October 2013 V2N7

The Modern

Equine Vet www.modernequinevet.com

It takes more than time to

heal wounds Gait analysis EEE changes its stripes Emergency ventilation Technician Update: Anesthesia

Vol 2 Issue 7 2013

Table of Contents

Cover story:

4 Takes more than time to heal horse wounds Cover photo by Bob Langrish boblangrish.com

orthopedics

New tool for gait analysis.................................................................... 9 emergency medicine

Portable respirator provides emergency first aid....................13 technician update

Jessie Loberg: Breed variations under general anesthesia..15

News

EEE changes its stripes.............................................................................8 US Davis hosts donkey health meeting............................................8 AAEP Foundation, Zoetis scholarships............................................ 11 New report offers strategies for managing free-ranging horses and burros................................................................................... 17 Heska introduces Element POC blood gas-electrolyte analyzer......................................................... 18 Cargill feed available for senior horses.......................................... 18 CONTACT US

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cover story

It takes more than

time to heal horse wounds Horse's size and environment present unique challenges

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Horses always seem to be hurting themselves, and their wounds offer unique challenges to the equine veterinarian because of the animal’s size and its environment, Stephanie S. Caston, DVM, DACVS–LA, told The Modern Equine Vet. “Usually, there is a large amount of trauma to the tissues and a lot of contamination, which is often different from what small animal veterinarians and medical doctors see. Their patients just are not often walking around in manure,” said Caston, of the department of veterinary clinical sciences at Iowa State University, College of Veterinary Medicine.

“That is the biggest difference for equine veterinarians: the wounds have more trauma and more contamination,” said Caston, who wrote a review of wound care in horses for Veterinary Clinics of North America: Equine Practice.

Wounds that heal by second4

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ary intention can include lacerations, punctures and degloving or shear injuries, and each requires a slightly different approach, but the basic healing is the same.

The interactions among growth factors, cytokines and other molecules create the extracellular matrix needed to heal a wound.

Understanding this complex interaction allows the equine veterinarian to optimize the wound-healing environment. Think about how a Petri dish with medium supports the growth of new cells.

Wound healing occurs in three stages: 1. The body creates a clot and then granulation tissue that provides the scaffolding on which the new tissue can build.

2. The wound contracts when the granulation bed is complete, and new skin cells grow at the edges.

3. The granulation tissue is remodeled to form a scar.

No matter the type of wound

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or its location, the basic tenets of healing are the same. Healthy tissue that is linked to a good blood supply is needed so it can grow more healthy tissue. To create this environment, veterinarians may have to: • Stabilize the patient.

• Débride the wound to remove necrotic and devitalized tissue.

• Lavage the wound to remove debris.

When deciding how to manage the patient, the location of the wound is just as important as the type of wound, especially in a horse, because some wounds can be life threatenting or career ending, particularly if they involve structures, such as the chest, abdomen, thorax or joints.

Caston suggested that veterinarians assess the wound by doing a careful visual examination, as well as, digital exploration with a gloved hand. Ultrasonography and radiographs might be warranted

Photo courtesy of Dr. Stephanie Caston

This horse suffered a small laceration (above left). Next to it (above right) is the laceration a month after injury and directly above is the same wound two months after injury.

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When wounds heal, they form granulation tissue. It is a necessary step to wound healing because it helps the wound resist infection, and it allows epithelial cells to crawl over it and fill in the wound, which makes it contract.

However, some horses develop too much granulation tissue, which is usually called proud flesh.

“Owners need to recognize that while proud flesh is a problem in horses, granulation tissue is important for healing,” explained Stephanie S. Caston, DVM, DACVS-LA, of the department of veterinary clinical sciences at Iowa State University, College of Veterinary Medicine.

“Proud flesh is excessive granulation tissue Chronic proud flesh after many months. Photo courtesy of Dr. Stephanie Caston. and some owners try to treat that at home.

They see granulation tissue forming, and they think it is proud flesh, so they put caustics on it. That can make the wound deeper and delay healing,” she said.

And they are painful for the horse.

Instead of "eating back” the proud flesh, it should be surgically trimmed by a veterinarian.

“There are many products on the market, and they do eat away the tissue, but they are not selective as a surgeon would be. If they get on normal skin or new skin, they can damage it.” to determine which structures are involved.

