Equine Disease Quarterly Newsletter

5ergot alkaloids on a dopaminergic receptor, it isimportant to remember that some of the alkaloids also bind to other receptor types, including
adrenergic and serotonergic receptors, and thus
may affect additional body systems.

CONTACT:
Karen McDowell, PhD
kmcd@uky.edu(859) 218-1104
Maxwell H. Gluck Equine Research Center
Tim Phillips, PhD
Department of Plant and Soil Sciences
University of Kentucky
Lexington, KY

Presorted Standard
US Postage Paid
Permit 51
Lexington KY

Department of Veterinary Science
Maxwell H. Gluck Equine Research Center
University of Kentucky
Lexington, Kentucky 40546-0099
Address Service Requested

F U N D E D B Y U N D E R W R I T E R S AT L LOY D ' S , LO N D O N

JANUARY 2019
Volume 28, Number 1

KENTUCKY

Equine Abortion: A Review of the 2016 and 2017
Breeding Seasons in KentuckyT

he loss of a developing fetus during pregnancy
can be a frustrating, emotional, and costly
experience for horse owners, farm workers, veterinarians, and the public. A thorough evaluation of
the aborted fetoplacental unit (fetus and placenta)
by a veterinary pathologist can help determine
the cause of abortion, identify new, unusual, or
foreign causes of fetal loss, rule out involvement
by infectious agents, and aid in the epidemiologic
monitoring of abortifacients (factors that can resultin abortion). A two-year review of equine abortions, from the 2016 and 2017 breeding seasons,was conducted at the University of Kentucky Veterinary Diagnostic Laboratory to evaluate current
abortion trends.
Dates listed below indicate data for the respective breeding season, not calendar year.
A total of 898 cases of equine abortion, 570
from 2016 and 328 from 2017, were evaluated.
The majority of cases were considered sporadic
and unrelated, except for one equine herpesvirus 1
abortion storm that was identified during the 2016
breeding season. Abortions during early gestation
began in May of the 2016 breeding season andJune of 2017 breeding season. The highest numberof abortions occurred in March of both years, andthe last abortions occurred in July of 2017 (2016breeding season) and May of 2018 (2017 breeding
season). Abortions were categorized into infectious(2016= 55% and 2017= 38%) and non-infectious
causes (2016= 45% and 2017= 62%).
Infectious causes of fetal death were attributed to bacterial, viral, fungal, and unidentified (presumably bacterial) agents that resulted inplacentitis and/or systemic infections. Placentitis
was the most common cause of infectious disease

and was identified in 280 cases (24.6%) in 2016
and 102 cases (20.2%) in 2017. Approximately 5%of abortions each year were attributed to ascending
placental infections through the mare’s cervix bybacteria such as Streptococcus zooepidemicus andEscherichia coli. Nocardioform/mucoid placentitis
was diagnosed in 145 (12.7%) and 27 (5.3%) cases
during 2016 and 2017, respectfully. Three cases of
mycotic placentitis were diagnosed in 2016, andone case was diagnosed in 2017. Placentitis due
to unidentified agents occurred in 79 (6.9%) casesin 2016 and 47 (9.3%) cases during 2017. Agentswere not identified, presumably, due to the use of
antimicrobial therapy, chronic resolved infections,or overgrowth by environmental organisms. Leptospiral abortion or perinatal death was identified infive cases (0.4%) during 2016 and 11 cases (2.2%)
in 2017. Abortion due to fetal bacterial septicemia
or pneumonia was diagnosed in 4.4% of cases in2016 and 1.6% of cases in 2017. Equine herpesvirus 1 was the only viral agent identified in fetusesover the two-year period, and it was responsiblefor 16 (1.4%) abortions or perinatal deaths in the2016 breeding season and 10 (2.0%) in the 2017
breeding season.
Non-infectious causes of abortion are considered sporadic events. They included abortion associated with umbilical cord torsion (2016= 3.9%
and 2017= 7.9%), fetal stress (2016= 1.8% and2017= 2.0%), placental “cervical pole” necrosis(2016= 0.5% and 2017= 0.4%), twin pregnancy(2016= 0% and 2017= 0.6%), miscellaneouscauses (hydrops, tissue necrosis of unknown etiology, and maternal stress and disease; 2016= 1.2%
and 2017= 2.0%), and abortion of undeterminedcause (2016= 14.9% and 2017= 27.5%).

C O M M E N TA RY
IN THIS ISSUE
Commentary
International
Third Quarter2018  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 2Biofilm-AssociatedEndometritis  .  .  .  .  .  .  .  . 3National
Tall Fescues .  .  .  .  .  .  .  .  .  . 4KentuckyAbortion of undetermined cause occurs quite
regularly and is frustrating to both clients and diagnosticians. Based on the human and veterinary
literature, many of these occur due to physiologic
abnormalities (e.g. fetal cardiovascular disease,
hypoxia), stress and disease in the pregnant mare,autoimmune disorders, genetic irregularities, environmental exposures, and endocrine abnormalities; all of which cannot be easily assessed or tested
for in the aborted fetoplacental units. A diagnosisof abortion of undetermined etiology isn’t completely without value, because infectious diseases
and other possible causes of abortion storms canbe readily ruled out.

In conclusion, equine abortion remains to
be unfortunately common. Both infectious andnon-infectious causes are frequently responsible.
Evaluation of the aborted fetoplacental unit byyour local veterinary diagnostic laboratory can aid
in determining the cause of abortion, help to monitor and track known abortifacients, and identify
new and possibly emerging causes of abortion.

Equine Abortion .  .  .  .  . 5

CONTACT:
Alan Loynachan, DVM, PhD
alan.loynachan@uky.edu(859) 257-8283
University of Kentucky Veterinary Diagnostic Laboratory
Lexington, KY

College of Agriculture,
Food and Environment
Department of
Veterinary ScienceL

ate-term abortion is one of the most devastating
issues horse breeders face. Every pregnancy represents a labor of love, with a substantial amountof time, energy and money put into achieving theperfect foal. Every pregnancy loss raises questions
concerning our ability to have prevented that loss
and whether we could have done more.
In this issue, Dr. Alan Loynachan addresses
the underlying causes of the 898 equine abortions
examined by the UK Veterinary Diagnostic Laboratory over the 2016 and 2017 breeding seasons.
This retrospective look is important to help us
identify areas where we can improve management
techniques and where we should focus our future
research efforts to best benefit horse owners andbreeders. As such, it’s critical that breeding farms
send their aborted foals to a veterinary diagnostic
laboratory, even if the cause of abortion appears
obvious.
Approximately 50% of the abortions evaluated were deemed non-infectious. Of these, mostare not likely to be management related with the
exception of twin pregnancies; however, twins did
not comprise a large percentage of the abortions
submitted. This is likely due to better management
techniques, namely identification and reduction oftwin pregnancies early in gestation, but also likely
reflects the failure of owners to submit abortions
with an obvious cause to the diagnostic laboratory. While this is understandable, it also makes
it difficult to accurately measure the frequency ofthese losses.
Infectious abortions comprised the other 50%
of submitted abortions, with placentitis representing the majority of these cases. Unfortunately,
we know little about what predisposes a mare todevelop placentitis, and still have trouble withearly, accurate and specific diagnosis. Even so,

there are steps that owners can take to aid in early
diagnosis, including endocrine monitoring, regular ultrasound evaluation of the placenta as well
as daily checks for premature mammary glanddevelopment, premature lactation, and purulent
vulvar discharge. If anything out of the ordinary is
noted, a veterinarian should be called to examine
the mare and start treatment if indicated.
As placentitis comprises the majority of the infectious abortions seen, the laboratory of Dr. Barry
Ball at the Gluck Equine Research Center has been
focusing on better understanding the causes andprogression of placentitis. By utilizing state-of-theart techniques to look at changing gene expression,
we have identified several potential targets which
we believe will function as diagnostic aids and/or
treatment options. Although more work is stillneeded to confirm our findings, we are optimisticthat better options for dealing with placentitis will
be available soon.
Again, I cannot stress enough the importanceof sending all aborted foals, including fetal
membranes and maternal serum, to a veterinary
diagnostic laboratory. When breeders fail to submit abortions, it becomes more difficult to spot
trends and, in turn, becomes more difficult to
identify and respond to emerging threats. It’s easy
to justify only submitting abortions without anobvious cause; however, the overall health of theequine breeding industry relies on the submissionof every abortion, every time.
CONTACT:
Shavahn Loux, PhD
Shavahn.Loux@uky.edu(859) 257-4757
Maxwell H. Gluck Equine Research Center
University of Kentucky
Lexington, KY

