TheModernEquineVet_Jan13V1N6

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Equine Vet www.modernequinevet.com

AAEP MEETING COVERAGE Racing after colic surgery Better than a Coggins WNV Update Technician Update

January 2013 | Vol 1 No 6

Stablizing fractures in the field

Table of Contents

Cover story: AAEP MEETING

4 Stablizing fractures Apply external fixation to protect the bones and tissues and prevent further injury.

Cover photo by Katrina Leigh /shutterstock

COLIC

From AAEP meeting: Return to racing.............................................. 8 Odds of returning to racing after colic surgery

infectious diseases

New ERAV vaccine available................................................................11 Better than a Coggins............................................................................12 Reproduction

Exercising's effects on reproduction..........................................14

Embryo transfer rates reduced

Technician Update

Developing vaccine against deadline Hendra virus.............18 Feedbag

20 Equine Grass Sickness 10 Headshaing treatment 16 Rags to riches 17 Mosquito virus could lead to new vaccines 17 WNV update LEGAL DISCLAIMER: The content in this digital issue is for general informational purposes only. PercyBo Publishing Media 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 reserves the right to alter or correct any content without any obligations. Further, 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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orthopedics

Be prepared for

nightmare situations The emergency repair of a fracture requires a clear head, quick action, and good communication

Handling fractures in the field requires an understanding of the biomechanics of the situation to enable the application of external fixation that will protect the bones and tissues at the fracture site, as well as prevent further injury, Scott E. Palmer, VMD, DABVP (equine), said at the recent 38th Annual Convention of the American Equine Practitioners Association held in Anaheim, California.

“These can be nightmare situations,” he admitted.

Veterinarians might have to apply temporary external fixation to enable the horse to be transported to a hospital or the fixation used in the field might be the final treatment for the horse. It depends on the situation.

The process goes like this: • clinical assessment, • medical treatment, • stabilize the fracture and • move the patient to a hospital or clinic for further treatment, if needed.

“Improper application of these devices can endanger the life of the patient. So, it is important that we are mindful of the way we provide external support,” said Palmer, hospital director and staff surgeon at the New Jersey Equine Clinic.

“The first step is to evaluate the horse's temperament, because the horse's temperament dictates what we have to do to manage the situation. If we have a compliant patient, we can do a great deal. But it will be much harder if we have a non compliant patient,” he said, adding that some horses require sedation.. “Less is more in those situations because too much sedation will make the horse ataxic.”

Initially the veterinarian must determine: • if the horse is weight bearing • whether it has an open or a closed fracture • whether the fracture is unstable or stable, and B

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Photos courtesy of Dr. S. Palmer Cheryl Ann Quigley / Shutterstock.com

• whether fracture repair is an option.

It is critical to be very conservative in the management of any horse that might have an occult fracture.

It might seem counter intuitive, but Palmer suggested stabilizing the fracture before taking a radiograph because the anxious horse might cause more damage during the radiographic examination. He suggested using PVC as a splint because the veterinarian can radiograph the injury through the PVC splint.

“Stabilize first because if you try to take a radiograph and the horse becomes anxious you can make things worse,” he said.

Gelocast (BSN Medical), designed to treat sprained joints in humans, can be used as a first layer to help reduce swelling in horses, but they do not provide adequate support to stabilize an equine fracture when used alone, according to Palmer.

However, there are many options for external fixation, he said. An effective splint should provide rigid support without damaging other tissue. This is where the understanding of the biomechanics comes in. When a fracture occurs, the muscles around it no longer have an intact bone frame over which to act.

As a result, muscle contraction moves the limb differently than originally intended. For example, the flexors of the forelimb act as adductors of the distal limb in the presence of an unstable fracture of the radius. This changes unphysiologic loading of the fracture site that can exacerbate the injury.

The Kimzey Leg Saver Splint is an excellent, but expensive, commercial splint and can be easily applied over a padded bandage to stabilize level 1 frac-

The basic materials that should be on hand to manage fractures in the field.

ModernEquineVet.com | January 2013

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orthopedics

tures. “This is a great tool to have in your truck,” he said.

The Robert Jones Bandage is good for level 2 fractures. The bandage is made of layers of cotton padding that is compressed with gauze and Elasticon bandage. Splints are then secured to the surface of the bandage with duct tape that is applied tightly to prevent them from moving.

“PVC pipe is a wonderful splinting material,” he said. PVC splints can be made by cutting a 4-inch pipe into thirds about 18 to 24 inches long for level 1 fractures, and about 32 inches long for level 2 fractures. Use a hoof rasp to smooth the edges of

the splint and apply Elasticon tape to prevent sharp edges from damaging tissue.

Other needed materials are rolls of cotton, gauze, ACE bandages, Elasticon, duct tape and 1×4 ft. boards that can be used for extended splints, which are needed for level 3 fractures. The wood splints need to be long enough to extend up past the shoulder (approximately 5 feet long) or the stifle.

“If you are the emergency vet at sporting events, you need to be prepared,” he said. It is extremely important to have some type of basic stabilization materials in the truck to respond quickly to these injuries. “Make sure you have all the bandage ma-

Splinting Guide Thoracic Limb Fractures Level 1

External fixation Apply a padded bandage and dorsal splint or use a Kimzey Splint.

Robert Jones bandage that incorporates caudal and lateral splints For foals -- a Robert Jones bandage that extends from the axilla to the toe with a lateral splint that extends up the lateral aspect of the chest and lies against the ribcage. Adult horses are often euthanized.