Healthy state

Débridement and lavage are important to get the wound back to a healthy state.

“We always want to clean the wounds with débridement or lavage them because they are often contaminated. How we débride, whether we use a scalpel or scissors, will depend on the location of the wound. With scissors or scalpel, we can cut off tissue that is contaminated or necrotic,” she said.

A joint wound might require arthroscopy to return it to a sterile environment.

“Remember if the horse got his leg caught in the fence — it could

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have been caught for minutes or hours, so there will be ground dirt into the wound, sometimes metal.

It might be impossible to get all the dirt out, but you have to do the best you can,” she said.

“But we want to be judicious when we débride the legs. We want to get as much contamination as we can with our débridement without removing too much because there is not a lot of skin on the legs.

Sharp débridement is best. You could mechanically débride with gauze but that is more damaging to the tissues. You will also get some débridement with lavage. Be careful not to remove too much tissue because the legs are notorious for having proud flesh.”

Although veterinarians should not let the wound become soaking

wet or oozing, studies have shown that wounds tend to do better in a moist environment so platelets can build the scaffolding and white blood cells, fibroblasts and epithelial cells can migrate through the wound.

“Puncture wounds can be tricky because people see a small wound and think it is not a big deal, but if the wound has entered a joint or the chest or abdomen, bacteria can set up housekeeping. That can be just as dangerous as a big laceration,” she said.

The veterinarian might have to open up the tract of the wound and lavage or débride it.

There is an old Irish proverb: Patience is the poultice to heal all wounds.

Many products are available

Photo courtesy of Dr. Stephanie Caston

Proud flesh

that help with wound healing, but wound starts to heal and the innothing will heal the wound over fection decreases, a hydrogel may night, she cautioned. And some be used, or maybe just plain cotproducts are quite costly because ton padding will be sufficient. the horse’s wound might be really “Regardless of the dressing, large. As with so many issues in you want to make sure the wound caring for the horse, veterinarians is as clean as possible. Choose must weigh the cost vs. the benefit. something that won’t irritate the No single dressing is appropriwound,” she said. ate for every wound. Before choosSome veterinarians use ading a wound-management strategy, juncts to help wound healing. do a comprehensive assessment Choices depend on many factors, of the animal’s medical history, type of wound, stage and location of the wound, and clinical factors such as the presence or absence of infection, as well as the work the horse does.

Then, consider the wound’s environment. Is the wound dry and cracking or moist and exudative? A good dressing will absorb fluid without sticking to the wound and causing nonselective débridement that hinders healing.

Good choices are foam dressings made from polyurethane and alginates that wick away the exudate but still permit some moisture.

If a wound is dry, a hydrocolloid or hydrogel will create a moister environment. Hydrocolloids protect the area and alleviate friction. Hydrogels have insoluble polymers that débride the wound with- Above: a highly contaminated and traumatized wound that out harming granulation tissue presented to the clinic a few days after it happened. The hoof was torn off when the colt was caught in the fence and fought and encourage cell migration. to free its leg. The rest of the injuries were sustained at the They are soothing and help same time.

Photo courtesy of Dr. Stephanie Caston ease pain.

The dressing choice may change as the wound heals. For such as ease of use, cost, how well instance, an oozing, infected the horse will tolerate it, as well wound with a lot of exudate may as, what structures are involved. require a foam dressing. As the Here are just a few choices:

• M edical-grade honey, which is bacteria static and bactericidal, has been used for many years.

Besides its antimicrobial properties, it also keeps a wound moist.

• Soft, borate-based bioactive glass dressings fill in the wound and supply the structure for new cells to build on. They create an environment that is hostile to bacteria, which allows wounds to heal.

• Negative-pressure dressings draw the edges of a wound together, remove infectious materials and promote granulation tissue, but the vacuum can be unweldy in a horse.

Not healing?

If a wound is not healing, there might be a foreign body or sequestrum, where the blood supply to the bone is cut off and it becomes a dead layer of bone.

That will need to be débrided before the wound will heal.

“Sometimes you get a wound that looks uncomplicated because the damage is not readily apparent. Other times, owners can manage the wound at home as long as they know what to expect and when to call you back.”

Tell owners to call you if the horse develops proud flesh, instead of trying to treat it for a prolonged period at home. (See box.)

