MAY 2023 VOLUME 32, NO.2

A PUBLICATION BY THE UNIVERSITY OF KENTUCKY DEPARTMENT OF VETERINARY SCIENCE, MAXWELL H. GLUCK EQUINE RESEARCH CENTER
FUNDED BY:

EQUUS / STANDARDBRED STATION, INC.
M&J INSURANCEIN TH I S I S S U ECOMMENTARY

INTERNATIONALINTERNATIONALFirst Quarter 2023...............1,2

A Note from the Editors of the Equine
Disease QuarterlyFirst Quarter 2023

Managing and feeding theorphaned or rejected foal frombirth to four months of age.....3,4

International report on equine
Over the last several years, the Equine Disease infectious diseases.

Quarterly (EDQ) has inevitably become a more
fluid publication with multiple behind-the-scenes
NATIONAL
changes in editors and staff, new sponsors—
Equine Respiratory Biosurveillance- including Equus Standardbred Station and
What have we learned?...........5,6 M & J Insurance, and of course, the move to an
Gastric Ulcers inHorses..........6,7 electronic format.
Since its inception, the EDQ has provided readerswith an opening commentary, in which an expert
provides opinions or thoughts on a timely topic,
often related to the articles within the issue. We
are excited to announce that beginning with thenext issue, the opening commentary will transition
into a University of Kentucky Department of
Veterinary Science spotlight.
The goal of this new format expands on what
the EDQ does best, communicating importantscientific research and disease knowledge to theequine industry. With this upcoming c h a n g e ,we aim to provide our departmental faculty,
staff, graduate students and collaborators theopportunity to highlight their research and display
the department’s dedication and enthusiasm to theadvancement of equine science and health. We arevery proud of the department’s accomplishments
and continued contributions to the global equine
industry. We hope you enjoy this new addition to
the EDQ.

The following report was composed withinformation provided by the University of
Kentucky Veterinary Diagnostic Laboratory andEquine Diagnostic Solutions, Inc.(EDS)—both in
Lexington, Kentucky, United States of America(USA); IDEXX Laboratories, Germany; theInternational Thoroughbred Breeders Federation;
the International Collating Centre (ICC) in
Newmarket, United Kingdom (UK); and by theAmerican Association of Equine Practitioners’
Equine Disease Communication Center (EDCC).
This report is retrospective and does not claim tobe complete. However, it provides an indicationof heightened activity of relevant contagious orenvironment-linked diseases among equids. To
further improve this data, it is encouraged toreport laboratory-confirmed infectious diseases
and toxicoinfections of Equidae to the ICC in
Newmarket, UK. Reporting of equine diseases
from the Southern Hemisphere and from mostparts of Asia was scarce. A case of glanders(caused by Burkholderia mallei) was reported
from eastern-central Russia near the Mongolian
border. Uruguay reported a single case of equine
infectious anemia (EIA) virus infection. North
America and Europe, including the British Isles,
consistently reported cases and outbreaks of
strangles (caused by Streptococcus equi spp.
equi). The numbers reported by EDCC and ICC
corroborate the laboratory data from EDS andIDEXX, and detection of the pathogen in nasal
swabs/pharyngeal or guttural pouch washes iswidespread. However, it is difficult to interpretdisease incidence from laboratory results, becausesome samples likely represent follow-up samples
derived from an ongoing outbreak.
MAY 2023 | 1

