The Modern Equine Vet June 2015

The Modern

Equine Vet www.modernequinevet.com

Vol 5 Issue 6 2015

Medical management of colic

Keeping an eye on the antifungals Foal with botulism

Table of Contents

Cover story:

4 Medical management of colic on the farm

Cover: Bob Langrish/www.boblangrish.com

Orthopedics

Compensatory lameness underappreciated...................................................................8 ophthalmology

Keeping an eye on the antifungals.................................................................................10 case presentation

Foal with botulism.................................................................................................................15 News

FDA releases Veterinary Feed Directive final rule.......................................3 Survival, fertility and uterine torsion.......................................................13 BIVI appoints new equine, cattle leadership........................................13 The hairy past........................................................................................................14

advertisers Shanks Veterinary Equipment.................................. 3 Luitpold Animal Health.............................................. 7

AAEVT............................................................................12

The Modern

Equine Vet Sales: Robin Geller • newbucks99@yahoo.com Editor: Marie Rosenthal • mrosenthal@percybo.com Art Director: Jennifer Barlow • jbarlow@percybo.com contributing writerS: Paul Basillo • Kathleen Ogle COPY EDITOR: Patty Wall Published by PO Box 935 • Morrisville, PA 19067 Marie Rosenthal and Jennifer Barlow, Publishers percybo media  publishing

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news notes

FDA releases Veterinary Feed Directive final rule The FDA recently announced the Veterinary Feed Directive (VFD) final rule, an important piece of the agency’s overall strategy to promote the judicious use of antimicrobials in food-producing animals. This strategy brings the use of these drugs under veterinary supervision so that they are used only when necessary for assuring animal health.

The VFD final rule outlines the process for authorizing use of VFD drugs (animal drugs intended for use in or on animal feed that require the supervision of a licensed veterinarian) and provides veterinarians in all states with a framework for authorizing the use of medically important antimicrobials in feed when needed for specific animal health reasons.

The FDA's final rule brings the use of antibiotics under veterinary supervision, so that they are used only when medically necessary for the animal.

The VFD final rule continues to require veterinarians to issue all VFDs within the context of a veterinarian-client-patient relationship and specifies the key elements that define that relationship.

These key elements include that the veterinarian: • engage with the client (i.e., animal producer or caretaker) to assume responsibility for making clinical judgments about patient health, • have sufficient knowledge of the animal by conducting examinations and/or visits to the facility where the animal is managed, and • provide for any necessary follow-up evaluation or care.

All veterinarians must adhere to a relationship that includes the key elements in the final rule.

“The actions the FDA has taken to date represent important steps toward a fundamental change in how antimicrobials can be legally used in foodproducing animals,” said Michael R. Taylor, FDA deputy commissioner for foods. “The VFD final rule takes another important step by facilitating veterinary oversight in a way that allows for the flexibility needed to accommodate the diversity of

circumstances that veterinarians encounter, while ensuring such oversight is conducted in accordance with nationally consistent principles.”

In December 2013, the agency published a guidance document, which called on animal drug manufacturers of approved medically important antimicrobials that are put into water or feed of food-producing animals to voluntarily stop labeling them as drugs that can be used to promote animal growth and change the labeling of their products for the remaining uses to require veterinary oversight of these drugs when they are used for therapeutic purposes. All of the affected makers of these drugs have committed in writing to participate in the strategy.

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www.shanksvet.com • info@shanksvet.com ModernEquineVet.com | Issue 6/2015

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cover story

Beyond IV saline and mineral oil—

Medical management of colic on the farm In some cases, the bulk of the 'heavy lifting' comes from fluids.

Photo courtesy of Dr. Reuss

It is no secret that equine veter-

inarians spend a lot of time thinking about colic. Estimates of incidence and prevalence vary among regions and causes of colic, but it is reasonable to assume that between three and episodes of colic occur for every 100 horse years.

For those horses that need treatment, this is a lot of fluids at a time when 5 liter IV bags are scarce.