Know what to expect for each stage of healing and arm clients with this information.

Remind them that equine wounds can take weeks to months to heal depending on many different factors.

MeV

For more information: Caston SS. Wound care in horses. Vet Clin Equine 2012;28:83-100.

http://www.ncbi.nlm.nih.gov/pubmed/?term=Caston+SS.+Wound+care+in+horses.+Vet+Clin+Equine+2012%3B28%3A83-100.

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news notes

A Virus Changes Its Stripes: Human Outbreak of Eastern Equine Encephalitis In the summer of 2010, the eastern Panamanian province of Darien experienced a phenomenon that had never been seen before in Latin America: a human outbreak of eastern equine encephalitis (EEE).

The mosquito-borne virus that causes the disease infects horses throughout the Americas. Human infections are diagnosed every year in North America and are taken quite seriously because they carry a 50% chance of mortality, and can result in lifelong neurological damage.

But 2010 marked a dramatic change in the way the virus behaved in Latin America.

“Until the Darien outbreak, we had become convinced that the virus in South America was fundamentally different in its ability to infect people and cause serious disease,” said University of Texas Medical Branch at Galveston professor Scott Weaver, senior author of a paper on the epidemic published in

Photo courtesy of UC Davis

UC Davis to Host Donkey Welfare Symposium

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The University of California, Davis School of Veterinary Medicine will host the inaugural Donkey Welfare Symposium on Nov. 1-3. The three-day event will feature informative lectures and hands-on laboratories for donkey enthusiasts, veterinarians, technicians and students.

More than 15 experts will present at the symposium, including Dr. Eric Davis, a leading authority on donkey health with more than 35 years of experience in animal welfare in rural areas and developing countries. Up to 21 hours of CE credit will be available for veterinarians, technicians and veterinary assistants. For those unable to attend the symposium in person, a live interactive webinar will be available for only the 13 hours of lectures. For more information and to register: www.vetmed.ucdavis.edu/CE/equine/Donkey_Welfare_Symposium.cfm.

Issue 7/2013 | ModernEquineVet.com

This negatively stained 1975 transmission electron micrograph revealed the presence of a number of Eastern equine encephalitis (EEE) virus virions in this tissue specimen.

Photo courtesy of the CDC

the New England Journal of Medicine. This epidemic broke that dogma very quickly, according to Weaver.

UTMB researchers collaborated with Panamanian scientists to investigate the outbreak, testing samples from 174 patients and many horses. In the end, they confirmed 13 human cases of EEE and one case of dual infection of both eastern and Venezuelan equine encephalitis.

“We saw only about a one in 10 case-fatality rate in Panama, which is low by US standards,” Weaver said. “Still, if this virus has changed and become more virulent for people, we need to know, number one, is it going to spread to other parts of Latin America or number two, are other Latin American strains likely to do the same thing?”

Weaver noted that earlier studies have shown that the EEE virus is common in many Latin American locations where human exposure to virus-carrying mosquitoes is high.

Since the virus is constantly mutating, it’s possible that a strain like the one seen in 2010 in Panama could take hold in an ecosystem in nearby Colombia, Ecuador or the Peruvian Amazon.

“With a situation where a lot of people are being exposed to the virus, there would be the potential for a lot of new disease,” Weaver said. “So it's important to understand what's happening in Panama both for the Panamanians and for people all over Latin America.”

MeV

For more information: Carrera JP, Forrester N, Wang E, et al. Eastern equine encephalitis in Latin America. N Engl J Med. 2013;369 (8):732 DOI:10.1056/ NEJMoa1212628

Orthopedics

Important step forward for

gait analysis of horses Gait and movement pattern are essential to the horse’s well-being regardless of its use.

New research makes it pos-

sible to use sensors to accurately measure a horse's movements and to quantify limb movement outside the traditional gait laboratory. This provides veterinarians, as well as breeders and trainers, with

a number of new possibilities, according to a study in the Journal of Biomechanics.

The work was a collaboration between the University of Copenhagen and The Royal Veterinary College in the United Kingdom.

Whether a veterinarian is trying to find the cause of lameness or di-

agnosing a disease, such as Wobblers disease, assessing the gait is essential. So far, veterinarians have only been able to study horse movement in a gait-laboratory, which commonly only allows

Friesian mare. Gait and movement pattern are essential to the horse, whether it's a question of the horse's well-being, competition riding or breeding.