INTERN ATIONAL
Equine influenza virus is currently circulating inEurope, including the British Isles (ICC report).
EDS reported that approximately 10% of nasal
swabs submitted for equine influenza virus testing
were positive; swabs were submitted from mostregions of the USA. Equine herpes virus (EHV)-4
or -1 respiratory disease was infrequently reported
in the USA and more so from operations in the
UK, Ireland and continental Europe. Few EHV
abortions were reported from North America,
and three EHV-1 abortions were reported from
central Kentucky, USA. Noteworthy, there was
not further propagation of virus within pregnant
mares on those farms. We believe this is due tohigh vaccination rates combined with fast andeffective management interventions. EHV-1
abortions typically occur in the last trimesterof pregnancy. Therefore, it is not unusual thatreported abortions have increased significantly
for continental Europe and the British Isles
compared to our previous (Q4)report.
Equidherpesvirus-associatedmyeloencephalopathy (EHM) also follows aseasonal pattern with the majority of outbreaks
associated with the cooler times of the year (first,
second and fourth quarters for the Northern
Hemisphere). Close to 20 outbreaks with variable
EHM prevalence were reported in North America,
and about 15 outbreaks were reported in Europe,
including the UK. Spain reported an EHM
outbreak at an equestrian event that was similar inorganization and setup compared to the Valenciaoutbreak of 2021.
Heightened awareness of early stages of infection,a rapid response with testing of animals, andbiosecurity management has shown to mitigate
outbreaks effectively.
EQUINE DISEASEQUARTERLYEDITORS
Rebecca Ruby
Lutz Goehring
Allen Page
STAFF
Holly Wiemers
Anita Hatchet
Hendri Smeenk

2 | EQUINE DISEASE QUARTERLY

A seasonal increase in EHV-1 detection from nasal
swabs was reported in the quarterly results of acommercial laboratory located in the Northern
Hemisphere (Fig. 1).
Note, the 3rd quarter (July – September) of
2021 and 2022 consistently reported the lowest
positivity rate for EHV-1 compared to the otherquarters. Few cases of EIA were reported in
N. America. A cluster of connected cases in theSouthern USA was reported in connection withillegal horse racing activities (‘bush’ racing),
where a form of blood doping is not uncommon.
Single EIA cases were also reported from Hungary
and Italy.
Insect vectors are active year-round in regions
bordering the Gulf of Mexico. Single cases ofEastern equine encephalitis were reported in
Florida and South Carolina, as well as a West
Nile virus (WNV) case from Florida. Another
WNV encephalitis case was identified in Libya,
Northern Africa.
Equine rotavirus was identified in 49 samples in
the USA. Most samples were positive for rotavirus
type B, and with few exceptions (Oklahoma, NewYork), most samples were derived from central
Kentucky.
Miscellaneous: Contagious equine
metritis:Three casesof
Taylorellaequigenitalis
infection were reported from Germany.
It is currently unknown whether thesecases were epidemiologically connected.
Lutz Goehring,
UniversityofKentucky
Gluck Equine Research Center – Department of
Veterinary Science
Email: l.goehring@uky.edu

INTERNATIONALManaging and feeding the orphanedor rejected foal from birth to fourmonths of age.
Each foaling season, foals are orphaned, rejected,
or born to mares that have no milk. This article
details a highly successful program for raisingthese foals, which has been implemented at several universities, veterinary hospitals and horse
farms. This feeding program is designed for those
who are managing healthy foals that are orphaned,rejected, or born from mares without milk or were
weaned early. Foals raised on this program growand mature the same as non-orphans.
Foals must ingest colostrum or be provided with
antibodies for immune protection. Colostrum,or the mare’s first milk, contains high levels ofwhole protein antibodies to protect the foal from
disease. Mares normally secrete colostrum up to
24 hours after foaling. All newborn foals need colostrum, ideally, within the first hour after birth. A
100 lb foal should receive 250 ml (approximately 1 cup) of colostrum each hour for the first six
hours after they are born. This is a total of 1500
ml, or about 3 pints of colostrum per 100 lb ofbody weight. Therefore, breeding farms shouldhave a minimum of 3 pints of frozen colostrum instorage. When needed, it should be removed fromthe freezer and thawed at room temperature or ina warm water bath. Never microwave colostrum
because that will destroy the antibodies and render them useless.
Following colostrum consumption, foals aretaught to drink milk replacer from a bucket. Foals
should start drinking from a shallow plastic bowl
or a bottle with a lamb nipple attached, depending on the foal’s aggressiveness. Most foals willlearn to drink from a shallow bowl or bucket very
quickly. A method to help foals learn to drink involves placing a finger in their mouths to stimulate the suckle reflex. While they are sucking,raise the bowl containing the milk replacer to theirmuzzle. After they begin to drink, slowly remove
the finger from the foal’s mouth. Repeat until theykeep drinking by themselves. Always bring themilk up to the foal; do not force the foal’s head
down. The first few days, warm the milk replacer
to 101.5° F to encourage consumption. This is thesame temperature as milk from the mare. Whenthe foal is drinking independently, hang a bucketat the foals’ shoulder height and provide the milk
replacer at room temperature. The bucket should
be a contrasting color to the wall to make it easy
for the foal to find.

