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• 2007–2008 Short Courses Offered by Colorado State University
• Eye on Clinical Research
  • Cryptorchidism
  • EHV Study Hopes to Better Understand Infection Pathway
  • Intestinal Adsorbent Holds Promise for Foal Diarrhea
• Pain-foal: WSU Study Results in New Guidelines for Controlling Pain in Neonatal Foals
• Virginia-Maryland Regional College of Veterinary Medicine Researchers Lead Pioneering Study in Equine Obesity

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2007–2008 Short Courses Offered by Colorado State University 

Colorado State University Equine Sciences is pleased to announce the dates of the 2007-2008 Equine Reproduction Short Courses, presented by the CSU Equine Reproduction Lab in Fort Collins, Colorado.

New for 2007: CSU Annual Equine Reproduction Symposium

Topic: The Problem Mare and Stallion, September 30–October 1, 2007

Equine Reproductive Ultrasonography, October 2, 2007

Equine Embryo Transfer, October 3−5, 2007

Reproductive Management & Artificial Insemination, November 1−4, 2007 and January 10−13, 2008

Techniques for Handling & Utilizing Cooled Semen, November 5, 2007 and January 14, 2008

Techniques for Handling & Utilizing Frozen Semen, November 6, 2007 and January 15, 2008

Colorado State University's Equine Reproduction Short Courses began in 1971 with one artificial insemination course and four participants. The series now has an annual attendance of more than 300 horse owners and veterinarians from all over the world. One distinguishing feature of these courses is a blending of time spent in lecture with time spent at the Equine Reproduction Laboratory applying new knowledge through active participation or demonstration. Approximately half of participants' time is spent in laboratory sessions.

Registration is now open! Please visit www.csuequine.com or contact the Short Course Coordinator for more information.

Short Course Coordinator

Equine Sciences Program

Colorado State University

Fort Collins, CO 80523-1679

970-491-8509 or 491-8373

Fax: 970-491-8419

Email:anna.morrison@colostate.edu

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Eye on Clinical Research 

Equine Hospital, Colorado State University

Cryptorchidism 

by: Dr. JoLynn Joyce

Cryptorchidism has been referred to as the most prevalent nonlethal developmental defect in horses. One reference stated that one of six colts between the ages of 2 and 3 that presented to a veterinary teaching hospital was a cryptorchid. Typically, this is recognized by owners and veterinarians as a failure of one or both testicles to properly descend during or shortly after birth. A complaint of “persistent stallion-like behavior” may be described by owners despite a history of previous castration. In such circumstances, the most likely explanation is incomplete removal of testicular tissue resulting in continued production of sexual hormones.

Historically, the standard approach for surgical correction consists of exploration under general anesthesia. However, more frequently at the Colorado State University Veterinary Medical Center (CSU-VMC), a standing laparoscopic procedure is being performed in which a laparoscopic camera along with instrumentation is inserted into the flank, resulting in complete visualization of potential intraabdominal testicular tissues. This procedure has a wide variety of advantages including better visualization of the reproductive tract, minimal invasiveness, lack of need for general anesthesia, and a quicker return to athletic function.

Recently at the VMC we performed a study evaluating pain responses during standing laparoscopic cryptorchidectomies. With results collected from 20 cryptorchid stallions, we found and developed a protocol for appropriate pain control during the procedure. The results of our study, along with other widespread advantages of standing laparoscopy, has made this technique a favorable alternative for cryptorchid castrations.

EHV Study Hopes to Better Understand Infection Pathway 

Equine herpesvirus (EHV) is an infectious agent that, in its various genotypes, causes a number of diseases in horses, including rhinopneuomonitis, infectious abortion, and infectious spinal cord disease. Dr. Lutz Goehring, an Assistant Professor in Equine Medicine, is studying various aspects of EHV.

“In Holland, where I pursued my PhD, I studied the EHV big picture,” said Dr. Goehring. “I wanted to understand how sequential outbreaks of EHV neurologic disease on a farm interact. It seemed that (true) ponies and young horses were infrequently affected, while aged horses, and particularly the warmblood breeds, the Thoroughbred, draft horse, Quarter Horse, and Standardbred, were most frequently affected compared with most of the pony breeds.”

