TheModernEquineVetAug12 by The Modern Equine Vet

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Equine Vet www.modernequinevet.com

Not Little Adults:

Lab results in foals New Kissing Spine Surgery Prevent training interruptions BFFS Stop Billing

August 2012 | Vol1 No3

Table of Contents

Cover story

8 Not little adults Laboratories report foal results referenced to normal adult values. Yet, many are different in foals.

orthopedics

Less invasive surgery for kissing spines............................................ 4 New technique provides long-lasting pain relief

Prosthesis for minature donkey........................................................... 7 Success has implicaations for rehabilitation of other equids

Technician Update

Collect payment at time of service....................................................18 Steps to changing the paradigm

behavior

Training modifications..................................11 Decisions crucial in developing horseâ&#x20AC;&#x2122;s potiential

BFFS

16 Equids like to be among their own kind Infectious diseases

14 Not all cases of Potomac fever near water 13 Rise in West Nile cases LEGAL DISCLAIMER: The content in the digital content is for general informational purposes only. PercyBo Publishing 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 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 Publishing. The content is for veterinary professionals. ALL RIGHTS RESERVED. Reproduction in whole or in part without permission is prohibited.

August 2012 | ModernEquineVet.com

ModernEquineVet.com | August 2012

orthopedics

Less

invasive surgery to treat kissing

A new surgical technique has been developed for treating overriding of the dorsal spinous processes (ORDSP), or kissing spine, which is less invasive and costly than traditional surgical techniques. Kissing spines is a common cause of equine back pain. Many veterinarians first try conservative and medical treatment, which involves injecting the spine with corticosteroids to decrease inflammation, sometimes adding bisphosphonates for pain. These treatments often are followed with rehabilitation therapy. Although they do treat the pain, the success of such conservative treatment can be short lived, and many horses eventually require surgery. Horses typically do better with surgery than conservative or medical therapy, according to Richard P. C. Coomer, MA, Vet MB Cert ES, DECVS, of the Cotts Equine Hospital in Narberth, U.K. Traditional surgery requires a resection of the DSP using either an oscillating saw or osteotome and hammer, or a Radiographic images or pre- and postoperative cases of kissing spines, which is an impingement of the summits of the dorsal spines beneath the saddle area causing back pain in some horses. The goal of surgery is to relieve the crowding of the spines.

August 2012 | ModernEquineVet.com

By Marie Rosenthal, MS

spines A

Technique provides long-term relief of back pain from ORDSP.

A: Standing on the left side, horses head left, a spinal needle is placed directly into the affected space on dorsal midline ot allow triangulation using the Mayo scissors. B: Finished surgical site, showing five operated spaces, each closed with simple interupted sutures in four metric monofilament nylon.

endoscopy under general anesthesia. Coomer and his colleagues developed a new technique called interspinous ligament desmotomy (ISLD), which aims to relieve tension on the afferent nociceptive receptors — those receptors that react to noxious stimuli — located in the ligament insertion, which eliminates the sensation of pain. The researchers recently compared ISLD with intralesional corticosteroid treatment in 68 horses with kissing spine and

reported their results recently in Veterinary Surgery. Thirty-eight horses received medical treatment of methylprednisolone administered in 1 to 7 spaces and 37 horses received ISLD in 3 to 8 spaces. In addition to medical or surgical treatment, all horses received controlled exercise and returned to work within 6 weeks after treatment. Although the pain resolved in 34 horses treated medically, the back pain recurred in 19 cases.

Back pain resolved in 35 of the surgical cases without any recurrence of pain. “By combining this [ISLD] with a controlled exercise program to release epaxial muscular spasm, permanent resolution of kissing spines was achieved,” the researchers wrote. Horses were sedated with a routine α-2 agonist and opiate, and the surgical site was marked with a sterile skin staple 6 cm abaxial to midline on the right side, where the surgeon could feel it ModernEquineVet.com | August 2012

orthopedics

Radiographic images of pre- and postoperative cases of kissing spines. This new technique aims to remove pain and facilitate spinal remobilization, rather than physically creating new space between the dorsal spines.

beneath the drape. Using Mayo scissors, the surgeons created a path through the top of the interspinous ligament (ISL) before cutting ventrally to divide the interspinous ligaments; the supraspinous ligament was left intact. They sutured the incision and applied a sterile adhesive dressing for 24 hours. Most horses were discharged on the day of surgery with prophylactic enrofloxacin (given for 5 days) and titrated doses of phenylbutazone for 10 days. Sutures were removed between 12 to 14 days. The horses that received the ISLD were 24 times more likely to experience a long-term reso-

“

The clinician has to be happy with the

diagnosis of kissing spines, and this is a learning curve of interpretation.

”

Richard P.C. Coomer

lution of their back pain over horses that received medical treatment. In addition, the horses showed radiographic improvement with a significant widening of the interspinous spaces. Coomer told The Modern Equine Vet that he would recommend ISLD over medical treatment “in any horse with back pain and x-ray signs of kissing spines.” The trick is in diagnosing kissing spine in the first place. “The clinician has to be happy with the diagnosis of kissing spines, and this is a learning curve of interpretation,” he said. Some owners decline surgery because of the cost. However, in his clinic ISLD costs about the same as two medical treatments, according to Coomer, making it fairly cost effective. In the United Kingdom, steroid medication would cost about the equivalent of $550, surgery about $1,100 to treat 5 spaces, not including the initial assessment and radiographs, physiotherapy and hospitalization costs on top, he explained. “Physiotherapy is optional and hospitalization only used for horses coming from away. We do most of these operations on an outpatient basis. Surgery cases typically range from £350 to £1,000 ($860-$1,570),” he said. There is a learning curve. “My early success rates were as good as now,” he said, “but I’m much quicker now. It is a conceptually simple, but deceptively tricky surgery, but most trained surgeons would have no difficulty.” MeV