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I N T E R N AT I O N A L

N AT I O N A L

Third Quarter 2018

T

Equine Disease Quarterly
Editors

Peter Timoney
Alan Loynachan
Cynthia Gaskill

Staff

Diane Furry
Tawana Brown
Dennis Duross
Anita Fleming
Correspondence should be
addressed to the editors,
Department of Veterinary
Science, Maxwell H. Gluck
Equine Research Center,
University of Kentucky,
Lexington, Kentucky USA,40546-0099
Telephone (859) 257-4757
Fax (859) 257-8542
Internet address:
http://gluck.ca.uky.edu/
equine-disease-quarterly
Material published in the
Quarterly is not subject tocopyright. Permission istherefore granted toreproduce articles, althoughacknowledgment of thesource and author is requested.
The University of Kentucky
is an Equal Opportunity
Organization.

Printed on recycled paper

he International Collating Centre, Newmarket, United Kingdom, and other sources
reported the following equine disease outbreaks.
The final four cases of African horse sickness tobe reported by the Republic of South Africa (RSA)
this season occurred during the first half of July;
two were in Eastern Cape Province, one in Free
State Province and one in KwaZulu-Natal.
An outbreak of glanders was reported by P.R.
China. The disease was confirmed in 17 horses at
an equestrian club, one of which died.
Equine influenza was confirmed in Colombia,
Germany and the USA. The disease occurred in 16
of 32 departments in Colombia, with over 2,700
recorded cases including one death. The German
outbreak involved five unvaccinated horses. Equine
influenza is endemic in the USA with evidence of
infection identified in three states.
Belgium, France, Germany, Ireland, Switzerland, the UK, and the USA reported multiple
outbreaks of strangles. The number of confirmed
outbreaks ranged from two in Germany and
Switzerland, three in Belgium, 17 in France, 60
in Ireland, and 154 in the USA. The disease isendemic in the UK and the USA.
Equine herpesvirus 1 related diseases were recorded by Argentina, Belgium, Canada, France,
Germany, Japan, RSA, Switzerland, and the USA.
Respiratory disease was diagnosed in Belgium (11outbreaks), France (two outbreaks), RSA (oneoutbreak), and the USA (outbreaks in numerous
states). Cases of EHV-1 abortion were reported
by Argentina (one outbreak involving 15 cases inThoroughbreds, all with incomplete vaccination
histories), Japan, and RSA (single case in eachcountry). EHV-1 neurologic disease was confirmed
in Canada (two outbreaks), Germany and Switzerland (single case in each country), and the USA(six outbreaks involving single cases of the disease).
Equine herpesvirus 4 respiratory disease wasdiagnosed in France (20 outbreaks), Germany(three cases involving two premises), and the UK(seven outbreaks, most of which represented single
cases of infection in unvaccinated horses).
Germany reported equine arteritis virus infection in a stallion.

Equine infectious anemia was confirmed in
Canada, France, and the USA. Two outbreaks involving single cases of asymptomatic infection wererecorded by Canada. France diagnosed a single
case, and the USA identified 17 cases involving
horses in five states, the preponderance in Texas.
The RSA reported equine piroplasmosis as
occurring in four provinces, with the majority ofconfirmed cases in Gauteng Province.
Contagious equine metritis was confirmed
in France (single clinical case in a mare) andGermany (10 cases, all in non-Thoroughbreds,
the majority were Icelandic horses; nine premises
were involved.)
Ireland and the USA reported outbreaks ofsalmonellosis. A total of 14 mares and foals wereinvolved in an outbreak in Ireland. Of 11 cases
diagnosed in the USA, nine were associated with
Salmonella serogroup B isolates.
Equine neorickettsiosis was reported by theUSA. The disease was confirmed in five states,with the highest number of cases (26) recorded in
Kentucky, of which six died.
Clostridial enterocolitis was diagnosed in alimited number of cases in the USA, all associatedwith Clostridium perfringens infection of undetermined toxin type.
The USA reported one case of proliferative
enteropathy (Lawsonia intracellularis infection).
The third quarter of 2018 saw cases of Easternequine encephalomyelitis confirmed in Canada (9)and the USA (39), the majority of which were inunvaccinated horses. Florida and Georgia were themost severely affected states in the USA.
West Nile virus infection was reported by
Canada (14 cases), France (6 cases), Greece (onecase), Germany (one case), Italy (105 cases), Romania (one case), RSA (one case), and the USA(140 cases, many in the state of Ohio).
Australia confirmed one case of Hendra virus
infection in an unvaccinated horse on a premises
in New South Wales.
A single case of equine encephalosis was diagnosed in a horse in the RSA Province of Gauteng.

Biofilm-Associated Endometritis

Bacterial endometritis (infection of the uterine mucosa) that is refractory to traditional
antimicrobial treatment is a significant challenge
to the equine breeding industry. A common survival strategy employed by bacterial pathogens is
the formation of a biofilm, which is a complex
and dynamic structure composed of aggregatesof bacteria surrounded by a thick protective layerof exopolysaccharide. Biofilms confer resistanceto immune mediated clearance by reducing thehost’s ability to recognize infection. Additionally,
biofilms protect bacteria from antibiotics by providing a diffusion barrier and creating a microenvironment that slows down bacterial metabolism
and replication, which makes them more tolerant
to antimicrobial agents.Using a model of equine
infectious endometritis, we have clearly identified
the ability of the bacterium Pseudomonas aeruginosato form a biofilm within the uterus of the mare.
The biofilm forms in multiple locations with thegreatest amount of adherent bacteria occurring between the tissue folds and in the uterine horns. Thissuggests that a traditional guarded culture swab
may not be ideal for detecting biofilm-associatedinfections and a low volume lavage may be a better
diagnostic tool. The bacteria are in greater numbers
deep within the endometrial glands as comparedto the luminal surface. To be successful in clearing
these infections, treatment options will need to becapable of penetrating deeper into the glands andtissue. For microscopic visualization of biofilms
within endometrial biopsies, Bouin’s solution
provides significantly better preservation of thebiofilm matrix on the surface of the endometrium
as compared to traditional formalin fixation.
Bacteria residing in a biofilm can be up to 1,000
times more refractive to treatment with antibiotics
as compared to free-living (planktonic) bacteria.
The simple administration of more or a higher
concentration of antibiotics has failed to eliminate chronic biofilm infections in both humanand veterinary medicine. The goal in treating a
biofilm-associated infection is to disrupt the biofilm material and kill the bacteria residing within
the biofilm.

