Equine Gastric Ulcers – How do
we diagnose and treat?
Ellie Burfoot BSc (Hons)
Agenda
• Introduction
• Prevalence – How common is this
disease?
• Anatomy/physiology
• Risk Factors
• Treatment
• Prevention
Introduction
Damage to the equine stomach lining due to
excessive stomach acid or problems with
the natural protection of the stomach lining
• Serious health problem in foals and horses
• Particularly prevalent in performance
horses
• Many risk factors
• May or may not show clinical symptoms
• May result in foal mortality
Prevalence – How common is this
disease?
• 93% racehorses in training (Murray et. al
1996, 1989)
• 60% other performance horses (McClure et
al. 1999, Mitchell 2001)
• More than 50% of foals have been shown
to have EGUS (Murray 1997)
• 37% in leisure/pleasure horses
• Donkeys – 50%?
How did nature intend the
horse to live?
Compartments of the Equine Stomach
Cardia
Squamous mucosa
Duodenum
Pylorus
Margo plicatus
Glandular
mucosa
Pagan, World Equine Vet Rev, 1997.
Squamous Mucosa
• Non Glandular
• No sub mucosal
glands.
• No secretary or
absorptive function.
• No mucus and high
susceptibility to
peptic injury.
• Most common
location for
gastric ulcers
Squamous Mucosa
Glandular Mucosa
2/3 of equine stomach.
• Contains many secreting cell
types:
• Gastric G cells  Gastrin.
• Mast cells and  Histamine.
• Chief cells  Pepsinogen 
Pepsin at pH <3.0.
• Mucus neck cells 
Bicarbonate and hydrophobic
mucus barrier.
• Parietal cells  Hydrochloric
acid
Glandular mucosa
Inhibit acid
secretion
Stimulate acid secretion
H2
Acetylcholine
Gastrin
Prostaglandins
Parietal
cell
Acid
Pump
H+
Bicarbonate barrier
H+
H+
Cl-
H+
Cl-
HCl
H+
Stomach
lumen
Ulcer Grading
• Range in severity – size and depth
• Scoring techniques – assess severity and
improvement through treatment
• Severity and clinical signs don’t always
correlate
Grade 0 Lesion
Intact
epithelium
May have
reddening
Freedom of Information (FOI) Summary for GASTROGARD Oral Paste for Equine Ulcers.
Photo courtesy of MJ Murray.
Grade 1 Lesion
Small
single or
multiple
lesions
Freedom of Information (FOI) Summary for GASTROGARD Oral Paste for Equine Ulcers.
Photo courtesy of MJ Murray.
Grade 2 Lesion
Large
single or
multiple
lesions
Freedom of Information (FOI) Summary for GASTROGARD Oral Paste for Equine Ulcers.
Photo courtesy of MJ Murray.
Grade 3 Lesion
Extensive,
often
coalescing,
ulcers with
areas of deep
ulceration.
Freedom of Information (FOI) Summary for GASTROGARD Oral Paste for Equine Ulcers.
Photo courtesy of MJ Murray.
Risk Factors
 Intermittent feeding
 Diet
 Intensive Exercise
 Physical Stress
Intermittent Feeding
• Acidity in the equine stomach is
greatest in absence of food
• Feeding decreases acidity
 Acid secretion stimulated by food
 Food neutralises most of the acid
 Bicarbonate in saliva neutralises
some acid
• If denied food ulcers can develop
within 24hrs
• Horses continuously grazing therefore
unlikely to develop ulcers
Physiology of the Equine
Stomach:Patterns of Acidity
8
Free Choice Timothy Hay
7
6
pH
5
4
3
2
1
0
6
12
0
Murray and Schusser, Equine Vet J, 1993.
Time
18
2
Physiology of the Equine
Stomach:Patterns of Acidity
7
Feed Deprivation
6
pH
5
4
3
2
1
0
6
12
0
Murray and Schusser, Equine Vet J, 1993.
Time
18
24
Exercise (+walk)
• High speed treadmill exercise abdominal
pressure increases (Lorenzo-Figueras and
Merritt, AJVR 2002)
• High speed treadmill exercise pH
decreases (Lorenzo-Figueras and Merritt, AJVR
2002)
• Acidic contents forced into acid sensitive
non glandular stomach region
Exercise and Gastric pH
Lorenzo-Figueras and Merritt, AJVR 2002
Physical Stress
•Stall Confinement
•Hospitalization,
•Transportation,
•Relocation
Murray, Vet Med, 1991.
Equine Gastric Ulcer Syndrome:
Stall confinement
Day 7 in stall
• Horses on pasture: normal mucosa
• 7 days stall confinement, free choice hay:
squamous lesions
Day 0 in stall
Day 7 in stall
Murray et al, Equine Vet J, 1996; Murray (personal communication), 1999.
Clinical Signs in Adult Horses
• Poor appetite.
• Poor bodily condition.
• Attitude changes.
• Decrease in performance.
• Mild to moderate colic.
Murray, AAEP, 1997.
Clinical Signs in Foals
• Poor appetite or intermittent
nursing.
• Colic.
• Poor body condition.
• Frequently lies on back.
• Bruxism (grinding of teeth).
• Ptyalism (excessive
salivation).
• Diarrhea or history of
diarrhea.
Murray, AAEP, 1997.
Diagnosis
• Ulcers difficult to diagnose due to
subtle, non-specific clinical signs
• Endoscopy