The chosen milk replacer should be an all-milk
product. To assure the equine milk replacer powder is ‘all-milk,’ look at the percentage of fiber
listed on the feed tag. It must be less than 0.2%
crude fiber or less than 0.4% acid detergent fiber.
All milk replacers containing 1.0% crude fiber orhigher, will contain a protein source that is lessexpensive, but not as digestible to the newborn
foal. Any protein source other than milk can cause
loose stools or diarrhea in the young foal, depending on how much is consumed per day. The selected ingredients in a foal’s food are based on the
foal’s ability to digest them and help maintain thenatural pH level in their digestive system. Make
sure to follow the mixing directions, to make a
10% solution, equivalent to mare’s milk. (Onepound of milk powder to one gallon of water.)Mares produce 3.0% - 3.5% of their body weightin milk per day, as a 10% milk solid solution.
This means a 1,000 lb (454 kg) mare will produce 30 to 35 lb (14 to 16 kg) or about 4 gal (18L) of milk per day. Table 1 can be used to determine, based on the size of the dam, the amountof milk the mare would have produced. Begin byproviding half the recommended amount on thefirst day. Gradually increase the amount over seven to 10 days, but no faster than one-half gallonor 2 L per day, until the recommended amount isbeing consumed. Once the foals are drinking therecommended amount, mix one half of the daily
amount, and make it available free choice, AM
and PM. Allowing the foal to drink small amounts
as often as it wants, will result in fewer digestive upsets, improved milk digestibility, optimal
weight gain and improved overall foal health.
Each time new formula is mixed, discard remaining milk, and clean the bucket before adding
fresh milk replacer. When fed at room temperature, acidified milk replacers will have a tart taste
which discourages a foal from drinking too muchat one time when offered free choice. For the first
30 days, foals will drink seven to ten times perhour. Feeding milk replacer free choice allows thefoal to drink as often as it would if a mare waspresent. Free choice feeding also greatly reduces
the chance of digestive upsets by preventing themfrom becoming too hungry and over drinking.
If they run out of milk for over one hour, they will
drink too fast at the next feeding. This should be
avoided as it may cause colic and/or diarrhea.

Material published in the
Quarterly is not subject
to copyright. Permissionis therefore granted toreproduce articles, althoughacknowledgment of the source
and author is requested.
Maxwell H. Gluck
Equine Research Center
Lexington, Kentucky USA,40546-0099
Telephone (859) 257-4757
Fax (859) 257-8542
gluck.ca.uky.edu