For more information: Coomer RPC, McKane SA, Smith N, Vandeweerd JME. A controlled study evaluating a novel surgical treatment for kissing spines in standing sedated horses. Vet Surg. 2012 Jun 25. doi: 10.1111/j.1532-950X.2012.01013.x. http://www.ncbi.nlm.nih.gov/pubmed/22731872 6

August 2012 | ModernEquineVet.com

orthopedics

Auburn University’s College of Veterinary MediThe prosthesis is made of carbon fiber, Kevlar and cine and the Hanger Clinic, formerly Hanger Prosthetfiberglass, materials that are strong and extremely light, ics and Orthotics, are working on a case that could and the same materials used for prostheses for Paralymhave implications in the treatment and rehabilitation of pic athletes. The materials are also flexible and adjustequines with congenital deformities or injuries. able to allow for growth and progression in Emma’s gait. Emma, a miniature donkey foal, arrived at the John Thomas Vaughan Large Animal Teaching Hospital with a severe hind limb deformity that required amputation of the limb and the placement of a prosthesis. Surgeon Fred Caldwell, DVM, DACVS, assistant professor in the department of clinical sciences, performed the procedure and worked with clinician Billy Fletcher from Hanger Clinic. “Billy was excited and enthusiastic to assist,” Caldwell said. “Once we proceeded with the surEmma in action, using her prosthetic limb. gery and amputated the distal limb, he provided a small footplate to incorporate into the cast to even out the length of her hind limbs so she could bear weight until we could A closer look at Emma’s first prosthetic device. As she grows, she could get the surgical site healed and have transition through eight or nine variations of the prosthesis before reaching full growth. her fitted with a prosthesis. It has been a group effort on behalf of many caring individuals willing to go to great lengths to The first finished prossave her.” thesis weighed less than The practice of using prostheses with large a pound; the most recent equines is relatively uncommon due to size and iteration, which is pink, weight-bearing limitations. Because Emma is a minis smaller, but weighs iature donkey, she will be fairly small as an adult, a little more to provide weighing about 350 lbs full grown. stability as she’s grown Auburn University’s Dr. Fred Caldwell and Dr. Elizabeth Yorke with Emma. Emma is now 11 weeks old and has thrived with taller and almost doubled her prosthesis. “She absolutely loved it from the gether weight since surgery. go,” Caldwell said. “It was a very impressive design “The next step is trying to make sure we keep the and she did very well in it. She has progressed to the prosthesis set up so she’s ambulatory and she can run second iteration of her prosthesis, which doesn’t incorand play and do things uninhibited, but also, to keep porate as much of the limb and allows her more range the area of concern, the surgical site, offloaded so Dr. of motion. She is getting stronger; she’s growing and Caldwell can do his job in keeping her completely doing wonderfully.” healed,” Fletcher said. MeV Fletcher, who sees patients in the Opelika, Ala. and — From a story by Carol Nelson, Office of Communications & Marketing, Columbus, Ga. Hanger Clinic locations, said that as Auburn University Emma grows, she could transition through eight or nine variations of the prosthesis before reaching full growth. At that point, she will be fitted with a piece that View a video at is more permanent. http://ocm.auburn.edu/featured_story/saving_emma.html.

ModernEquineVet.com | August 2012

All images courtesy of Auburn University.

Miniature donkey receives second prosthetic limb

cover story

Neonatal foals:

Not little adults Laboratories report foal results referenced to normal adult values. Yet, many values are different in the foal. B y

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R o s e n t h a l ,

Zagorulko Anton/Shutterstock

Every veterinarian orders blood

tests when they assess a critical foal. When reading the results, remember that laboratories often report foal results referenced to normal values in adult horses, not juveniles, said Debra C. Sellon, DVM, PhD, DACVIM, who spoke recently at the 2012 AVMA Convention in San Diego. “For most laboratories that veterinarians use, the reference ranges that you receive are for adult horses. If you are not aware of the differences, it could lead to an incorrect diagnosis or inappropriate treatment, or an unnecessary treatment in many cases. Being aware of the differences in reference ranges helps us be more accurate in our assessments,” said Sellon, who is pro-

August 2012 | ModernEquineVet.com

M S

fessor of veterinary clinical sciences at Washington State University, College of Veterinary Medicine.

Red Blood Cells

Ask the lab to provide cytology results, as well as, reference ranges for blood work, she suggested, because the morphology of the cells can provide information. “A CBC is not complete unless you have someone who can look at the cells,” she said. Foals tend to have smaller red blood cells (RBC) than adult horses. Therefore, the total RBC will be higher. It takes about a year for those cells to become as large as an adult’s RBCs. There are usually three values that veterinarians look at concerning the RBCs — the total red cell

count, the hemoglobin count, and the packed cell volume. The number of RBCs is very important in determining how much oxygen is in the blood. “When foals are born, their packed cell tends to be on the high side because of the placental transfer of blood,” she said. Often veterinarians think the critical neonate that is only 1 or 2 hours old needs fluids, but they don’t usually. “Rarely does a foal need highvolume fluid resuscitation at birth. And they are not usually hypoglycemic because they have blood glucose that they shared with mom. Fluids do decline pretty quickly over the first few days, and the packed cells start to drop,” she said. An important value that is often overlooked is the mean corpuscular hemoglobin concentration, which looks at the concentration per volume. Because the foal’s RBCs are smaller than an adult, it has fewer hemoglobin molecules in each cell, but the concentration or the amount of hemoglobin per volume is the same.