EHV can infect the blood vessels of the spinal cord, causing a stroke-like phenomenon. Usually multiple sites are affected and the more sites that are affected, the more dramatic the neurologic presentation will be. The virus is transported inside white blood cells to the spinal cord. In most horses, there is circulating equine herpesvirus, but there is very little or no disease. How the virus makes the jump from white blood cells to the spinal cord in certain horses is the focus of Dr. Goehring's research.

“We currently are looking for the pathway that allows the transfer of EHV from the white blood cells into the spinal cord blood vessels in some horses,” said Dr. Goehring. “Our laboratory is culturing the inner cell layer of spinal cord blood vessels for studies in which we try to reproduce the infection of the cells by means of contact with already infected white blood cells. It is challenging; however, we hope to better understand how EHV infects the spinal cord blood vessels and eventually improve the health outcomes for infected horses.”

Intestinal Adsorbent Holds Promise for Foal Diarrhea 

“The early neonatal period (first days to weeks of life) is a critical time for the development of disease in our equine neonates,” said Dr. Jaci Lawler, and Equine Internal Medicine Resident at the Colorado State University Veterinary Medical Center. “Foals are particularly susceptible to a variety of pathogens at this time.”

One important cause for concern is neonatal diarrhea. It can result in significant illness, including severe dehydration and multiple organ disease.

One of the major causes of foal diarrhea is Clostridium perfringens, an intestinal tract bacterium. Dr. Lawler noted that the organism causes diarrhea through the production of toxins, which damage the gut wall, allowing leakage of proteins and fluids from the gastrointestinal tract.

“Although occurrence is sporadic, the disease can be associated with significant death losses,” said Dr. Lawler. “Pioneering research at CSU has resulted in the development of specialized tests which can detect the type of toxin produced by the Clostridial bacteria, information useful for the management of the disease.”

It is particularly challenging to try to prevent and control this disease because there is no licensed equine vaccine and the bacteria can normally be found in the soil and gastrointestinal tracts of healthy adult horses and foals. CSU researchers are investigating the use of intestinal adsorbents as a potential treatment for this sometimes life-threatening condition.

Dr. Lawler recently conducted research to evaluate the ability of a clay product, given orally, to bind major Clostridial toxins. Laboratory results showed that this product, commercially available as Bio-Sponge (Platinum Performance, Inc.), effectively bound such toxins. Additionally, Bio-Sponge did not interfere with antibody adsorption by the equine neonate and did not result in failure of passive transfer (FPT).

Bio-Sponge may help reduce the incidence of equine neonatal clostridial enterocolitis and that is exciting news for horse owners and veterinarians,” said Dr. Lawler. “Early intervention is still the most important factor for successful outcomes as intestinal adsorbents cannot replace fluid losses and antibiotics.”

Reprinted from: Equine Hospital Newsletter, Spring/Summer 2007, Veterinary Medical Center, James L. Voss Veterinary Teaching Hospital, College of Veterinary Medicine and Biomedical Sciences, Colorado State University

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Pain-foal: WSU Study Results in New Guidelines for Controlling Pain in Neonatal Foals 

For several years, equine researchers at Washington State University have led investigations into new ways to control pain in horses. Recently, Dr. Marta Gonzalez Arguedas, a WSU equine medicine resident, completed a clinical trial that for the first time gives veterinarians insights into a drug called butorphanol that is commonly used to treat pain and produce sedation in neonatal or newborn foals. Neonatal pain management is a relatively new area of interest within human medicine, and it is almost nonexistent in horses.

“We wanted to extend our studies to look at foals, because our current understanding of equine neonatal pain is minimal,” said Dr. Debra Sellon, a WSU board-certified equine medicine specialist and professor who has studied pain management in adult horses.

“There have been studies on pain management in older horses, but none of these reports has addressed the difficulties in recognizing, assessing, and treating pain in neonatal foals,” Dr. Gonzalez said. “Drugs used for pain management in adult horses cause different physiological, behavioral, and pharmacological effects than in foals. Unfortunately, equine practitioners often have to rely on data obtained from adult horses or other species when administering pain medications in neonatal foals. But extrapolating drug dosages for use in foals from established adult horse doses is often not valid.”

