university of kentucky gluck equine · and muriel gluck and the horse industry,” said mats...

Gluck Center Celebrates 25 Years of Improving the Health and Well-being of the HorseThe Maxwell H. Gluck Equine Research

Center is celebrating 25 years as a named center focused on improving the health and well-being of the horse. The world-renowned Gluck Center, within the Department of Veterinary Science in the University of Ken-tucky’s College of Agriculture, is the only scientific institute in the United States where virtually all faculty conduct full-time research in equine health and diseases.

Six of the 10 major vaccines currently used to protect against equine infectious diseases were developed by faculty in the Department of Veterinary Science. They are among a long list of other accomplishments with an inter-national impact on equine research.

“The Gluck Center opened its doors 25 years ago, due to the generosity of Maxwell and Muriel Gluck and the horse industry,” said Mats Troedsson, director of the Gluck Center and chair of the Department of Vet-erinary Science. “Landmark discoveries have been made in vaccine research and produc-tion, development of diagnostic tests for infectious diseases, drug detection in racing and performance horses, sequencing of the equine genome, identification and detection of genetic diseases and traits, parasite control and reproductive health and management.”

The Department of Veterinary Science, es-tablished in 1915, has a long history of dis-tinguished service. The Gluck Center capital-ized on the department’s strong foundation to reach major international equine research milestones including:

•Developed diagnostic serological tests for contagious equine metritis (CEM), Tyzzer’s disease, equine protozoal myeloencephalitis (EPM), equine herpesvirus myeloencepha-lopathy, strangles and equine viral arteritis

•Developed enzyme-linked immunosor-bent assay (ELISA) test for drug detection

•Demonstrated the usefulness of artificial lights and progesterone/estradiol treatments for hastening the onset of the breeding sea-son

•Determined the genetic basis for and de-veloped tests for inheritance of certain color coat traits

•Provided leadership in the sequencing of the complete genome of the horse and struc-tural characterization of horse genes

•Key part of a team from the College of Agriculture that performed the definitive ex-periments identifying the cause of Mare Re-productive Loss Syndrome

The Gluck Center faculty continues to con-duct equine research in six targeted areas: genetics and genomics, infectious diseases and immunology, musculoskeletal science, parasitology, pharmacology/toxicology and reproductive health.

The Gluck Center is also a World Organ-isation for Animal Health (O.I.E)-designated reference laboratory for equine rhinopneu-monitis, equine influenza and equine viral arteritis.

“We are facing continuous and new chal-lenges in equine health and well-being with

25 years, p. 4A special 25 years logo (top) was created to mark the Gluck Center’s history and

its future of “Moving Forward.” The late Maxwell and Muriel Gluck (center) donated

$3 million to UK for construction of the facility on the condition the gift be matched by the state and members of the horse industry. (Below) James Bassett III, Muriel Gluck

and former UK President Otis A. Singletary broke ground for the center in 1985.

University of Kentucky GLUCK EQUINE

Research & Service Report

SPRING FEATURESLetter from the Director, p. 3News & Events, 4Infectious Diseases and Immunology, p. 6Parasitology, p. 9Pharmacology/Toxicology, p. 10Reproductive Health, p. 11

VOLUME IV, ISSUE I SPRING 2012www.ca.uky.edu/gluck

BOARD OF DIRECTORS2012

UNIVERSITY OF KENTUCKYGLUCK EQUINE RESEARCH FOUNDATION

Dr. Walter W. Zent, ChairTom Goncharoff, Vice ChairDr. Eli Capilouto, President

Dr. Kumble R. Subbaswamy, Vice PresidentDr. M. Scott Smith, Secretary

Angela Martin, Treasurer

Bruce AddingtonJane Beshear

Dr. Stuart BrownCase Clay

Dr. Nancy CoxDr. Rolf EmbertsonWilliam S. Farish, Jr.

Ginny GrulkeG. Watts Humphrey, Jr.

Lisa LourieDr. Jamie MacLeodDr. Stephen ReedDan RosenbergDr. Robert Stout

David SwitzerOlly Tait

Dr. Mats TroedssonF. E. “Butch” WiseDr. Naoya Yoshida

Chris YoungArt Zubrod

GLUCK EQUINERESEARCH FOUNDATION

FOR MOREINFORMATIONCONTACT:

Dr. Ed SquiresExecutive Director

Jenny BlandfordFoundation Coordinator

Gluck Equine Research Foundation108 Gluck Equine Research CenterLexington, Kentucky 40546-0099

Phone: (859) 218-1089Fax: (859) 257-8542E-mails: [email protected] [email protected]

MAXWELL H. GLUCK EQUINE RESEARCH CENTERhttp://www.ca.uky.edu/gluck

GLUCK EQUINE RESEARCH & SERVICE REPORT The UK Gluck Equine Research & Service Report is produced by UKGERF and the Department of Veterinary Science. It is published twice a year on behalf of all

equine researchers and veterinarians and others in the horse industry who are committed to thecontinued improvements in equine research and technology. Research material is meant to be shared. However,

materials are copyrighted and require reprintpermission from UKGERF. The Gluck Equine Research & Service Report is

available online at: http://www.ca.uky.edu/gluck.

The mission of the Gluck Equine Research Center is scientific discovery, educationand dissemination of knowledge for the benefit of the health and well-being of horses.

GLUCK EQUINE RESEARCH FOUNDATION PAGE 2

About the Gluck Equine Research Foundation

A Letter from the Director

Dr. Mats Troedsson


Thanks to a generous donation by the Gluck family, the Maxwell H. Gluck Equine Research Center opened its doors to a new laboratory and office build-ing to accommodate researchers from the Department of Veterinary Science 25 years ago. During the past 25 years, the Gluck Center has developed into a unique equine research unit within the University of Kentucky College of Agriculture, with internationally-recognized faculty members, research staff and graduate stu-dents devoting all their time to research that benefits the health and well-being of horses around the world.