The mean cell volume at birth is close to normal, but over the first few days, it drops until it actually goes below what would be considered adult normal. It takes quite some time before those numbers get back up to the normal range. “Iron in foals turns out to be important, and there are a number of ways we can go wrong therapeutically and diagnostically,” Sellon said. Generally, horses consume a lot of iron in their diet, because almost all the food they eat contains iron. Normal adult horses are rarely deficient in iron because of dietary problems. Iron attaches to transferrin and travels around the body to the organs. Iron’s primary purpose is to help make red blood cells. Once the horse has enough iron to produce a

good supply of red cells, it starts to store it. Storage forms are largely ferritin, which is stored in the liver and bone marrow. Relatively little iron is in the free form. The serum iron in foals is high. The saturation of iron indicates how much iron is attached to transferrin. In the first three days of life, foals can have almost 100% saturation. Therefore, foals do not need iron supplementation, especially in the first few days of life. “If you give oral iron to foals at this stage of life, there is no transferrin to buffer that iron. Since it cannot attach to transferrin, you get free iron, which is hepatic toxic,” she warned. After a few days, the saturation numbers will decrease to the adult values. In adults, about one-third of transferrin has iron attached to it. When they get a little older — past that first week or so — foals might develop an iron deficiency, but they do not need it when they are only a few days old. The total iron content in the body affects how much transferrin is present. When the iron is depleted, the body cranks out transferrin, which looks for iron to attach to it. If less than one-third of transferrin has iron attached to it, it could signal the older foal is iron deficient. “We found that this is not un-

common in foals that are housed indoors, and we now watch it very closely in critical care foals, particularly those that are on milk replacement instead of mom’s milk and are not outside where they can ingest dirt,” she said. A study of warmbloods in Europe looked at horses that are raised in box stalls versus those that are allowed out on the paddock. The study’s purpose was to assess whether raising the horses in box stalls had a negative impact on orthopedic disease, but they also found some interesting facts about the horses’ blood work. After 1 to 3 months of age, foals that were raised in stalls the entire time or most of the time had a lower total serum iron than foals that were raised in the pasture. When the foals were allowed access to pasture, they returned to normal within a month or so. “If you have foals that live primarily inside, especially if they are inside without access to dirt, you need to watch them for iron deficiency,” she said. “You can use oral supplementation, but you want to be careful that you use just enough oral supplementation to give the appropriate amount for body weight. I never recommend doing this cavalierly because they are quite suffiModernEquineVet.com | August 2012

cover story

cient in iron for the first few days of life.

White blood cells

Veterinarians usually keep a close eye on the white blood cell (WBC) count because they are worried about infection, particularly sepsis. When the foal is in utero, the WBC count is low. Then, there is a surge of cortisol that helps to stimulate delivery, but it also stimulates the production of WBCs. When a foal is born, it has a normal WBC. Normal foals have a neutrophil to lymphocyte ratio >2.5 at birth, but it can be much lower in premature foals because the adrenal cortex is relatively unresponsive to adrenocorticotrophic hormone (ACTH). “If the foal is not quite ready for birth for whatever reason, the foal would not have received that cortisol surge, and the neutrophil count will be quite low. They will have a much lower N:L ratio. The problem with this is that septic foals can also have a really low neutrophil count because they are septic. So, it can be hard to tell whether that neutrophil count is low because they weren’t ready for birth or because they were septic,” Sellon said. A low WBC count in premature foals is a bad prognostic indicator. Although a high level of neutrophils can indicate a disease process, it also indicates that the immune system can mount a response, she explained.

Proteins

Many actions take place in the critical foal that has an infection, as the body tries to mount a response. Anytime bacteria come into the blood, they stimulate immune cells and macrophages that express many molecules to go after the bacteria and that sets up the release of many cytokines. The inflammatory molecules 10

August 2012 | ModernEquineVet.com

interact with all the cells in the body. One of those molecules, interleukin-6 (IL-6), will stimulate the liver, which will decrease some proteins and increase others. Albumin levels will decline. This is important if the veterinarian is planning on prescribing medications that are protein

Prognostic Indicators Critical care in neonates is expensive, and veterinarians can help guide owners to make better decisions if they recognize some prognostic indicators from the hematology and blood chemistry results. Here are 3 bad prognostic indicators: 1. Low WBC count - Premature foals born with a higher WBC count have a better chance of survival than foals that maintain low neutrophil counts, especially if that white count stays low over the a few days. 2. Blood glucose concentrations that are either too high or too low 3. High lactate, which signals poor cardiovascular function

bound. If there is less albumin, there will be less protein binding of the drug, and there will be more free drug, which can increase the adverse event profile of the drug in foals. Another protein that decreases with infection is transferrin because bacteria need iron to replicate. Serum amyloid A is another molecule that is becoming more important in assessing foals. Levels should go up quite a bit with infection, but come down rapidly

if the foal is responding to treatment. Not all laboratories report serum amyloid A, however, so ask about it and encourage the reporting of that number, she suggested. Two enzymes on the chemistry panel are significantly different in foals than adults. Foals have quite high alkaline phosphatase (AP) up to 1,000 or more, primarily due to the rapid development of bone. “No matter how high it is,” she said, “it could be normal for that foal.” Gamma glutamyl transferase (GGT) tends to be quite high in foals between 2-8 weeks of age, even in foals with normal livers. “If you do a panel in foals be prepared for a high GGT that is often normal,” she said. “It usually comes back down about 6 weeks of age.” Blood glucose concentrations can be all over the map. However, if the blood glucose is very high or very low, especially very low, this can be a poor prognostic indicator, she said. Lactate is a good indicator of cardiovascular function and perfusion. The higher the lactate, the lower the survival rate because the cardiovascular function is poor, she said. The blood pressure is low, and they are not able to perfuse. The lower the lactate, the higher the blood pressure. Monitoring the heart rate is less productive, she added. “Critical care in foals is really expensive, and we can guide the owners. In some foals, it doesn’t matter what the chances are, we just have to try, and in others, owners really need to know before they invest the money,” she said. The laboratory results can help guide owners in making the right decisions, she said, but remember to review those results with the little patients in mind, not adult horses. MeV

behavior

Training program

modifications might prevent interruptions Racehorse owners want horses

that race, and yet, many horses in training fail to start in a race. A new study shows that the decisions made by trainers are crucial in allowing horses to fulfill their racing potential. A group of researchers in New Zealand performed a prospective cohort study to collect data about training activities of 2-year-old Thoroughbreds. They studied 205 horses across 14 trainers for two racing seasons. â&#x20AC;&#x153;Some 2-year-old horses are able to start training and progress

