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 How did nature intend thethe

horse to livehorse to live??

Compartments of the Equine Stomach

Squamous mucosa

Glandular mucosa

Pagan, World Equine Vet Rev, 1997.

Duodenum

Cardia

Pylorus

Margo plicatus

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 Mucosa2/3 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

Stomach lumen

Parietal cell

H+Cl-

Cl-H+

H+

HCl

H+

H+

Acid Pump

H2 Gastrin Acetylcholine Prostaglandins

Stimulate acid secretionInhibit acid secretion

Bicarbonate barrier

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.

Small single or multiple lesions

Grade 1 Lesion

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

Time0

1

2

3

4

5

6

7

8

pH

0 6 12 18 24

Free Choice Timothy Hay

Murray and Schusser, Equine Vet J, 1993.

Physiology of the Equine Stomach:Patterns of Acidity

Time0

1

2

3

4

5

6

7

pH

0 6 12 18 24

Feed Deprivation

Murray and Schusser, Equine Vet J, 1993.

• 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 (+walk)

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

Murray et al, Equine Vet J, 1996; Murray (personal communication), 1999.

• Horses on pasture: normal mucosa• 7 days stall confinement, free choice hay: squamous lesions

Day 0 in stall

Day 7 in stall

Day 7 in stall

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

Stomach lumen

Parietal cell

Bicarbonate barrier

H+Cl-

Cl-H+

H+

HCl

H+

H+

Acid PumpAcid pump Inhibitor

GASTROGARD®

H2 Gastrin Acetylcholine Prostaglandins

Antacids

H2 Receptor Antagonists

Stimulate acid secretion

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 UlcersEXERCISE

• 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!