Great accomplishments have been made by the research groups in the areas of genetics and genomics, infectious diseases and immunology, musculoskeletal sci-ences, parasitology, pharmacology/toxicology and reproductive health. Vaccines and diagnostic tests that are used to prevent and diagnose diseases have been developed, contributions to the sequencing of the equine genome has been made, reference standards have been established for detection of performance enhanc-ing drugs, and causes of costly pregnancy losses have been identified and effective management and treatments have been developed.

Today we are facing continuous and new challenges in equine health and well-being with the threats of new emerging infectious diseases and bacterial resis-tance to antibiotics. Other issues are parasite resistance to dewormers, stricter regulations on medication for race and performance horses, an anticipated flow of genetic information through the sequencing of the equine genome, debili-tating musculoskeletal injuries in the equine athlete, rapidly developing research on regenerative medicine and imminent threats to equine breeding industries by reproductive diseases and abortions. The Gluck Center is well prepared for these challenges. As the only scientific institution in the United States that has faculty working full-time on equine health issues, the Gluck Center will continue to play an important role in the horse and veterinary communities. We are looking for-ward to the next 25 years at the Gluck Center with confidence.

As I have stated so many times before, we could not have accomplished what has been done at the Gluck Center over the past 25 years if we did not have a devoted support from individuals and organizations within the equine commu-nity. Your financial support and contributions has been the engine that drives our research and that eventually benefits the health and well-being of our horses. Your support is more important than ever in these challenging financial times.

Thank you for your past and future contributions to our program!

Dr. Mats Troedsson, DVM, PhD, Dipl. ACTGluck Equine Research Center Director

and Department of Veterinary Science [email protected]


the threats of new emerging infectious diseases, bacterial resistance to antibiotics as well as parasite resistance to deworm-ers, stricter regulations on medication for race and performance horses, an antici-pated flow of genetic information through the sequencing of the equine genome, debilitating musculoskeletal injuries in the equine athlete and imminent threats to equine breeding industries by reproductive diseases and abortions,” Troedsson said. “The Gluck Center is well prepared for these challenges and will continue to play an important role in the horse and veteri-nary communities. We are looking forward to the next 25 years with confidence.”

25 years, continued

Several events are scheduled in conjunc-tion with the 25th anniversary. The year’s events kicked off in January with the in-augural UK Ag Equine Programs’ UK Equine Showcase and 3rd Annual Ken-tucky Breeders’ Short Course at the UK

The Gluck Center opened its doors in 1987.

Veterinary Diagnostic Laboratory. In Feb-ruary, there was a grand opening of the UK Gluck Center Equine Reproduction Facilities at Maine Chance Equine Cam-pus.

Future events this year include: •Gluck Center rededication celebration

July 12 at the Gluck Center •Equine Research Hall of Fame in fall

2012 Groups or individuals wishing to tour the

Gluck Center should contact Jenny Bland-ford at [email protected] or 859-218-1089.

Jenny Blandford is the Gluck Equine Research Foundation Coordinator at the Gluck Center.

UK’s Equine Initiative Renamed UK Ag Equine Programs The University of Kentucky’s Equine

Initiative has changed its name to UK Ag Equine Programs.

The name change was undertaken by the College of Agriculture in consultation with its internal and external stakeholders to better reflect the breadth of equine of-ferings at UK and the college’s long-term commitment to serving the state’s signa-ture equine industry.

The Equine Initiative was launched in 2005 when the College of Agriculture set out to radically change how it served Kentucky’s signature equine industry and provide a suite of services appropriate for a land-grant university. In a nod ac-knowledging the success of those efforts and a continued commitment to the state’s equine industry, the college has adopted a new name to better position its equine programs for continued success.

“In short, we have indeed transformed the ‘initiative’ into established, world-class, service-oriented programs across the board,” said Nancy Cox, PhD, UK College of Agriculture associate dean for research, Kentucky Agricultural Experiment Station director and administrative leader for the UK Ag Equine Programs.

That was a sentiment echoed by Norm Luba, executive director of the North American Equine Ranching Information Council and chair of the College of Agri-culture’s equine advisory committee.

“With remarkable efficiency, the Uni-versity of Kentucky has delivered on its promise of initiating a diverse portfolio of

equine research, teaching and service pro-grams,” he said. “The UK Ag Equine pro-gram is now a permanent resource to the Kentucky horse industry, as well as poised to benefit an international horse industry that looks to Kentucky as the horse capital of the world.”

“The name change reflects the broad na-ture and many areas of expertise, across many departments, of our equine pro-grams at UK,” said Ed Squires, PhD, Dipl. ACT (hon.), director of UK Ag Equine Programs and executive director of the UK Gluck Equine Research Foundation. “We continue our commitment to be a world leader and premier resource for the equine industry.”

Before the formation of the Equine Ini-tiative, a long and storied legacy of world-class equine health and nutrition research was already in place, as well as a handful of successful outreach programs targeted to horse owners. But, despite being located in the “horse capital of the world,” there wasn’t a dedicated undergraduate degree in equine studies. There was also no focal point that would allow the public to access

all of the topnotch equine work produced in the college.

A four-year, standalone undergraduate degree in equine science and management was launched, an internship program cre-ated, several new equine-focused faculty and staff were hired and new outreach programs, such as the successful Horse Pasture Evaluation Program, were created. New partnerships were formed with other equine organizations and other state insti-tutions of higher education.

Seven years later, the undergraduate pro-gram now has more than 220 equine stu-dents enrolled, with half of them coming to Kentucky from out-of-state to pursue their interests in equine undergraduate education and subsequent career opportu-nities. There have been 39 graduates and 94 students complete required internships during that time. New research has been undertaken in areas ranging from equine health to economics.