Tall Fescues – Endophyte-infected,
Endophyte-free, and Novel Endophyte

A series of in vitro (within a laboratory setting,such as in a test tube) studies were conducted toassess biofilm dispersal and/or bacterial killing by
antibiotics and non-antibiotic agents alone or in
combination against Gram-negative bacteria (E.
coli, K. pneumoniae and P. aeruginosa). Data would
indicate that antibiotics and non-antibiotic agentsare more effective against biofilms if administeredconcurrently. When dealing with bacterial infections protected in biofilms, the treatment period
should be at least 72 hours in duration, withrepeated treatments every 24 hours (i.e. a uterine
infusion of the selected combination once every 24
hours for three consecutive days). Following thistreatment protocol, the biofilm was completed disrupted and bacterial killing ensued. Assessment ofantibiotic sensitivity of the offending pathogen(s)is still important as inherent genetic resistance ofthe bacteria involved will not be overcome solely
by the addition of the non-antibiotic compounds.
A recent in vivo study evaluated the intrauterine
treatment of a preformed Pseudomonas aeruginosabiofilm with a combination of ceftiofur and trisEDTA or ceftiofur and tris-EDTA alone. Of fivemares treated with a combination of ceftiofur andtris-EDTA, all effectively cleared the infection.
This contrasted with only two of five mares treatedwith ceftiofur and one of five mares with trisEDTA. The findings confirmed greater efficiency
in killing preformed biofilm within the uterus byusing a combination of antibiotic (ceftiofur) andnon-antibiotic (tris-EDTA) agents.
Advances in our understanding of the significance of biofilms in human and veterinary medicine will in time lead to improved diagnostics andmore effective treatment modalities. Fortunately
several therapeutic options are currently available
to clinicians for the treatment of biofilm-associatedequine bacterial endometritis.
CONTACT:
Ryan A. Ferris, DVM, MS, Dipl. ACT
rferris@summitequineinc.com
Summit Equine Inc.
Newberg, Oregon

T

MATT BARTON, UK AGRICULTURAL COMMUNICATIONS

all fescue (Lolium arundinaceum) is one of
the most widely grown perennial grasses in
the world and covers approximately 37 million
acres in the United States alone. It can be infectedwith an endophytic fungus (Epichloë coenophiala),
which in a symbiotic relationship with the plant
produces chemicals called alkaloids that confer
benefits to the plant. This tall fescue, native toEurope, was introduced into the United States in
the 1800s. In 1931, E.N. Fergus, a University of
Kentucky agronomist, collected tall fescue seedfrom the Suiter farm in Menifee County, KY, on
the basis of winter hardiness, persistence in hightraffic areas, and drought resistance, giving riseto the cultivar of fescue known as Kentucky 31(KY31). However, some of the alkaloids, primarily
the ergot alkaloids produced by infected plants, aredetrimental to grazing animals, including horses.
Historically, the endocrine hallmark of fescue
toxicosis in several animal species is a decreasein the circulating concentration of the hormone
prolactin. Prolactin is secreted by the pituitary
gland, and control of its secretion is complex
and not completely understood. Prolactin exerts
effects on a variety of systems including milk production, steroidogenesis (estrogens, progesterone
and testosterone), hair growth and shedding,libido, and synthesis of surfactant by the fetal
lungs. Importantly, prolactin may also exert aneffect on the feto-placental unit by altering steroid
synthesis and/or metabolism and maturation of
the fetal adrenal-pituitary axis, which is necessary
for parturition. One major regulator of prolactin
secretion is dopamine, a hormone produced by the
hypothalamus. Dopamine, interacts with receptors
in the pituitary gland and inhibits the secretionof prolactin.
Ergovaline is the most abundant ergot alkaloid
in tall fescue. Ergovaline, and several other alkaloids from fescue, have similar chemical structures
to dopamine and can bind to dopamine receptors,
thereby causing a decrease in prolactin secretion,
resulting in partial or complete agalactia (theinability to produce milk) in foaling mares. Additional problems associated with KY31 fescue

consumption in foaling mares include alteredhormone concentrations, extended gestation,
thickened placenta, placental retention, dystocia,
birth of dysmature foals, and increased foal andplacental weights. Dopamine receptors have beenfound in tissues other than the pituitary, including ovarian tissues and the corpus luteum, but theroles of those receptors in fescue toxicosis, if any,
have not been fully elucidated. The drug domperidone is frequently used in broodmares that are
exposed to KY31 fescue and prevents or reverses
the adverse reactions of ergovaline. Domperidone
functions by binding to dopamine receptors, butrather than suppressing prolactin production, it
competes with dopamine and allows for normal
prolactin secretion.
Because of the adverse health effects of common
endophyte infected fescue in grazing animals, varieties of tall fescue which do not contain the fungal
endophyte have been identified. Even thoughthese endophyte-free varieties do not produce
ergot alkaloids, animal performance is excellent.
However, the plants do not persist well in pastures
or compete well with other pasture grasses. Morerecently, endophyte strains that do not produce
the alkaloids that are harmful to animals but still
confer vigor and persistence to the plant, havebeen identified and inserted into tall fescue. These
are called novel endophyte varieties of fescue, andsome of these are commercially marketed as “Jesup
Max Q,” “Texoma Max QII,” and “Baroptima
Plus E34.” More recently, “Lacefield Max QII”
was released by Dr. Tim Phillips in the Department of Plant and Soil Sciences at the Universityof Kentucky. The Alliance for Grassland Renewal
is an association of seed companies, universities,
and government agencies that regulate themselves
by establishing certain quality control standards
for novel endophyte tall fescues. For example, allseeds sold under the Alliance tag must be 95%
pure, have 70% live (viable) endophyte, and have
independent confirmation that the fescue variety
does not cause fescue toxicosis in animals and will
persist well under conventional grazing conditions.
Although this article emphasizes the effects of

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I N T E R N AT I O N A L

N AT I O N A L

Third Quarter 2018

T

Equine Disease Quarterly
Editors

Peter Timoney
Alan Loynachan
Cynthia Gaskill

Staff

Diane Furry
Tawana Brown
Dennis Duross
Anita Fleming
Correspondence should be
addressed to the editors,
Department of Veterinary
Science, Maxwell H. Gluck
Equine Research Center,
University of Kentucky,
Lexington, Kentucky USA,40546-0099
Telephone (859) 257-4757
Fax (859) 257-8542
Internet address:
http://gluck.ca.uky.edu/
equine-disease-quarterly
Material published in the
Quarterly is not subject tocopyright. Permission istherefore granted toreproduce articles, althoughacknowledgment of thesource and author is requested.
The University of Kentucky
is an Equal Opportunity
Organization.

Printed on recycled paper

he International Collating Centre, Newmarket, United Kingdom, and other sources
reported the following equine disease outbreaks.
The final four cases of African horse sickness tobe reported by the Republic of South Africa (RSA)
this season occurred during the first half of July;
two were in Eastern Cape Province, one in Free
State Province and one in KwaZulu-Natal.
An outbreak of glanders was reported by P.R.
China. The disease was confirmed in 17 horses at
an equestrian club, one of which died.
Equine influenza was confirmed in Colombia,
Germany and the USA. The disease occurred in 16
of 32 departments in Colombia, with over 2,700
recorded cases including one death. The German
outbreak involved five unvaccinated horses. Equine
influenza is endemic in the USA with evidence of
infection identified in three states.
Belgium, France, Germany, Ireland, Switzerland, the UK, and the USA reported multiple
outbreaks of strangles. The number of confirmed
outbreaks ranged from two in Germany and
Switzerland, three in Belgium, 17 in France, 60
in Ireland, and 154 in the USA. The disease isendemic in the UK and the USA.
Equine herpesvirus 1 related diseases were recorded by Argentina, Belgium, Canada, France,
Germany, Japan, RSA, Switzerland, and the USA.
Respiratory disease was diagnosed in Belgium (11outbreaks), France (two outbreaks), RSA (oneoutbreak), and the USA (outbreaks in numerous
states). Cases of EHV-1 abortion were reported
by Argentina (one outbreak involving 15 cases inThoroughbreds, all with incomplete vaccination
histories), Japan, and RSA (single case in eachcountry). EHV-1 neurologic disease was confirmed
in Canada (two outbreaks), Germany and Switzerland (single case in each country), and the USA(six outbreaks involving single cases of the disease).
Equine herpesvirus 4 respiratory disease wasdiagnosed in France (20 outbreaks), Germany(three cases involving two premises), and the UK(seven outbreaks, most of which represented single
cases of infection in unvaccinated horses).
Germany reported equine arteritis virus infection in a stallion.