Many horses never fulfill their racing potential By Marie Rosenthal, MS straight to a trial without any breaks during training, whereas, other horses experience a break during training before they reach their first trial,â&#x20AC;? explained Charlotte

Bolwell, PhD, MSc, a research officer at Massey University in New Zealand. A trial race is an important milestone in New Zealand, Bolwell said, it is a race without betting and allows the horses to get some experience before racing for purses. Bolwell and her colleagues wanted to know what lead to interruptions in training to reduce the number of lost training days and increase the proportion of horses that progress to their first trail uneventfully. They recorded daily training data for each horse, including

TheModernEquineVet.com | August 2012

behavior

distances worked at canter, highspeed exercise and reasons why training was interrupted. They analyzed the data to see if the interruptions in training were due to musculoskeletal injury or a trainer’s decision to stop training (voluntary interruption with no known condition or disease present). Out of the 205 horses, there were 134 interruptions. Training was interrupted at least 134 times before the first trial start; 115 were voluntary

es that were younger than 2 years old when they started their training. “Most horses entered training before they were officially 2 years old and the risk of a voluntary interruption decreased as the age of the horse at the start of training increased,” the researchers

Gender seemed to be the biggest risk factor for interruptions due to musculoskeletal injury with females being less likely to interrupt training due to an injury than males. Another study by Bolwell and her colleagues that looked at yearling exercise during sales

The primary reason for voluntary interruptions were do to a trainer’s decision to give the horse a break.

and 19 were due to musculoskeletal injury. Voluntary interruptions appear to be based on the trainer’s decision to give the horse a rest from training, often because the trainers felt the horses were not mature enough for the regimen. The trainers frequently noted that the horse needed to “strengthen and grow” or “mature,” according to the researchers. This frequently occurred in hors-

wrote in the New Zealand Veterinary Journal. However, it might still be worthwhile to bring younger horses to the track to give them time to acclimate to the routine. “Some trainers use this initial time in the stable for education and to allow the horse time to become familiar with the stable routines and track work,” she explained. “The results show that the primary reason for voluntary interruptions were due to a ‘break’ as part of the trainers’ methods or practices. There may be an opportunity to look at the structure of trainers’ programs and the timing of these interruptions during the training program so that 2-year-old horses are kept in training until after the first trial start.”

show preparation suggested that early conditioning might play a role in future training and racing ability. Bolwell said that she is still studying this observation. “No association was seen between distance worked at canter or the number of high-speed events and the interruptions due to musculoskeletal injury, however, the study had low numbers of these interruptions, and there may not have been enough power to detect any significant associations,” she said. Different factors were associated with whether a horse had a voluntary break from training or a break due to injury. Trainers might be able to modify some of the factors to reduce the number of lost training days and the costs associated with those lost training days. MeV

For more information: Bolwell CF, Rogers CW, French NP, Firth EC. Risk Factors for interruptions to training occurring before the first trial start of a 2-year-old Thoroughbred racehorses. NZ Vet J. 2012 Jul;60(4):241-6. http://www.ncbi.nlm.nih.gov/pubmed/22712776 Bolwell CF, Rogers CW, French NP, Firth EC. Exercise in Thoroughbred yearlings during sales preparation: A cohort study. Equine Vet J. 2012 Jan;44(1):20-4. doi: 10.1111/j.2042-3306.2011.00370.x. Epub 2011 Jun 8. http://www.ncbi.nlm.nih.gov/pubmed/21649716 Find more information about the work being done at Massey Equine Research. erc.massey.ac.nz 12

August 2012 | ModernEquineVet.com

news notes

The CDC recently reported that this season is one of the worst for human cases of West Nile Virus (WNV) since the virus was first discovered in 1999. As of the end of August, the CDC reported 1,118 human cases of West Nile virus disease, and more than 40 have died. About 75% of the cases have been reported from five states (Texas, Mississippi, Louisiana, South Dakota and Oklahoma) and almost half of the cases have been reported from Texas. Forty-seven states have reported WNV in people, birds or mosquitoes. Horses are also susceptible to this disease and many states have reported equine cases (See map), including the five listed above. Although the CDC uses the term “veterinary” cases for any non-human mammal cases of WNV, 99.9% of veterinary cases occur in horses, according to the CDC. However a few cases have been reported in dogs, bears, bats, etc. thus the broader label. Last year, 87 equine WNV cases were reported in 30 states. So far, this year, there have been more than

Map courtesy of CDC

Rise in West Nile Threat

75 cases of equine WNV reported in 19 states. Besides vaccination, take steps to eliminate mosquito breeding sites — get rid of standing water! Because equine veterinarians work outside, they should take steps to protect themselves from mosquito bites. People and animals should stay inside during mosquito feeding times, typically early morning and evening, and use mosquito repellents. MeV