Several events have been held, includ-ing a series of equine-specific field days, an equine research showcase and series of short courses, equine career fairs and a dis-tinguished lecture series featuring leaders in the equine industry. Additionally, an on-line monthly newsletter about UK equine research was launched and now reaches more than 45,000 monthly subscribers.

The college has begun to transition to the new name and expects this transition to take several months.

Holly Wiemers, MA, is communications direc-tor for UK Ag Equine Programs.


Equine Reproduction Facilities Open at UK’s Maine Chance Equine Campus

The wall in the stallion facility recognizes donors (top). Visitors tour the mare facility during the

grand opening on Feb. 2.

Lloyd’s of London Marks 30th Year of Support to UK Department of Veterinary Science

Lloyd’s, p. 6

A grand opening celebration for Univer-sity of Kentucky’s Equine Reproduction Facilities was held Feb. 2 at UK’s Maine Chance Equine Campus. The celebration recognized the generosity of supporters who funded the remodeling.

The remodeled facilities, consisting of two state-of-the-art barns with laborato-ries, will help faculty at UK’s Maxwell H. Gluck Equine Research Center develop the best equine reproductive research pro-gram in the country and give the Gluck Equine Research Center, an affiliate of UK’s Ag Equine Programs, better oppor-tunities to match the signature equine in-dustry it serves. The mare facility and sepa-rate stallion facility will be used for studies on reproductive health. Laboratory facili-ties have been constructed for handling semen, embryos and reproductive tissues.

Lexington is often viewed as the epicen-ter of the state’s signature equine industry and, as such, reproductive health is of top concern to industry stakeholders.

“This reproductive lab is evidence of the vision of many stakeholders who encour-aged UK to provide research worthy in what is arguably the Thoroughbred repro-duction center of the world,” said Nancy Cox, associate dean for research of UK’s College of Agriculture, Kentucky Agri-cultural Experiment Station director and administrative leader for UK Ag Equine Programs. “We are fortunate to have the leadership of Dr. Mats Troedsson (chair of the Department of Veterinary Science and director of the Gluck Equine Research

Center) and his new team of reproductive researchers to implement this vision in this 21st century facility.”

Major donors who supported remodeling the facilities included area horse farms and organizations, as well as notable equine veterinarians. Donors include: diamond sponsors Lisa and Robert Lourie and Shadwell Farm; platinum sponsors Ash-ford Stud, Darley USA, Flaxman Holdings Limited, G. Watts Humphrey Jr., Kentucky Thoroughbred Association/Kentucky Thoroughbred Owners and Breeders and Walter W. and June Zent; gold sponsors William D. Fishback Jr., Kevin B. Pfiester

and Tom Riddle; silver sponsors Stuart E. Brown II, Ed Squires and Mats Troeds-son; and bronze sponsors Butler Animal Health, Ed Fallon, Luke Fallon, Hancock Farm, Kristina Lu and Peter Morresey.

Funds donated by stakeholders were matched through UK’s research challenge trust fund.

“Bringing state-of-the-art laboratory facilities to the horses at Maine Chance Equine Campus will help us address clini-cal equine reproductive health and fertility issues of importance to the horse indus-try,” Troedsson said.

“This is truly a team effort between vet-erinarians, breeding farms, the University of Kentucky College of Agriculture and the state of Kentucky,” said Squires, di-rector of UK Ag Equine Programs and executive director of the Gluck Equine Research Foundation.

Areas of reproductive health research at the Gluck Equine Research Center in-clude causes, diagnosis and treatment of embryonic and fetal loss in mares; early embryonic development; uterine infection; nutritional effects on reproduction; stal-lion behavior; diagnosis and treatment of fertility problems in stallions; and fescue toxicosis.

Some other issues being addressed in-clude pregnancy losses, high-risk pregnan-cies and methods to enhance fertility of mares and stallions.

Jenny Blandford is the Gluck Equine Research Foundation Coordinator at the Gluck Center.

Global insurer Lloyd’s of London re-cently presented the University of Ken-tucky College of Agriculture a check for $45,000, in continuing support of The Equine Disease Quarterly, an equine health research-based publication produced by the Department of Veterinary Science.

The award-winning publication provides timely, researched-based reports on some of the most important issues facing the equine industry. The publication reaches more than 18,000 readers in 93 countries. Available on the Internet, its articles are regularly abstracted by a variety of scientif-ic and lay equine publications worldwide.

“The continued sponsorship of The

Lloyd’s Equine Disease Quarterly by Lloyd’s of London makes it possible for our Maxwell H. Gluck Equine Research Center to reach the equine community in Kentucky and across the globe with the latest information on equine health,” said UK President Eli Capilouto. “The Gluck Center exemplifies UK’s commit-ment to research that makes a difference in the commonwealth, the nation, and the world.”

Mats Troedsson, DVM, PhD, Dipl. ACT, director of the Gluck Center and chair of the Department of Veterinary science, echoed President Capilouto’s assessment.

“The financial support from Lloyd’s has

allowed us to continuously publish The Equine Disease Quarterly since 1992,” he said. “The newsletter has become a valu-able source of information for the equine veterinary community and the internation-al equine industry. The value of our part-nership with Lloyd’s of London cannot be overemphasized, and we are very thankful to the longstanding support that has made this success possible.”

This donation represents Lloyd’s 30th year of collaboration with the Department of Veterinary Science on research and other activities with nearly $1 million of support.


Infectious Diseases and Immunology

This reproductive season (June 2011–Feb. 2012) the University of Ken-tucky’s Veterinary Diagnostic Laboratory (UKVDL) confirmed 21 cases (as of Feb. 17) of equine leptospiral abortion in the Central Kentucky region. This is the high-est number of cases seen by the laboratory since 31 cases in 2009-2010 and 40 cases in 2006-2007 were diagnosed. Both out-breaks coincided with increased rainfall.