Apply a simple full-leg padded bandage with a caudal splint to fix the carpus

Purpose Neutralize bending forces at the fracture site and protect soft tissue Prevent movement of the fracture site when load is applied to limb Prevent abduction of the distal portion of the injured limp

Injury Phalanges, proximal sesamoid bones and distal metatarsus

External fixation Apply a padded bandage and a plantar splint. Or use a Kimzey Splint

Purpose Neutralize bending forces at the fracture site and protect soft tissue

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Middle and proximal metatarsus

Apply a Robert Jones bandage with a plantar and lateral splint

Prevent movement at the fracture site when load is applied to the limb.

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Fractures of the tibia and tarsus.

Prevent abduction and rotation of the limb during transport to hospital for surgical repair

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Fractures of femur or pelvis

Foals: use a Robert Jones bandage with extended lateral splint. Adults: euthanasia Splinting is not necessary, keep horses quiet and assist while loading and transporting to a hospital.

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Pelvic Limb Fractures Level 1

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Injury fractures of the phalanges, proximal sesamoid bones, & distal metacarpus fractures of the mid forelimb (distal radius to mid-metacarpus) fractures of the middle and proximal radius

fractures of the humerus, ulna, and distal scapula

January 2013 | ModernEquineVet.com

Provides support for carpal extension, which is essential for normal weightbearing.

terials and splints clean and ready to go.”

If possible, get people to help. For example, to stabilize a level 1 fracture, one person should hold the horse, another person should hold up the leg to help align the bones and the veterinarian should stabilize the injury.

Prognosis

tied loosely so the horse can use it for balance. If the horse has a thoracic limb fracture, position the horse facing toward the rear so it can use the pelvic limbs to brace itself when the truck stops. If the horse has a pelvic limb fracture, place it facing forward so it can use the thoracic limbs to brace itself. Ship foals with mom if possible.

“Proper splinting and transportation can help save lives,” he said. “Make sure you have the proper materials on hand so you are not spending precious time looking for splints and bandage materials. Level 1 fractures are the most common fractures. If you can stabilize them quickly and efficiently, you can save the horse’s life.”

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Photos courtesy of Dr. S. Palmer

Closed fractures have a better prognosis than do compound fractures and simple fractures have a better prognosis than do comminuted fractures, according to Palmer. The prognosis depends on the specific bone involved, the degree of inflammation and soft tissue damage, as well as, the degree of bone comminution.

Foals and yearlings tend to do better than do older hors- A Kimzy Splint applied to stabilize a Level I fracture of the thoracic limb. es.

Transporting injured horsFor more information: es is challenging. Try to limit the trauma of loading Palmer SE. How to stabilize equine fractures in the field. Presented at the 58th Annual and unloading the horse as much as possible. Use AAEP Convention. Dec 1-5, 2012 in Anaheim, Calif. a partitioned space to limit the horse’s movement, restrain it with chest or rump bars and keep the head

Having a Conversation Clients and trainers want to know immediately what is the extent of the horse’s injury. Be up front with them, suggested Scott E. Palmer, VMD, DABVP (equine), because some horses will need to be euthanized, and they need to be prepared for that. A veterinarian cannot save every horse.

“Once the horse is stabilized, you need to discuss the options with the owner. What are the resources that are available? What are the expectations of the owner? What is the value of the horse? And is the injury so severe that the horse should be euthanized right away?” He asked.

These discussions are difficult, he said. The horse is in pain, the owner is upset, and it is part of the veterinarian’s responsibility to be a calming influence under those circumstances.

“Be sure to take a moment, settle everyone down and discuss the treatment options,” he said. Make sure that everyone understands the nature of the injury and the prognosis — and that the prognosis is just that — a prediction. Things can still go south.

If an occult fracture is suspected, make sure the client knows that there might be more going on and go back in a week or so to obtain another set of radiographs.

“If you indicate your suspicions up front everyone will be on the same page if things go wrong down the road, rather than the owner thinking you missed the diagnosis,” he said.

ModernEquineVet.com | January 2013

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Racing after

colic surgery One small study says racing Thoroughbreds return to racing Thoroughbreds tend to return to racing

and perform as well as expected after colic surgery, according to a recent study that was presented at the 58th Annual Convention of the American Association of Equine Practitioners held in Anaheim, Calif.

Before a horse is taken into surgery for colic, owners want to know the horse’s prognosis, and they are not just asking if the horse will survive, but whether it will be able to compete again.

“That is especially important in the racing industry, where the horse is often part of a business model and has to be able to perform to earn its keep,” said Joy E. Tomlinson, DVM, who is now at the New Bolton Center in Pennsylvania.

While at the Chino Valley Equine Hospital in California, Tomlinson and her col-

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leagues performed the retrospective cohort study to see if race horses returned to racing after colic surgery, and whether the surgery affected the horse’s earnings.

They looked at 85 horses from 2 to 7 years old that survived to discharge after exploratory surgery for acute colic and compared them with two matched controls each.

The 170 controls were identified from the last race before surgery.

Forty-nine percent of patients were females, 14% were intact males and 37% were geldings. Thirty-one of the horses had small intestinal lesions, primarily volvulus, but only 11 required resection. Fifty-four horses had large intestinal lesions, which included displacements, impactions of the large colon or cecum and large colon torsions. Two of them required large colon resection.

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Shutterstock/mark higgins

Colic

In total, 59 (69%) of the surgery candidates returned to racing vs.

125 (73%) of the control horses.