MAY 2023 | 3

INTERN ATIONAL
After the foal drinks the liquid milk replacer
before the next feeding, add a handful of milkbased pellets into the same bucket. The pellet
may be milk or milk based with the starch in the
milk-based pellet rolled oats rather than othercereal grains. Using the same bucket makes thefoals more comfortable consuming this new feed.
At the next liquid feeding, discard any remainingpellets. Repeat this process until the foal eats
the pellets, at this time pellets are provided ina separate bucket and can also be offered freechoice. Please note, a weanling feed formulatedwith cereal grains, fat and fiber, with the added
minerals is not recommended yet. During the firsttwo months of age, the foal will have very small
amounts of the enzymes needed to breakdown
nonstructural carbohydrates in weanling feed.
Feeding these feeds too early can lead to diarrhea,
malabsorption and colic. The digestive systemchanges according to their age, not their size.
So age, rather than height and bodyweight,
will determine when additional feed should be
introduced.
When the foal is eight weeks old, begin reducing
the liquid milk replacer by one gallon (4.5 L) the
first day and replace it by adding one additional
pound of milk-based pellets. Once the foal
consumes the added pellets, reduce an additional
gallon/day of liquid, and provide another poundof the pellets per day. Continue until the pellets
replace all the liquid solution. This transition
should take about one week. This gradual change
will reduce the chance of digestive upset.
To anticipate the amount of milk replacer (powder)
and pellets needed, it is useful to calculate theexpected consumption over the first four monthsof life. Foals weighing 100 lb at birth, should
consume four gallons per day and therefore willneed (200 lb) of foal milk replacer until weaned
from liquid milk at two months of age. They will
also need 600 lb of the milk-based pellets to be fed
free choice from the first week to four months ofage. If the foals are larger or smaller, the amountof foal food will change accordingly

4 | EQUINE DISEASE QUARTERLY

If the foal is over three weeks old when orphaned,
provide just the milk-based pellets free choice.
At this age their molars are in and they can chew
and swallow the pellets. Provide the pellets freechoice up to four months of age. Between three tofour months of age, begin mixing the milk-basedpellets with a weanling feed by subtracting one
pound of the milk-based pellets and adding one
pound of the ‘weanling’ feed, every other day.
The weanling feed should be fortified with thelevel of nutrients needed to support the young
weanling’s skeletal development and complement
the protein (amino acids) and minerals in the typeof forage (hay/pasture) your foal is now eating.
It should also state on the feed tag, “formulated
to be fed to weanlings”. Check the feeding
directions on the tag or bag, to find out how muchis recommended to be fed per day to meet the
foal’s nutrient needs according to their age andsize, i.e., bodyweight, for optimal skeletal andsoft tissue development.
The milk-based pellet is formulated for the
young foal and is fed free choice until they are
four months old, or their BCS exceeds 5.5 (on a
1 to 9 scale). After four months of age, it is notnecessary to feed milk, because the foal can begin
digesting some non-structured carbohydrates
from a weanling feed in their foregut, and soft,
immature hay, i.e., structured carbohydrates intheir hindgut. This orphaned or rejected foal andearly weaned feeding and management program,promotes optimal growth, health, and nutrient
absorption, while reducing the chance of digestive
upsets and skeletal anomalies. Following it willallow the owner/manager to provide appropriate
nutrition for the foal’s normal developmental andcompensate for the changes that normally occur
in the foal’s digestive system.
DonKapper
dkapper46@gmail.com(330)464-5180
Retired Director of Equine Nutrition and Technical
Services of Progressive Nutrition, Harlan, Iowa;
Director of Equine Nutrition and Senior VicePresident of Buckeye Nutrition, Dalton, Ohio

NATIONAL
Equine Respiratory Biosurveillance- Today, this program has resulted in one of thelargest equine infectious upper respiratory
What Have We Learned?
Since 2008, Merck Animal Health has
conducted a voluntary equine respiratory
biosurveillance program, in conjunction withprivate veterinarians, to study the prevalenceand epidemiology of relevant viral and bacterial
respiratory pathogens. This program has
increased awareness of respiratory pathogens in
the veterinary community, provided invaluableepidemiological information pertaining tocommon and less characterized respiratory
pathogens and provided equine influenza virus
sequence data to monitor how the virus ischanging and to evaluate and improve vaccine
efficacy.
As a veterinary profession, management of
infectious disease is one of the most consistent
challenges we face. Ongoing surveillance is anextremely important tool to monitor emerging
trends, manage disease outbreaks and improve
preventive strategies.
The voluntary equine respiratory biosurveillance
program was born through the vision of two
individuals and conversations that took placealmost 17 years ago between D. Paul Lunn, BVSc,
MS, PhD, MRCVS, Dipl. ACVIM—current
Dean of the University of Liverpool’s Schoolof Veterinary Science—and D. Craig Barnett,
DVM—retired Director of Equine Veterinary
Professional Services at Merck Animal Health.
In late 2007, a partnership was formed between
Merck Animal Health and the University ofCalifornia, Davis School of Veterinary Medicine
that established UC Davis, led by Nicola
Pusterla, DVM, DACVIM, AVDC-Equine, as the
program’s real-time PCR laboratory for sample
submissions. In March 2008, the biosurveillance
program came to fruition as the Infectious Upper
Respiratory Disease Study. The goals of the study
were four-fold. First, to provide participating
veterinarians with a valuable diagnostic tool toassist in providing accurate and timely diagnosis
to treat and manage infectious respiratory
diseases. Second, to provide the equine industry
with a better understanding of the prevalence andepidemiology of common respiratory pathogens.
Third, to identify and monitor the current
circulating strains of major equine respiratory
pathogens. Lastly, to evaluate the efficacy of
current vaccination protocols.