The total number of cases in Kentucky is unknown but the UKVDL receives a high percent of abortions which occur in the Bluegrass region.

Equine leptospirosis is a bacterial dis-ease found worldwide that affects many species, including horses and people. The source of the bacteria is the urine of wild animals including mice, squirrels, fox, skunks, opossums and deer. Other domes-tic species such as cattle, dogs and pigs can also be a source of infection. Horses are infected when bacteria enters through the skin or mucosal membranes of the eye or mouth by contact with blood, urine or tis-sues from infected animals. This infection can also occur when horses splash infected urine into their eyes or by eating hay or feed contaminated by infected urine.

Once infected, horses may experience fever, become listless or may go off their feed. The eyes can become painful, causing swelling, squinting, blinking, cloudiness,

UKVDL Provides Equine Leptospirosis Abortion Update

and tearing. Pregnant mares will often lose their foals late in gestation. Adult horses can die of liver and/or kidney failure and may show jaundice in the latter stages of the disease. If you see any of these signs in your horse, consult with your veterinarian.

The UKVDL can assist veterinarians in the diagnosis of leptospirosis by testing blood and urine for evidence of the dis-ease. In addition, aborted or weak foals that die should be submitted to the labora-tory for a complete necropsy and testing

for the disease. Leptospirosis is a zoonotic disease—one

that can be transmitted from animals to humans. Veterinarians and owners should be sure to use care when handling a suspect animal so as to not be exposed. Use of protective gloves and glasses when work-ing with the animals that have aborted is recommended. Be sure to wash any ex-posed body parts thoroughly with antibac-terial soap. Remove contaminated bedding

Lloyd’s, continued

Lloyd’s of London recently presented the University of Kentucky College of Agriculture

a check for $45,000, in continuing support of The Equine Disease Quarterly, an equine

health research-based publication produced by the Department of Veterinary Science.

Equine Leptospirosis Abortions with FA Confirmation Testby Breeding Season 2006 - 2012

Month

Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May

Abor

tions

0

2

4

6

8

10

12

14

2006-2007 2007-2008 2008-2009 2009-2010 2010-2011 2011-2012

UKVDL confirmed equine leptospirosis abortion cases (by Fluoroscent Antibody testing) from 2006 to the present.

Leptospirosis, p. 7

“Lloyd’s is the global leader in blood-stock insurance, and we are proud to sup-port the critical research needed to ensure equine health,” said Julian Lloyd, chair of Lloyd’s Livestock Committee and blood-stock underwriter at the Amlin Syndicate. “The Equine Disease Quarterly is the pre-mier publication of its type, and we are glad to continue our partnership with the University of Kentucky in its promotion and distribution.”

Published four times yearly, the Quarter-ly is available to subscribers at no charge. It is co-edited by Roberta Dwyer, DVM, MS, Dipl. ACVPM, a professor in the depart-ment of veterinary science, Peter Timoney, MVB, PhD, FRCVS, Frederick Van Len-nep Chair in Equine Veterinary Science at the Gluck Equine Research Center, and Neil Williams, DVM, PhD, Dipl. ACVP,

from the UK Veterinary Diagnostic Labo-ratory.

The current version of The Equine Dis-ease Quarterly is located online at http://www.ca.uky.edu/gluck/q_oct11.asp. For more information about the Department of Veterinary Science and the Gluck Equine Research Center, visit http://www.ca.uky.edu/gluck/index.htm.

Lloyd’s of London is a 323 year-old in-surance and reinsurance market, whose member syndicates underwrite risk in more than 200 countries via approved brokers. As a global leader in specialty in-surance, Lloyd’s remains committed both to supporting equine research and provid-ing the insurance coverage essential to the well-being and prosperity of bloodstock interests worldwide.


Vaccination Strategies and Immunity in Young HorsesMany serious infectious diseases occur

early in life and vaccination, along with management measures, remains the pri-mary method for effective control of in-fectious disease.

Amanda Adams, PhD, assistant profes-sor at the University of Kentucky Gluck Equine Research Center, said young hors-es should be vaccinated to aid in preven-tion of disease, induce immunity, and re-duce severity and spread of disease.

The goal of any vaccination program is to induce immunity, which is a state of having sufficient biological defenses to avoid infection, disease, or other unwant-ed biological invasion. The three types of immunity are natural acquired immunity (induced by infection), artificially acquired immunity (induced by vaccination), and passive acquired immunity (provided to the foal via colostrum).

The neonatal foal is born with a naive immune system, but inherits immediate protection through the vaccinated mare’s colostrum, Adams said. The initial ma-ternal antibodies provided by the mare, decline over time, subsequently leaving the foal uniquely susceptible to a variety of infectious diseases. Dependent upon the quantity and quality of maternal anti-bodies the mare passes to her the foal, the duration of protection varies hugely from foal to foal.

“Make sure not to interfere in the face of maternal antibodies or leave the foal unprotected after the waning of material antibodies,” Adams said. “Foals need to develop adequate immunity against viral

and spray stall areas with a disinfectant. A video on stall disinfection by Roberta Dw-yer, DVM, MS, Dipl. ACVPM, a professor in the Department of Veterinary Science at UK is available at: http://www.you-tube.com/watch?v=L3eROIm08HM.

Many veterinarians are treating mares suspected to be infected prophylactically, i.e. prior to seeing clinical signs or abor-tion. Contact your veterinarian for more information. The drugs of choice for in-fected horses are oxytetracycline, strepto-mycin or penicillin. Vaccines are available for dogs and cattle, but unfortunately not for horses. The cattle vaccine has been used in horses with poor results and often

Leptospirosis, continuedwith side effects.