Equine infectious anemia was confirmed in
Canada, France, and the USA. Two outbreaks involving single cases of asymptomatic infection wererecorded by Canada. France diagnosed a single
case, and the USA identified 17 cases involving
horses in five states, the preponderance in Texas.
The RSA reported equine piroplasmosis as
occurring in four provinces, with the majority ofconfirmed cases in Gauteng Province.
Contagious equine metritis was confirmed
in France (single clinical case in a mare) andGermany (10 cases, all in non-Thoroughbreds,
the majority were Icelandic horses; nine premises
were involved.)
Ireland and the USA reported outbreaks ofsalmonellosis. A total of 14 mares and foals wereinvolved in an outbreak in Ireland. Of 11 cases
diagnosed in the USA, nine were associated with
Salmonella serogroup B isolates.
Equine neorickettsiosis was reported by theUSA. The disease was confirmed in five states,with the highest number of cases (26) recorded in
Kentucky, of which six died.
Clostridial enterocolitis was diagnosed in alimited number of cases in the USA, all associatedwith Clostridium perfringens infection of undetermined toxin type.
The USA reported one case of proliferative
enteropathy (Lawsonia intracellularis infection).
The third quarter of 2018 saw cases of Easternequine encephalomyelitis confirmed in Canada (9)and the USA (39), the majority of which were inunvaccinated horses. Florida and Georgia were themost severely affected states in the USA.
West Nile virus infection was reported by
Canada (14 cases), France (6 cases), Greece (onecase), Germany (one case), Italy (105 cases), Romania (one case), RSA (one case), and the USA(140 cases, many in the state of Ohio).
Australia confirmed one case of Hendra virus
infection in an unvaccinated horse on a premises
in New South Wales.
A single case of equine encephalosis was diagnosed in a horse in the RSA Province of Gauteng.

Biofilm-Associated Endometritis

Bacterial endometritis (infection of the uterine mucosa) that is refractory to traditional
antimicrobial treatment is a significant challenge
to the equine breeding industry. A common survival strategy employed by bacterial pathogens is
the formation of a biofilm, which is a complex
and dynamic structure composed of aggregatesof bacteria surrounded by a thick protective layerof exopolysaccharide. Biofilms confer resistanceto immune mediated clearance by reducing thehost’s ability to recognize infection. Additionally,
biofilms protect bacteria from antibiotics by providing a diffusion barrier and creating a microenvironment that slows down bacterial metabolism
and replication, which makes them more tolerant
to antimicrobial agents.Using a model of equine
infectious endometritis, we have clearly identified
the ability of the bacterium Pseudomonas aeruginosato form a biofilm within the uterus of the mare.
The biofilm forms in multiple locations with thegreatest amount of adherent bacteria occurring between the tissue folds and in the uterine horns. Thissuggests that a traditional guarded culture swab
may not be ideal for detecting biofilm-associatedinfections and a low volume lavage may be a better
diagnostic tool. The bacteria are in greater numbers
deep within the endometrial glands as comparedto the luminal surface. To be successful in clearing
these infections, treatment options will need to becapable of penetrating deeper into the glands andtissue. For microscopic visualization of biofilms
within endometrial biopsies, Bouin’s solution
provides significantly better preservation of thebiofilm matrix on the surface of the endometrium
as compared to traditional formalin fixation.
Bacteria residing in a biofilm can be up to 1,000
times more refractive to treatment with antibiotics
as compared to free-living (planktonic) bacteria.
The simple administration of more or a higher
concentration of antibiotics has failed to eliminate chronic biofilm infections in both humanand veterinary medicine. The goal in treating a
biofilm-associated infection is to disrupt the biofilm material and kill the bacteria residing within
the biofilm.

Tall Fescues – Endophyte-infected,
Endophyte-free, and Novel Endophyte

A series of in vitro (within a laboratory setting,such as in a test tube) studies were conducted toassess biofilm dispersal and/or bacterial killing by
antibiotics and non-antibiotic agents alone or in
combination against Gram-negative bacteria (E.
coli, K. pneumoniae and P. aeruginosa). Data would
indicate that antibiotics and non-antibiotic agentsare more effective against biofilms if administeredconcurrently. When dealing with bacterial infections protected in biofilms, the treatment period
should be at least 72 hours in duration, withrepeated treatments every 24 hours (i.e. a uterine
infusion of the selected combination once every 24
hours for three consecutive days). Following thistreatment protocol, the biofilm was completed disrupted and bacterial killing ensued. Assessment ofantibiotic sensitivity of the offending pathogen(s)is still important as inherent genetic resistance ofthe bacteria involved will not be overcome solely
by the addition of the non-antibiotic compounds.
A recent in vivo study evaluated the intrauterine
treatment of a preformed Pseudomonas aeruginosabiofilm with a combination of ceftiofur and trisEDTA or ceftiofur and tris-EDTA alone. Of fivemares treated with a combination of ceftiofur andtris-EDTA, all effectively cleared the infection.
This contrasted with only two of five mares treatedwith ceftiofur and one of five mares with trisEDTA. The findings confirmed greater efficiency
in killing preformed biofilm within the uterus byusing a combination of antibiotic (ceftiofur) andnon-antibiotic (tris-EDTA) agents.
Advances in our understanding of the significance of biofilms in human and veterinary medicine will in time lead to improved diagnostics andmore effective treatment modalities. Fortunately
several therapeutic options are currently available
to clinicians for the treatment of biofilm-associatedequine bacterial endometritis.
CONTACT:
Ryan A. Ferris, DVM, MS, Dipl. ACT
rferris@summitequineinc.com
Summit Equine Inc.
Newberg, Oregon

T

MATT BARTON, UK AGRICULTURAL COMMUNICATIONS

all fescue (Lolium arundinaceum) is one of
the most widely grown perennial grasses in
the world and covers approximately 37 million
acres in the United States alone. It can be infectedwith an endophytic fungus (Epichloë coenophiala),
which in a symbiotic relationship with the plant
produces chemicals called alkaloids that confer
benefits to the plant. This tall fescue, native toEurope, was introduced into the United States in
the 1800s. In 1931, E.N. Fergus, a University of
Kentucky agronomist, collected tall fescue seedfrom the Suiter farm in Menifee County, KY, on
the basis of winter hardiness, persistence in hightraffic areas, and drought resistance, giving riseto the cultivar of fescue known as Kentucky 31(KY31). However, some of the alkaloids, primarily
the ergot alkaloids produced by infected plants, aredetrimental to grazing animals, including horses.
Historically, the endocrine hallmark of fescue
toxicosis in several animal species is a decreasein the circulating concentration of the hormone
prolactin. Prolactin is secreted by the pituitary
gland, and control of its secretion is complex
and not completely understood. Prolactin exerts
effects on a variety of systems including milk production, steroidogenesis (estrogens, progesterone
and testosterone), hair growth and shedding,libido, and synthesis of surfactant by the fetal
lungs. Importantly, prolactin may also exert aneffect on the feto-placental unit by altering steroid
synthesis and/or metabolism and maturation of
the fetal adrenal-pituitary axis, which is necessary
for parturition. One major regulator of prolactin
secretion is dopamine, a hormone produced by the
hypothalamus. Dopamine, interacts with receptors
in the pituitary gland and inhibits the secretionof prolactin.
Ergovaline is the most abundant ergot alkaloid
in tall fescue. Ergovaline, and several other alkaloids from fescue, have similar chemical structures
to dopamine and can bind to dopamine receptors,
thereby causing a decrease in prolactin secretion,
resulting in partial or complete agalactia (theinability to produce milk) in foaling mares. Additional problems associated with KY31 fescue