Even if the veterinarian does manage to get his or her hands on a steady supply of IV fluids, that route may not be practical for situations where there is no dedicated stall or if the owner is uncomfortable with ongoing administration.

“We may not have to panic as much as we think,” said Sarah M. Reuss, VMD, DACVIM, of the University of Florida College of

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Veterinary Medicine. “Enteral fluids—those given via nasogastric tube (not IV)—seem almost too good to be true in some respects, but they can get a lot more done than you might expect.”

Goals of therapy

For cases of acute colic where there is a good chance that signs will resolve following medical therapy, the bulk of the heavy lifting comes from fluids. The main goals are to replace ongoing losses and to maintain hydration. Assessment of jugular fill, capillary refill time, and owner-provided history can give you a solid approximation of the horse’s hydration status.

“We know that [hydration status] is important, but we don’t always think of it objectively,”

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said Dr. Reuss at the 60th Annual AAEP Convention in Salt Lake City. “When a horse is dehydrated for any reason, we know they are drawing a lot of intestinal water into the vascular space to preserve volume. We have to take that into account. If an owner says that the horse hasn’t had anything to drink in several days, then the colon is probably vacuum-packed because the horse sucked all the water out of there.”

Maintenance of hydration and support of the cardiovascular status are critical. Rates vary from horse to horse and clinician to clinician, but a good ballpark estimate places the maintenance fluid rate at approximately 50 mL/kg/day for an adult horse. If the horse isn’t eating, that rate is likely to be lower.

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cover story

“You also have to take ongoing losses into account,” Dr. Reuss said.

“Nasogastric reflux and diarrhea are going to increase the horse’s ongoing losses. Remember that lactation can rapidly deplete fluid volume in a mare when she has active colic.”

The ancillary goal of fluid therapy in colicky horses is to hydrate the contents of the horse’s colon. Non-strangulating displacements and impaction are two types of colic that can be treated medically.

Finding a better route

The focal point of Dr. Reuss’ message was that, yes, sterile IV fluids are expensive and can be hard to find, but enteral fluids deserve another look.

There are some contraindications for the enteral route, such as in horses that are so markedly dehydrated that they are in hypovolemic shock. These horses are going to need some sort of IV resuscitation at the start. In addition, putting fluids into a nonfunctional GI tract or in a horse with excessive diarrhea or reflux isn’t going to get you very far.

“Enteral fluids are less expensive and more accessible,” she noted. “They are significantly easier to prepare, they are much more forgiving in terms of bacterial contamination, and you have

DIY Isotonic Enteral Solutions Plain water administered enterally once is an option for some colicky horses, but the potential for electrolyte abnormalities should not be discounted, especially if high doses are indicated in a horse that has been off feed for a number of days. In general, some sort of isotonic crystalloid solution is going to be ideal.

If there is no gram scale, a 60-mL syringe case and a bucket will do.

Fill the case to the flange with light salt, then fill it the rest of the way with regular table salt. After dumping that into bucket, fill the flange halfway with baking soda and dump it in as well. Add 20 L of water, and you have a roughly isotonic solution that is safe to administer enterally.

some leeway if the electrolytes are a little off.”

It is reasonable to assume that in a horse with a functional small intestine, most of the enterally ad-

How Much to Give?

©shutterstock/ file404

Several studies show many different effective rates for dosing enteral fluids for multiple conditions. “I think most people feel comfortable giving at least 5 L enterally at any one given time,” Dr. Sarah M. Reuss said. “With some horses you can try to creep that amount up to about 6 to 10 L per administration via intermittent delivery. Unfortunately, colicky horses with significant ingesta in the colon can tolerate a little less fluid than that, so tailor the use of fluid to the individual horse and use your judgement. If they become painful after administration, check them for reflux.”

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ministered fluid will empty from the stomach within 15 minutes and will begin to arrive in the cecum and colon within 1 to 2 hours.

When the large colon is involved, enteral fluids tend to get to the large colon fairly quickly.