Credit: Š zuzule / Fotolia

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OrthoPedics

How it works A state of the art gait laboratory use infrared motion capture measurements of movement in three dimensions — a number of reflective markers are attached to the horse, and the resulting movement in a three-dimensional space are interpreted in a computer. Motion capture is precise down to 1 mm toward measuring displacement of body segments.

So-called force plates that measure the hoof’s interaction with the ground in three dimensions as well as the force it creates are used as the reference standard for ground contact times.

Inertial sensors accurately estimate the movement of the lower leg in the horse, both in the direction of movement and vertically, with a high accuracy, while the dimension of right to left (medio-laterally) has a high measurement error, making the it useless for gait analysis.

Inertial sensors placed immediately above the horse’s fetlock joint used to measure the timing for the hoof’s contact with the ground, compared with using force plates, had a measurement error, less than 7 milliseconds, and an error less than 1 millisecond for lift-off from the ground.

study of a few steps at a time on a straight line.

Using inertial sensors; small sensors containing technology similar to that found in a cellphone, i.e. gyroscopes, accelerometers and magnetometers, Emil Olsen, DVM, PhD, MRCVS and his collaborators managed to accurately measure horse movement (displacement) as well as the timing of the hoof ’s contact with the ground.

“Our previous research shows that inertial sensors placed right above the horse’s fetlock joint can be used to reliably determine the timing of the hoof ’s contact with the ground.

"We're a big step closer to being able to measure movement during training of a horse under real-life conditions." ­—Dr. Emil Olsen “Furthermore, we’re a big step closer to being able to measure movement during training of a horse under real-life conditions, because we have also managed to validate the method against the reference standard motion capture, and this provides us with tools to evaluate the development and change in coordination and symmetry simultaneously,” explained Olsen, who was with the University of Copenhagen when the work was done. He is now with Cornell University College of Veterinary Medicine.

Better, cheaper treatment

Using this new method, veterinarians will be able to analyze the movement patterns of horses with

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lameness much better than before.

Professional trainers will also be able to use the sensors, for example to check whether a horse actually moves rhythmically, which is an important criteria in dressage, as well as, other equestrian disciplines.

Although veterinarians are expected to be the primary users of this new method, there will be scientific applications for researchers because the sensors allow them a more thorough look into the motor skills and movement patterns of horses than previously seen, although practicing veterinarians are the primary target of the new method.

“Our goal with this new system is to achieve a broader screening of the horse’s coordination, and through that, to be able to discover diseases and problems earlier. It will also be possible to monitor diagnostics and rehabilitation outside of the gait lab with equipment economically within reach for most vets,” Olsen said.

The sensor system has already hit the market, an example is Equigait (equigait.com), a product developed by Olsen’s PhD supervisor Thilo Pfau, PhD, a lecturer in bioengineering at the Royal Veterinary College. The new research results presented here haven’t yet been implemented in any particuMeV lar product.

newsnotes

AAEP Foundation, Zoetis award scholarships

Technician walking horse with sensors to measure gait.

Four 2013 veterinary graduates who have dedicated their careers to equine health care were awarded $4,000 scholarships from Zoetis and the American Association of Equine Practitioners (AAEP) Foundation during the Focus on Students meeting recently held in Charlotte, NC. The annual AAEP Foundation and Zoetis Veterinary Student Scholarships reward graduating veterinary students with a dedication to equine medicine for their academic excellence, leadership in their school and chapter, and their long-term goals. These $4,000 awards are available thanks to the donations of Zoetis customers who participated in the Industry Support Program from Feb. 1 though April 30, 2013.

Photos courtesy of Dr. Thilo Plau

The award winners are: Megan Hays, VMD University of Pennsylvania

Alicia Yocom, DVM University of California, Davis

Shannon Smith, DVM Cornell University

Amy Cook, DVM Iowa State University

Inertial sensors are small sensors that use technology similar to that found in a cellphone to accurately measure horse movement as well as the timing of the hoof's contact with the ground.