consumption in foaling mares include alteredhormone concentrations, extended gestation,
thickened placenta, placental retention, dystocia,
birth of dysmature foals, and increased foal andplacental weights. Dopamine receptors have beenfound in tissues other than the pituitary, including ovarian tissues and the corpus luteum, but theroles of those receptors in fescue toxicosis, if any,
have not been fully elucidated. The drug domperidone is frequently used in broodmares that are
exposed to KY31 fescue and prevents or reverses
the adverse reactions of ergovaline. Domperidone
functions by binding to dopamine receptors, butrather than suppressing prolactin production, it
competes with dopamine and allows for normal
prolactin secretion.
Because of the adverse health effects of common
endophyte infected fescue in grazing animals, varieties of tall fescue which do not contain the fungal
endophyte have been identified. Even thoughthese endophyte-free varieties do not produce
ergot alkaloids, animal performance is excellent.
However, the plants do not persist well in pastures
or compete well with other pasture grasses. Morerecently, endophyte strains that do not produce
the alkaloids that are harmful to animals but still
confer vigor and persistence to the plant, havebeen identified and inserted into tall fescue. These
are called novel endophyte varieties of fescue, andsome of these are commercially marketed as “Jesup
Max Q,” “Texoma Max QII,” and “Baroptima
Plus E34.” More recently, “Lacefield Max QII”
was released by Dr. Tim Phillips in the Department of Plant and Soil Sciences at the Universityof Kentucky. The Alliance for Grassland Renewal
is an association of seed companies, universities,
and government agencies that regulate themselves
by establishing certain quality control standards
for novel endophyte tall fescues. For example, allseeds sold under the Alliance tag must be 95%
pure, have 70% live (viable) endophyte, and have
independent confirmation that the fescue variety
does not cause fescue toxicosis in animals and will
persist well under conventional grazing conditions.
Although this article emphasizes the effects of

2

3

4

I N T E R N AT I O N A L

N AT I O N A L

Third Quarter 2018

T

Equine Disease Quarterly
Editors

Peter Timoney
Alan Loynachan
Cynthia Gaskill

Staff

Diane Furry
Tawana Brown
Dennis Duross
Anita Fleming
Correspondence should be
addressed to the editors,
Department of Veterinary
Science, Maxwell H. Gluck
Equine Research Center,
University of Kentucky,
Lexington, Kentucky USA,40546-0099
Telephone (859) 257-4757
Fax (859) 257-8542
Internet address:
http://gluck.ca.uky.edu/
equine-disease-quarterly
Material published in the
Quarterly is not subject tocopyright. Permission istherefore granted toreproduce articles, althoughacknowledgment of thesource and author is requested.
The University of Kentucky
is an Equal Opportunity
Organization.

Printed on recycled paper

he International Collating Centre, Newmarket, United Kingdom, and other sources
reported the following equine disease outbreaks.
The final four cases of African horse sickness tobe reported by the Republic of South Africa (RSA)
this season occurred during the first half of July;
two were in Eastern Cape Province, one in Free
State Province and one in KwaZulu-Natal.
An outbreak of glanders was reported by P.R.
China. The disease was confirmed in 17 horses at
an equestrian club, one of which died.
Equine influenza was confirmed in Colombia,
Germany and the USA. The disease occurred in 16
of 32 departments in Colombia, with over 2,700
recorded cases including one death. The German
outbreak involved five unvaccinated horses. Equine
influenza is endemic in the USA with evidence of
infection identified in three states.
Belgium, France, Germany, Ireland, Switzerland, the UK, and the USA reported multiple
outbreaks of strangles. The number of confirmed
outbreaks ranged from two in Germany and
Switzerland, three in Belgium, 17 in France, 60
in Ireland, and 154 in the USA. The disease isendemic in the UK and the USA.
Equine herpesvirus 1 related diseases were recorded by Argentina, Belgium, Canada, France,
Germany, Japan, RSA, Switzerland, and the USA.
Respiratory disease was diagnosed in Belgium (11outbreaks), France (two outbreaks), RSA (oneoutbreak), and the USA (outbreaks in numerous
states). Cases of EHV-1 abortion were reported
by Argentina (one outbreak involving 15 cases inThoroughbreds, all with incomplete vaccination
histories), Japan, and RSA (single case in eachcountry). EHV-1 neurologic disease was confirmed
in Canada (two outbreaks), Germany and Switzerland (single case in each country), and the USA(six outbreaks involving single cases of the disease).
Equine herpesvirus 4 respiratory disease wasdiagnosed in France (20 outbreaks), Germany(three cases involving two premises), and the UK(seven outbreaks, most of which represented single
cases of infection in unvaccinated horses).
Germany reported equine arteritis virus infection in a stallion.

Equine infectious anemia was confirmed in
Canada, France, and the USA. Two outbreaks involving single cases of asymptomatic infection wererecorded by Canada. France diagnosed a single
case, and the USA identified 17 cases involving
horses in five states, the preponderance in Texas.
The RSA reported equine piroplasmosis as
occurring in four provinces, with the majority ofconfirmed cases in Gauteng Province.
Contagious equine metritis was confirmed
in France (single clinical case in a mare) andGermany (10 cases, all in non-Thoroughbreds,
the majority were Icelandic horses; nine premises
were involved.)
Ireland and the USA reported outbreaks ofsalmonellosis. A total of 14 mares and foals wereinvolved in an outbreak in Ireland. Of 11 cases
diagnosed in the USA, nine were associated with
Salmonella serogroup B isolates.
Equine neorickettsiosis was reported by theUSA. The disease was confirmed in five states,with the highest number of cases (26) recorded in
Kentucky, of which six died.
Clostridial enterocolitis was diagnosed in alimited number of cases in the USA, all associatedwith Clostridium perfringens infection of undetermined toxin type.
The USA reported one case of proliferative
enteropathy (Lawsonia intracellularis infection).
The third quarter of 2018 saw cases of Easternequine encephalomyelitis confirmed in Canada (9)and the USA (39), the majority of which were inunvaccinated horses. Florida and Georgia were themost severely affected states in the USA.
West Nile virus infection was reported by
Canada (14 cases), France (6 cases), Greece (onecase), Germany (one case), Italy (105 cases), Romania (one case), RSA (one case), and the USA(140 cases, many in the state of Ohio).
Australia confirmed one case of Hendra virus
infection in an unvaccinated horse on a premises
in New South Wales.
A single case of equine encephalosis was diagnosed in a horse in the RSA Province of Gauteng.

Biofilm-Associated Endometritis

Bacterial endometritis (infection of the uterine mucosa) that is refractory to traditional
antimicrobial treatment is a significant challenge
to the equine breeding industry. A common survival strategy employed by bacterial pathogens is
the formation of a biofilm, which is a complex
and dynamic structure composed of aggregatesof bacteria surrounded by a thick protective layerof exopolysaccharide. Biofilms confer resistanceto immune mediated clearance by reducing thehost’s ability to recognize infection. Additionally,
biofilms protect bacteria from antibiotics by providing a diffusion barrier and creating a microenvironment that slows down bacterial metabolism
and replication, which makes them more tolerant
to antimicrobial agents.Using a model of equine
infectious endometritis, we have clearly identified
the ability of the bacterium Pseudomonas aeruginosato form a biofilm within the uterus of the mare.
The biofilm forms in multiple locations with thegreatest amount of adherent bacteria occurring between the tissue folds and in the uterine horns. Thissuggests that a traditional guarded culture swab
may not be ideal for detecting biofilm-associatedinfections and a low volume lavage may be a better
diagnostic tool. The bacteria are in greater numbers
deep within the endometrial glands as comparedto the luminal surface. To be successful in clearing
these infections, treatment options will need to becapable of penetrating deeper into the glands andtissue. For microscopic visualization of biofilms
within endometrial biopsies, Bouin’s solution
provides significantly better preservation of thebiofilm matrix on the surface of the endometrium
as compared to traditional formalin fixation.
Bacteria residing in a biofilm can be up to 1,000
times more refractive to treatment with antibiotics
as compared to free-living (planktonic) bacteria.
The simple administration of more or a higher
concentration of antibiotics has failed to eliminate chronic biofilm infections in both humanand veterinary medicine. The goal in treating a
biofilm-associated infection is to disrupt the biofilm material and kill the bacteria residing within
the biofilm.

