Feed Routines Play Role in Equine GI Problems
By Lou Anne Epperley, DVM
For Veterinary Practice News
Posted: July 10, 2012, 5:40 p.m. EDT
It’s taken a lot of guts to become Dr. Frank Andrews, career-long student of equine gastroenterology and gastric ulcers.
The director of the Equine Health Studies Program at Louisiana State University’s School of Veterinary Medicine holds the titles DVM, MS and diplomate, American College of Veterinary Internal Medicine (large animal).
Right dorsel colitis. Photos Copyright of Freedom Health LLC
After collaborating on more than 27 scientific articles, most of which seek to discover ways mankind interferes with the delicate workings of horse digestive components, Andrews has learned common-sense nutritional practices that could save clients and veterinarians a belly full of pain, anxiety and heartache.
“There’s so much myth and tradition with horses, especially with feeding,” Andrews said. “Although we make our money on horses with colic, we’d like to see more preventive medicine out there.”
A diet high in nonstructural carbohydrates, particularly soluble sugar, combined with heavy training and stall confinement can predispose race and performance horses to gastric ulcers.
Under normal conditions, horses spend about 10 to 12 hours daily eating, which allows them to maintain a full stomach and a continuous nutrient supply and the necessary microbes in the hindgut, Andrews said. Horses grazing at pasture are less likely to succumb to equine gastric ulcer syndrome. Continuous grazing provides a flow of saliva and ingesta that buffer stomach acid, keeping the pH above 4.0 for most of the day.
Severe ecchymoses, left dorsel colon
In contrast, Andrews said, withholding feed from horses before racing or during stable confinement drops the gastric pH, creating an acid environment for the non-glandular mucosa of the stomach. The lack of mucosal protective factors makes this area most susceptible to ulcers when a horse is intermittently fed.
A Danish study showed increased risk of ulceration when the forage feeding interval was greater than six hours. Continuous forage feeding may be critical to reducing gastric ulcers, Andrews noted.
Severe colonic ulceration, rightdorsal colon
Severe glandular ulceration
“That’s the biggest problem with performance horses nowadays,” he said. “They’re stalled, with little pasture turnout, and bolus feeding two to three times a day. Then there are times during the day and night when they don’t have a lot to eat and are standing around.”
Stabled horses should have access to hay “24/7,” Andrews said, and a mixture of grass hay and alfalfa hay offers some buffering capacity for stomach acid. In fact, alfalfa hay can be fed as a horse’s sole diet, but could make a horse “hotter,” or more hyper, than desired, he said. Alfalfa hay’s high protein and calcium content has been shown to buffer stomach contents, preventing ulcers and relieving abdominal pain, he said.
Equine Fecal Blood Test Looks for Colonic Ulcers
A large number of equine colic cases blamed on gastric ulcers may actually originate with ulcers in the colon, according to the president and founder of a company that makes a stall-side test to distinguish the two.
“Colonic ulcers are more prevalent than gastric ulcers, and if a horse has gastric ulcers, he almost certainly has colonic ulcers,” said John Hall, president and founder of Freedom Health LLC of Aurora, Ohio. “Until now, there has been no mechanism for a vet to determine whether a horse has gastric or colonic ulcers, or both.”
Introduced in January 2012, the Succeed Equine Fecal Blood Test uses antibodies to detect occult albumin and hemoglobin in 15 minutes from a fecal sample. Albumin is the component that can clue in a practitioner to possible colonic ulcers, Hall said.
While gastric ulcers can be visualized using a three-meter endoscope, the accessible area constitutes only about 10 percent of the gastrointestinal tract where ulcers could form. From hundreds of necropsies, Dr. Franklin L. Pellegrini, DVM, Freedom Health’s vice president of Veterinary Science, discovered that up to 63 percent of horses in one research cohort had colonic ulcers, and often had gastric ulcers as well.
In the Equine Fecal Blood Test, the presence of albumin above a certain level is proof of a colonic ulcer, Hall said.