Additionally, there are few options when choosing pain medications for use in newborn foals. Classes of drugs such as nonsteroidal antiinflammatory drugs (NSAIDs) and alpha-2-agonists can produce more severe adverse effects in sick or compromised foals than in adults. Another class of drug, called opioids, has been the therapeutic mainstay for pain management in neonatal humans, and can control moderate and even severe pain.

“Because we did not know much about the use of opioids and pain management in neonatal foals, I did a lot of research and reading about pain assessment and management in infants,” she said, “Hopefully, the years of study and research on neonatal pain in humans can be used by equine neonatologists as a framework for further research in equine neonatology. The clinical situations are similar because newborn infants cannot communicate with words that they are in pain, so their doctors have to interpret what they are feeling.”

The original clinical trial conducted at WSU was designed to evaluate the behavioral and physiologic effects that butorphanol, an opioid drug, had on neonatal foals. It was also designed to observe the pharmacokinetic effects, or how long it took the drug to be absorbed, distributed, metabolized, and excreted from a foal's blood after it was administered either intravenously or intramuscularly. Butorphanol has been determined to be an effective drug in treating pain in adult horses, but it can cause them to display excitement or become more active.

“We were surprised with some of the effects butorphanol had on foals,” Dr. Gonzalez said. “It caused them to become sedated, rather than more active, and also increased their appetite and caused them to spend more time nursing than our control group. It didn't cause much change in their heart rate or respiratory rate, which is good for foals that are already sick because it does not compromise them.”

Butorphanol is a narcotic and only available for use by a veterinarian or under the direct supervision of a veterinarian.

“This study will provide veterinarians with better information and data on when and how much butorphanol to give neonatal foals,” Dr. Sellon said. “It is hard to know for sure if a foal is in pain, but there are a lot of medical conditions that we expect to cause pain, such as any type of injury, joint infections, or surgery. The results of this study were very helpful, and we are now studying the effects of other drugs in foals.”

Dr. Gonzalez presented these findings at the annual American College of Veterinary Internal Medicine conference in Seattle in June, and the study will be submitted for publication this year. The project, which began in 2005, was funded by the Morris Animal Foundation and the WSU Mary V. Schindler Equine Research Endowment. For more information about pain management options for horses and foals, contact Dr. Debra Sellon at dsellon@vetmed.wsu.edu, or the WSU Veterinary Teaching Hospital at 509-335-0711.

Reprinted from: Equine News, Summer 2007, Vol. 4, Number 3, Washington State University College of Veterinary Medicine

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Virginia-Maryland Regional College of Veterinary Medicine Researchers Lead Pioneering Study in Equine Obesity 

Press Release

America's growing obesity problem has alarmed physicians and public health officials, and veterinarians have recently focused attention on fat dogs and cats. Now, a team of researchers in the Virginia-Maryland Regional College of Veterinary Medicine and the College of Agriculture and Life Sciences at Virginia Tech has determined that horses are also facing serious health risks because of obesity.

Fifty-one percent of the horses evaluated during the pioneering study were determined to be overweight or obese and may be subject to serious health problems such as laminitis and hyperinsulinemia. Just as with humans, the culprits appear to be overeating and lack of exercise.

“This study documented that this is an extremely important problem in horses that has been under-reported,” said Dr. Craig Thatcher, a professor in the veterinary college's Department of Large Animal Clinical Sciences and Diplomate in the American College of Veterinary Nutrition.

Thatcher and his colleagues believe the study results suggest that horse owners should change some of the ways in which they care for their horses and hinted that horses could emerge as an important model for studying the health implications of human obesity.

“Obesity, over the past decade, has become a major health concern in horses,” said Dr. Scott Pleasant, an associate professor in Department of Large Animal Clinical Sciences and Diplomate in the American College of Veterinary Surgeons. “This is primarily because of its association with problems such as insulin resistance and laminitis.”

In fact, it was a spike in pasture-associated laminitis cases that led Pleasant to grow curious and seek the collaboration of Thatcher, an internationally renowned veterinary nutritionist, on the innovative research project. Dr. Ray Geor, the Paul Mellon Distinguished Professor of Agriculture in the College of Agriculture and Life Sciences and director of the Middleburg Agricultural Research and Extension Center in Middleburg, Virginia, and Dr. Francois Elvinger, an epidemiologist and associate professor in the Department of Large Animal Clinical Sciences, also worked on the study.