Justin Black/Shutterstock

Consider vaccinating alpacas against WNV Colorado State University veterinarians are recommending the use of equine West Nile vaccines to help prevent the virus in alpacas. Although llamas seem to be fairly resistant to developing severe disease signs, the disease can be fatal in alpacas. “Transmission of the virus varies from year to year and depends on a number of factors, including mosquito numbers, but it is present again this year in Colorado livestock. Four equine cases of West Nile disease have been diagnosed in horses from Fremont, Weld, and Montrose counties in Colorado so

far this season,” said Rob Callan, DVM, PhD, head of Colorado State’s Livestock Veterinary Service at the Veterinary Teaching Hospital. WNV is carried by infected birds and is spread locally by mosquitoes that bite infected birds. Bites from infected mosquitoes can then pass the virus to humans and animals. Based on the limited data available, vaccination of alpacas against West Nile virus is recommended between 4-16 months of age. However, this is an offlabel use of the vaccine. MeV

ModernEquineVet.com | August 2012

infectious diseases

Horses infected with

Potomac horse fever may not live near water

Different Neorickettsia species infect certain veterbrates, but not others. B

Although Potomac horse fever usually is associated with waterways, cases can occur in horses that don’t live near a river or stream, according to a review of the disease by several parasitologists and vector biologists. “Despite its common name, transmission cycles of Potomac horse fever are not restricted to only rivers and streams, but can also occur in lakes and even on dry land far away from water,” Jefferson A. Vaughan, PhD, MS, professor of biology at the University of North Dakota. Potomac horse fever (also called equine monocytic ehrlichiosis) is a potentially fatal febrile disease caused by the intracellular bacteria Neorickettsia risticii, which are normally endosymbiotic within digeneans (think Wolbachia and heartworm). The disease got its name from the first cases reported in the 1970s — a group of horses surrounding the Potomac River in the DC area. Since that time, cases have been reported throughout the United States, Brazil and South Korea, according to the chapter in 14

August 2012 | ModernEquineVet.com

Advances in Parasitology. Although there has been considerable research on neorickettsial diseases, few have looked at the quantitative aspects of transmission of these bacteria and their ecological and evolutionary interrelationships with their invertebrate and vertebrate hosts. This is

Potomac horse fever is a potentially fatal febrile disease caused by the intracellular bacteria Neorickettsia risticii.

what Vaughan and his colleagues attempted to do in this report. They found that for Potomac horse fever: •N . risticii is the most geographically widespread of the Neorickettsia species • N. risticii infects the greatest phylogenetic range of Digenea than any other species of Neorickettsia. •N . risticii is unique in that the horse is a ‘dead-end’ host for the digenean vector of the neorickettsia. Digeneans have never been reported from horses that have been autopsied after dying from Potomac horse fever. •P otomac horse fever may have come originally from South America. Digenean flukes are the vector of N. risticii. “Neorickettsia are unique among the Anaplasmataceae in that both vertical transmission and horizontal transmission (at least from fluke to vertebrate) have been documented,” the scientists wrote. There are biological differences

Courtesy of Advances in Parasitology

among the neorickettsial species, and different species produce illness within certain vertebrate species, but not others. For example, N. sennetsu causes disease in people, but not horses, while N. risticii causes disease in horses but not people. Yet, if horses are inoculated with N. sennetsu, they develop immunity against N. risticii, according to the article. Bats and swallows are one of the primary hosts of adult flukes that carry N. risticii. Fluke eggs containing neorickettsiae are passed out with the host feces. If they end up in a stream or pond, the hatchlings will use freshwater snails as intermediary hosts. When the weather warms, a new batch of parasite larvae known as cercariae leave the snail and enter the water where they penetrate and encyst within aquatic insects, such as caddis flies and mayflies, which are the secondary intermediate host. The bat or swallow eats the insects, reacquiring the fluke. Horses are believed to be dead-end hosts in the complex life cycle of the fluke parasite but can still become infected with the bacteria by accidently ingesting parasite-infected caddis flies and mayflies. “A sort of Trojan horse within a Trojan horse within a horse,” Vaughan joked. Clinical signs of this vectorborne disease include fever, depression, anorexia and colitis accompanied by acute diarrhea. More severe disease has caused laminitis and abortions. The disease can be fatal with mortality approaching 30% if the infected horse doesn’t receive antibiotics. This recent review was based on a biological viewpoint, rather than the clinical characteristics of the neorickettsia disease, Vaughan said. MeV

Life cycle N. risticii

Bats and swallows are one of the primary hosts of adult flukes that carry N. risticii. Fluke eggs containing neorickettsiae are passed out with the host feces and if they end up in a stream or pond, the hatchlings will use freshwater snails as intermediary hosts. When the weather warms, a new batch of parasite larvae known as cercariae leave the snail and enter the water where they penetrate and encyst within aquatic insects, such as caddis flies and mayflies, which are the secondary intermediate host. The bat or swallow eats the insects, reacquiring the fluke. Horses are believed to be deadend hosts in the complex life cycle of the fluke parasite but can still become infected with the bacteria by accidently ingesting parasite-infected caddis flies and mayflies. “

For more information: Vaughan JA, Tkach VV, Greiman SE. Neorickettsial endosymbionts of the digenea: diversity, transmission and distribution. Adv Parasitol. 2012;79:253-97. http://www.ncbi.nlm.nih.gov/pubmed/22726644 Tkach VV, Schroeder JA, Greiman SE, JA Vaughan. New genetic lineages, host associations and circulation pathways of Neorickettsia endosymbionts of digeneans. Acta Parasitologica 2012, 57(3): 285–292. DOI: 10.2478/s11686-012-0043-4; ISSN 1230-2821 ModernEquineVet.com | August 2012

behavior

Apples and oranges:

Equid species like to be Horses, mules and donkeys are often housed together and treated the same. They shouldn’t be. B y

M a r i e

R o s e n t h a l ,

Although donkeys and mules can be useful as companion animals for horses, a new study suggests that they really prefer to be with their own kind. The animals are not homogenous, and they display different social hierarchy, according to Leanne Proops, PhD, a specialist in social cognition in horses.