“Age or sex had no significant interaction with surgery to effect whether a horse was likely to be racing within six months of surgery,” Tomlinson told The Modern Equine Vet. When they talked to owners and trainers about 20 horses that did not return to racing, they found that six suffered colic-related complications, such as laminitis and repeated episodes of colic. Five went back into training, but then suffered another injury or illness, and nine were retired without any attempts to retrain. Most of those were retired for breeding purposes, she said.

Earnings

The researchers looked at race earnings, starts and earnings per start for up to 42 months postsurgery. There was no difference in total earnings, according to Tomlinson, but the horses that did not undergo surgery were able to continue racing while those that had surgery were recovering.

Horses that required surgery earned a mean of $29 less per start than control horses, and they tended to have fewer starts than control horses. In the 36 months after being laid up by surgery for six months, the horses earned a mean of $7,866 less than the control horses, according to Tomlinson, but none of these differences were statistically significant.

Because there is a huge variation in earnings among Thoroughbreds, Tomlinson warned veterinarians not to quote actual figures as gospel — for instance, don’t

Returned to Racing

59 85 of

colic surgeries returned to racing

125 170 of

control horse returned to racing

Earnings Starts

0.26 fewer Earning

$7,866 Earnings per start*

$29 per start tell an owner “your horse will lose more than $7,000 because it will be laid up for six months.”

However, she said that veterinarians could advise owners that most horses have a good prognosis after colic surgery.

She said there are three issues that need to be discussed with owners when determining whether to take a racehorse to surgery for colic: • Cost of the procedure, • Lost earnings and • Future earnings.

“When you are discussing with your clients whether or not you should take a horse to colic surgery there are three financial aspects you should think about. The one we are most comfortable with is

the cost — the cost of hospitalization and the procedure. You can give an estimate of medical cost.

“The next is the cost of the earnings that horse will lose because of being laid up. That is harder for us to estimate, and it is probably better if the trainer estimates this,” she said. The losses will be different for a Kentucky Derby favorite than a horse in a claiming race.

“And the last one is whether or not the horse will make it back to the track. Will he still do as well?

As far as we can tell from these data, they do tend to return to racing and perform as well as expected. With this information, I think you can better communicate to clients what the prognosis is for their horse following colic surgery.” MeV

For more information: Tomlinson JE. Racing performance and earnings in Thoroughbreds after colic surgery: a retrospective cohort study. Presented at the 58th Annual AAEP Convention. Dec 1-5, 2012 in Anaheim, Calif.

ModernEquineVet.com | January 2013

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headshaking

Headshaking: success seen with new treatment A pioneering new surgical procedure called caudal compression of the infraorbital nerve might be a new treatment for headshaking that is related to facial pain, according to a recent study published in the Equine Veterinary Journal.

The procedure uses platinum coils that are placed into the nerve endings within the canal to relieve the pain. Researchers from the University of Bristol’s School of Veterinary Sciences and the Uni-

versity of Liverpool have seen a long-term success rate of nearly 50% after the surgical procedure.

This surgery could be a viable option for headshaking in horses, according to Veronica Roberts, MA(Oxon), MA, VetMB (Cantab), clinical fellow in equine medicine in the University's School of Veterinary Sciences, who led the study.

The researchers reviewed clinical records of 58 horses that underwent this surgery between June 2004 and January 2011. The horses, aged 1 to 17 years, were used for general riding, show jumping, eventing, or dressage and had a history of headshaking.

The study found:

Photos courtesy of Dr. V. Roberts

• Surgery was initially considered a success in 35 of 57 (63%) horses, but headshaking recurred between nine and 30 months later in nine horses.

• The research team repeated the surgery in 10 horses.

• The overall success rate at an average follow-up time of 18 months, considering only the response to the last surgery performed, was 49%.

• Owners reported nose rub-

For more information: Roberts VL, Perkins JD, Skärlina E, et al. Caudal anaesthesia of the infraorbital nerve for diagnosis of idiopathic headshaking and caudal compression of the infraorbital nerve for its treatment, in 58 horses. Equine Vet J. 2013 Jan;45(1):107-110. doi: 10.1111/j.20423306.2012.00553.x. Epub 2012 Mar 13. http://www.ncbi.nlm.nih.gov/pubmed/22413870

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bing in 30 horses at long-term follow-up after surgery.

• Nose rubbing resolved in all but four horses that were later euthanized.

“Headshaking in horses is a major welfare issue, and more research is needed on the pathogenesis of this pain syndrome to improve medical and surgical therapies. Headshaking is a significant cause of distress for some horses and this treatment in selected cases is needed even though the failure rate is limited.”

The researchers concluded that the caudal compression procedure offers the best prognosis for a successful outcome for horses that face euthanasia. However, surgical treatment of the disorder needs to be improved together with further research into the pathogenesis of the disorder.

The next step

There are striking clinical similarities between headshaking in horses and facial pain syndromes in people, most notably trigeminal neuralgia, according to Roberts.

Although some progress has been made toward diagnosing and treating headshake.

MeV

See YouTube videos of Mille before and after caudal compression of the infraorbital nerve surgery for headshaking.

Millie-headshaking post op http://www.youtube.com/watch?v=_D2rkKEJvoQ Millie-headshaking pre op http://www.youtube.com/watch?v=gqJIJdtGHpg

vaccine

New vaccine for

ERAV

Product addresses equine respiratory disease that is difficult to diagnose.

The US Department of Agriculture recently granted a conditional approval for a new vaccine for equine rhinitis A virus (ERAV), an often overlooked cause of respiratory disease in horses.

