longer than 91 days has not been determined. Maximal acid suppression occurs after three to five days of treatment with omeprazole.

Safety • GastroGard Paste was well tolerated in the following controlled efficacy and safety studies.

• In field trials involving 139 horses, including foals as young as one month of age, no adverse reactions attributable to omeprazole treatment were noted.

• In a placebo controlled adult horse safety study, horses received 20 mg/kg/ day omeprazole (5x the recommended dose) for 90 days. No treatment related adverse effects were observed.

• In a placebo controlled tolerance study, adult horses were treated with GastroGard Paste at a dosage of 40 mg/kg/day (10x the recommended dose) for 21 days. No treatment related adverse effects were observed.

• A placebo controlled foal safety study evaluated the safety of omeprazole at doses of 4, 12 or 20 mg/kg (1, 3 or 5x) once daily for 91 days. Foals ranged in age from 66 to 110 days at study initiation. Gamma glutamyltransferase (GGT) levels were significantly elevated in horses treated at exaggerated doses of 20 mg/kg (5x the recommended dose). Mean stomach to body weight ratio was higher for foals in the 3x and 5x groups than for controls; however, no abnormalities of the stomach were evident on histological examination.

Reproductive Safety In a male reproductive safety study, 10 stallions received GastroGard Paste at 12 mg/kg/day (3x the recommended dose) for 70 days. No treatment related adverse effects on semen quality or breeding behavior were observed. A safety study in breeding mares has not been conducted.

For More Information Please call 1-888-637-4251 Marketed by: Merial, Inc., Duluth, GA 30096-4640, U.S.A. Made in Brazil ®GastroGard is a registered trademark of Merial, Inc. ©2016 Merial, Inc. All rights reserved. Rev. 05-2011

INFECTIOUS DISEASES

Ashley Boyle (center) of Penn Vet took the lead in writing a new consensus statement on treating, controlling, and preventing the equine infectious disease strangles.

even be good enough.”

In the new statement, Dr. Boyle and colleagues instead recommend “guttural pouch sampling,” a technique that tests the fluid that sits in an area between a horse’s ear and throat, akin to the human Eustachian tube, in combination with using an endoscope to visually assess the area for unruptured abscesses.

“We’re trying to encourage more primary care veterinarians to do this, even though it’s time consuming, because this is how the disease perpetuates itself,” Dr. Boyle said. “In the end it is easier, faster, and more effective than doing the 3 throat washes. That’s one of our big take-home messages.”

Another change is a shift away from considering bacterial culture to be the best method of diagnosis. “We no longer consider this the gold standard,” Dr. Boyle said, because horses with low levels of bacteria may still be carriers but not give a positive result on this test.

The authors see DNA amplification technologies such as polymerase chain reaction (PCR)—along with visualization of the guttural pouch—replacing culture as this standard. “There is also a lot of work being done by my colleagues in Europe looking at genomic sequencing,” she said. “At some point

in the future we may be able to use this technology to trace where an outbreak originated.”

The publication lays out best practices for quarantine and examination to prevent the spread of disease, and biosecurity protocols to reduce transmission in facilities where infected horses have been housed.

It spells out treatment protocols—urging judicious use of antibiotics—and explains how to recognize, evaluate the risk for, and treat one of the more serious complications of strangles—an autoimmune reaction known as purpura hemorrhagica, which can be fatal. It also explores the pros and cons of strangles vaccines, the use of different blood tests that can measure previous exposure to disease and determine when it is safe to give vaccines.

While the consensus statement is aimed at veterinarians, Dr. Boyle said that owners can implement some of the recommendations. For example, horses are not thought to be contagious until 24 to 48 hours after the onset of fever, so an owner could start monitoring their horses' temperatures if they suspect an outbreak, Dr. Boyles suggested.

Even though strangles is not associated with mortality, it is a global problem and quite costly, as management protocols can be extensive.

MeV

For more information: Boyle AG, Timoney JF, Newton JR, et al. Streptococcus equi infections in horses: Guidelines for treatment, control, and prevention of strangles—revised consensus statement. J Vet Intern Med. 2018;32(2):633-647. https://onlinelibrary.wiley.com/doi/full/10.1111/jvim.15043 12

Issue 8/2018 | ModernEquineVet.com

NEWS NOTES

By Cynthia McVey Cornell University Three-year-old colt, Pistol, was only in light training and not under saddle when he suddenly presented with pain that appeared to be located in the front leg.

“He just wasn’t quite right one day,” explained owner Terri Sikora, of Lansing, N.Y. “It wasn’t that he couldn’t walk, but he wasn’t himself either.” She restricted his play by putting him out to pasture with an older gelding but, within days, his symptoms progressed from slightly off to significant lameness. Ms. Sikora called Christina Cable, DVM, DACVS, of Early Winter Equine.