The UKVDL is conducting a national se-ro-epidemiological study of equine lepto-spirosis to better understand the distribu-tion of horse exposure to leptospires and to lend strength to the idea of a vaccine for the horse. The results of this study will be published this year and will be presented at the Equine Diagnostic and Research Semi-nar at the UKVDL on August 30.

Prevention of equine leptospirosis in-volves good management to keep wildlife out of areas where horses live and eat. Horses should not be allowed to drink from stagnant water or ponds that might be contaminated with cattle urine. Areas

where known infected animals have been should be disinfected before introducing new animals.

Visit the UKVDL website for the latest statistics on leptospirosis, herpes, and no-cardioform placentitis related abortions at http://vdl.uky.edu/documents/bulletins/EquineHealthBulletin2012.pdf.

For more information contact Craig Cart-er, DVM, PhD, Dipl. ACVPM, director of the UKVDL and professor of epidemiol-ogy, 859-257-8283 or [email protected]; or Jacqueline Smith, epidemiology section chief at the UKVDL, [email protected] or 859-257-8283.

Craig Carter provided this information.

and bacterial infections in the environ-ment. This makes it somewhat a challenge to pinpoint the timing of the foal’s first vaccination, since you will need to know the duration of the maternally derived an-tibodies in order to start a foal vaccination regime.”

According to Adams, vaccination of foals can be associated with a number of difficulties due to their limited cell medi-ated immune response to the currently available vaccines. She said it has been ob-served in numerous studies that if mater-nal antibodies are still circulating at a high level in the foal, they can block the foal’s response to multiple types of equine influ-enza vaccines.

It was shown in a 2001 study that 3-month-old foals failed to show increases in antibody titers against either influenza or tetanus subisotypes in response to two doses of vaccines. They generally needed one to three additional booster doses of vaccine to achieve titers similar to those achieved by yearlings after two doses. All three groups of inactivated, live, or vec-tored recombinant vaccines, however, failed to overcome maternal interference

of antibody production, Adams said. “They are simply immunologically unre-

sponsive until later in life,” she said. It has been proposed that mares during

pregnancy produce factors that inhibit cell mediated responses in order to prevent fe-tal rejection, Adams said, eventually caus-ing delayed cell mediated responses in the foal. However, the underlying mechanisms responsible need further investigation.

Weaning is a considerable experience of physical and mental stress. Several studies in other species emphasize the impact of weaning on the effect of lowering cell-me-diated immunity, however, little is known about this in foals. Adams recently per-formed a study in which cellular immunity was measured following abrupt weaning in foals and showed a significant reduction in cytokine production, which is important for fighting pathogens.

“Vaccination in the face of weaning stress may not be the best timing to induce a protect immune response. But, further studies are needed to determine the right time,” Adams said. “Always minimize the weaning-associated stress which might

Vaccination, p. 8

Multiple vaccines are available and provide advantages and limitations. Moreover, different classes of vaccines stimulate the immune system in very different ways.

Three types of vaccines: Inactivated vaccines: short-term protection, induce a strong antibody responseLive vaccine: cross reactive, longer term protection, induce both antibody and cell-mediated im-mune responsesVectored vaccine: recombitant, cell-mediated immunity, longer term protection, induce primarily cell-mediated immunity with some antibody response


help limit the impact that weaning has on the immune response.”

A vaccination regime for the foal is de-pendent upon vaccination status of the mare, the age of the foal, geographic lo-cation, and exposure levels for foals and weanlings. Adams’ advised to consult your equine veterinarian for a tailor-made vac-cination strategy since foal immunity is based on both exposure and protection.

Core vaccinations for foals include East-ern and Western Encephalitis (EEE and WEE) viruses, West Nile virus, tetanus, and rabies. If foals are exposed to other

Young horses are more susceptible to infectious diseases because of the nature of the equine placenta -- no maternal an-tibody is directly transferred to the foal in utero, according to David Horohov, PhD, William Robert Mills chair and profes-sor at the University of Kentucky Gluck Equine Research Center.

Horohov said a foal’s cell mediated im-mune system is known to be competent, but naive. Foals are born with an imma-ture immune system that has to develop to produce antibodies on its own over time. However, the initial ingestion of colos-trum allows for passive transfer of immu-noglobulins, which provide almost imme-diate immunity against various infections, all dependent upon quantity and quality of the maternal antibodies.

“But, foals do not approach adult levels prior to about 3 months old,” Horohov said.

In most cases, foals born without ade-quate amount of colostral antibodies from the mare are uniquely susceptible to infec-tious agents, Horohov said. A failure of passive transfer is not always obvious since the foal does not exhibit any clinical signs until weeks later. Horohov recommends breeders keep an eye on the neonatal foal and make sure it obtains healthy levels of

horses, they should also receive vaccina-tion against equine herpesvirus types 1 and 4 as well as equine influenza virus (EIV).

When vaccinating with EIV, maternal an-tibodies can persist until 6 months old and prevent immune responses in foals vac-cinated prior to reaching that age, so it is especially important to wait before admin-istering the vaccine to the foal. It is recom-mended that foals begin vaccinations at 3 to 4 months old, followed by one to two boosters at four-week intervals.

Mares should be vaccinated with a booster vaccine one to two months prior

Vaccination, continuedto parturition, which induces antibody re-sponses that are then passed on the foal via colostrum to provide protection to the foal. Typically this includes vaccinations for tetanus, encephalomyelitis viruses, in-fluenza virus, and rhinopneumonitis virus, with additional vaccinations for Strepto-coccus equi, Potomac Horse Fever, and in some circumstances, botulism dependent on exposure level and geography, among other factors.

Shaila Sigsgaard is a contributing writer.

Common Infectious Diseases of the Young Horse antibodies within the first 12 hours.