ERAV has been isolated from Thoroughbreds with acute respiratory disease in the United States, Canada, Australia, Japan and Europe, and it is emerging as an important disease in these regions, according to an article in the Journal of Virology. In a recent U.S. study, 73% of all sampled horses younger than 3 years old exhibited serum-neutralizing (SN) antibodies to ERAV, and 90% of those 4 or older were positive.

“Researchers are continuing to learn more about the prevalence of this disease,” said John Tuttle, DVM, senior associate director, equine professional and technical services At Boehringer Ingelheim Vetmedica Inc. (BIVI).

“Performance horses that are comingled, stabled, entering training and 1 – 2 years of age or older appear to be at risk.”

This disease, which affects both upper and lower airways, maybe spread by contact through nasal secretions and aerosol inhalation.

Early, specific diagnosis is the foundation of effective management of equine respiratory dis-

ease, however, clinical signs are similar to other respiratory diseases and so the disease is frequently missed. ERAV is often confused with rhinopneumonitis, which is caused by equine herpes virus 1 and 4.

Clinical signs associated with ERAV infection include fever, serous nasal discharge, coughing, abnormal lung sounds, anorexia, pharyngitis, lymphadenitis, increased tracheal mucus production, and occasionally, leg edema.

“Obviously, any number of factors can contribute to respiratory diseases in horses, which is why ERAV can be so difficult to diagnose,” Tuttle said.

Infection is accompanied by viremia that develops 3 to 7 days following infection and typically lasts for 4 or 5 days, with disappearance of virus from blood coinciding with onset of antibody production.

“The role of ERAV in causing acute respiratory disease in horses may be underestimated due to the lack of sensitivity of traditional diagnostic testing,” Tuttle said. “The virus can be detected from horses with acute, respiratory disease using virus isolation, PCR or paired SN assay testing.”

Promising results

The USDA granted BIVI a conditional license for Equine Rhinitis

Artist rendering of ERAV. Courtesy of BIVI.

A Virus vaccine. A conditional license is granted when a company can demonstrate a need for the product. The data required for conditional licensure are the same as for a fully licensed product: demonstration of a reasonable expectation of efficacy, acceptable safety and purity during tmanufacturing.

Efficacy and potency test studies are in progress. A conditionally licensed vaccine may be distributed as authorized in each state, and used by, or under the supervision of veterinarians.

“We are excited to offer a safe vaccine option for veterinarians and horse owners,” Tuttle said.

“And as a worldwide leader in equine health-care solutions, we also have an obligation to help educate the industry about the prevalence, diagnosis and treatment of this disease.”

For more information about ERAV diagnosis and vaccination, contact BIVI veterinary technical services at 866-638-2226. MeV

For more information: Warner S, Hartley CA, Stevenson RA, et al. Evidence that equine rhinitis A virus VP1 is a target of neutralizing antibodies and participates directly in receptor binding. Journal of Virology. 2001;75. Link: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC114494/

ModernEquineVet.com | December 2012

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infectious diseases

Three-tiered

better for finding

Photo courtesy Alex Wild/alexanderwild.com

A recent study show that a

three-tiered strategy might be a better approach than the agar gel immunodiffusion test (AGID, Coggin’s test) alone to diagnose equine infectious anemia (EIA).

The Coggin’s test quickly became the gold standard for diagnosing EIA after its introduction more than 40 years ago, and it has done a great job at finding cases and reducing the risk of this fatal disease.

“The Coggins test alone dramatically reduced the risk of EIA wherever in the world it was used,” said Charles Issel, DVM, PhD, of the Gluck Equine Research Center, University of Kentucky.

In the United States, a Coggin’s test often is required before a horse can be transported from one state to another or before it can compete in various events.

Nearly 2 million samples are

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tested each year. Most tests are negative and cases are rare. Fewer than 200 cases of EIA were reported between 2008 and 2010, according to the USDA. However, a small number of those reported as negative may be false-negatives, according to Issel. “Our early control of EIA may have reduced the number of strains of EIAV that produced disease (because they replicated more efficiently), and we are now left with less pathogenic strains that replicate less and stimulate lower levels of antibody. That would make more of the new infections possibly interpreted as negative in the Coggins test,” he explained.

About EIA

EIA is a blood-borne equid disease that is often fatal. There is no treatment, and survivors become persistent carriers. The risk of transmitting the disease during periods of apparent normalcy is low, but it can occur, he said.

In the study, the researchers looked at samples routinely collected in Italy and compared the results of the Coggin’s test with several other tests. They found

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that 124 of 96,468 samples tested were positive using the Coggin’s test, but 331 were positive using a C-ELISA test. They then took the 207 samples that were positive on C-ELISA but negative on the Coggin’s test and retested them with an immunoblot test.

The immunoblot tests showed that 25 samples were reactive for multiple EIAV proteins, the remainder were not specific for EIA and thus falsely-positive on the ELISA test.

The researchers were able to investigate more fully the 25 horses whose samples were positive on the comparative serology and found that 22 horses had been from premises where EIA had occurred in the past.

“We also have found a number of horses infected with our genetically weakened strains that do not become positive on the AGID test which are positive on other approved tests.

“When we discovered that, we developed a three-tiered testing strategy that would do a better job of finding these. When we applied the strategy to find all the infected equids in a surveillance project in Italy, we were

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strategy

EIA

Under the new strategy, fewer horses would be tested overall, saving considerable money.

surprised to find 17% more cases by using our ‘threetiered strategy’ on over 96,000 samples,” he explained.

Because of technological advances that enable more sensitive tests, Issel urged states and laboratories to consider and adopt a three-tiered strategy.