Intermittent vs continuous

“There are benefits for intermittent administration of nasogastric fluids,” Dr. Reuss said. “By overwhelming small intestinal absorption, you are hypothetically going to get a tidal wave of fluid into the colon where it will hopefully rehydrate the horse and move things along. The other benefit to large, intermittent doses is that we are going to stimulate the gastrocolic reflex and hopefully get some motility from that.”

On the other hand, continuous delivery of nasogastric fluids can offer less risk for gastric distention. The caveat is that it is not as easy to check the horse for reflux with a continuous system, and decreased gastric emptying can occur after 72 hours with an indwelling nasogastric tube, so the horse may need a break.

“I am a big proponent of enteral fluids, but they are not perfect,” Dr. Reuss said. “You are going to have self-limiting diarrhea, and there is a chance for epistaxis.

With repeated intubation or longterm indwelling intubation, you might see some rhinitis, pharyngitis, or esophagitis. The biggest problem is explaining to clients that if the horse somehow gets the tube out, then the client needs to call the veterinarian to come back out to the farm and reassess. They can’t just cram it back in there.”

Beyond mineral oil

“Mineral oil is one of the things that clients expect us to administer in the face of colic,” Dr. Reuss said. “We shouldn’t do things

simply to make clients happy, but sometimes you need to appease them a little bit.”

It may be expected, but mineral oil has turned out to be less of the “be-all, end-all” colic treatment. It may provide some lubrication but does not actively break up impactions.

Dr. Reuss does use mineral oil as a marker of transit time. She’ll administer the oil and tell the owner to expect shiny manure or a shiny perineum in about 12 to 24 hours.

If nothing shows at that point, then there are most likely some transit time issues in that horse.

“Mineral oil has often been given as a cathartic, or what we thought was a cathartic,” Dr. Reuss said. “We would give it to

In a medical case of colic, such as non-strangulating displacement, the ancillary goal of fluid therapy in a colicky horse is to hydrate the contents of the horse's colon.

horses who we suspected had gotten into something they shouldn’t have, or if they had a suspected intoxication. We have evidence now that we may need to rethink that theory, especially in cases of blister beetle toxicosis.” A study from Oklahoma State that used rat models actually found that mineral oil was associated with decreased survival times in rats that were treated with mineral oil for cantharidin toxicosis. “We can’t definitively extrapolate from the rat model,” she explained, “But the rats who were administered mineral oil had higher urine cantharidin concentrations than the rats who received Bio-Sponge [Platinum Performance], charcoal, or MeV no intervention at all.”

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orthopedics

Compensatory lameness underappreciated B y The first “law of sides” in

equine veterinary medicine holds that an apparent ipsilateral lameness is likely to be a primary hindlimb lameness with a compensatory— but false—forelimb lameness. The law is well understood, but few studies have been done to categorize it.

As part of a larger study, Sylvia Maliye, BSc, BVM&S, and her colleagues aimed to assess and investigate compensatory lameness to shed some light on the issue.

Dr. Maliye, a veterinarian at the Weipers Centre Equine Veterinary Hospital in Glasgow, Scotland, reported her findings at the annual meeting of the American Association of Equine Practitioners in Salt Lake City.

“Until this study, evidence of compensatory forelimb lameness had been limited to individual

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Researchers sought to establish whether a correlation between hindlimb and compensatory forelimb parameters existed. cases,” Dr. Maliye said. “Clinical hindlimb lameness is assumed to result in compensatory ipsilateral forelimb lameness, but this ‘law of sides’ has not been fully categorized in a significant number of clinical cases.”