“Besides adequate colostrum, vaccina-tion of the mare prior to pregnancy is probably the best protection against viral and bacterial infections in foals, until it’s capable to develop antibodies on its own later in life,” Horohov said. “Foal mortal-ity is a significant problem for the equine industry and infectious disease plays a ma-jor role in this matter.”

According to a study performed in Cen-tral Kentucky, the primary causes of foal mortality from birth to 9 months old in two-thirds of all foals was from infectious diseases such as Septicemia, gastro-intes-tinal disease, and/or respiratory disease. The majority of sepsis cases and deaths occurring in the youngest foal, according to Horohov, suggest that the illness is likely to be related to birth. Septicemia is a systemic disease associated with the pres-ence of bacteria in the blood spreading to the central nervous system, other organs, bones, and joints. Bacteria are normally present in the foal’s environment, but oc-casionally they invade the foal and take ad-vantage of its immature immune system. Some of the dominant bacteria involved in foal septicemia are Escherichia coli (32%), Salmonella (11%), Klebsiella (7%), En-terococcus (2%), and Actinobacillus (7%).

Foal diarrhea “Foal diarrhea is one of the most com-

mon illnesses and probably the most dif-ficult to deal with,” Horohov said.

The agents causative for foal diarrhea range from bacteria to viruses to parasites. He said there are probably be a lot of cas-es which go undiagnosed. Agents causing foal diarrhea include rotavirus, Clostridi-um, Salmonella, and the parasite Parascaris equorum. While most foals carry clostrid-ial bacteria, it is yet unknown why some foals develop severe diarrheal disease. The role their immune system plays in prevent-ing this disease is unknown.

Foal respiratory disease Signs of foal respiratory disease vary

from the occasional snotty foal to bron-chopneumonia depending on the severity of the respiratory problem, Horohov ex-plained. The agents involved are typically viruses with equine herpesvirus, (EHV-1, EHV-4, EHV-2), equine adenovirus, equine rhinovirus and equine influenza being the likely candidates. These infec-tions result in acute febrile infection and typically resolve after a few days. Bacterial agents such as Rhodococcus equi, Streptococ-cus equi, Actinobacillus, salmonella, E. coli, and Klebsiella are typically more severe

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Young Horse, p. 9


Parasitology

The foal and the juvenile horse belong to the age groups which should be given the most attention in terms of parasite control. These groups are particularly sus-ceptible to parasitic infection, because un-like older horses, they do not yet have the advantage of acquired immunity to some types of parasites. Martin Nielsen, DVM, DipEVPC, PhD, assistant professor at the University of Kentucky’s Gluck Equine Research Center, recommends designing a parasite control program for foals and young horses with the goal of avoiding parasitic disease, reducing the rate of de-velopment of drug resistance, and allow-ing development of acquired immunity in the horses.

“In order to design a reliable parasite control program, we need knowledge about two key issues—know your drugs and your parasites,” Nielsen said. “There might be huge differences from farm to farm when it comes to drug efficacy, and it should be born in mind that different para-sites are present simultaneously. To avoid parasitic disease with manifestations such as stunted growth, diarrhea and colic, you will need to achieve information on the ef-ficacy of drugs used on your farm. We still want to have efficient drugs available in the future for the ‘wormy’ foal.”

According to Nielsen, the cornerstone in parasitology is running fecal egg counts as part of an up-to-date parasite control program. On this basis, he recommends

Deworming Strategies for the Young Horse

foal owners to have a few egg counts per-formed to exhibit the exposure level of ascarids and strongyles.

“It’s useful information to know when ascarids are actually kicked out and the strongyles are taking over as well as to monitor the ongoing efficacy of the drugs 14 days after the initial treatment of the foals,” Nielsen said.

What happens during the first year of the horse’s life?

There is a distinct timeline in terms of which parasites a horse get exposed to as it grows up, Nielsen said.

He added breeders should pay particu-lar attention to the ascarid parasites (large roundworms), as they are considered the most pathogenic in foals.

Strongyloides westeri: (the threadworm),

a mildly pathogenic parasite, is uniquely capable of reproduction in the environ-ment, whereas most other parasites repro-duce in the horse, Nielsen said. Parasite infection is transmitted in three possible ways: lactogenic transmission where larvae are passed from mother to foal through the milk, fecal-oral route, where infective larvae are ingested while grazing, and the transdermal route where the larvae pen-etrate the skin of the horse and enter the blood stream.

“We rarely see any parasitic disease as-sociated with this parasite, and it occurs almost entirely in the very young foal. This suggests that the foal builds up a strong immunity a few weeks after birth,” Nielsen said. “The good news is that we don’t have any signs of drug resistance. The tradition has been to treat mares prior to parturi-tion, but it’s questionable whether treat-ment prior to foaling is needed if mares are well maintained.”

“Parascaris equorum (the large round-worm) is the number one important parasite in foals less than six months of age with a prevalence of 80% to 100%,” Nielsen said.

The infective eggs release their larvae in the small intestine and the larvae sub-sequently migrate quite extensively within the body. They travel to the liver and lungs where they might cause airway symptoms.

“It has been suggested that this exten-

and last longer. These infections require therapeutic intervention and can be life-threatening if not treated promptly.

One of the main causes of respiratory disease in foals is the hardy bacterium Rhodococcus equi, which commonly causes pneumonia. Half of the causes of foal mortality from 1 to 6 months old are asso-ciated with bacterial agents such as Rhodo-coccus equi, Salmonella, and Streptococcus equi spp., whereas one-third are associated with viruses. Foals younger than 6 months old are susceptible to Rhodoccocus equi, whereas foals younger than 3 months old are at even higher risk.

“The tricky part is that they might have become exposed and infected before 2 weeks old and the initial clinical signs of

disease typically manifest several weeks lat-er. The peak in disease in young foals likely occurs when maternal antibodies derived from the mare decline,” Horohov said.