This would require using the sensitive ELISA tests first, instead of the Coggin’s, then using the more specific Coggin’s test to confirm a positive ELISA. If the results of the first two tests are mixed or inconclusive, Issel recommends using the immunoblot test.

“An easy way to do this would be to order ELISA tests rather than AGID tests for EIA. The ELISA tests are ‘tier one’ in the strategy because there are fewer false-negative results in ELISA tests,” he said. “Several states already only use ELISA tests in their initial tests and Oklahoma adopted the three tiered strategy about 5 years ago.”

As part of the strategy, fewer horses would be tested overall.

The new strategy calls for group-

Photo courtesy of Dr. Charle Issel

In the United States today, about $50 million is spent each year for EIA testing.

ing states according to their EIA infection risk based on historical testing results. So, instead of being tested when a horse is moved from one state to another, it would be tested based on the state’s recommended testing schedule, provided it stayed within the same risk region.

If it moved to another region, it would be tested again.

“In the US today, about $50 million is spent each year for EIA testing. The USDA and the Animal Health Association’s Committee on Infectious Diseases of the Horse have recommended ‘smarter testing’ to reduce testing on equids not at risk, increasing targeted testing to find the reservoir in untested equids, and using the three-tiered testing strategy,” he said.

MeV

For more information: Issel CJ, Scicluna MT, Cook SJ, et al. Challenges and proposed solutions for more accurte serological diagnosis of equine infectious anaemia. Veterinary Record. 2012; Nov. 16 epublished ahead of print. http://www.ncbi.nlm.nih.gov/pubmed/23161812

ModernEquineVet.com | January 2013

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reproduction

Exercise

affects reproductive ability in

horses

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Pictureguy /ShutterStock

The study found: Exercise induced > serum cortisol concentrations (P<0.05).

Embryo recovery rates < in exercised (20/46, 43%) compared with controls (14/21, 67%). <quality Grade 1 embryos were recovered from partial-exercised mares compared with control and full exercosed mares (P<0.05).

No differences were found in follicle ovulatory diameter among exercised and nonexercised mares.

prior to and during fertilization,” said Christopher Mortensen, PhD, co-researcher of the study and assistant professor at the University of Florida.

The impact of exercise on early pregnancy is still an area that needs more research, Mortensen said. Researchers are looking to study embryo quality because advancing technology has allowed embryo transfer to become a vital part of the horse industry.

“What we hypothesize that is the reduced hormone concentrations may be having an effect on

Photo courtesy of Dr. C. Mortensen

Embryo recovery rates were reduced in horses that were exercised compared with those that were not, according to a recent study in the Journal of Animal Science.

Researchers at Clemson University and the University of Florida wanted to know the effect of exercise on mare reproductive health and embryo transfer. They divided light-horse mares into three research groups: A control group that received no exercise, a group that got some exercise and a group that got full exercise.

Their goal was to measure reproductive blood flow and embryo number and quality.

The light exercise group were moderately exercised for 30 minutes daily during the periovulatory period and rested after ovulation for seven days. The full exercise group was exercised for 30 minutes daily throughout the reproductive cycle.

Results from the study showed that exercise induced greater cortisol concentrations in horses.

Cortisol has been shown to have effects on reproduction, according to the researchers.

Embryo-recovery rates were reduced in exercised horses compared with the control group.

There was no significant difference in embryo-recovery rates for lightly exercised and fully exercised groups, but the lightly exercised group had the lowest embryo quality score.

“This led us to conclude that exercise was just as detrimental, if not more so, to the period just

the mare’s oocytes, meaning they are not as ‘competent’ and have a reduced ability to be fertilized, or if fertilized, compromised embryo development,” said Mortensen.

These findings could have implications for human pregnancy.

“While many studies in women have shown intense exercise can be detrimental to female pregnancy, there are virtually no studies examining maternal exercise and effects on the early developing embryo.

Furthermore, there are few studies examining stress and the female reproductive blood flow response,” said Mortensen.

MeV

For more information: Smith RL, Vernon KL, Kelley DE, et al. Impact of moderate exercise on ovarian blood flow and early embryonic outcomes in mares. Journal of Animal Science. 2012; 90 (11): 3770 DOI:10.2527/jas.2011-4713 http://www.journalofanimalscience.org/content/90/11/3770

ModernEquineVet.com | January 2013

15

news notes

Rescue and adoption: Rags to Riches stories

Photo courtesy of Ericka Caslin

A new competition hopes to shed light on the issue of unwanted horses by demonstrating that even some really broken down horses can still be productive if given half a chance.

Unwanted Horse Coalition Director, Ericka Caslin, went to Richmond, Va., to judge the inaugural Rags to Riches Horse Rescue Competition at the Equine Extravaganza. The judges rated the horses rescue story on a scale from 1 to 10 based on the passion and allure of the story behind the horse’s rescue, how far the horse has come since its rescue, and if the horse would be a ambassador for equne rescue.

Caslin and the other judges heard the stories of 10 rescue horses, which were chosen out of many entries, based on video submissions received since July.

The breeds showcased ranged from Quarter Horses, Paints, to off the All he needed was a second changce track Thoroughbreds, a Percheron/TB cross, and Appaloosas.

During the first part of the competition, the finalists presented their horses’ stories to the judges.

“A few stories really stood out,” said Caslin. “Some of these horses were on the brink of death, and to see that someone cared enough to give them a second chance at life is really incredible. What is even more amazing to me is that these horses are competing successfully in disciplines, such as dressage and eventing. These stories were very heartwarming and emotional.”