Donkey Sanctuary’s Axnoller Farm in Dorset. “We wanted to know which individuals were the highest ranking, who their close associates were and the extent to which the group as a whole, and the different subgroups of equines, adhered to a strict dominance hi-

They should not be considered an homogenous group, and where possible should be housed with

”

members of their own subspecies.

Elnur /ShutterStock

“

“Horses, mules and donkeys have different social structures, differing levels of dominance and prefer to form bonds with members of their own subspecies,” said Proops, from the school of psychology at the University of Exeter in the U.K. In this study, Proops and her colleagues observed the social interactions of a group of 16 mules, donkeys and horses housed at The

August 2012 | ModernEquineVet.com

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Leanne Proops, PhD erarchy,” Proops told The Modern Equine Vet. “All the incidences of aggression in the group — who attacked whom and the response of the victim, as well as which individuals spent their time

in close proximity to each other were noted. “Horses, donkeys and mules are often housed together and treated the same,” she said. Many of the donkeys, mules and horses had bonded closely with a member of a different equid subspecies before coming to the sanctuary. Former owners often described the original companions as “inseparable,” she said. Yet, they immediately found new friends of the same equid type as themselves when housed with

among their own kind members of their own subspecies. “We wanted to document this observation to improve their welfare, to highlight that these equines are different; that they have different social structures, dominance levels and friendship preferences,” she said. After monitoring the animals for 70 hours, they found that the original observation was true: different equids formed distinctive affiliations with members of their own subspecies. The researchers also learned that the groups were ordered

in a hierarchy with ponies being the most dominant, followed by mules and donkeys in that order. They recorded 675 aggressive behaviors and 638 submission behaviors. Of these, less than 10% were contrary to the established hierarchy. In most cases, the ponies dominated over the others. The researchers found significant differences in rank among the equid groups, but not between genders. The mixed group did not appear to link age or height to rank, but height was important to rank within the pony group. The researchers were a little surprised that they did not see a correlation between age or sex and rank or affiliation, but they thought perhaps the sample size was too small for these factors to be seen. The strength of the hierarchy varied within each equid subgroup, she said, with ponies having the most linear hierarchy and donkeys having the least linear hierarchy. Mules came somewhere in between and tended to follow the pony structure. “Each group displayed different social organization and levels of dominance and preferred to associate with animals of the

same equid type if given the opportunity,” the researchers wrote in Behavioural Processes. Although the equids formed distinctive affiliations with their own subgroups, the mules tended to spend more time close to the ponies compared with the donkeys, the researchers observed. This could be a factor of “child” rearing. Since mules are a hybrid of a female horse and male donkey, they would have been raised by a female horse, hence the affinity for ponies. Hinnies, on the other hand are a hybrid of a female donkey and a male horse, and they tend to prefer donkeys over horses. Although equids are often housed together, this study shows that they really like to be among their own subspecies if given the opportunity. Therefore, it might be appropriate to house them with members of their own subspecies, Proops suggested. “They should not be considered an homogenous group, and where possible should be housed with members of their own subspecies,” she said. MeV

For more information: Proops L, Burden F, Osthaus B. Social relations in a mixed group of mules, ponies and donkeys reflect differences in equid type. Behav Processes. 2012 Jul;90(3):337-42. Epub 2012 Apr 3. Abstract available. http://www.ncbi.nlm.nih.gov/pubmed/22709577 ModernEquineVet.com | August 2012

technician update

Small animal practices tend to do

a better job collecting payment at time of service than equine practices do, Sherri L. Rigby, DVM, PhD, DACT, told a group of veterinary technicians at the AVMA Convention held recently in San Diego. “Some equine practices have been slow to move to collecting payment at time of service, and there are several reasons.

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August 2012 | ModernEquineVet.com

she said. “Every practice should provide an estimate up front.” Equine veterinarians have a different historic relationship with their clients than companion animal veterinarians have. The typical equine client used to be a farmer who received payments in lump sums and then would pay off all his vendors. Veterinarians used to oblige the farmers with monthly billing, expecting that the farmer would pay the bill before the end of the year. Equine clients today tend to be people who have jobs, a steady income and credit cards,” Rigby said. “Why are we still doing monthly billing statements and not expecting payment at the time of service?” She asked. Many veterinarians make an assumption about what a client is willing to pay for a patient’s care, instead of assessing the value of the veterinarian’s services. But no

For one thing, changing business practices takes time and training of the team. For some, talking about money with clients is not easy.” said Rigby, who is the area manager East, Veterinary Technical Services at Bayer HealthCare. The cost to treat a critically ill horse can be considerable and sometimes exceeds the monetary value of the horse, but that does not mean the owner will refuse to pay those costs. Veterinarians and technicians should not prejudge owners and assume that they won’t pay their fees. Instead, they should provide the owner or the owner’s agent with the available options for the medical care of the horse, as well as an estimate of what those options will cost. “Estimates are very important,”

DenisNata /ShutterStock

Collect payment at time of service

veterinarian can tell by looking at the client how much that client is willing to spend on the animal, she said. People have different ideas about what is considered expensive. Some people would not pay $200 for a pocketbook; others pay $3,000. Money carries a lot of emotional baggage and means something different to each person, she reminded. For instance, a person who considers money as a bartering tool to get goods and services will feel differently about how that money is spent than someone who considers money a security blanket. In addition, the economic downturn has had a profound effect on people’s purchasing decisions. More people are sav-

People have different ideas about what is considered expensive. Some people would not pay $200 for a pocketbook; others pay $3,000. ing money, and fewer people are spending beyond their means. The economy has also had a profound

effect on some owners’ ability to pay for the horse’s medical care, even if they want to spend that money. Some just can’t afford it. The degree of emotional attachment to the animal, as well as the owner’s view about whether the animal is “just an animal” or a family member also play into the decision to spend money on the animal’s health care. That range is broad and goes from “horses are just animals” and large amounts of money should not be spent on them to “my horse is part of the family” and no amount of money is too much to spend. Rigby cautioned veterinarians and veterinary technicians about passing judgment on clients that don’t want to spend their money on the horse’s health care.