Dr. Maliye and her colleagues wanted to establish the characteristics of the compensatory fore-

Study by the Numbers HLO • 19 horses total (7 mares, 10 geldings) • 10 horses with distal tarsal osteoarthritis • 8 horses with suspensory ligament desmitis • 1 horse with thickening of the plantar soft tissues and annular ligament constriction 8

HL with IFL • 10 horses total (6 mares, 4 geldings) • 5 horses with distal tarsal osteoarthritis • 4 horses with suspensory ligament desmitis • 1 horse with plantar proximal P1 fragment

Issue 6/2015 | ModernEquineVet.com

HL with CFL • 8 horses total (3 mares, 5 geldings) • 2 horses with distal tarsal osteoarthritis • 6 horses with suspensory ligament desmitis

limb component in a clinical population to ascertain the effect of hindlimb lameness on head movement and the forelimbs in horses with naturally occurring lameness. They also sought to establish whether a correlation between hindlimb and compensatory forelimb parameters existed, and to identify the proportion of horses exhibiting characteristics of compensatory forelimb lameness.

“My hypothesis was that forelimb lameness due to hindlimb lameness is common and related to an alteration in the loading and weight bearing phases of forelimb movement,” she said.

For the study, 37 clinical cases of hindlimb lameness were identified from September 2011 to October 2014. Horses with hindlimb lameness that had positive response to diagnostic anesthesia were identified. The asymmetry of the pelvic movement needed to be greater than 0.17 and PDMax and PDMin needed to be greater than +/-3 mm to be considered hindlimb lameness. Forelimb lameness was defined as a vector sum (the square root of the sum of HDMax2 and HDMin2) greater than 8.5 mm.

“The lameness investigation was undertaken on a level concrete surface,” Dr. Maliye said.

“The horses needed to provide at least 30 strides for the data to be

Photo courtesy of Dr. Maliye

Dr. Sylvia Maliye used sensors to help determine whether forelimb lameness was related to an alteration in the loading and weight-bearing phases of forelimb movement.

included in the study. All parameters were collected before and after diagnostic anesthesia.”

The hindlimb cases were defined as hindlimb lameness only (HLO), hindlimb lameness with ipsilateral forelimb lameness (HL with IFL), and hindlimb lameness with evidence of contralateral forelimb (HL with CFL) lameness.

“Following diagnostic anesthesia, we found a reduction in head movement asymmetry in the HLIFL and the HO group, but no effect was seen in the HL with CFL group,” Dr. Maliye said. “There was no effect on the head movement asymmetry on the HL with CFL group. There was also a reduction in vector sum in the HLO group and the HL with IFL groups.”

An analysis that drilled down a little more showed no difference in the severity of any of the hindlimb lameness parameters among the groups.

Sensors and Scopes The horses in the study were analyzed using an inertial sensorbased lameness system. The system had been objectively assessed using diagnostic anesthesia of the equine foot in a study in 2013.

An accelerometer is placed on the horse’s head, and gyroscopes are fitted to the right forelimb pastern and between the tuber sacrale.

The sensors measure head height in space (HDMax and HDMin) and pelvic height in space (PDMax and PDMin) during the push-off and impact phases. Vertical head and pelvic movement asymmetry assigned to each limb is also measured.

“Our study showed that one can expect to see changes in head movement in nearly 50% of horses with hindlimb lameness,” she re-

ported. “Ipsilateral forelimb lameness represents 56% of the cases of compensatory lameness. Many horses may not show evidence of forelimb lameness, but the trend is similar. Evidence of subclinical lameness is there, even if it is not a ‘true’ lameness. Even in these horses, one may see a significant change in head movement asymmetry, so it is important to look for subtle changes.”

Results also showed a significant change to the push-off and impact components, as well as head movement asymmetry assigned to the ipsilateral forelimb.

“Compensatory lameness is likely under-recognized,” Dr. Maliye said. “It is a common and important phenomenon affecting all horses on either a clinical or a subclinical level. Compensatory lameness should be considered before deciding which limb is the primarily lame limb.”

MeV ModernEquineVet.com | Issue 6/2015

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ophthalmology

Keeping an eye on

antifungals antifungal medications are not FDA approved for horses, and most of the data behind the drugs comes from in vitro studies that can be difficult to extrapolate to the clinical setting.

Caroline Monk, DVM, and colleagues are attempting to help clinicians navigate the sea of antifungal uncertainty and clarify the data to help them better care for their patients.