According to Horohov, numerous stud-ies have demonstrated foals are deficient in their production of interferon-gamma (IFNγ) in comparison to the mature horse. It has been proposed they are born with an inherent inability to mount a Th1-based cell mediated immune response which may contribute to their susceptibility to intra-cellular pathogens such as Rhodococcus equi.

“We do not yet fully understand the un-derlying mechanism responsible for this deficiency, however,” he said.

Horohov and his colleagues previously examined whether common immunos-

timulants could accelerate the young foal’s ability to produce IFNγ to better fight in-fections. Resistance to this disease appears to be associated to IFNγ production.

“We were able to measure increased lev-els of IFNγ after 14 days, whereas earlier on in life they seemed incapable to respond to the stimulants,” Horohov said.

This indicates that a foal’s ability to pro-duce IFNγ increases with age. He said the risk for infectious disease in the foal is likely to be a combination of the foal’s immune status, environmental factors, and farm management. All factors play a sig-nificant role and prevention may be our best choice to decrease the risk of infec-tious disease.


Young Horse, continued

According to Dr. Martin Nielsen, the cornerstone in parasitology is running fecal egg counts as part of an

up-to-date parasite control program.

Deworming, p. 10


PharmacologyEquine Drug Testing and Therapeutic Medication Regulation Book Released

The fourth edition of “World Rules for Equine Drug Test-ing and Therapeutic Medication Regula-tion” was released by Wind Publica-tions on Feb. 14 and has sold more than 100 copies. Authors of the 286-page

book are Thomas Tobin, MVB, MSc, PhD, MRCVS, DABT, professor at the University of Kentucky Gluck Equine Research Cen-ter, Kimberly Brewer, DVM, a private prac-titioner, and Kent Stirling, executive direc-tor of the Florida Horsemen’s Benevolent and Protective Association .

The newly released fourth edition covers medication rules around the world for the first time and features a forward written by Kentucky First Lady Jane Beshear. The book addresses specific regulatory proce-dures in place around the world to regulate the use of therapeutic medications, endog-enous, dietary, and environmental substanc-es in racing and performance horses. The book is based on the Association of Racing Commissioners International (ARCI) clas-

sification system for foreign substances and lists as many as possible of the specific reg-ulatory thresholds/withdrawal time guide-lines in place for the approximately 99 such substances, acepromazine to xylazine, in use around the world.

Some widely used therapeutic medications are associated with an unusually high risk of inadvertent identifications or overages; where appropriate, each of these substances is marked with a HORSEMEN’S ALERT, which sets forth the reasons for the alert and suggests avoidance actions. Additional-ly, and somewhat unusually, three substanc-es are listed as CHEMIST’S ALERTS, and the rationale for setting forth the chemists alert is provided.

Regulatory thresholds are defined as plas-ma or urinary concentration of drugs/drug metabolites and are the essential regulatory tools. What the horseperson needs, how-ever, are withdrawal time guidelines, simple unambiguous medication administration guidelines scientifically linked to the regu-latory threshold and which serve to greatly reduce the probability of a therapeutic med-ication “overage.” Appendix 1 of the book reviews the critically important matter of withdrawal time guidelines and the factors

Deworming, continuedsive migration could explain the strong immunity, which apparently kicks in at about 6 months of age,” he said. “Take a fecal sample about the time of weaning. This will provide you with information on when these ascarids disappear and the strongyles take over.”

This is important because it will affect our choice of dewormer, he added. Large numbers of roundworms can lead to intes-tinal impaction, which is associated with a reserved prognosis for survival.

“Timing and correct choice of drugs therefore should be the key focus in any ascarid control program. Frequent treat-ment with four to six intervals has been the tradition leading to widespread resis-tance to ivermectin and moxidectin. Foals 6 months old and older have started en-countering strongyle parasites which can be divided into two main groups of the 100% prevalent small strongyles (cyathos-tomins) and the large strongyles.

“The strongyle parasites will accompany

the horse for the rest of its life. The large strongyles are considered far the most pathogenic parasite, but they have become very rare in managed horse populations,” Nielsen said.

Younger horses tend to have larger worm burdens and shed more strongyle eggs than the mature horse but horses at all ages harbor cyathostomins, Nielsen said.

“This could suggest that the immunity to strongyles is fairly limited. We see wide-spread evidence of resistance to benzimad-oles, emerging levels of pyrantel resistance as well as beginning signs of ivermectin and moxidectin resistance. The good news is that we still have no signs of resistance in large strongyles,” Nielsen said.

The fourth parasite encountered by foal is the ubiquitous tapeworm, also known as Anoplocephala perfoliata (flatworm). Usu-ally it occurs at the same time in the time-line as the strongyles. Tapeworms are flat, segmented worms transmitted to the horse by ingesting an intermediate host, the orib-

atid mites, infected with the tapeworm. “Because this parasite is uniquely depen-

dent on the oribatid mite, only horses lo-cated in areas where these mites are pres-ent on pasture are at risk for tapeworms,” Nielsen said.

Farm prevalences often vary in the range of 20-80%. In the horse the parasites stay in the intestine attached to the wall and may cause impactions, intussusceptions or spasmodic colic, but infection often goes unnoticed.

“So far, there are neither established treatment traditions for this parasite nor reports of drug resistance. We don’t yet have efficient methods available to measure drug resistance in tapeworms,” Nielsen said. “I would recommend an initial tape worm treatment from about 12 months of age, and it should be considered in combi-nation with strongyle treatment based on a modified egg or a serum antibody mea-surement (ELISA) spring and summer.”


influencing withdrawal time guidelines are presented in some detail.