Radiographs of Pistol’s leg were inconclusive, so Dr. Cable referred Pistol to the Cornell University Equine and Nemo Farm Animal Hospital (ENFAH).

“The sudden and obvious lameness was our biggest concern. Three-year-old colts don’t usually show that amount of pain, so we were concerned that it was going to be very bad news,” said Lisa Ann Fortier, PhD, James Law Professor of Equine Surgery at Cornell.

At Cornell, radiographs of the shoulder joint suggested bone damage in the area, but the results were not definitive. “If an X-ray is off by 10 or 15 degrees, it’s easy to miss the injury. It’s not a very sensitive technique,” Dr. Fortier said.

They tried nuclear scintigraphy, a very sensitive and more effective diagnostic tool for bone injuries, which indicated bone damage in the socket part of the shoulder joint.

“It didn’t tell us exactly what the injury was, but it confirmed that the shoulder was the source of his lameness,” explained Dr. Fortier, who then recommended diagnostic arthroscopic surgery in the shoulder to determine what the injury was and whether it was reparable.

“We had no way of knowing what I’d find or if he’d suffered irreparable damage. There just may not be good news at the end of exploratory surgery,” she said. “In this case, Pistol had the best kind of owner who wanted to know everything she could to make the best decision for her horse, as difficult as it might be.”

During surgery, Dr. Fortier saw a half-centimeter

of cartilage damage in the glenoid area of the shoulder. She debrided it and found the underlying bone had mild to moderate damage. The affected cartilage was located right above the bone marrow contusion detected on the bone scan. Pistol likely jammed his leg and the ball hit the socket, causing damage to bone and cartilage.

In addition to removing the diseased cartilage and bone, Dr. Fortier injected a bone marrow concentrate into the joint at the end of surgery. The concentrate was derived through a process developed in Dr. Fortier’s lab in 2010 that includes extracting bone marrow from the sternum and concentrating it in a special centrifuge. The concentrate contains stem cells, anti-inflammatories, proteins and growth factors that help repair bone and cartilage.

The FDA has since approved the procedure for both animals and humans. “It’s an effective way to harvest the body’s ability to heal, so there’s no chance of rejection.”

Dr. Fortier remained worried there might be nerve damage that there was no way to diagnose. This was in large part because of the extent of his lameness. Since going home, however, his recovery has gone so well and so quickly that she’s convinced the pain was caused by the damage found during surgery. Dr. Fortier recommended a regimen of stall rest and hand walking until he can be moved into full-size turnout.

“This was the most rewarding case because the owner wants to do the right thing for her horse, the referring veterinarian did all the right diagnoses and our advanced diagnostic tools and ability to do the arthroscopic surgery brought the process full-circle back to the owner. And she has provided the best after-care,” Dr. Fortier said.

MeV

Courtesy of Cornell University.

Cornell-Developed Bone Marrow Concentrate Gets Colt Back in the Saddle

Pistol recovered well after receiving a bone-marrow concentrate treatment and shoulder arthroscopic surgery.

For more information: Fortier LA, Potter HG, Rickey EJ, et al. Concentrated bone marrow aspirate improves full-thickness cartilage repair compared with microfracture in the equine model. J Bone Joint Surg Am. 2010;92(10):1927-1937. https://insights.ovid.com/pubmed?pmid=20720135.

This article first appeared on the Cornell website at https://bit.ly/2R22rSn.

ModernEquineVet.com | Issue 9/2018

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TECHNICIAN UPDATE

Mare’s Pregnancy: Double the Trouble

By Elyse Rowley, MS

Photo courtesy of Ms. Elyse Rowley

On April 24, 2015, a 12- year-old Thoroughbred mare of unknown parity was referred to our internal medicine practice for premature lactation. The mare had been exposed to a stallion for pasture breeding April through June 2014, although the exact date that the stallion was removed could not be confirmed.

Pregnancy was confirmed via rectal palpation in late September 2014 and early April 2015. At the time of referral, the referring veterinarian palpated a very small fetus per rectum, inconsistent with the approximate due date and active mammary gland development and lactation. This examination of the mare was the first by the referring veterinarian.

At the first hospital examination, the mare was extremely anxious and prone to kicking for both rectal temperature and examination of her udder. Her rectal temperature was 101° F, pulse was 60 beats per minute, respiration was 28 breaths per minute, and her mucous membranes were pale pink and moist with a capillary refill time of less than 2 seconds. The thorax and abdomen were auscultate and were within normal limits. Her eyes and nose were clear, and she walked normally.

Abdominal distention and mammary gland development with intermittent dripping was consistent with late-term pregnancy. Due to her temperament

Twins show up on the ultrasound image.