Tall Fescues – Endophyte-infected,
Endophyte-free, and Novel Endophyte

A series of in vitro (within a laboratory setting,such as in a test tube) studies were conducted toassess biofilm dispersal and/or bacterial killing by
antibiotics and non-antibiotic agents alone or in
combination against Gram-negative bacteria (E.
coli, K. pneumoniae and P. aeruginosa). Data would
indicate that antibiotics and non-antibiotic agentsare more effective against biofilms if administeredconcurrently. When dealing with bacterial infections protected in biofilms, the treatment period
should be at least 72 hours in duration, withrepeated treatments every 24 hours (i.e. a uterine
infusion of the selected combination once every 24
hours for three consecutive days). Following thistreatment protocol, the biofilm was completed disrupted and bacterial killing ensued. Assessment ofantibiotic sensitivity of the offending pathogen(s)is still important as inherent genetic resistance ofthe bacteria involved will not be overcome solely
by the addition of the non-antibiotic compounds.
A recent in vivo study evaluated the intrauterine
treatment of a preformed Pseudomonas aeruginosabiofilm with a combination of ceftiofur and trisEDTA or ceftiofur and tris-EDTA alone. Of fivemares treated with a combination of ceftiofur andtris-EDTA, all effectively cleared the infection.
This contrasted with only two of five mares treatedwith ceftiofur and one of five mares with trisEDTA. The findings confirmed greater efficiency
in killing preformed biofilm within the uterus byusing a combination of antibiotic (ceftiofur) andnon-antibiotic (tris-EDTA) agents.
Advances in our understanding of the significance of biofilms in human and veterinary medicine will in time lead to improved diagnostics andmore effective treatment modalities. Fortunately
several therapeutic options are currently available
to clinicians for the treatment of biofilm-associatedequine bacterial endometritis.
CONTACT:
Ryan A. Ferris, DVM, MS, Dipl. ACT
rferris@summitequineinc.com
Summit Equine Inc.
Newberg, Oregon

T

MATT BARTON, UK AGRICULTURAL COMMUNICATIONS

all fescue (Lolium arundinaceum) is one of
the most widely grown perennial grasses in
the world and covers approximately 37 million
acres in the United States alone. It can be infectedwith an endophytic fungus (Epichloë coenophiala),
which in a symbiotic relationship with the plant
produces chemicals called alkaloids that confer
benefits to the plant. This tall fescue, native toEurope, was introduced into the United States in
the 1800s. In 1931, E.N. Fergus, a University of
Kentucky agronomist, collected tall fescue seedfrom the Suiter farm in Menifee County, KY, on
the basis of winter hardiness, persistence in hightraffic areas, and drought resistance, giving riseto the cultivar of fescue known as Kentucky 31(KY31). However, some of the alkaloids, primarily
the ergot alkaloids produced by infected plants, aredetrimental to grazing animals, including horses.
Historically, the endocrine hallmark of fescue
toxicosis in several animal species is a decreasein the circulating concentration of the hormone
prolactin. Prolactin is secreted by the pituitary
gland, and control of its secretion is complex
and not completely understood. Prolactin exerts
effects on a variety of systems including milk production, steroidogenesis (estrogens, progesterone
and testosterone), hair growth and shedding,libido, and synthesis of surfactant by the fetal
lungs. Importantly, prolactin may also exert aneffect on the feto-placental unit by altering steroid
synthesis and/or metabolism and maturation of
the fetal adrenal-pituitary axis, which is necessary
for parturition. One major regulator of prolactin
secretion is dopamine, a hormone produced by the
hypothalamus. Dopamine, interacts with receptors
in the pituitary gland and inhibits the secretionof prolactin.
Ergovaline is the most abundant ergot alkaloid
in tall fescue. Ergovaline, and several other alkaloids from fescue, have similar chemical structures
to dopamine and can bind to dopamine receptors,
thereby causing a decrease in prolactin secretion,
resulting in partial or complete agalactia (theinability to produce milk) in foaling mares. Additional problems associated with KY31 fescue

consumption in foaling mares include alteredhormone concentrations, extended gestation,
thickened placenta, placental retention, dystocia,
birth of dysmature foals, and increased foal andplacental weights. Dopamine receptors have beenfound in tissues other than the pituitary, including ovarian tissues and the corpus luteum, but theroles of those receptors in fescue toxicosis, if any,
have not been fully elucidated. The drug domperidone is frequently used in broodmares that are
exposed to KY31 fescue and prevents or reverses
the adverse reactions of ergovaline. Domperidone
functions by binding to dopamine receptors, butrather than suppressing prolactin production, it
competes with dopamine and allows for normal
prolactin secretion.
Because of the adverse health effects of common
endophyte infected fescue in grazing animals, varieties of tall fescue which do not contain the fungal
endophyte have been identified. Even thoughthese endophyte-free varieties do not produce
ergot alkaloids, animal performance is excellent.
However, the plants do not persist well in pastures
or compete well with other pasture grasses. Morerecently, endophyte strains that do not produce
the alkaloids that are harmful to animals but still
confer vigor and persistence to the plant, havebeen identified and inserted into tall fescue. These
are called novel endophyte varieties of fescue, andsome of these are commercially marketed as “Jesup
Max Q,” “Texoma Max QII,” and “Baroptima
Plus E34.” More recently, “Lacefield Max QII”
was released by Dr. Tim Phillips in the Department of Plant and Soil Sciences at the Universityof Kentucky. The Alliance for Grassland Renewal
is an association of seed companies, universities,
and government agencies that regulate themselves
by establishing certain quality control standards
for novel endophyte tall fescues. For example, allseeds sold under the Alliance tag must be 95%
pure, have 70% live (viable) endophyte, and have
independent confirmation that the fescue variety
does not cause fescue toxicosis in animals and will
persist well under conventional grazing conditions.
Although this article emphasizes the effects ofEquine Disease Quarterly Newsletter

5ergot alkaloids on a dopaminergic receptor, it isimportant to remember that some of the alkaloids also bind to other receptor types, including
adrenergic and serotonergic receptors, and thus
may affect additional body systems.

CONTACT:
Karen McDowell, PhD
kmcd@uky.edu(859) 218-1104
Maxwell H. Gluck Equine Research Center
Tim Phillips, PhD
Department of Plant and Soil Sciences
University of Kentucky
Lexington, KY

Presorted Standard
US Postage Paid
Permit 51
Lexington KY

Department of Veterinary Science
Maxwell H. Gluck Equine Research Center
University of Kentucky
Lexington, Kentucky 40546-0099
Address Service Requested