Filamentous fungi are the most common culprits behind cases of fungal keratomycosis. Etiologic differentiation can be difficult and time consuming, and susceptibility testing even more so. Varying levels of

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penetration by antifungal medications can cause yet another hurdle in the path to treatment success.

“Resistance is always a possibility,” Dr. Monk said here at the 60th Annual AAEP Convention. “It has been reported in the human literature, and it is probably going to be more prevalent in the equine arena as well.”

Polyenes

Polyenes such as amphotericin B and natamycin target ergosterol in the pathogen’s cell membrane.

Natamycin is the only FDA-approved topical antifungal agent. It is formulated as a 5% suspension.

“Natamycin is sometimes di-

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luted to a 3.3% solution because it is slightly less irritating to the cornea and it is less viscous,” said Dr. Monk, who is a resident in ophthalmology at the University of Florida veterinary hospitals. “This medication has excellent coverage for filamentous fungi. If you’re going with the odds in a horse with keratomycosis, chances are you’re suspecting filamentous fungi.”

Azoles

The azole class of drugs also target ergosterol, but they inhibit its synthesis through the cytochrome P450 system.

Imidazoles are a subgroup of

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Shutterstock/Inge Jansen

Most ophthalmologic topical

Povidone-iodine

Povidone-iodine (Betadine, Purdue products) is an antiseptic agent with antibacterial and antifungal properties. It is widely used as a surgical preparation, but some veterinarians advocate for its use as a therapy.

The application of a 2% dilute povidone-iodine solution every 24 hours has been suggested as a treatment for fungal keratitis, but Dr. Monk explained that this should be limited to adjunctive therapy only.

A large metastudy found that the use of 5% povidone-iodine solution did not reduce the bacterial load in corneal ulcers in humans, most likely due to the lack of pen-

etration to the corneal stroma.

Case Study #1

Silver sulfadiazine (SSD)

Presentation • 16-year-old Paint Horse gelding with a 3-day history of squinting and tearing Diagnosis • Superficial nonhealing ulcer based on history and examination Treatment Plan • Debridement of the ulcer and prophylactic support of the cornea until the wound heals Drug choice • Miconazole 1% ophthalmologic ointment is broad-spectrum and fairly inexpensive. When compounded, it is well-tolerated by the eye. The ointment form will not reach the concentration that may come from a solution, but the ointment will last longer.

Silver sulfadiazine historically has been used as a burn treatment.

It is formulated as a 1% dermatologic cream, and it has broad antibacterial and antifungal activity.

In vitro data are limited in horses, and the evidence behind the use of the drug as an antifungal ophthalmologic agent is inconclusive.

“If finances are a concern, I would recommend silver sulfadiazine over the OTC miconazole preparations,” Dr. Monk said. “A published paper did show that SSD penetrates well into the cornea and covers some of the fungi that are found there. It is probably the safest of the off-label uses.”

Treatment considerations

“The reasons for therapy in patients with fungal keratitis may not be as straightforward as you might think,” she explained.

Prophylactic treatment can be indicated in a patient with a corneal lesion that may not yet be infected with a fungus, but where future infection is a concern. This can happen in tropical or humid areas where fungus is more of a risk, or in patients that have received prior treatment with steroids.

“Empiric treatment is another reason,” Dr. Monk said. “Some subjective characteristics of the ocular lesion lead you to suspect a fungal infection in the absence of conclusive evidence, such as a granular plaque or a deep stromal abscess.”

Actual targeted therapies are cases where a sample has been obtained and infection with a fungus is confirmed via positive cytology, visualized hyphae, or through culture and susceptibility testing.

“The problem with targeted therapy is that sometimes it can take three weeks for fungal culture, and by that time the eye may have already declared itself.”

MeV

Case study #2 Presentation • 8-year-old Warmblood mare with 1-week history of severe ocular pain. Treatment initiated by the referring veterinarian consisted of triple-antibiotic ointment 3 times daily Diagnosis • Deep stromal abscess with secondary uveitis Treatment Plan • Due to location of the lesion, obtaining a sample for identification is not possible. Treatment plan involves controlling the uveitis with flunixin meglumine and atropine and placement of a lavage system for frequent and long-term therapy.