The language of equine forensic science is that of science and law, and much of it is unfamiliar to horsepersons. Appendix 2, therefore, presents the language, definitions, and abbreviations used in equine forensic science. Appendix 3 lists the equine thera-peutic medications identified by the Ameri-can Association of Equine Practitioners (AAEP) and by the Racing Medication and Testing Consortium; it is noted the thera-peutic medication status of some of these substances is under review. Appendix 4 sets forth the need for suitable reference stan-dards for therapeutic medication regulation and outlines National and local HBPAs contributions in this critically important area of forensic science. Appendix 5 lists the Horsemen’s Benevolent and Protective Associations that have supported these re-search efforts, and the book closes with Ap-pendix 6, a list of scientific references.

The book can be purchased on Amazon at: http://www.amazon.com/Equine-Test-ing-Therapeutic-Medication-Regulation/dp/1936138425/ref=sr_1_fkmr1_1?ie=UTF8&qid=1329331893&sr=8-1-fkmr1.


Reproductive HealthEndometritis Responds Well to Treatment, Except in Cases of Susceptible BroodmaresMats Troedsson, DVM, PhD, Dipl. ACT,

DECAR, Professor and Chair, director of the University of Kentucky Gluck Equine Research Center and chair of the depart-ment of veterinary science, lectured at UK’s Veterinary Diagnostic Laboratory (UKVDL) on endometritis in September.

“Endometritis is a fine-tuned interaction between the host immune system and in-vading agent for which targeted treatment works best. It is important to distinguish between ‘normal’ and ‘abnormal,’ mares since only 10% to 15% of broodmares are susceptible to persistent endometritis,” Troedsson said.

Endometritis is an inflammation of the lining of the uterus that can be caused by breeding or the introduction of bacteria into the uterus. Typically, endometritis re-solves quickly. But in some mares, chronic, recurrent uterine inflammation is a persis-tent problem that can interfere with preg-nancy.

“While most young mares have a re-markable ability to clear inflammation, older, multiparous (having foaled two or more times) mares can fail to clear con-taminants from the uterus and are consid-ered ‘susceptible,’ ” Troedsson said.

Several issues may contribute to suscep-tibility. Delayed uterine clearance may be caused by impaired myoelectrical activity or other uterine pathologies (Woodward et al). Horizontal uterine placement allows the mare to more readily clear pathogens than a pendulous (i.e. downward facing, or slanted) uterine placement. In studies, susceptible mares accumulated nitric oxide following induced inflammation, which impairs smooth muscle contraction, there-by inhibiting uterine clearance, Troedsson said.

“Recent data from our laboratory sug-gest that the innate immunity may play an additional role in the development of susceptibility to persistent endometritis,” Troedsson said. “It is not clear at this time however, how cytokine expression and im-paired uterine contractility are connected. More research in this area is needed.”

Breeding-induced endometritisBreeding-induced endometritis is nor-

mal and serves to clear the uterus of ex-

cess semen and contaminants, Troedsson explained. In this transient inflammation, which most mares resolve in 24 to 36 hours, there is a quick expulsion of sperm from the uterus. If not resolved in a time-ly fashion, the inflammation will provide a uterine environment that is harmful to the embryo and often results in pregnancy loss.

In persistent breeding-induced endome-tritis:

•Uterine contractility is impaired, result-ing in delayed uterine clearance

•Impaired cytokine modulation appears to play a role in susceptibility

•Six hours is the critical timeframe to clear breeding-induced endometritis

When treating breeding-induced endo-metritis, lavage and low doses of oxytocin can assist the uterus to clear the inflamma-tion, Troedsson explained. Low doses of oxytocin, 5 to 20 units, result in beneficial muscle contraction, whereas higher doses of 30 to 40 units result in a disadvanta-geous muscle cramp.

Use of prostaglandin F2alpha rather than oxytocin has also been shown to aid uterine clearance. If given after ovulation, however, this treatment could be detri-mental to fertility because it may delay de-velopment of the corpus luteum.

“With prostaglandin, we are administer-ing it to treat fertility, but we have found it may reduce the chance of pregnancy if given at the wrong time,” Troedsson said.

According to Troedsson, causal agents of infectious endometritis include:

•Streptococcus equi sp zooepidemicus •E. coli•Pseudomonas aeruginosa •Klebsiella pneumoniae •Taylorella equigenitalisIn bacterial infections:•There is an increased endometrial gene

expression of cytokines that helps to clear the infection

•There are imbalanced cytokine respons-es to infection in susceptible mares

•Cytokine response may differ in re-sponse to infection and breeding

“To treat infectious endometritis, you must treat the underlying breakdown of uterine defense and administer antibiot-

ics. Most mares respond well to antibi-otic treatment, which includes intrauterine infusion, systemic treatment, or both,” Troedsson said.

“Some mares develop recurrent endome-tritis, which can be very resistant to anti-biotics. One theory is that the infectious agent is protected by a biofilm, a group of microorganisms growing on a solid sub-strate that are resistant to antibiotics. For a treatment to be effective, it must break down the biofilm. Although the endome-trium is a likely environment for bacteria to build up a biofilm, it has not yet been proven,” he said. “Another cause may be the presence of dormant bacteria in the endometrium.”

This has been demonstrated by Danish researchers and suggested to be a cause of persistent endometritis.

Both Settle and corticosteroids had a significant effect on clearance of uterine pathogens. The effect of treatment on endometrial cytokine expression was less clear, and the mechanism is still unknown with regards to these and other alternative treatments.

Troedsson explained that the underly-ing causes and best treatment options for the 10% of susceptible mares who suffer from persistent endometritis are still being researched by several teams at universities around the world.

“Ongoing research contributes to the body of knowledge, but the causative agents and best treatments remain ill-de-fined,” he said. “There is a gray zone be-tween resistance and susceptibility to en-dometritis.”

Karin Pekarchik is a former editorial officer in UK’s Agricultural Communications Services.

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