6 Steps to Collect

Have clear practice policies

Establish clear billing and payment policies

Agree to be consistent

Clarify who discusses money issues with the client and back that person up

Ensure the practice team is trained about the new policy and knows how to discuss fees

Practice leadership must support and enforce the policies.

ModernEquineVet.com | August 2012

technician update

“We cannot be judgmental because we encounter someone who does not want to spend the money on the horse,” she said. “And that can be hard for us to accept because we view that horse differently from the owner. In equine practice, we typically view all horses as our patients, and we value most

all of our patients similarly. Each owner has his or her own perspective of the horse’s monetary value versus their emotional bond to the horse. We must realize each perspective is valid.” Some veterinarians become very defensive when they bring up money because they are afraid that cli-

Be a vet not a bank

Carsten Reisinger/ShutterStock

If the veterinary practice is going to act like a bank, it should use some of the tools that banks use, such as charging clients finance charges for balances carried over 30 days or a billing fee if they don’t pay the entire bill when the service is performed. Sherri L. Rigby, DVM, PhD, DACT, suggested that all invoices have a tear-off stub with the option to pay by credit card. These stubs help ensure payment is credited to the correct account and may encourage clients who have cash in their bank accounts to make a payment using their credit card rather than missing a payment. “Credit cards are an invaluable collection tool,” she said. “But if you take credit cards you have an obligation to keep that information secure and to check periodically that the credit card is still good and that the owner still wants veterinary charges made to that card.” If clients can’t pay there are options other than bankrolling the client. • Perhaps, they can get a loan from a family member. • Use a credit agency, such as Care Credit, which provide low-interest loans to help pay for vet bills. Also ask about insurance. If the owner has insurance on the horse, find out what kind of insurance and the complete information about that insurance. “People need to know they have options, but veterinarians don’t have to be the bank,” said Rigby.

August 2012 | ModernEquineVet.com

ents will think they don’t care about the horse; they only care about the money. Rigby said that often happens with owners, too. They think if they ask how much a service costs, the veterinarian will think they don’t care about the horse. This misperception could be cleared up if people would just communicate with each other, she said. Since 2002, Bayer Animal Health has partnered with the Institute for Healthcare Communication to develop the Bayer Communication Project (vetcommunications. org). This communication skills training program is intended to help veterinary students, veterinarians and veterinary technicians enhance their communication skills, thus, leading to better health outcomes for the patient and the veterinary practice. For some veterinary health care team members and horse owners, conversations about money are the most difficult ones to have. To make an informed decision, owners need to know and understand all of their options, the likely outcome of the medical intervention and any complications or changes in the horse’s activity. They also need to have an honest estimate of the costs, with the caveat that the costs could increase with unforeseen setbacks or complications. Be clear at the outset what complications can occur. Never underestimate the cost of a service. Don’t talk about how expensive a procedure will be, instead describe recommended health care options and the financial aspect of those options. “Optimal health care of the horse and the veterinary practice depends on the veterinarian and veterinary technicians learning to communicate effectively with clients,” she said. MeV

the FEED bag

Avoid certain Mediterranean tall fescue varieties By Marie Rosenthal, MS Equine fescue edema can result from grazing on Mediterranean tall fescue varieties that contain a natural insecticide. Mediterranean tall fescue varieties are grown in temperate climates. Horses that graze on other types of fescue have not been affected. Because equine fescue edema can be fatal, veterinarians should respond immediately if they suspect the disease. However, the edema is slight, so

cides that protect the plant. The Max P/Max Q endophyte only produces small amounts of this substance when it is growing inside Continental tall fescue varieties, but it produces large amounts of this substance when it is growing inside Mediterranean tall fescue varieties. “Endophytes are passed on to new plants in the seeds that are formed on the existing plants, this makes it very hard to completely remove Max P/ Max Q carrying Mediterranean fescue varieties from their pastures,’” explained Bourke.

Equine fescue edema resulted from a compound inside the plant called N-Acetyl Norloline, which is produced in the grass in large amounts by the Max P endophyte (called Max Q in the United States). it is difficult to see. Australian researcher Christopher A. Bourke, PhD, recommended that vets do blood work to measure blood protein levels and consider plasma fluid therapy if the albumin level falls too low. Bourke a principal research scientist at the Orange Agricultural Institute in New South Wales, Australia, found that equine fescue edema resulted from a compound inside the plant called N-Acetyl Norloline, which is produced in the grass in large amounts by the Max P endophyte (called Max Q in the United States). An endophyte is a fungus that grows inside the plant, producing natural insecti-

Bourke made the discovery after 48 of 56 horses on six Australian farms experienced loss of appetite, depression and swelling of the head, neck, chest and abdomen, while grazing on pastures that contained the Mediterranean tall fescue grass. “The edema that occurs is the result of falling blood albumin levels. It can be seen in the head, neck, brisket and belly areas, but it will also be occurring in the wall of the large bowel and in the wall of the uterus (in mares) but this internal edema will not be visible to the naked eye,” Bourke said. This toxicity is not related to fescue toxicosis, added Bourke MeV

For more information: Bourke CA, Hunt E, Watson R. Fescue-associated oedema of horses grazing on endophyte-inoculated tall fescue grass (Festuca arundinacea) pastures. Aust Vet J. 2009 Dec;87(12):492-8. http://www.ncbi.nlm.nih.gov/pubmed?term=%22Fescue-associated%20oedema%20of%20horses%20grazing%20on%20endophyteinoculated%20tall%20fescue%20grass%20(Festuca%20arundinacea)%20pastures