For more information: Olsen E, Pfau T, Ritz C. Functional limits of agreement applied as a novel method comparison tool for accuracy and precision of inertial measurement unit derived displacement of the distal limb in horses. Journal of Biomechanics. 2013;46 (13): 2320 DOI:10.1016/j.jbiomech.2013.06.004 http://www.jbiomech.com/article/S0021-9290(13)00268-6/abstract

Veterinary student applicants are nominated for the scholarships by representatives from their colleges. In addition to academic excellence, recipients are evaluated on their leadership abilities and involvement in activities benefiting the health and welfare of horses. Each accredited college or school of veterinary medicine with an AAEP student chapter may use its own criteria to nominate one fourth-year veterinary student who plans to enter equine practice.

For more information about this scholarship program, visit the AAEP Foundation’s website at www.aaep.org/zoetis_scholarship.htm. MeV

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Emergency Medicine

Portable ventilation system within reach

Respiratory or cardiovascu-

Photos courtesy of Dr. Yves Moens

lar arrest in horses poses a huge challenge to veterinarians because ventilation equipment is generally hard to operate and requires electricity and compressed air.

Anesthesiologists at the University of Veterinary Medicine, Vienna (Vetmeduni Vienna) have developed an inexpensive device to enable veterinarians to provide ventilation of large animals. It is easy to transport and can save animal lives in emergencies. In a recent publication in the Journal of Equine Veterinary Education the scientists confirm that their emergency ventilator works in horses.

The medical treatment of horses requires not only specialized knowledge but also specialized equipment because a horse requires a large volume of air. It is not easy to supply this during an emergency. Suitable respirators are available in hospitals but are seldom available in the barn, in the pasture, in the woods, during transport or at other places where emergencies can and do occur.

Yves Moens, Dr.med.vet, DECVA, head of the Vetmeduni’s clinical unit of anesthesiology and perioperative intensive care medicine, and his colleagues have long been concerned by the number of horses that die avoidable deaths because of the lack of a suitable ventilation device. The scientists have designed a

Small device could saves lives of large animals.

ventilation pump for large animals with which veterinarians can simply and quickly resuscitate animals in the field. The device is similar to the bellows used to inflate air mattresses and is easy to carry and to use. In the event of an emergency, the veterinarian can intubate the animal and operate the ventilator pump, which is connected to the bellows, by foot. Exhalation is effected via a second valve that is manually controlled.

has developed highly sophisticated equipment and narcotics.

Researchers at Vetmeduni are developing improved anaesthetic techniques and ventilation equipment to reduce the risks during surgery.

Small device produces a lot of air

An adult horse needs about 5 to 6 L of air in its lungs to oxygenate its bloodstream. A correspondingly large bellows would be too large to be operated by one man and could not be transported in a conventional car. Although the Vetmeduni’s emergency ventilator can only provide 2.5 L of air, the researchers believed that it would be sufficient for the respiration of horses if the bellows are activated several times in quick succession.

They tested this idea on five anesthetized Haflinger horses during castration surgery in a pasture.

The veterinarians showed that gradual ventilation with the 2.5 L pump is sufficient to keep the animals alive.

Respiration outdoor provides safety for animals and humans.

In recent decades, anesthetic medicine for humans and animals

The respiratory pump is one of the outcomes. “It improves the safety of large animals in the field, both during routine anaesthesia and in emergencies. It will also help veterinarians to provide emergency first aid in these circumstances and respect the guidelines for good practice,” said Moens. The respiratory pump is inexpensive and easy to use and could help veterinarians treat their patients in the field. MeV

This portable device could be life saving for horses.

For more information: von Ritgen S, Auer U, et al. A commercial foot pump for emergency ventilation of horses, proof-of-principle during equine field anaesthesia.

Equine Veterinary Education. 15 AUG 2013, DOI: 10.1111/eve.12069 http://onlinelibrary.wiley.com/doi/10.1111/eve.12069/abstract ModernEquineVet.com | Issue 7/2013

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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.

For more information visit www.aaevt.org

*American Association of Equine Veterinary Technicians and Assistants

technician update

Breed considerations when putting a horse under

By Jessie J. Loberg, BA, AAS, CVT, VTS-EVN

What are the risks?