Drug choice • Voriconazole 1% ophthalmologic every 4 hours via lavage system. This drug has excellent penetration to the deep layers of the cornea. It will target most of the fungi implicated in this type of lesion.

Photo courtesy of Dr. Dennis E. Brooks

this class, and miconazole is the most common of these. It is considered to have good coverage for filamentous fungi and fairly good penetration to the deeper layer of the cornea, but questions have been raised about miconazole’s reported activity.

Over-the-counter vaginal and dermatologic miconazole preparations have been used in horses as a cost-effective option, but Dr. Monk noted that these preparations contain benzoic acid, which causes moderate eye irritation.

Triazoles are another subgroup, and are a particular favorite of Dr. Monk. “Itraconazole is the one that most people are familiar with,” she said. “It is occasionally compounded with DSMO to improve penetration, although even then, it has not been found to reach the anterior chamber.”

Studies of itraconazole have found that perhaps it may not be as good of a broad-spectrum choice as it was once thought to be.

Voriconazole is a more recent entry into the field. It has a very wide spectrum of coverage over filamentous fungi, and it also has excellent penetration to the deeper layers of the cornea.

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news notes

Survival, fertility and uterine torsion

Overall rates of survival to discharge for mares and foals were higher than in previous studies, at 90.5% and 82.3%.

Mare age, breed and parity were not found to affect the incidence of uterine torsion.

Overall rates of survival to discharge for mares and foals were higher than in previous studies, at 90.5% and 82.3% respectively. Of the cases that were discharged, all survived to foaling.

The clinics preferred correction and was used in 169 of the affected mares. A small number of difficult cases were treated by ventral midline laparotomy or flank laparotomy under general anesthesia. Two mares were

For more information: Spoormakers TJP, Graat EAM, ter Braake F, et al. Mare and foal survival and subsequent fertility of mares treated for uterine torsion. Equine Vet J 2015 Jan 15. doi: 10.1111/evj.12418.

[Epub ahead of print]. http://onlinelibrary.wiley.com/doi/10.1111/evj.12418/ abstract

euthanized without correction and in one mare, uterine torsion spontaneously resolved. Mare and foal survival were both significantly higher in cases treated by standing flank laparotomy (92.5%, 88%) than other methods (65%, 35%). Stage of gestation had a significant effect on mare and foal survival, with higher survival rates of 95.7% and 90.6% respectively at <320 days of gestation, compared with 73.2% and 56.1% at >320 days. In these later stages of gestation, standing flank laparotomy did not significantly alter survival rates compared with other methods. The degree of rotation of the uterine torsion was also important, with mare and foal survival rates of 97.8% and 90% when rotation was <360⁰, significantly higher than 77.1% and 73.5% when rotation was greater.

Direction of the rotation (clockwise or anti-clockwise) was not a factor.

One hundred and twenty-three mares from the study group were later rebred, 93.5% of them successfully. This was not affected by correction method or stage of gestation at which uterine torsion occurred.

MeV

BIVI appoints new equine, cattle leadership Boehringer Ingelheim Vetmedica Inc. (BIVI) appointed Scott King, DVM, the new director of the U.S. Cattle Marketing team, and Amanda McAvoy as senior associate director of the U.S. Equine Marketing team.

Dr. King previously served as the senior associate director of equine marketing, and brings 15 years of marketing expertise to his new position. Prior to beginning his career at BIVI, Dr. King also held marketing roles at Land O'Lakes-Purina Feed as well Scott King, DVM as at Bayer Animal Health as marketing manager of Director of U.S. Cattle Marketing Equine and Pet Products.

Before his marketing career, Dr. King practiced veterinary medicine for 10 years after graduating from the College of Veterinary Medicine at the University of Missouri, Columbia.

Ms. McAvoy has served as the north-central cattle region manager with BIVI since January 2013.

Previously, she was senior brand manager for Equine Pharmaceuticals, and played a strategic role in the market growth of Prascend (pergolide mesylate).

