1. Smarter Strategies for
Equine Digestive Health
Lydia F. Gray, DVM, MA
Medical Director/Staff Veterinarian
Jessica Normand
Director of Supplement Marketing
October 27, 2011

2. Your Presenters
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3. Agenda
1. Digestive tract of the horse
2. Common digestive problems
3. What can horse owners do?
4. Questions & Answers
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4. Digestive Tract of the Horse
Overview
• Type of Digestive Tract
– Non-ruminant herbivore
– Hindgut fermentor
• Designed to graze 17 hours per day (per NRC*)
• “Trickle-Feeders”
• Needs at least 1% body weight per day or 50% of total
ration as forage
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*National Research Council

5. Digestive Tract of the Horse
1. Mouth
2. Esophagus
3. Stomach Foregut
4. Small intestine
5. Large intestine - Hindgut
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Illustration courtesy of Rick Gore Horsemanship, ThinkLikeAHorse.org

6. Digestive Tract of the Horse
Illustration courtesy of Rick Gore Horsemanship, ThinkLikeAHorse.org
Illustration courtesy of Ohio State University Extension, Bullet 762-00 6

7. Digestive Tract of the Horse: Mouth
Anatomy: Lips, teeth, tongue, salivary glands
Main Functions:
• Grasp food
• Chew
• Moisten (horses salivate 5-10 liters per day)
Management Suggestions:
• Regular dental care, especially in older horses
• Provide plenty of forage intake
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8. Digestive Tract of the Horse: Esophagus
Anatomy: 4-5 feet long
Main Functions: transport food from mouth to stomach
Related Issues:
• Movement of food is one-way
• “Choke” occurs when feed becomes lodged in esophagus (not in
the airway)
Management Suggestions:
• Feed small grain meals frequently
• Spread grain out in a shallow trough
• Put large fist-sized stones in the feed tub
• Wet grain or add chopped forage to grain
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9. Digestive Tract of the Horse: Stomach
Anatomy:
• 2-4 gallons in capacity (10% of total tract capacity)
• Residence time 30 min to 12 hrs depending on meal
size/composition; average transit time is 2-4 hrs
• First 1/3 is the non-glandular region where 80% of ulcers occur
• Gastric acid produced 24/7 (10-30 liters of gastric juices secreted
per day)
Main Functions:
• Regulates passage of feed into small intestine
• Adds gastric acid to assist in chemical breakdown of feed
• Secretes pepsinogen to begin protein digestion
• Holding and mixing tank for food
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10. Digestive Tract of the Horse: Stomach
Related Issues:
• Small capacity is not suited for large, infrequent meals
– Feeding large meals can lead to distension and colic
• Secretion of gastric acid continues even when stomach is empty—
contributes to development of ulcers
Management Suggestions:
• Offer small, frequent grain meals
• Have grass hay available at all times (unless obese)
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11. Digestive Tract of the Horse:
Anatomy:
Small Intestine
• Approximately 70 feet in length (30% of total tract capacity)
• Transit time is 30-90 minutes
• Sections are the duodenum, jejunum and ileum
Main Functions:
• Digestion of proteins, simple carbohydrates and fats via enzymes
from the pancreas and intestinal lining
• Absorption of most of end-products of digestion: amino acids,
glucose, vitamins, minerals and fatty acids (via bile from the liver)
Illustration courtesy of Ohio
State University Extension,
Bullet 762-00
11

12. Digestive Tract of the Horse:
Small Intestine
Related Issues:
• Volume of feed consumed and rate of passage affect digestion
and absorption of nutrients
Management Suggestions:
• Feed small grain meals frequently
• Minimize Non-Structural Carbohydrate (NSC) levels in grain,
depending on individual horse/activity level
• Monitor pasture consumption to prevent too much intake
• Make small changes in type and amount of feed gradually
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13. Digestive Tract of the Horse:
Large Intestine
Anatomy:
• Cecum is 4 ft long/holds 8 gallons (15-20% of total tract capacity )
• Colon is 20-24 ft long (40-50% of total tract capacity)
• Total transit time is 35-50+ hours
Main functions:
• Fermentation of dietary fiber (structural carbohydrates) via bacteria, protozoa
and fungi into volatile fatty acids (VFAs)
• Fermentation process also produces most of the B vitamins, Vitamin K and
some amino acids
• Other functions are water resorption and absorption of VFAs, B vitamins and
some minerals
Illustration courtesy of Ohio
State University Extension,
Bullet 762-00 13