Predisposing factors that put a horse at risk for a HYPP episode are stress related, including trailering, fasting, sedation and general anesthesia. Clinical signs of a perioperative HYPP episode (>5.5 mmol/L K+) include focal muscle fasciculations generally in the area of the neck, flank and shoulder that may lead to full-body fasciculations (myotonia), inspiratory stridor and hypercapnea. The electrocardiogram will show prolonged, flattened p-waves, prolonged QRS complexes and spiked T waves. An important consideration for HYPP horses undergoing anesthesia, is weakness leading to a prolonged recovery.

We are going to focus on the management of these horses undergoing general anesthesia.

The anesthetic success for a patient with MH relies on the cooling of the patient and adequate ventilation to decrease carbon dioxide (CO2) levels. If a patient is predisposed to developing MH and must

Photos courtesy of Jessie Loberg.

Due to their docile nature, the quarter horse and paint breeds tend to be easy horses to handle for anesthetic procedures. One consideration for these breeds, however, is the genetic diseases that predispose them to greater anesthetic risk.

Malignant hyperthermia (MH) is a gene mutation that causes hypercapnea and hyperthermia (>104째 F) in affected horses when exposed to anesthetic gases, such as Halothane, or the neuromuscular blocking agent, succinylcholine. This genetic mutation affects fewer than 1% of the quarter horse population and because halothane is not used in most practices anymore, MH is rarely seen.

Hyperkalemia is an electrolyte imbalance that occurs in foals with ruptured bladder, older horses in renal failure, or in horses that are affected with the hyperkalemic periodic paralysis (HYPP) gene.

This gene is present in quarter horses, paints, and Appaloosas that come from the "Impressive" sire.

Due to their docile nature, the quarter horse and paint breeds tend to be easy horses to handle for anesthetic procedures. One consideration for these breeds, however, is the genetic diseases that predispose them to greater anesthetic risk.

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technician update undergo anesthesia, dantrolene should be administered at 4 mg/kg PO, 30-60 minutes prior to induction of anesthesia. If MH is detected intraoperatively, the application of water to the skin, fans and cool IV fluids can be used to decrease the patient's temperature. Alcohol can also be applied to the skin, but watch the fumes! Sodium bicarbonate should also be administered and mechanical ventilation should be performed to decrease CO2 levels.

Management of hyperkalemia due to an HYPP episode relies on the dilution of potassium and the management of CO2 and resulting acidosis. It is important that the patient is as stable as possible prior to induction of anesthesia. Acetazolamide, a potassium-wasting diuretic, should be administered to decrease blood levels of potassium at a dose of 3 mg/kg PO. If a patient is predisposed to HYPP, it is advisable to pre-medicate with calcium gluconate at a dose of 0.2-0.4 mls/kg added to the fluids. This should help to stabilize the cell membrane and reduce the amount of potassium that being leaked from the cell.

If an HYPP episode occurs perioperatively, stabilize the patient. This can be accomplished by administering an isotonic fluid that does not contain potassium, such as 0.9% NaCl to dilute potassium and increase levels of sodium and chloride at a surgical rate. Dextrose can be added to fluids to help drive potassium into the cells. Also, sodium bicarbonate can be administered at a dose of 1-2 mEq/kg IV to

counteract the acidosis that may also be occurring.

Insulin has also been reported to help decrease potassium levels, however, an equine dose has not been established. Finally, the last consideration for the anesthetized HYPP patient is the use of a ventilator to control CO2 levels between 35-45 mmHg, which will also help maintain potassium levels.

If properly managed under anesthesia, a patient that undergoes an HYPP episode during surgery can successfully recover from anesthesia. It is of utmost importance that these patients are minimally stressed during induction and recovery. Recovery from anesthesia should be monitored and the people responsible should be prepared for weakness and the potential for respiratory collapse. It would be recommended to have an emergency tracheotomy kit available in case of stress and respiratory collapse.

The recovery team should also keep the horse as quiet and calm as possible during recovery.

MeV

About the author:

Jessie J. Loberg, BA, AAS, CVT, VTS-EVN, is a faculty instructor at the Bel-Rea Institute of Animal Technology in Denver. She is also the president-elect of the American Association of Equine Veterinary Technicians and Assistants (AAEVT and the president of the Academy of Equine Veterinary Nursing Technicians (AEVNT).

For more information: Bailey JE, Pablo L, Hubbell JA. Hyperkalemic periodic paralysis episode during halothane anesthesia in a horse. JAVMA 1996;208:1859-1865.