Only definitive method of
diagnosis

Can be difficult due to length of
digestive tract

Not all veterinary practices may
have 3m endoscope required
Treatment of Gastric Ulcers
• Eliminate clinical signs
• Promote healing of ulcer
• Prevent recurrence
Inhibit gastric acid
secretion
Treatment of Gastric Ulcers
•
Main traditional drug therapies
Antacids
Histamine H2 Receptor Antagonists
Ulcer-coating agents (sucralfate)
•
•
Not approved for use in horses
No large-scale assessment of safety or
effectiveness
•
No recommended dose or administration schedule
•
Variable results
•
Horses removed from training
Omeprazole
•
Proton pump inhibitor binds to H+K+ - ATPase pump
• Blocking pump shuts down the acid secretion
allowing ulcers to heal
•
Only medication capable of blocking pump
•
Identifying pump stimulator not necessary.
• First and only medication approved for use in and
prevention of gastric ulcers in foals and horses
• Do not have to remove horse from training. Most
widely prescribed anti-ulcer therapy in humans
(Losec)
• Suppressor of gastric acid secretion
• GastroGard® - Omeprazole paste - developed
specifically for EGUS in horses
The Acid Pump
Stimulate acid secretion
H2 Receptor
Antagonists
H2
Gastrin
Acid pump Inhibitor
Acetylcholine
Prostaglandins
Parietal cell
Acid
Pump
GASTROGARD®
H+
Bicarbonate barrier
H+
H+
Cl-
H+
H+
ClAntacids
HCl
Stomach
lumen
Ulceration does not just affect
racehorses!
Case study 1
• 8 yo Welsh section C
• Jumping pony
• At pasture for 4 hrs per day (overweight), good
eater
• No history of ulcers but really naughty in stable
and under saddle
• Better jumper in summer
• Bad cribber & wind sucks
• Recently lethargic, and had bout of colic
• Scoping revealed squamous ulceration grade 2/3
localised to fundus, appearing to be along fold
Case Study 2
• 6 year old advanced eventer currently off
work at pasture as season over 2 months
previous I.e on holiday
• During season difficult to keep weight on
and can be bucking bronco especially
when show jumping
• Ulceration in squamous region grade ¾ in
glandular grade 4
Case Study 3 - 9yo Warm blood
Dressage
• Kept lying down, especially before a competition
although never developed colic
• Became lethargic and thin, poor coat
• Grade 2 ulcers
• 4 weeks GastroGard at 4mg/kg.
• Clear after 4 weeks.
• In an effort to cut costs switched to ranitidine.
Signs reappeared almost immediately
• Now on low dose GastroGard throughout the
season
• Increased frequency of feeds from 2 to 4 times
daily and always has a full hay net
Case Study 4: 14yr old KWPN
Paralympic Team Dressage horse
• Team dressage horse always done well,
recently seen inconsistent performances
especially if travelled
• Pain on girthing up and bucking bronco
for first few strides!
• Routine scoping of Team GB horses
revealed grade 3 squamous and
glandular ulcers
• Successfully treated for 2 weeks, and
performance is more consistent and no
bucking!
Prevention of Gastric Ulcers
ENVIRONMENTAL
•
Turn the horse out to pasture as much
as possible
Prevention of gastric Ulcers
FEEDING PRACTICE
• Regular feeding - the less time a horse
has an empty stomach the better
• Have hay available at all times while the
horse is in the stall – 2/3 hay nets?
• Alfalfa hay can help buffer stomach acid
due to high calcium and protein content
(Nadeau et al 2000)
• Limit grain rations
• Scatter feeding and apple bobbing!
Prevention of Gastric Ulcers
EXERCISE
•
Don’t train on an empty stomach
•
Consider exercise regime – increased risk of ulcer
formation in horses under intense training
schedules
The Take Home Message!
• Ulcers can affect any breed, age or
discipline.
• As horse owners you can prevent ulcers
through good management.
• Clinical signs are subtle and non specific.
• Ulcers can be successfully treated with no
long term affects.
Gastroscopy Clinic at
Priors Farm
• Wednesday 6th June
• 6-8 horses can be scoped.
• If you feel your horse is a suitable
candidate please speak to one of the Vets
tonight or phone the practice.
• Gastroscopy will be free on the day for
those horses selected.
Thank you!