The second part of the competition was moved to the outdoor arena of the Equine Extravaganza.

The horse and rider/handler demonstrated the horses’ talents. They were judged on the compatibility of horse and rider, how far the horse has come since its rescue, the horses’ healthy appearance, the cre16

January 2013 | ModernEquineVet.com

ativity of the performance, and how well the performance was executed.

“The horse and rider combinations really got creative during the arena demonstration of the Rags to Riches competition. We saw a horse play soccer, we saw a rider ride her horse bareback with a flag, we saw a lunging demonstration, a barrel racing demonstration, and we saw some really fantastic dressage tests,” said Caslin The win went to How Do You Like Me Now and his rider, Caitlin Schoemmell. How Do You Like Me Now was rescued in 2010 and had an initial body score of 1.5. His first day of training was May of 2010 and he went to his first show in May of 2011.

He was won many championships at shows and is now jumping 2'6" courses and is safe enough for children to ride. His owner, Caitlin, helps educate people about rescuing horses and the joys a rescue horse can bring to people’s lives.

Second place honors went to Box of Chocolates and her rider, Brittany Kuntz. Box of Chocolates, fondly called Cocoa around the barn, was rescued from the Camelot auction in 2010. She was so badly injured, that she walked on the insides of her feet.

Brittany and her mother were not sure if Cocoa could ever be ridden, but they were willing to save her to keep at their farm. After using the Parelli method to initially trainer her, Cocoa is now successfully competing in horse trials, consistently placing, and jumping 3' regularly.

Third place honors went to Days End Chino and Emily Benton. After being rescued from a farm in Maryland and receiving a body condition score of 1.5, vets were not sure if Chino would live. With a lot of love, care, and training, Chino thrived and was able to be adopted into a forever home in September 2010. He is now competing successfully in dressage and eventing competitions.

The rescue chosen by the winner of the Rags to Riches competition received a prize package from A Home for Every Horse. This year’s winning rescue organization was the United States Equine Rescue League of North Carolina.

Organizations across the country continue to work to address the issues of unwanted horses. Equine care facilities are struggling and many of our nation’s rescues are either at capacity or near capacity.

For more information about joining the UHC or unwanted horses, please visit the UHC website at www.unwantedhorsecoalition.org.

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Mosquito virus could lead to new vaccines and drugs A mosquito sample collected three decades ago in Israel’s Negev Desert has yielded an unexpected discovery: a previously unknown virus that's closely related to some of the world’s most dangerous mosquitoborne pathogens but, curiously, incapable of infecting non-insect hosts.

Researchers believe this attribute could make the Eilat virus a useful tool for studying other alphaviruses, a genus of largely mosquito-borne pathogens that includes the viruses responsible for Venezuelan equine encephalitis, western equine encephalitis and eastern equine encephalitis. In addition Eilat might help researchers develop new vaccines, therapies and diagnostic techniques.

“This virus is unique — it's related to all of these mosquito-borne viruses that cause disease and cycle between mosquitoes and animals, and yet, it is incapable of infecting vertebrate cells,” said University of Texas Medical Branch at Galveston (UTMB) graduate student Farooq Nasar, lead author of a paper on the virus, which is available online in the Proceedings of the National Academy of Sciences.

Eilat was discovered in a virus sample that Joseph Peleg of Hebrew University sent to Dr. Robert Tesh, of the UTMB, director of the World Reference Center for Emerging Viruses and Arboviruses. The collection holds more than 5,000 identified viruses and dozens of unidentified samples.

All the researchers knew about Peleg’s specimen was that it killed insect cells while leaving animal cells untouched, an unusual behavior. So they sent it to a lab at Columbia University to sequence the genetic material. There were two new viruses in the sample. One virus killed insect cells, and the other — Eilat virus — infected them without doing any harm.

“We were extraordinarily lucky to have that other virus in our sample, because without the cell death it caused, we never would have done the work that led us to Eilat,” Nasar said. “Essentially, we found it by accident.”

Eilat’s inability to grow in animal cells — even its genetic material cannot replicate in them — makes it unique among alphaviruses, and it also makes it likely that the virus could be valuable to researchers who study alphaviruses. For example, the UTMB researchers say, Eilat could be transformed into a vaccine against one of its dangerous relatives by making changes to the genes that produce its envelope proteins, which are exposed on virus particle surfaces and stimulate the critical parts of the immune response.

“We have taken the genes for the envelope proteins of very dangerous viruses like eastern equine encephalitis

and used them to replace the genes for Eilat’s structural proteins,” Nasar said. “That gives us viruses that we can grow in insect cells that can't do anything in vertebrate cells at all, but still produce immunity against eastern equine encephalitis — they can be used to vaccinate animals, and hopefully someday people.”

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WNV season just around the corner In 2012, 42 states reported 654 cases of West Nile virus (WNV) in horses with Louisiana and Texas having the most confirmed veterinary cases — 62 and 117 respectively. Only eight states reported no veterinary cases of West Nile last year.

Vaccination remains the most effective way to protect horses against this mosquito-borne disease. The risk of infection for unvaccinated horses can be as high as 50 times the risk of vaccinated horses, according to Pfizer Animal Health, the maker of West Nile Innovator.

WNV is a core vaccination requirement, along with vaccinations for Eastern equine encephalomyelitis, Western equine encephalomyelitis, tetanus and rabies. All horses should receive a WNV vaccine annually, according to the recommendations of the American Association of Equine Practitioners.

To remind horse owners of the importance of vaccination against West Nile, Pfizer is launching a commercial for Innovator.