Amanda McAvoy Prior to joining BIVI, McAvoy was a product Senior Associate Director, manager for Merial Ltd., where she launched Equioxx U.S. Equine Marketing injection and had a role in managing nearly all the company's equine and cattle brands during her six-year term. Preceding her marketing positions, she served as a territory manager for Merial for seven years.

McAvoy holds a bachelor's degree from the University of Missouri, Columbia, in agriculture, with minors in animal science and agricultural economics. MeV ModernEquineVet.com | Issue 6 /2015

Photo courtesy of BIVI

When uterine torsion occurs at less than 320 days of gestation, survival rates are much more favorable than during later stages of gestation, according to a recent study.

If correction by standing flank laparotomy is feasible, there are higher survival rates for both mare and foal compared with cases where other methods have to be used. Uterine torsions over >360⁰ are associated with lower survival rates. Uterine torsion had no deleterious effect on subsequent fertility.

The aim of this retrospective study was to further define survival rates for mares and foals following uterine torsion, and to evaluate the success of correction of uterine torsion by standing flank laparotomy compared with other methods. The clinical records of 189 mares that presented to three referral centers in the Netherlands were analyzed. The researchers found that 77.5% of torsions occurred at <320 days of gestation, the rest at >320 days. The most common degree of torsion was 180–360⁰ (66.9% of mares). The more severe torsions >360⁰ were more common in later stages of gestation.

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news notes

The hairy past — Tail hair as an indicator of behavior and ecology in horses the study of animal nutrition and migration. For the first time, our method makes it possible for the first time to establish exact time lines for an animal’s ecology and behavior. Previous time lines were estimations and not entirely accurate. Now researchers have a relatively simple method with which to correctly interpret their data,” she said.

Special life of wild equids in Mongolia

Tail hair is assumed to provide researchers with information about the ecology and behavior of Przewalski’s horses, wild asses and free-ranging domestic horses in the Mongolian Gobi. All three species share the same habitat in a 9,000 m2 strictly protected area of southwest Mongolia. Closely related species usually compete for food. Moreover, the grassland in the region is quite barren. A key question for the researchers is: “What allows the animals to coexist in this region?” The project is still ongoing.

For the isotope analysis, the tail hair is cut into 1 cm long segments and placed individually in little tin or silver cups before being burnt at a temperature of 1,450° C. Isotopes are then measured in the developing gases using mass spectrometry, a method to sort individual atoms by mass.

Today, isotope analysis is used in many different fields. The method can help to determine the regional origin of animals, food or natural fibres. Isotope analysis is also used to detect cases of doping or environmental contamination.

MeV

For more information: Sturm BM, Pukazhenthi B, Reed D, et al. A protocol to correct for intra- and interspecific variation in tail hair growth to align isotope signatures of segmentally cut tail hair to a common time line. Rapid Commun Mass Spectrom. 2015;29:1047-1054

Photo courtesy of xxxxx

Martina Burnik Šturm and Petra Kaczensky from the Research Institute of Wildlife Ecology at the University of Veterinary Medicine Vienna investigated the ecology of free-ranging horses and wild asses in the Gobi desert of Mongolia. To find out how different wild equid species live together in the Mongolian Gobi, what they eat, drink and how they migrate, the scientists look for answers in hair.

Analyzing the chemical composition of hair by looking at the ratio of different isotopes of hydrogen, oxygen, carbon and nitrogen can provide important insights about water intake, nutrition and habitat.

Dr. Burnik Šturm developed a method to clearly align hair segments to time. The habitat of free-ranging equids in Mongolia helped her in this approach. The Mongolian Gobi is subject to extreme climatic conditions. Temperatures vary greatly at different times of the year, and so does the composition of the chemical elements in the hair. By comparing the isotope data from hair with satellite information freely available from NASA’s Earth Observing System Data and Information System (EOSDIS), she assigned a summer-winter rhythm to each hair. This allowed her to calculate the exact time corresponding to 1 cm of hair.