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and fractious behavior for venipuncture, the mare received IV xylazine immediately following blood collection and prior to ultrasound evaluation. Complete blood count was performed with a white blood cell (WBC) count of 11,470 per μL with normal differential. Serum amyloid A (SAA) was 0 μg/mL. Once the mare was sedated, we were able to perform transabdominal ultrasound, which revealed 2 distinct heartbeats and 2 ribcages, with 1 fetal thorax measuring larger than the other. No significant placental abnormalities and no other abdominal abnormalities were detected. The mare was diagnosed with twins of undetermined gestational age.

The risks associated with twin pregnancies, including dystocia, stillbirth of one or both foals, and weakness at birth, were discussed with the owner.

The owner declined referral to an intensive care unit due to associated costs. The mare was admitted to a veterinary foaling facility for 24 hour/day monitoring of a high-risk pregnancy, and was prescribed altrenogest PO SID and banamine PO SID for 7 days.

Repeat ultrasonography was recommended at weekly intervals if no changes in clinical or vital signs developed. Serial ultrasounds over the following 8-week period were performed documenting the growth of twin fetuses. Over this time, the mare’s temperament and fractious behavior gradually improved through consistent efforts by the clinic staff.

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

*American Association of Equine Veterinary Technicians and Assistants

Photo courtesy of Ms. Elyse Rowley

TECHNICIAN UPDATE

The mare exhibited signs of stage-1 labor beginning at 5:30 AM on June 23, 2015. Stage-2 began at 7:10 AM, and at 7:35 AM, the first of the twins was delivered vaginally with minimal assistance.

The foaling team present had been pre-arranged, and included a staff reproduction specialist, two staff veterinarians, one technician and the consulting internist. The first twin, a chestnut colt, was quickly followed by the second twin, a black filly, at 7:39 AM. Both foals were delivered with minimal assistance.

Shutterstock/nelelena

TEACHING POINTS

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This case is valuable as it describes the diagnosis and management of twin foals, with a host of complications, outside of a hospital’s ICU setting.

The medical management of this case would be applicable to a premature singleton outside of an ICU as well.

Critical to the successful outcome of this case were the owner’s willingness to provide the medical support the foals required and the team approach provided by the foaling facility, technicians, staff veterinarians and consulting internist.

Issue 9/2018 | ModernEquineVet.com

The colt was pale and minimally responsive initially, so oxygen was administered via mask at 10 L/min for 30 minutes. Following oxygen therapy, the colt was more responsive with pink mucous membranes. Each foal weighed approximately 25 lbs. Both foals exhibited generalized weakness, moderate forelimb carpal valgus deformities and domed foreheads.

Radiographs of the carpal and tarsal cuboidal bones of each foal showed Grade-3 ossification. Thoracic radiographs showed normal lung aeration for each foal.

Indwelling Mila foal feeding tubes were placed in each foal, as neither was able to stand and nurse in the first 18 hours.

Due to the mare’s temperament, it was unsafe to milk her for colostrum. Therefore, the foals each received 250 mL of banked colostrum via indwelling NGT, in 50 mL aliquots over the first 6 hours of life. Feedings with reconstituted Mare’s Match powder were delivered every 2 hours thereafter at 20% of body weight until the foals were able to stand and nurse with assistance.

Initial lab work for the filly revealed a WBC=7.24 with a lymphocytosis, SAA=0, IgG>800, creatinine of 9.2 mg/dL, BUN within normal limits and a urine specific gravity (USG) of 1.035. An over-the-wire Mila extended use IV catheter was placed and the filly received IV fluid boluses of 250–500 mL lactated Ringer’s solution (LRS) with 1.25% dextrose every 4 hours. Prophylactic antimicrobial therapy was initiated with Naxcel at 10 mg/kg IV TID. Initial lab work for the colt revealed a WBC=8.52 with a lymphocytosis, SAA=0, IgG>800, creatinine of 7.6 mg/dL, BUN within normal limits and a USG of 1.030. An over-the-wire Mila extended-use IV catheter was placed and the colt received IV fluid boluses of 250-500mL LRS with 1.25% dextrose every 4 hours. The colt also received prophylactic antimicrobial therapy with Naxcel at 10 mg/kg IV TID. Following 24 hours of fluid therapy, the filly’s creatinine had decreased to 1.3 mg/dL, BUN was within normal limits and USG=1.002. IV fluid administration was reduced and USG was monitored throughout the day. The filly was able to stand and nurse unassisted, then developed diarrhea with mild colic signs on day 2. She was treated with a single dose of banamine IV and started on metroni-

NEWS NOTES

dazole PO BID plus Biosponge paste PO BID. Following 24 hours of fluid therapy, the colt’s creatinine had decreased to 1.2 mg/dL, BUN was within normal limits and USG=1.003. IV fluid administration was reduced and USG was monitored throughout the day. The colt was assisted to stand and nurse every 1 to 2 hours on day 2.