Transmitted by mosquitoes, WNV causes infection and inflammation of the central nervous system. Horses do not always show clinical signs. For horses that show clinical illness, the virus can include fever, weakness or paralysis of hind limbs, impaired vision, ataxia, aimless wandering, walking in circles, hyperexcitability or coma. The case-fatality rate for horses exhibiting clinical signs of West Nile infection is approximately 33%.

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http://www.youtube.com/watch?v=pGjmQK2LN4Y

ModernEquineVet.com | January 2013

17

technician update

Developing equine vaccine against deadly

Hendra virus

Pfizer Animal Health has licensed the technology used to develop a new vaccine as an aid in the prevention of clinical disease caused by Hendra virus in horses from The Henry M. Jackson Foundation for the Advancement of Military Medicine Inc. (HJF).

The new vaccine, called Equivac HeV, is now available for use in Australia. Since its first appearance in 1994, the Hendra virus has killed more than 80 horses and four of the seven people infected to date. An equine vaccine is crucial to breaking the cycle of Hendra virus transmission from flying foxes to horses and then to people, as it helps prevent the horse from both developing the disease and transmitting the virus to other horses and to humans. Current experiFigure. Hendra virus particles visualized by electron microscopy. ments have shown that vaccinated horses surTransmission electron micrograph of Hendra virus negative stained with 2% phosphotungstic acid. vived infection by Hendra Image courtesy of the AAHL Biosecurity Microscopy Facility, Australian Animal Health Laboratory (AAHL) Livestock virus and have shown no Industries CSIRO, Australia. evidence of virus, disease, replication or shedding of the virus, a critical finding to help prevent transmission.

To date, Hendra virus has been found only in Australia. The nation experienced an unprecedented number of 18 outbreaks across Queensland and New South Wales in 2011, during which 22 horses died or were euthanized. Authorities detected the first case of Hendra virus antibodies in a dog within a natural environment that same year. The virus has appeared seven times in 2012, causing equine deaths and cases of human exposure to infection. In July 2012, a woman with significant exposure risk was given an 18

January 2013 | ModernEquineVet.com

experimental human monoclonal antibody therapy on a compassionate use basis.

Dimitar Dimitrov, PhD, of the NIH, working in collaboration with Christopher C. Broder, PhD, of the Uniformed Services University of the Health Sciences (USU), developed the antibody, known as m102.4.

The Hendra and Nipah viruses, members of the paramyxovirus family, are highly infectious agents that emerged from flying foxes in the 1990s to cause serious disease outbreaks in humans and livestock in Australia, Bangladesh, India, Malaysia and Singapore. Recent Nipah outbreaks have resulted in acute respiratory distress syndrome and encephalitis, person-to-person transmission, and greater than 75% case fatality rates among humans.

The vaccine is derived from the original work of Broder and Katharine Bossart, PhD, assistant professor at Boston University School of Medicine. The National Institute of Allergy and Infectious Disease (NIAID) supported the work.

Progression of the technology is the result of a close, ongoing collaboration with Pfizer Animal Health and a team at Commonwealth Scientific and Industrial Research Organisation's (CSIRO) Australian Animal Health Laboratory (AAHL) in Geelong, Australia.

The vaccine component is a soluble portion of a Hendra virus G glycoprotein, known as Hendra-sG. It is this glycoprotein that mediates viral infection.

The recent work to develop and evaluate Equivac HeV was jointly funded by CSIRO; Pfizer Animal Health; the Australian government through its Department of Agriculture, Fisheries and Forestry; and the Queensland government through its Department of Employment, Economic Development and Innovation. NIAID provided funding to support production of the vaccine component in the United States.

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AAEVT Membership

AAEVT* membership is open to US and international equine veterinary technicians, assistants, practice managers, and support staff employed in the veterinary industry. It is also open to students of AVMA/CVMA accredited programs

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) • Subscription to THE HORSE Magazine, compliments of Intervet Schering/Plough 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.

ModernEquineVet.com | January 2013 For more information visit www.aaevt.org

*American Association of Equine Veterinary Technicians and Assistants

19

news notes

Equine Grass Sickness â&#x20AC;&#x201D; Still an Enigma

By Dr. Hanspeter Meier Equine Clinic, University of Berne More than 100 years ago, an outbreak of grass sickness was recognized in Scotland, and this devastating disease remains one of the great unsolved mysteries in equine medicine. Still not knowing its cause, and therefore lacking any means for causal therapy, the disease is a continuing threat. As its name suggests, grass sickness is strongly associated with grazing and occurs in acute, subacute and chronic forms with a considerable overlap in clinical signs. The major symptoms relate to partial or complete paralysis of the digestive tract. Considering the nature of the damage to the nervous system, combined with epidemiological factors, a type of toxin is suggested as the causative agent.

Many potential causes have been examined but none has survived scientific scrutiny despite almost 90 years of investigation. However, the cause was associated with exposure to grazing or the ground right from the beginning and therefore it was also considered that grass sickness might be a form of botulism. The first reports of botulism in horses in connection with feedstuffs were reported in the United States and additional cases also were associated with grazing. Beside this, some symptoms of these two diseases are comparable.

That grass sickness might be caused by Clostridium botulinum was first proposed almost 90 years ago in 1923. However, these investigations failed to demonstrate clear evidence and the idea lost favor.