On average, the tail hair of Mongolian wild asses reaches 1 cm in 19 days. Przewalski’s tail hair takes 17 days and the tail hair of domestic horses only 13 days to grow 1 cm.

“We found that tail hair growth varies greatly among species and even among individuals. To assume that closely related species exhibit similar hair growth rates and to use average growth rates for individuals will most probably lead to incorrect results,” Dr. Burnik Šturm said.

“Isotope analysis of hair is a common method in

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Issue 6/2015 | ModernEquineVet.com

case presentation

Foal with botulism recovers after month-long hospitalization botulism, and PCR testing confirmed that Bossy’s Cookies was positive for Type A botulism, which relaxes the entire muscular system by inhibiting nerve transmission to the muscles. Type A botulism tends to be the most severe form. When treated properly, Type A botulism patients can make a full recovery, but that can take several weeks. Dr. Magdesian, along with resident Dr. Jamie Prutton, fourth-year student Anatasha Plummer and the VMTH patient care team, began treating Bossy’s Cookies with botulism antitoxin and IV penicillin.

Photo courtesy of UC Davis.

Bossy’s Cookies, a newborn pony/Paint cross filly, was brought to the University of California Davis Veterinary Medical Teaching Hospital at 10 days old for a progressive neurological disorder.

Following three days of normal activity after birth, she was down for prolonged periods in her stall, staggering and unable to rise on her own. Her owners initially suspected a neck injury, as she was not able to raise her head or neck, and seemed to have abnormal range of motion through her cervical spine.

If assisted, she could stand and was able to nurse if her head was supported in the proper position, but could not lift her head to reach the udder on her own.

Initially when she went down, her attitude seemed positive and responsive, but Bossy’s Cookies became quieter and weaker as days progressed. She was not standing as long or walking as well, and spent most of her time in lateral recumbency.

Bossy’s Cookies was examined by her veterinarian near her home in the Inland Empire region of Southern California. Radiographs showed no damage to her spine or fractures of any kind. Euthanasia was considered, but her owners decided to take her the 400 miles to UC Davis first.

Bossy’s Cookies was examined by the Large Animal Clinic’s Equine Surgical Emergency and Critical Care Service, as well as the Equine Medicine Service. Gary Magdesian, DVM, an expert in neonatology and critical care, thought that the animal had signs of a neuromuscular disease, especially botulism. He conferred with Bossy’s Cookies veterinarian back home and decided it was worth testing for botulism, which is potentially treatable. Because time is of the essence with botulism, treatment for it began immediately.

Botulism can be a fatal illness caused by a toxin produced by bacteria. In horses, botulism can occur three different ways: 1. toxico-infectious botulism, where young foals eat spores from the environment which proliferate inside their gut, allowing the organism to produce toxins; 2. by eating toxin that’s already been made in spoiled feed or water, generally caused by anaerobic conditions in the feed or the presence of dead animals in the feed; and 3. wound botulism, where a bacterial organism proliferates in a necrotic wound.

Electrophysiology testing conducted by VMTH research associate Dr. Colette Williams and clinician Dr. Monica Aleman was compatible with

After receiving botulism antitoxin and supportive care, Bossy's Cookies is expected to make a complete recovery.

When Bossy’s Cookies first arrived at UC Davis, she was too weak to eat. Tube fed at first, she was able to eat on her own shortly after beginning the botulism antitoxin treatments. She started to make other improvements also—gradually at first, but then more significant strides to indicate a recovery.

Within a week, she made efforts to stand on her own. By two weeks, those efforts became stronger, as she was nearly able to stand. At three weeks, she was able to stand with minor assistance and eager to be up and walking around her stall. By four weeks, Bossy’s Cookies stood on her own and was bright and active. Now at home, she continues to get stronger daily.

Recumbent foals need round the clock care, which Bossy's Cookies could receive at UC Davis.

Dr. Magdesian expects Bossy’s Cookies to make a full recovery.

MeV ModernEquineVet.com | Issue 6/2015

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