F U N D E D B Y U N D E R W R I T E R S AT L LOY D ' S , LO N D O N

JANUARY 2019
Volume 28, Number 1

KENTUCKY

Equine Abortion: A Review of the 2016 and 2017
Breeding Seasons in KentuckyT

he loss of a developing fetus during pregnancy
can be a frustrating, emotional, and costly
experience for horse owners, farm workers, veterinarians, and the public. A thorough evaluation of
the aborted fetoplacental unit (fetus and placenta)
by a veterinary pathologist can help determine
the cause of abortion, identify new, unusual, or
foreign causes of fetal loss, rule out involvement
by infectious agents, and aid in the epidemiologic
monitoring of abortifacients (factors that can resultin abortion). A two-year review of equine abortions, from the 2016 and 2017 breeding seasons,was conducted at the University of Kentucky Veterinary Diagnostic Laboratory to evaluate current
abortion trends.
Dates listed below indicate data for the respective breeding season, not calendar year.
A total of 898 cases of equine abortion, 570
from 2016 and 328 from 2017, were evaluated.
The majority of cases were considered sporadic
and unrelated, except for one equine herpesvirus 1
abortion storm that was identified during the 2016
breeding season. Abortions during early gestation
began in May of the 2016 breeding season andJune of 2017 breeding season. The highest numberof abortions occurred in March of both years, andthe last abortions occurred in July of 2017 (2016breeding season) and May of 2018 (2017 breeding
season). Abortions were categorized into infectious(2016= 55% and 2017= 38%) and non-infectious
causes (2016= 45% and 2017= 62%).
Infectious causes of fetal death were attributed to bacterial, viral, fungal, and unidentified (presumably bacterial) agents that resulted inplacentitis and/or systemic infections. Placentitis
was the most common cause of infectious disease

and was identified in 280 cases (24.6%) in 2016
and 102 cases (20.2%) in 2017. Approximately 5%of abortions each year were attributed to ascending
placental infections through the mare’s cervix bybacteria such as Streptococcus zooepidemicus andEscherichia coli. Nocardioform/mucoid placentitis
was diagnosed in 145 (12.7%) and 27 (5.3%) cases
during 2016 and 2017, respectfully. Three cases of
mycotic placentitis were diagnosed in 2016, andone case was diagnosed in 2017. Placentitis due
to unidentified agents occurred in 79 (6.9%) casesin 2016 and 47 (9.3%) cases during 2017. Agentswere not identified, presumably, due to the use of
antimicrobial therapy, chronic resolved infections,or overgrowth by environmental organisms. Leptospiral abortion or perinatal death was identified infive cases (0.4%) during 2016 and 11 cases (2.2%)
in 2017. Abortion due to fetal bacterial septicemia
or pneumonia was diagnosed in 4.4% of cases in2016 and 1.6% of cases in 2017. Equine herpesvirus 1 was the only viral agent identified in fetusesover the two-year period, and it was responsiblefor 16 (1.4%) abortions or perinatal deaths in the2016 breeding season and 10 (2.0%) in the 2017
breeding season.
Non-infectious causes of abortion are considered sporadic events. They included abortion associated with umbilical cord torsion (2016= 3.9%
and 2017= 7.9%), fetal stress (2016= 1.8% and2017= 2.0%), placental “cervical pole” necrosis(2016= 0.5% and 2017= 0.4%), twin pregnancy(2016= 0% and 2017= 0.6%), miscellaneouscauses (hydrops, tissue necrosis of unknown etiology, and maternal stress and disease; 2016= 1.2%
and 2017= 2.0%), and abortion of undeterminedcause (2016= 14.9% and 2017= 27.5%).

C O M M E N TA RY
IN THIS ISSUE
Commentary
International
Third Quarter2018  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 2Biofilm-AssociatedEndometritis  .  .  .  .  .  .  .  . 3National
Tall Fescues .  .  .  .  .  .  .  .  .  . 4KentuckyAbortion of undetermined cause occurs quite
regularly and is frustrating to both clients and diagnosticians. Based on the human and veterinary
literature, many of these occur due to physiologic
abnormalities (e.g. fetal cardiovascular disease,
hypoxia), stress and disease in the pregnant mare,autoimmune disorders, genetic irregularities, environmental exposures, and endocrine abnormalities; all of which cannot be easily assessed or tested
for in the aborted fetoplacental units. A diagnosisof abortion of undetermined etiology isn’t completely without value, because infectious diseases
and other possible causes of abortion storms canbe readily ruled out.

In conclusion, equine abortion remains to
be unfortunately common. Both infectious andnon-infectious causes are frequently responsible.
Evaluation of the aborted fetoplacental unit byyour local veterinary diagnostic laboratory can aid
in determining the cause of abortion, help to monitor and track known abortifacients, and identify
new and possibly emerging causes of abortion.

Equine Abortion .  .  .  .  . 5

CONTACT:
Alan Loynachan, DVM, PhD
alan.loynachan@uky.edu(859) 257-8283
University of Kentucky Veterinary Diagnostic Laboratory
Lexington, KY

College of Agriculture,
Food and Environment
Department of
Veterinary ScienceL

ate-term abortion is one of the most devastating
issues horse breeders face. Every pregnancy represents a labor of love, with a substantial amountof time, energy and money put into achieving theperfect foal. Every pregnancy loss raises questions
concerning our ability to have prevented that loss
and whether we could have done more.
In this issue, Dr. Alan Loynachan addresses
the underlying causes of the 898 equine abortions
examined by the UK Veterinary Diagnostic Laboratory over the 2016 and 2017 breeding seasons.
This retrospective look is important to help us
identify areas where we can improve management
techniques and where we should focus our future
research efforts to best benefit horse owners andbreeders. As such, it’s critical that breeding farms
send their aborted foals to a veterinary diagnostic
laboratory, even if the cause of abortion appears
obvious.
Approximately 50% of the abortions evaluated were deemed non-infectious. Of these, mostare not likely to be management related with the
exception of twin pregnancies; however, twins did
not comprise a large percentage of the abortions
submitted. This is likely due to better management
techniques, namely identification and reduction oftwin pregnancies early in gestation, but also likely
reflects the failure of owners to submit abortions
with an obvious cause to the diagnostic laboratory. While this is understandable, it also makes
it difficult to accurately measure the frequency ofthese losses.
Infectious abortions comprised the other 50%
of submitted abortions, with placentitis representing the majority of these cases. Unfortunately,
we know little about what predisposes a mare todevelop placentitis, and still have trouble withearly, accurate and specific diagnosis. Even so,

there are steps that owners can take to aid in early
diagnosis, including endocrine monitoring, regular ultrasound evaluation of the placenta as well
as daily checks for premature mammary glanddevelopment, premature lactation, and purulent
vulvar discharge. If anything out of the ordinary is
noted, a veterinarian should be called to examine
the mare and start treatment if indicated.
As placentitis comprises the majority of the infectious abortions seen, the laboratory of Dr. Barry
Ball at the Gluck Equine Research Center has been
focusing on better understanding the causes andprogression of placentitis. By utilizing state-of-theart techniques to look at changing gene expression,
we have identified several potential targets which
we believe will function as diagnostic aids and/or
treatment options. Although more work is stillneeded to confirm our findings, we are optimisticthat better options for dealing with placentitis will
be available soon.
Again, I cannot stress enough the importanceof sending all aborted foals, including fetal
membranes and maternal serum, to a veterinary
diagnostic laboratory. When breeders fail to submit abortions, it becomes more difficult to spot
trends and, in turn, becomes more difficult to
identify and respond to emerging threats. It’s easy
to justify only submitting abortions without anobvious cause; however, the overall health of theequine breeding industry relies on the submissionof every abortion, every time.
CONTACT:
Shavahn Loux, PhD
Shavahn.Loux@uky.edu(859) 257-4757
Maxwell H. Gluck Equine Research Center
University of Kentucky
Lexington, KY

Equine Disease Quarterly Newsletter

5ergot alkaloids on a dopaminergic receptor, it isimportant to remember that some of the alkaloids also bind to other receptor types, including
adrenergic and serotonergic receptors, and thus
may affect additional body systems.