Moreover, doubts persisted because of the anaerobic and ubiquitous nature of C. botulinum. In 1999, new interest in the organism began. Researchers showed that green grass blades can contain botulinum toxin. On a European stud farm where grass sickness

occurred twice within eight months, grass and soil samples and necropsy specimens were tested for the presence of bacterial forms and toxin of C. botulinum. Different types of the germ (A-E) and neurotoxin (BoNT) were found and showed that growing grass contained free BoNT. Bacterial forms in soil were numerous in May, but were not found in August and September. It is speculated that biofilms adhere to lower parts of the grass and allow C. botulinum to survive within a bacterial consortium while being trapped and protected from dehydration.

Other indications for the involvement of clostridia are some similarities with the equine atypical myopathy, with Clostridium sordellii as a suspected causative agent. Here, we also encounter a regional, seasonal, and pasture-associated disorder that is characterized by degenerative alterations. Also, environmental factors seem to influence the incidence of both diseases as well as access to pasture, certain weather conditions and the degree of resistance in older horses.

The exact role the toxins of C. sordellii or C. botulinum play in the respective diseases has yet to be defined. Researchers in 1924 demonstrated statistically highly significant protection against grass sickness by vaccinating horses with a mixture of botulinum toxin and antitoxin, and today work continues in the United Kingdom toward demonstrating efficacy of a botulinum toxoid against equine grass sickness. Such progress will take more time, and we must make sure to use other preventive measures to the best of our knowledge. Careful husbandry and meticulous pasture management must be of the highest standards.

It brings to mind the saying of the French physiologist Claude Bernard (1813-1878): â&#x20AC;&#x153;It is not the germ that causes disease but the terrain in which the germ is found,â&#x20AC;? an opinion that is older than the grass sickness itself.

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Careful husbandry and meticulous

pasture management may help prevent

equine grass sickness.

For more information: This article is used with permission, and first appeared in the Equine Disease Quarterly, published by the Gluck Equine Research Institute. http://www.ca.uky.edu/gluck/q/2013/jan13/Q-Jan-2013.pdf 20

January 2013 | ModernEquineVet.com

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The right to help others, not just ourselves Americans really hate being told what to do. Tell us we have to do it, and we resist. We just can’t help ourselves.

Several health care workers have been fired recently because they refused to get a mandated influenza vaccine, after hospitals responded to this particularly bad cold and flu season by mandating the vaccine. Their choice doesn’t make sense to me.

Why wouldn’t you want to protect the very people — the old, the very young and those with comorbid conditions — that you are trying to keep healthy?

This should not be about an individual rights, but about the right to help and protect others.

There are three undisputed facts that all healthcare workers should consider, according to the American Academy of Physicians.

Consider the facts

Courtesy of CDC

1) Influenza vaccines are safe and effective, 2) U nvaccinated healthcare workers spread influenza to their patients, 3) H ospitalized and other vulnerable patients can have prolonged hospitalizations, severe illnesses, and can die as a result of influenza transmission from HCWs. Just about every healthcare setting has documented cases of health care workers transmitting influenza to patients. Multiple studies show that 70% or more of HCWs continue to work despite being ill with influenza, increasing exposure of patients and co-workers. Serologic studies suggest that up to 25% of HCWs have evidence of influenza infection each season.

A review of nosocomial influenza outbreaks in the hospital setting compared attack rates of pa-

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tients with those of healthcare workers and found that the healthcare worker attack rates mirrored, and even surpassed, patient attack rates in epidemic areas of the hospital. In addition, the study reported median excess patient mortality rates of 16%, with rates in excess of 33 to 60% for patients in the intensive care and transplant units.

For most of us, the flu is a nuisance. We get sick, maybe even lose a few days work, then our immune systems kick in, and we get better. But for those with compromised immune systems, the flu can be deadly. According to the CDC, the proportion of deaths attributed to pneumonia and influenza was 7.3% above the epidemic threshold this year, and there have been nine influenza-associated deaths among children.

As I write this editorial, the percentage of people who have gone to the doctor for influenza like illnesses have doubled since last year. Almost half the country has reported influenza, including Washington, DC. The ACP says that influenza can be transmitted while asymptomatic, allowing people to spread the infection to patients, other staff, family and friends before they know they are ill. So, why wouldn’t you want to get a simple shot that could prevent at least 65% of these illnesses?

ies – you earned it.

This year’s flu season is bad. I didn’t have the flu, because I make sure I get vaccinated every year, but I spent three days in bed with an upper respiratory infection that then became bronchitis. I was sick as a dog, but my doctor told me to be thankful it wasn’t the flu because the flu this year is worse.

Take simple precautions to protect yourself, your family and your staff so that you can keep helping your patients. Get a flu shot, encourage your staff to get flu shots and take precautions if you become sick.

Your patients might not be human, but they deserve the best you can give them, and no one is at their best when they are sick.

Stay healthy and have a great New Year.

Marie Rosenthal, MS Editor The Modern Equine Vet

Although you are not required to receive an influenza vaccine because your patients aren’t human, it still might be a good idea. This one selfless act could help protect your clients, your staff, your spouses and significant others, your children and your grandchildren. It might also be the difference between staying out on the road and taking care of your patients and staying home in bed miserable.

If you do get one of the many other upper respiratory viruses that are going around, please stay home and encourage your staff to stay home to minimize the spread of this infection. Don’t tough it out. Besides infecting others, you could wind up in the hospital with pneumonia or bed-ridden even longer with bronchitis or some secondary problem.

Stay home, drink lots of juice and watch bad mov-

By Dr. Robert M. Miller

Consider getting vaccinated

Dr. Miller’s books and videos are available for sale at www.robertmmiller.com ModernEquineVet.com | January 2013

23

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