Over the next several days, both foals were weaned off IVF while continuing medical treatment with Naxcel, metronidazole and Biosponge. Their WBCs remained within normal limits and differentials normalized. USG remained less than 1.005 and physical exams were within normal limits, apart from bilateral carpal valgus deformities. They were confined to the stall with their dam due to incompletely ossified cuboidal bones.

On June 30, 2015, the colt was observed during nursing to have a bulge in his proximal right cervical region. Radiographs of the cervical spine revealed a malformation of the occipital-atlanto-axial region.

Radiographs of both foal’s cuboidal bones on June 30th revealed improved, but incomplete ossification.

On July 1st, the filly exhibited swelling in the left forelimb carpal region. Careful palpation confirmed the swelling to be caused by rupture of the common digital extensor (CDE) tendon. A support bandage was placed on the filly’s left forelimb and the owner elected to continue medical support for both foals.

On July 8th, radiographs revealed complete ossification of the cuboidal bones of both foals. Additionally, the carpal valgus ALD had improved significantly in the filly, while remaining moderate in the colt. Consultation with the resident veterinarian/farrier resulted in placement of glue-on lateral extension shoes to aid in correction of the colt’s carpal valgus ALD. The foals were allowed small pasture turnout with their dam for 20 minutes on July 8th. Continued care consisted of the monitoring of vital signs and angular limb deformity (colt), as well as support bandage changes (filly) for an additional 2 weeks.

Both foals continued to nurse and grow normally, being discharged to the owner on July 16, 2015, with continuing care provided by the referring veterinarian. MeV

About the author

Elyse Rowley is the veterinary assistant to Phoebe Smith, DVM, DACVIM, at Riviera Equine Internal Medicine and Consulting, where they practice mobile internal medicine in central and southern California.

She and Dr. Smith first worked together in a hospital ICU setting, then started working together again after they each had a child to practice the medicine that they love in a mobile/field setting.

Horses' Rabies Risk Higher Than Dogs' Risk The risk of rabies is actually 4 times higher among horses than dogs, according to recent surveillance data.

“Everybody is at risk for developing rabies. Your horse is probably at a higher risk for being exposed at pasture, but being in a stall does not preclude exposure,” said Bonnie R. Rush, DVM, MS, DACVIM, Interim Dean at Kansas State University’s College of Veterinary Medicine. “The consequences of interacting with a horse that has rabies are significant.”

Two public examples of equine rabies cases are the 2008 Missouri State Fair; and the 2006 Tennessee Walking Horse National Celebration, which required the notification of more than 150,000 people for potential rabies exposure.

IN THE YEAR

2016

There were 20 rabid equids— approximately 2.8 rabies cases per 1 million horses.

JAVMA. 2018;252(8):945-957

According to a meta-analysis, in 2016 there were 58 rabid dogs. Fifty-eight cases divided by 78 million domestic dogs equates to approximately 0.74 rabies case per 1 million dogs. There were 20 rabid equids. Twenty cases divided by 7.2 million horses equates to approximately 2.8 rabies cases per 1 million horses.

Rabies is the deadliest among the five core equine diseases, which also include eastern equine encephalomyelitis (EEE), western equine encephalomyelitis (WEE), tetanus and West Nile. Horses are continually exposed to wildlife and mosquitoes that transmit core equine diseases. Owners should be warned that whether they keep the horse in a barn or pasture, it is still at risk for the core diseases, including rabies.

“Any of the core diseases can be a death sentence for an exposed horse—and alarmingly, with exposure to an animal infected with rabies—family members, friends and any other persons exposed are also at risk of losing their lives to rabies disease, which is always fatal,” said Kevin Hankins, DVM, MBA, senior technical services veterinarian with Zoetis. “A horse owner’s best defense against these devastating diseases is through annual core disease vaccination.”

Dr. Hankins recommended that veterinarians discuss a horse’s core and risk-based vaccination needs consistently with owners.

For more information: Ma X, Monroe BP, Cleaton JM, et al. Rabies Surveillance in the United States during 2016.

JAVMA. 2018;252(8):945-957. https://avmajournals.avma.org/doi/pdf/10.2460/javma.252.8.945 American Horse Council; Washington, DC; 2017 Economic Impact of the U.S. Horse Industry.

American Association of Equine Practitioners. Vaccination Guidelines. https://aaep.org/guidelines/vaccination-guidelines.

Centers for Disease Control and Prevention. Horse Stabled at Tennessee Walking Horse 2006 National Celebration Tested Positive for Rabies. https://www.cdc.gov/rabies/resources/news/2006-09-09.html.

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