biosurveillance data sets. This comprehensive,
ongoing national surveillance study monitors
equine herpesvirus types 1 and 4, EIV,
Streptococcus equi subspecies equi (S. equi; thecause of strangles) and equine rhinitis A and B
viruses.
To date, more than 11,000 samples have been
voluntarily submitted from veterinarians acrossthe United States. To be included in the study,
samples must have been obtained from a horsewith a temperature greater than 101.5° F and thatexhibited at least one of the following clinicalsigns: nasal discharge, cough, lethargy or central
nervous system abnormalities. Submissions
consisted of two nasal swabs collected from
one nostril and a completed questionnaire.
Samples were shipped overnight to the UC Davis
laboratory for next-day quantitative PCR testing.

This dataset has generated several scientificpublications and presentations. Additionally, thedata has been used to provide biannual reports
to participating veterinarians that bring new
information to the forefront and provide timely
updates to share with horse owners. Since 2008,
results of this surveillance program have yielded
insight into the prevalence and seasonalityof these important respiratory pathogens. Of
samples in which equine respiratory pathogens
were detected, EHV-4 was the most common(representing 31% of positive samples) followed
closely by EIV (29%) and S. equi (22%).
In the United States, EIV peaks annually in Marchwith broad occurrence in winter and spring, andEHV-4 occurs more commonly in the fall from
September to November. Most importantly, alldiseases occurred throughout the year and should
not be excluded due to seasonal expectations
It is critical for veterinarians and horse owners
to understand the importance and value ofidentifying the pathogen(s) associated withrespiratory outbreaks. Not only can this data
lead to more effective treatments and biosecurity
decisions, it helps the entire horse industry better
prepare for future challenges.
Duane E. Chappell, DVMAssociate
Director, Equine Professional Services andPharmacovigilance
Merck Animal Health, USA
Phone: 866-349-3497
Email: duane.chappell@merck.com

MAY 2023 | 5

NATIONAL

Gastric Ulcers in Horses
Gastric ulcers are very common in horses withprevalence rates ranging from 50-90% dependingon the population being evaluated. Gastriculcers are found in all types of horses including
broodmares, show horses, ponies and evenwild populations. The clinical signs of gastriculcers in horses can range from mild signs suchas inappetence, decreased weight gain, poor
performance, rough hair coat and occasional
grumpiness, to more severe signs such as
intermittent mild to severe colic, weight loss,
and severe behavioral issues (especially undersaddle). As a result, the diagnosis and treatmentof g astric ulcer s can be very important to the
management of any performance or nonperformance horse.
The equine stomach is composed of a nonglandular, or squamous, component as well as a
glandular component (image 1).
The squamous mucosa makes up approximately
one-third of the stom ach , has no glands andis typically responsible for mixing food. This
portion of the stomach has very little protection
from the acidic environment present in the lower
portion of the stomach.