Hyperkalemic Periodic Paralysis (HYPP) (2009). UC Davis Veterinary Medicine, Veterinary Genetics Laboratory. August 2011 @ http://www.vgl.ucdavis.edu/services/hypp.php.

Orsini JA, Divers TJ. Manual of Equine Emergencies Treatment and Procedures, 2nd Edition. Saunders 2003 Spier SJ (2007). HYPP: getting to grips with Hyperkalemic Periodic Paralysis. Retrieved August 2011 from http://www.Horsetalk.co.nz

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based methods are used to inform management decisions may help increase public confidence in the Wild Horse and Burro Program.

news notes

I

could use the best science available to improve n 1971 Congress tasked the Bureau of Land management of horses and burros on the range.

Management (BLM) with the “protection, In fulfilling its task, the committee’s goal is to management, and control of wild free-roaming provide BLM with tools that could be used to horses and burros on public lands.” BLM is also decrease the use of and spending on holding responsible for managing these lands for other uses, facilities and to manage healthy populations on such as recreation, mining, forestry, livestock the range. grazing, and habitat for wildlife. Managing these sometimes competing interests and maintaining a “thriving natural ecological To see a video about this study go to The U.S. Bureau of Land Management's balance on public lands,” as(BLM) the law http://www.youtube.com/watch?v=phwOcmY2PsE&feature=youtu.be 45∞N current practice ofmandates, removing free-ranging horses from has proved challenging. public lands promotes high population growthBLM rate, To amaintain that balance, and maintaining them in long-term holding facilities established Herd Management is both economically unsustainable and incongruent Areas in locations where the with public expectations, according to a new report by horses and burros were found in the National Research Council.

1971 and limited them to these 40∞N The report said that tools already exist for BLM areas.

Horses and burros are to better manage horses and burros on healthy ecoup (gathered) and systems, enhancerounded public engagement and confidence, removed when a thriving natural and make the program more financially sustainable. ecological balance is threatened.

It also provides evidence-based approaches that if WildtheHorse and Burro implemented couldThe improve management of these Program is facing a financial animals on public lands in the West.

35∞N crisishorse because most animals Most free-ranging populations are growing Management at 15-20% a year,removed meaningfrom theseHerd populations could Areas are not adopted by private double in four years and triple in six years. With no inowners.

Thepopulation expense will of main120∞W 115∞W 110∞W tervention by BLM, the horse increase taining unadopted animals in to the point of self-limitation, where both degradation Figure 1. This map shows Herd Management Areas managed together or with This map shows Herd long-term holding facilities for of the land and high rates of horse mortality will occur butU.S. cautioned that scaling up use theseTerritories methodsastocomplexes.

Forest Service Wild Horse (or of Burro) Aggregating Management Areas the rest of their lives consumes due to inadequate forage and water, the report said. theneighboring larger and Herd moreManagement disseminated horse in Areas on populations which free movement of horses or burros managed together known orU.S. likely into Management Area complexes data quality about half of theinprogram’s In addition, periodic droughts the West cause theiswestern will beHerd challenging, ” said Guy Palm- can orimprove with U.S. Forest and enhance population management.

Herd Management Areas shown in white are immediate and often unpredictable impacts.

There is er, DVM, PhD, director of the school of global animal budget.

The National Research Service Wild Horse not managed as part of a complex. SOURCE: Mapping data and complex little if any publicCouncil support committee for allowing was thesetasked impacts health at Washington State University and chair of the (or Burro) Territories information provided by the Bureau of Land Management. as complexes. Aggreon either the horse or the landBLM to take study committee. withpopulation investigating ways SOURCE: Mapping data and complex information provided by the Bureau of Land Management.

New report offers science-based strategies for managing free-ranging horses and burros

HMA Complexes

place, and both go against BLM’s program mission.

However, the current removal strategy used by BLM perpetuates the overpopulation problem by maintaining the number of animals at levels below the carrying capacity of the land, protecting the rangeland and the horse population in the short term but resulting in continually high population growth and exacerbating the long-term problem.

To manage horse populations without periodic removals would require widespread and consistent application of birth control, the committee determined.

Three methods in particular — porcine zona pellucida (PZP) and GonaCon for mares and chemical vasectomy for stallions — were identified as effective approaches.