“Laminitis is a failure of the connective tissue bond between the horse's hoof and the bone within the hoof,” explains Pleasant, noting the highly publicized struggle that the racehorse Barbaro had with the disorder as a result of his catastrophic injury at the 2006 Preakness.

“When that bond fails, and the hoof and bone start to fall apart, it is extremely painful to the horse,” he continued. “Laminitis is one of the most devastating and debilitating problems that we see with the horse.”

Funded in part by the Virginia Horse Industry Board, the study hypothesized that overweight horses may suffer from insulin and sugar imbalances, chronic inflammation, and oxidative stress, a malady that occurs as a result of changes to metabolic processes that alter the delicate balances between the destruction and creation of new cells in the body.

Other problems caused by equine obesity are heat stress, increased bone, tendon, and joint injuries, and reduced performance levels.

Until now, only one other study had looked at obesity in horses. A 1998 owner-reported survey of horse-owners conducted by the USDA's National Animal Health Monitoring System (NAHMS) suggested approximately 5% of horses were overweight.

Based on the horses routinely seen through clinical practice in the Veterinary Teaching Hospital, however, the researchers suspected the incidence might be higher. “We thought it was at a level of at least 15%,” said Thatcher.

The research team designed a prospective study and examined 300 horses from 114 different farms chosen randomly from approximately 1,000 horses that have been treated through the college's Equine Field Service program.

Two independent body-conditioning scores (BCS), which assess the amount of fat cover on the horses, were assigned to each animal. Each horse was checked for signs of laminitis, and blood was drawn to assess glucose and insulin levels as well as other hormones, cytokines, and oxidative biomarkers.

Although laboratory testing and data analysis are still underway, the research team already has made some alarming discoveries.

Fifty-one percent of the horses in the study were found to be overweight, and 19 percent were found to be obese. Eighteen percent of the overweight horses and 32% of the obese horses were hyperinsulinemic.

The study also suggests that equine obesity may result from natural grazing behavior instead of the overfeeding of grains and other feed supplements, which defies conventional thinking on equine weight matters. Most of the horses examined in the study were fed primarily pasture and hay with very little grain and concentrate.

Instead of overfeeding of grain and concentrates, the evidence indicates that improved forage and lack of exercise are the two most common contributing factors in equine obesity.

Horses today are managed much differently from their evolutionary roots, indicated Pleasant. “The horse evolved as a free-roaming grazer on sparse pasture types,” he said. Later the horse served primarily as a work animal, serving as a source of transportation and draft power. Today, most horses serve as companions and light performance animals,” he said.

This research project remains underway and has laid the groundwork for a series of provocative new studies.

“Other studies by our group have clearly shown that obesity and insulin resistance are important risk factors for pasture-associated laminitis. This study underscores the importance of obesity to equine health,” says Geor, noting that current studies are further exploring how obesity, diet, and exercise management alter insulin resistance and therefore the susceptibility of horses and ponies to laminitis. The goal is development of management strategies that assist in the avoidance of this devastating disease.

The researchers are now focusing more specifically on the role of hormone levels, oxidative stress, inflammatory biomarkers, and antioxidant mechanisms. However, the preliminary data clearly demonstrate that this research has important implications for both equine and human health.

The Virginia-Maryland Regional College of Veterinary Medicine (VMRCVM) is a two-state, three-campus professional school operated by the land-grant universities of Virginia Tech in Blacksburg and the University of Maryland at College Park. Its flagship facilities, based at Virginia Tech, include the Veterinary Teaching Hospital, which treats more than 40,000 animals annually. Other campuses include the Marion duPont Scott Equine Medical Center in Leesburg, Va., and the Avrum Gudelsky Veterinary Center at College Park, home of the Center for Government and Corporate Veterinary Medicine. The VMRCVM annually enrolls approximately 500 Doctor of Veterinary Medicine and graduate students, is a leading biomedical and clinical research center, and provides professional continuing education services for veterinarians practicing throughout the two states. Virginia Tech, the most comprehensive university in Virginia, is dedicated to quality, innovation, and results to the commonwealth, the nation, and the world.

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• Craig Thatcher (middle) and Scott Pleasant (right) measure a horse for their obesity study among horses.