14. Digestive Tract of the Horse:
Large Intestine
Related Issues:
• Passage of NSC to hindgut is undesirable; causes overproduction of
lactic acid (“hindgut acidosis”)
• Numerous turns and folds increase risk of intestinal dysfunction
such as impaction
Management Suggestions:
• Feed small meals frequently, with lower NSC %
• Make feed changes slowly to allow microbes to adjust
• Maintain regular feeding schedule
• Avoid moldy feed or hay
• Deworm appropriately
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15. Common Digestive Problems
1. Gastric Ulcers
2. Colic
3. Diarrhea
4. Colonic Ulcers/Right Dorsal Colitis and Hindgut
Acidosis
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16. Common Digestive Problems:
Gastric Ulcers
• Up to 90% of racehorses and nearly 60% of active show
horses have gastric ulcers
• Please visit http://www.smartpak.com/webinars for
our in-depth Gastric Ulcer presentation
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17. Common Digestive Problems: Colic
• Responsible for more deaths in horses than any other disease
• Proven causes include:
– Hay and grain changes
– Increased stall time
– Dehydration
– Change in activity
– Parasites
– Cribbing
– Sand
– Previous colic
• Anecdotal causes:
– Lack of dental care Cohen ND, Factors predisposing to colic, 8th Congress on Equine
– Travel Medicine and Surgery, 2003
– Weather White NA, Equine Colic II: Causes and risks for colic, 52nd Annual
Convention of the AAEP, 2006
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18. Common Digestive Problems: Diarrhea
• Definition: Abnormal frequency and liquidity of fecal
discharges (from Dorland’s Illustrated Medical
Dictionary)
• A definite cause of diarrhea can be identified in less
than 50% of cases
• Acute vs. chronic
The Treatment of Diarrhea in the Adult Horse. Naylor RJ and Dunkel B. Equine Veterinary
Education, Sept 2009, vol. 21, No. 9; pp. 494-504.
Adult Equine Diarrhea Workup. Merrit AM. 45th Annu Conv Am Assoc Equine Pract
1999:45:276-279.
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19. Common Digestive Problems:
Colonic Ulcers/Right Dorsal Colitis
and Hindgut Acidosis
• Right Dorsal Colitis (RDC) and Colonic Ulcers are one and the same
• Diagnosis can be challenging
• #1 risk factor is NSAID use, also stress, dehydration and possibly
parasites and hindgut acidosis
• Treatment for RDC is NO FORAGE for up to 3 months so diagnosis is
important
Pellegrini FL. Results of a large-scale necroscopic study of equine colonic ulcers. J Equine Vet Sci. 2005:
25:3):113-117.
Cohen ND, Carter GK, Mealey RH, Taylor TS. Medical management of right dorsal colitis in 5 horses: a
retrospective study). J Vet Intern Med. 1995 Jul-Aug:9(4):272-276.
McConnico RS, Morgan TW, Williams CC, et al. Pathophysiologic effects of phenylbutazone on the right
dorsal colon in horses. Am J Vet Res. 2008 Nov;69(11):1496-1505.
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20. What Can Horse Owners Do?
1. Diet
2. Housing
3. Activity
4. Veterinary Care
5. Supplements
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21. What Can Horse Owners Do?
Diet
• Forage-based (1-2% of horse’s body weight per day)
• Limit grain (consider ration balancers and multi-vitamins
as alternatives)
• Change BOTH hay and grain gradually
• Provide fresh grass (unless obese/metabolic condition)
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22. What Can Horse Owners Do?
Housing
• Provide adequate turnout
• Offer socialization
• Ensure access to clean, fresh water
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23. What Can Horse Owners Do?
Activity
• Provide consistent exercise
• Change exercise gradually (duration, frequency, intensity)
• Monitor your horse’s fitness level
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24. What Can Horse Owners Do?
Veterinary Care
• Annual physical exam
• Body condition score and weight
• Parasite control
• Dental care
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25. What Can Horse Owners Do?
Supplements for
• Ulcers & Gastric Health
• Digestion & Hindgut Health
• Sand Colic
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26. Supplements for Ulcers & Gastric Health
• Note the important role of prescription medications
(omeprazole, ranitidine, cimitidine)
• Natural agents available in supplements:
– Antacids such as calcium and magnesium carbonate
– Amino acids such as L-glutamine
– Soothing herbs such as licorice
– Soluble fiber such as pectin
– Other
Venner M, Lauffs S, Deegen E. Treatment of gastric lesions in horses with pectin-lecithin complex.
Equine Vet J Suppl. 1999 Apr;(29):91-96.
Aly AM, Al-Alousi L, Salem HA. Licorice: a possible anti-inflammatory and anti-ulcer drug. AAPS
PharmSci Tech, 2—5 Sep 20;6(1):E74-82.
Noe JE. L-Glutamine use in the treatment and prevention of mucositis and cachexia: a naturopathic
perspective. Integr Cancer Ther. 2009 Dec;8(4)): 409-415. 26