“The committee recommended these approaches based on the evidence of their efficacy with other populations, notably the horses on Assateague Island,

No complex

NV5

OR1

CA1

NV6

OR2

CA2

NV7

OR3

CA3

NV8

UT1

CA4

NV9

UT2

ID1

NV10

UT3

ID2

NV11

W 1

NM1

NV12

W 2

NV1

NV13

W 3

NV2

NV14

W 4

NV3

NV15

NV4

NV16

The committee also strongly recommended that BLM improve and standardize its methodology for estimating population size, stressing the importance of accurate counts as the basis for all management strategies. A large body of scientific literature suggests that the proportion of animals missed in current surveys ranges from 10-50%.

Additionally, an examination of the genetics and health of population groups as well as of the range lands they occupy can be used to assure that both the animal populations and the ecosystem are being appropriately managed. Developing an iterative process whereby public participants could engage with BLM personnel scientists on data gathering and assessment would increase the transparency, quality, and acceptance of BLM's decision-making process.

The study was sponsored by the U.S. Bureau of Land Management.

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gating neighboring Herd Management Areas on which free movement of horses or burros is known or likely into Herd Management Area complexes can improve data quality and enhance population management.

Herd Management Areas shown in white are not managed as part of a complex.

For more information: National Research Council. Using Science to Improve the BLM Wild Horse and Burro Program: A Way Forward. Washington, DC: The National Academies Press, 2013. http://www.nap.edu/catalog.php?record_id=13511 ModernEquineVet.com | Issue 7/2013

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news notes

Heska introduces Element POC blood gas-electrolyte analyzer Heska Corp. launched a new rapid blood analyzer called the Element POC, which is available throughout North America.

This latest generation, handheld, wireless analyzer delivers rapid blood gas, electrolyte, metabolite, and basic blood chemistry testing to the North American veterinary healthcare market, and is available exclusively through Heska.

www.heska.com/Products/Lab-Systems/Element-POC-Analyzer.aspx

The new Element POC is a point of care device that offers superior data management, WiFi and Bluetooth connectivity, and a broad testing menu that includes the critical care parameters valued most by practitioners in one comprehensive, easy to use "credit card" style test card that can be stored at room temperature. Compared to other handheld analyzers on the market, the Element POC may save veterinarians up to 50% on the costs of testing, while improving ease of use and patient outcomes.

“The addition of Element POC to our product line complements our existing chemistry and hematology suite and leapfrogs the competition.

Element POC brings unmatched value and savings by delivering real-time critical care parameters at a price per test that will save veterinarians and their clients thousands of dollars each year. After many years of working towards this point, we at Heska are proud to secure the leadership position by bringing the world's most advanced blood-gas, lactate, electrolyte, metabolite and chemistry point of care testing to the market," said Steve Eyl, executive vice president of commericial operations at Heska.

MeV

New feed available for senior horses Cargill announced it has introduced a new veterinarianrecommended Nutrena SafeChoice Senior horse feed formulated to help improve senior horse nutrition.

SafeChoice Senior is an added-fat, controlled starch, complete feed formula, ideal for senior horses and their unique needs. It is designed for horses 15 years and older, specifically those suffering from unexpected age-related weight loss, decline in energy, difficulty maintaining muscle mass, dull hair coat or having difficulty chewing hay.

The nutritionally balanced feed contains amino acid fortification and higher-fat levels to help maintain energy and manage unwanted weight loss. The controlled starch and sugar design is effective for horses with equine metabolic sensitivities.

SafeChoice Senior boasts balanced Omega 3 and 6 fatty acid levels to help keep inflammation in balance and is enriched

with essential amino acids to support muscle maintenance.

The feed also contains Nutri-Bloom Advantage, which research shows should supported to improve fiber digestion by up to 15% through support of the digestive tract, as well as pre and probiotics.

SafeChoice Senior was developed at the Cargill Innovation campus in Elk River, Minn., and through strategic partnerships with several universities and horse owners.

“This latest innovation from the SafeChoice line marks a major step forward for senior horse nutrition,” said Jackie Rieck, marketing manager for Nutrena feeds. “We are committed to continually testing new ways to provide better nutrition for horses, and we are excited to bring this new product to our favorite senior horses.”

MeV www.cargill.com/news/releases/2013/NA3076683.jsp