ModernEquineVeterinarian.com | August 2012

news notes

AAEP Foundation Names Recipients of more than $220,000 in Grant Funds

By Dr. Robert M. Miller

Recipients of more than $220,000 in grant money from the AAEP Foundation are: • AAEP Foundation Laminitis Research Project • AAEP Past Presidents’ Research Fellow • AAEP Student Chapters (Short courses, stipends to attend the AAEP Annual Convention, chapter activity support and scholarships.) • American Veterinary Medical Association Foundation (Congressional Science Fellowship) • American Youth Horse Council (Leadership Symposium) • Christian Veterinary Mission (Fast Horses Seminar in Mongolia) • Equine Research Coordination Group • Equitarian Programs (Workshops and working equid outreach in Mexico and Costa Rica.) • Gambia Horse & Donkey Trust (Disaster Relief) • Grayson-Jockey Club Research Foundation (Equine Research) • Horses and Humans Research Foundation (Research for rehabilitation for military veterans.) • Markel Insurance Company/AAEP Foundation Student Scholarships • Morris Animal Foundation (Equine Research) • National FFA Organization (Student Workshops)

Dr. Miller’s cartoons and videos are available for sale at www.robertmmiller.com 22

August 2012 | ModernEquineVet.com

•P rofessional Association of Therapeutic Horsemanship International(Conference and Annual Meeting) •R ood and Riddle Foundation (Opportunities in Equine Practice Seminar) • The Race For Education/Platinum Performance/ AAEP Foundation Winner’s Circle Scholarships •U niversity of Kentucky Gluck Equine Research Center (9th International Conference on Equine Infectious Diseases) •U nwanted Horse Coalition and its Operation Gelding Program •W orld Equine Veterinary Association (International Congress) MeV

USA Equestrian Trust Supports AAEP Foundation Laminitis Research Project The American Association of Equine Practitioners (AAEP) Foundation recently received a $10,000 grant from the USA Equestrian Trust (USAET) to support The Laminitis Research Project. Launched in 2011, the laminitis project aims to establish research to find good solutions for laminitis. The project’s first study, “A Case-Control Study of Pasture- and Endocrinopathy-Associated Laminitis (PEAL) in Horses,” is underway by researchers at Texas A&M University. They are examining the causes of acute laminitis in horses. Initial results are expected in August 2013. Because the foundation has identified epidemiologic studies of laminitis as the highest priority, it established a Laminitis Research Advisory Board, and principal investigator Noah Cohen, VMD, MPH, PhD, DACVIM, developed an investigation strategy with the board. The first study is designed to collect data from naturally occurring first-time cases of acute laminitis not caused by colic, infection or excessive weight-bearing on one limb. Boehringer Ingelheim Vetmedica Inc. and others are supporting this study. MeV

finish line

A friend of mine called the other day to tell me that Sierra died. He had been a good friend to her, and she missed him deeply. Sierra was an older, broken down horse that she bought off a friend, who got him at an auction. He had problems from the get-go. “I had no idea how lame he was until I got him to the farm,” Robin told me. The veterinarian told her that he had navicular disease, which a ferrier helped with special rocker shoes that he wore for many years. Robin finally decided to let Sierra go barefoot, and he seemed more comfortable without shoes. (At least, he didn’t harass the ferrier anymore!) Sierra had no documentation when she got him, so Robin has no idea how old he was, but the veterinarian thought he was about 16 or 17 when she bought him, and she had him 18 years. The first time she showed him a whip, she saw the whites of his eyes and he snorted at her. “It took a lot of love and time to show him that I would never use the whip on him. In later years, he would just walk over and smell the whip and I would scratch his belly with it,” she said. He was the alpha when he was around other horses, so he was kept in his own paddock. But he was good tempered around people, especially if they gave him a treat. Robin loved his soft, beautiful eyes and how he came to trust her over the years. She referred to him as her “1,000 lb dog in disguise.” Just like a dog, he had a good sense of time. Whenever Robin had a lesson with him, he would stop at 45 minutes almost on the dot. After the lesson, he always licked her hand. Her job was pretty stressful, and Sierra was her relief. She loved spending time with him and appreciated how he looked out for her when they were on the trail. She was able to ride him until pretty close to the end. But the last few months, she could only walk and brush him and keep him comfortable. Near the end, he just couldn’t get up anymore, and the veterinarian had to put him down. “I would have gotten him those wheels they use for dogs if I could have,” she said. She loved him that much. That sentiment reinforced something I heard at AVMA this month. Veterinarians often are reluctant to recommend treatments that are expensive because Robin and Sierra they are afraid clients won’t pay for them. Yet, here was an old horse that certainly wasn’t “worth” the value of the veterinary care, except to my friend Robin. To Robin, he was a good friend and family member, and if she could have provided a good quality of life, she would have kept him. I had a big dog that was diagnosed with cancer when he was 10 years old. I spent $5,000 on cancer treatments, and he lived three months. If his quality of life had been good, I would have kept up the treatments, regardless of the cost. He was my once in a lifetime dog. Provide owners with all the information they need to make informed decisions. Tell them their options, possible outcomes, and be honest about the cost, so they can make a decision that is right for them. But ultimately, the cost is not your problem. It’s theirs. Whether it’s a Thoroughbred or an old backyard horse the kids ride on Saturday, you can’t tell what an owner is willing to spend, because you have no idea what that animal means to that person. And remember that not every owner is in the financial position to help horses that are critically ill. Don’t condemn them for not mortgaging their home or dipping in the kid’s college fund for the horse. Sometimes they can’t, even if they love the animal. Sierra was a sweetheart, and I’m so glad he gave my friend pleasure for so many years.

Photo by David Adams

Don’t be too quick to judge clients

Marie Rosenthal, MS Editor The Modern Equine Veterinarian ModernEquineVet.com | August 2012

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