27. Supplements for Ulcers & Gastric Health
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28. Supplements for
Digestion & Hindgut Health
• Ingredients include:
– Probiotics (live beneficial bacteria)
– Prebiotics (nourishment for the “good bugs” in the hindgut)
– Digestive Enzymes (e.g. amylase, protease, lipase)
– Oat Beta Glucan
Immunomodulatory activities of oat beta-glucan in vitro and in vivo. Estrada A, Yun CH,
Van Kessel A, et al. Microbiol Immunol. 1997;41(12):991-8.
Glycemic responses of oat bran products in type 2 diabetic patients.
Tapola N, Karvonen H, Niskanen L, et al. Nutr Metab Cardiovasc Dis. 2005 Aug; 15(4):
255-61.
Pre - and Probiotics: Potentials for Equine Practice
Jullian V, Proceedings of the 3rd European Equine Nutrition & Health Congress, Mar. 17-
18, 2006
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29. Supplements for
Digestion & Hindgut Health
Effects of dietary short-chain fructooligosaccharides on the intestinal microflora of horses subjected to a
sudden change in diet. Respondek F, Goachet Ag, Julliand V. J Anim Sci. 2008 Feb;86(2):316-23
Effect of live yeast culture supplementation on apparent digestibility and rate of passage in horses fed a high-
fiber or high-starch diet. Jouany JP, Gobert J, Medina B, et al J Anim Sci. 2008 Feb;86(2):339-47.
Effect of a preparation of Saccharomyces cerevisiae on microbial profiles and fermentation patterns in the large
intestine of horses fed a high fiber or a high starch diet. Medina B, Girard ID, Jacotot E, Julliand V. J Anim Sci
2002 Oct;80(10):2600-9
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30. Supplements for Sand Colic
• “Monthly Purge”
• Primary ingredient: Psyllium Seed Husk (as a source of fiber)
• Other ingredients
– Probiotics
– Prebiotics
– Chia Seed
Fecal Sand Clearance Is Enhanced With a Product Combining Probiotics, Prebiotics, and Psyllium in Clinically Normal
Horses, A. D. Landes, D. M. Hassel, J. D. Funk and A. E. Hill, 53rd Annual Convention of the AAEP, 2007
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31. Questions & Answers
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32. Questions
1. My Morgan mare becomes somewhat distressed when she goes to CDEs. I am
concerned that she may develop gastric upset and be vulnerable to developing
ulcers due to the stressors of being away from home and not having turnout.
Any suggestions?
2. Do senior horses have digestive issues?
3. Does daily exercise play a part in equine digestive health...also how many
times a day should you feed...what about deworming ?
4. Do the different kinds of hay affect how the G.I tract works. Is one easier to
digest?
5. Does the use of probiotics aid in the prevention of ulcers?
6. How should I deal with chronic low grade diarrhea?
7. I am curious how my horse’s body processes protein.
8. I am giving my horses a probiotic. Can you discuss the benefits/disadvantages
of this.
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33. Questions
9. I have 4 horses on small acreage. They get daily turn out in dry lots. I
supplement them with the recommended dose of Sand Clear for seven days in
a row, once a month as per directions. Any more suggestions for preventing
sand colic?
10. I have a 17 yo QH gelding. He has a lot of water in his bowels. Mostly when
he passes gas the water comes out hits his tail and makes a mess. Of course
he is a cremello! Worse when he is on hay than pasture.
11. I have a QH Mare that has frequent stools that are very soft and occasionally
watery. She eats well, keeps weigh well and is basically and easy keeper. She
has been checked for sand and is wormed regularly. Any ideas?
12. I have had a 5 year old colic twice, what can I do to help prevent it from
happening again?
13. I have heard so many different answers to this question: how long between
meals and riding/ lunging/ etc?
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34. Questions
14. I used to have a filly that ate dirt. Why is that?
15. Are there any digestive supplements that help prevent a colic-prone horse
from colicing?
16. If you are daily feeding a horse a certain type of grain will it cause any
problems to suddenly change the type of grain you are feeding them?
17. Impaction colic due to lack of water in stall 2 years ago, should this horse
remain on u-guard pellets BID indefinitely even though scope shows no ulcers?
18. I’m interested in learning about hind gut ulcers, thanks!!
19. Is it easy for a horse's digestive tract to get off balance if measures aren't
taken to give them digestive health, especially with lots of showing?
20. I have 1 horse that lives to eat. I put his hay in a hay bag and feed 3 times a
day. He will colic if you are a bit late in feeding even 10 mins. what can I give
him if anything that will help he with his colic? I do feed orchard with small
amounts of alfalfa.
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35. Questions
21. I have a horse who is sensitive to stress. He doesn't really show it
outwardly just get a bit runny. What would a good food for a horse like
him be. I have been thinking alfalfa and local and little grain. He is in
regular work. 6 yrs old. Holsteiner TB
22. Is it better to prevent sand colic through a daily supplement or one you
feed 1-a few times a year?
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36. Thank you for attending our Webinar!
Please visit us at
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Or call us at 1-800-461-8898 if we can answer
any further questions.
~ Your Friends at SmartPak
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