A high hemoglobin level is evidence of a bleeding gastric ulcer, he said. The test has a 96 percent positive predictive value; additional statistical information is available from the company. The test’s albumin threshold is set high enough above the normal value that it can also be used to help rule in or out protein-losing enteropathy, Hall said.
“Colic is rarely a gastric issue; colic is a hindgut issue,” Hall said. “First and foremost, we’ve got to get people to recognize that colonic ulcers exist and are probably the leading cause of colic.”
Freedom Health’s flagship product is Succeed Digestive Conditioning Program, a daily supplement designed to address gastrointestinal illness often affecting performance horses that are stalled for much of the day and grain-fed. The nutraceutical aims to normalize a horse’s foregut and hindgut bacterial flora, in part by slowing down the passage of grains through the GI tract and maximizing nutrient uptake, Hall said. Succeed also protects the intestinal tract from mycotoxins and enhances the system’s natural repair mechanisms, he said.
Freedom Health in June introduced a new veterinary formula of Succeed along with the “Succeed Healthy Gut Commitment.”
Hall said the program will compensate veterinarians for colic treatment of any horse in their care regularly and consistently using Succeed VF, as long as the colic is not deemed caused by non-gut-related issues such as reproductive, kidney or lung problems.—L.E.
To maintain the gastric juice pH, alfalfa hay should be fed at intervals no greater than every five hours.
Cereal grain feeds should be lower on corn content and higher in oats and barley, Andrews said. Feeding cattle ration to save money could be a mistake, because it contains a higher percentage of corn. This equine gastroenterologist prefers complete low-starch feeds over sweet feeds high in soluble sugar. Sweet feeds, notably Omolene and similar formulas, tend to escape enzymatic digestion in the small intestine and proceed to the large intestine, where they rapidly ferment and increase volatile fatty acid and lactate, lowering the pH.
This opens the door for lactic-acid-producing bacteria, which can cause lactic acidosis and laminitis.
Along that line, fiber content of feed is key, Andrews said, adding that fiber helps tie up some of the nonstructural carbohydrates and move them more rapidly through the digestive tract. Nonstructural carbohydrates should comprise no more than 10 percent of the total ration, he said.
A general guideline is to feed grain twice daily, he said. Hard-working performance or race horses can be fed up to five pounds of grain four times daily, with at least six hours between feedings. The six-hour interval tends to keep volatile fatty acids at a low level. Andrews’ research shows that five pounds is the upper threshold quantity, per feeding, for a typical 1,000-pound horse.
So sensitive is the equine gastrointestinal system that a small tweak in the feed regimen can result in a large tummy ache.
“In the healthy GI tract, there are good bacteria that keep the bad bacteria in check,” Andrews said. “You can have a horse on a grass hay diet and you get a new batch of hay, you’ve just made a change in that horse’s diet, even if the hay is from the same source. Different nutritional components now enter that digestive tract, and those bacteria see a new food source.”
Again, an overgrowth of “bad” bacteria in the large intestine can change its pH, so that a simple change in hay can lead to colic—“colonic acidosis,” Andrews said.
“Same thing with switching grain,” he said. The cecum and colon are most susceptible to fermentation.
A Texas A&M veterinary study that abruptly changed the hay batch on a group of horses showed increased risk of colic about two weeks following the change, Andrews said.
Therefore, Andrews recommends blending new hay into the old hay over a seven-day period, literally weighing the hay on a bathroom scale if necessary. On Day 1, feed six parts old hay to one part new hay; Day 2, five parts old hay to two parts new hay; and so on to complete the transition.
For grains, he recommends stretching the transition over about 10 days, using the example of five pounds of ration twice daily. On Day 1, feed 4.5 pounds of the present ration blended with 0.5 pound of the new ration, increasing the new and decreasing the old by 0.5 pounds daily until the transition is complete.
“I’m always really conservative when I change horses’ diets,” he said.
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