CONTACT:
Karen McDowell, PhD
kmcd@uky.edu(859) 218-1104
Maxwell H. Gluck Equine Research Center
Tim Phillips, PhD
Department of Plant and Soil Sciences
University of Kentucky
Lexington, KY

Department of Veterinary Science
Maxwell H. Gluck Equine Research Center
University of Kentucky
Lexington, Kentucky 40546-0099
Address Service Requested

F U N D E D B Y U N D E R W R I T E R S AT L LOY D ' S , LO N D O N

JANUARY 2019
Volume 28, Number 1

KENTUCKY

Equine Abortion: A Review of the 2016 and 2017
Breeding Seasons in KentuckyT

he loss of a developing fetus during pregnancy
can be a frustrating, emotional, and costly
experience for horse owners, farm workers, veterinarians, and the public. A thorough evaluation of
the aborted fetoplacental unit (fetus and placenta)
by a veterinary pathologist can help determine
the cause of abortion, identify new, unusual, or
foreign causes of fetal loss, rule out involvement
by infectious agents, and aid in the epidemiologic
monitoring of abortifacients (factors that can resultin abortion). A two-year review of equine abortions, from the 2016 and 2017 breeding seasons,was conducted at the University of Kentucky Veterinary Diagnostic Laboratory to evaluate current
abortion trends.
Dates listed below indicate data for the respective breeding season, not calendar year.
A total of 898 cases of equine abortion, 570
from 2016 and 328 from 2017, were evaluated.
The majority of cases were considered sporadic
and unrelated, except for one equine herpesvirus 1
abortion storm that was identified during the 2016
breeding season. Abortions during early gestation
began in May of the 2016 breeding season andJune of 2017 breeding season. The highest numberof abortions occurred in March of both years, andthe last abortions occurred in July of 2017 (2016breeding season) and May of 2018 (2017 breeding
season). Abortions were categorized into infectious(2016= 55% and 2017= 38%) and non-infectious
causes (2016= 45% and 2017= 62%).
Infectious causes of fetal death were attributed to bacterial, viral, fungal, and unidentified (presumably bacterial) agents that resulted inplacentitis and/or systemic infections. Placentitis
was the most common cause of infectious disease

and was identified in 280 cases (24.6%) in 2016
and 102 cases (20.2%) in 2017. Approximately 5%of abortions each year were attributed to ascending
placental infections through the mare’s cervix bybacteria such as Streptococcus zooepidemicus andEscherichia coli. Nocardioform/mucoid placentitis
was diagnosed in 145 (12.7%) and 27 (5.3%) cases
during 2016 and 2017, respectfully. Three cases of
mycotic placentitis were diagnosed in 2016, andone case was diagnosed in 2017. Placentitis due
to unidentified agents occurred in 79 (6.9%) casesin 2016 and 47 (9.3%) cases during 2017. Agentswere not identified, presumably, due to the use of
antimicrobial therapy, chronic resolved infections,or overgrowth by environmental organisms. Leptospiral abortion or perinatal death was identified infive cases (0.4%) during 2016 and 11 cases (2.2%)
in 2017. Abortion due to fetal bacterial septicemia
or pneumonia was diagnosed in 4.4% of cases in2016 and 1.6% of cases in 2017. Equine herpesvirus 1 was the only viral agent identified in fetusesover the two-year period, and it was responsiblefor 16 (1.4%) abortions or perinatal deaths in the2016 breeding season and 10 (2.0%) in the 2017
breeding season.
Non-infectious causes of abortion are considered sporadic events. They included abortion associated with umbilical cord torsion (2016= 3.9%
and 2017= 7.9%), fetal stress (2016= 1.8% and2017= 2.0%), placental “cervical pole” necrosis(2016= 0.5% and 2017= 0.4%), twin pregnancy(2016= 0% and 2017= 0.6%), miscellaneouscauses (hydrops, tissue necrosis of unknown etiology, and maternal stress and disease; 2016= 1.2%
and 2017= 2.0%), and abortion of undeterminedcause (2016= 14.9% and 2017= 27.5%).

C O M M E N TA RY
IN THIS ISSUE
Commentary
International
Third Quarter2018  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 2Biofilm-AssociatedEndometritis  .  .  .  .  .  .  .  . 3National
Tall Fescues .  .  .  .  .  .  .  .  .  . 4KentuckyAbortion of undetermined cause occurs quite
regularly and is frustrating to both clients and diagnosticians. Based on the human and veterinary
literature, many of these occur due to physiologic
abnormalities (e.g. fetal cardiovascular disease,
hypoxia), stress and disease in the pregnant mare,autoimmune disorders, genetic irregularities, environmental exposures, and endocrine abnormalities; all of which cannot be easily assessed or tested
for in the aborted fetoplacental units. A diagnosisof abortion of undetermined etiology isn’t completely without value, because infectious diseases
and other possible causes of abortion storms canbe readily ruled out.

In conclusion, equine abortion remains to
be unfortunately common. Both infectious andnon-infectious causes are frequently responsible.
Evaluation of the aborted fetoplacental unit byyour local veterinary diagnostic laboratory can aid
in determining the cause of abortion, help to monitor and track known abortifacients, and identify
new and possibly emerging causes of abortion.

Equine Abortion .  .  .  .  . 5

CONTACT:
Alan Loynachan, DVM, PhD
alan.loynachan@uky.edu(859) 257-8283
University of Kentucky Veterinary Diagnostic Laboratory
Lexington, KY

College of Agriculture,
Food and Environment
Department of
Veterinary ScienceL

ate-term abortion is one of the most devastating
issues horse breeders face. Every pregnancy represents a labor of love, with a substantial amountof time, energy and money put into achieving theperfect foal. Every pregnancy loss raises questions
concerning our ability to have prevented that loss
and whether we could have done more.
In this issue, Dr. Alan Loynachan addresses
the underlying causes of the 898 equine abortions
examined by the UK Veterinary Diagnostic Laboratory over the 2016 and 2017 breeding seasons.
This retrospective look is important to help us
identify areas where we can improve management
techniques and where we should focus our future
research efforts to best benefit horse owners andbreeders. As such, it’s critical that breeding farms
send their aborted foals to a veterinary diagnostic
laboratory, even if the cause of abortion appears
obvious.
Approximately 50% of the abortions evaluated were deemed non-infectious. Of these, mostare not likely to be management related with the
exception of twin pregnancies; however, twins did
not comprise a large percentage of the abortions
submitted. This is likely due to better management
techniques, namely identification and reduction oftwin pregnancies early in gestation, but also likely
reflects the failure of owners to submit abortions
with an obvious cause to the diagnostic laboratory. While this is understandable, it also makes
it difficult to accurately measure the frequency ofthese losses.
Infectious abortions comprised the other 50%
of submitted abortions, with placentitis representing the majority of these cases. Unfortunately,
we know little about what predisposes a mare todevelop placentitis, and still have trouble withearly, accurate and specific diagnosis. Even so,

there are steps that owners can take to aid in early
diagnosis, including endocrine monitoring, regular ultrasound evaluation of the placenta as well
as daily checks for premature mammary glanddevelopment, premature lactation, and purulent
vulvar discharge. If anything out of the ordinary is
noted, a veterinarian should be called to examine
the mare and start treatment if indicated.
As placentitis comprises the majority of the infectious abortions seen, the laboratory of Dr. Barry
Ball at the Gluck Equine Research Center has been
focusing on better understanding the causes andprogression of placentitis. By utilizing state-of-theart techniques to look at changing gene expression,
we have identified several potential targets which
we believe will function as diagnostic aids and/or
treatment options. Although more work is stillneeded to confirm our findings, we are optimisticthat better options for dealing with placentitis will
be available soon.
Again, I cannot stress enough the importanceof sending all aborted foals, including fetal
membranes and maternal serum, to a veterinary
diagnostic laboratory. When breeders fail to submit abortions, it becomes more difficult to spot
trends and, in turn, becomes more difficult to
identify and respond to emerging threats. It’s easy
to justify only submitting abortions without anobvious cause; however, the overall health of theequine breeding industry relies on the submissionof every abortion, every time.
CONTACT:
Shavahn Loux, PhD
Shavahn.Loux@uky.edu(859) 257-4757
Maxwell H. Gluck Equine Research Center
University of Kentucky
Lexington, KY