6 | EQUINE DISEASE QUARTERLY

The glandular portion (lower p o r t i o n ) makes
up the remainder of the stomach and contains
specialized glands that secrete acid and othersubstances that breakdown food. The lower
portion of the stomach contains numerous
protective mechanisms to keep it safe from acid.
Although both parts of the stomach can develop
ulcers, occurrence in the non-glandular mucosa ismore common. n the wild, horses spend most of
their day grazing. As a result, the equine stomach
has adapted to constantly secrete acid, which isthen buffered by saliva from chewing as well as
the feed -itself. In some man-made environments,
feeding conditions are very different to that in
the wild. This results in the stomach remaining
empty for prolonged periods of time, exposing
the vulnerable squamous mucosa to higher
levels of acid. High-grain diets and stressors(such as transport and stall confinement) can
also contribute to the development of ulcers.
Long-term administration of medications such as
nonsteroidal anti-inflammatory drugs (NSAIDs)
can lead to a decrease in protective factors andpredispose horses to ulcers predominantly in theglandular mucosa. This class of drugs include
common medications such as flunixin meglumine
and phenylbutazone.

NATIONAL
Definitive diagnosis of gastric ulcers can only bemade by direct visualization of ulcers using an
endoscope, a technique known as gastroscopy.
Although tentative diagnosis can be made basedon clinical signs and, potentially, response totherapy, the location and severity of ulcers cannot
be determined with this method. Gastroscopy isa quick and minimally invasive procedure thatallows the veterinarian to visualize the upper
airway, esophagus, stomach (both glandular andnon-glandular portions) and the proximal small
intestine. After assessment of non-glandular
ulcers, a numerical grade is assigned which thencan be used for comparative evaluation. Grade0 is typically considered a normal horse with noevidence of ulceration, while a horse with grade
4 ulceration has deep, bleeding ulcers throughout
the non-glandular mucosa (images 2 and 3). The
mainstay of treatment is prolonged suppressionof acid, the formation of a protective layer overthe ulcerations and maintaining adequate bloodflow to the site of ulceration. Omeprazole iscurrently the only Food and Drug Administration
approved treatment for gastric ulcers, and it works
by suppressing acid secretion in the stomach.
Although there are many other products currently
available, the formulation of this medication
makes it the treatment of choice for gastric ulcers
in horses. Another potential treatment for ulcers
is sucralfate, which is a gastroprotectant thatbinds to ulcers and creates a protective barrier,thereby providing immediate (although relatively
short-lived) relief. Glandular ulcers may require
additional therapy if first line treatment does not
result in improvement.

In addition to pharmacologic intervention,
management strategies are crucial to themaintenance of an ulcer free horse. By providing
free choice access to roughage in the form ofgrass or hay, large changes in stomach pH can be
minimized. Alfalfa hay, which tends to be slightly
higher in calcium, can be a good option as its
buffering capacity is above that of regular grasshay. In addition, limiting or controlling stressful
conditions plays a major role in the treatment
and prevention of gastric ulcers in horses. While
there are many supplements on the market thatclaim to prevent or treat gastric ulcers, they maylack validation and are not considered effective.
Although there is a lack of peer-reviewed
scientific research regarding most supplements on
the market, those containing pectin and/or lecithin
may provide the most benefit.
Gastric ulcers in horses can be challenging to
identify and, in many cases, challenging to treat.
By using medication to modify the acidic stomach
environment in combination with management
strategies to maintain a more “natural”
environment, we can help treat and prevent mostulcers in horses.
Nimet S. Browne, DVM, MPH, DACVIM
Hagyard Equine Medical Institute4250 Iron Works Pike
Lexington, KY 40511

Image 2. Gastroscopy image. Over a dozen grade
3 ulcers are located in the squamous mucosa.

Image 1. Gastroscopy image. The stomach iscomposed of both glandular and non-glandular
components.

Image 3. Gastroscopy image. A hemorrhagic ulcer islocated in the pylorus (the lower portion of the stomachthat connects to the small intestine).

MAY 2023 | 7