Horses find lush grass irresistible, right? It’s the perfect feedstuff for horses, right? Not always. In fact, certain grasses can be downright dangerous for some horses. A closer look provides the answer: the problem isn’t the grass, but a specific sugar in the grass.
Fructans are sugars found in many cool-season forages. Fructans are short- and long-chain carbohydrates composed of fructose molecules. These bonds cannot be digested in the stomach and small intestine, so these easily fermented sugars pass into the hindgut, a situation that leads to rapid production of lactic acid and volatile fatty acids (VFA). VFA are the normal byproducts of forage digestion, so horses handle them well. Lactic acid, however, is neither efficiently used by other bacteria nor easily absorbed from the hindgut. The resulting accumulation of lactic acid in the hindgut is one of the most direct causes of colic and laminitis in horses on pasture.
When high concentrations of fructans are found in pasture grasses or when large grain meals are fed, horses digest these highly fermentable sugars in the hindgut. A condition known as subclinical acidosis can result. Signs of subclinical acidosis include decreased feed intake, mild to moderate colic of unknown origin, poor feed efficiency with weight loss, poor attitude, loss of performance, and development of vices such as cribbing and wood-chewing. Horses with hindgut acidosis are more susceptible to colic and laminitis than those with a healthy hindgut environment.
Research supports the use of a hindgut buffer, such as EquiShure, in cases of high fructan intake. Buy online.
EquiShure, a time-released buffer, helps neutralize gut conditions by preventing the drastic drop in pH associated with high lactate production. It also supports microorganisms that use lactic acid, thereby enhancing the natural production of VFA from starch and cellulose. These VFA moderate the dramatic effects of lactic acidosis. Buy online.
One study conducted at Kentucky Equine Research (KER) demonstrated the efficacy of EquiShure given to horses that had been denied access to pasture. Horses that had not been turned out on pasture for several weeks were given 24-hour free-choice access to fall pasture. One group of horses was given EquiShure for one week prior to turnout and another group served as controls and was given no buffer. Initial pH readings revealed a moderate decrease in pH despite the buffer, but an analysis of VFA proved that the drop in pH was associated with increased VFA production. Therefore, more VFA were being produced and were available to the horses as energy sources.
Additional analysis demonstrated that lactic acid was greater in the control group compared to the EquiShure-fed group, which meant EquiShure was effective and the hindgut was functioning optimally.
Total VFA from fecal samples after exposure to pasture.
Change in fecal lactic acid (d-lactate) after exposure to pasture.
Use table below to determine recommended daily amount based on horse's grain intake, forage source, and weight. Top-dress EquiShure® on daily grain ration. For best results divide recommended daily amount equally among grain meals. 1 scoop = 30 g.
|Weight of Horse||300 kg
|Grain Intake||Forage Source||Amount of EquiShure® per day|
|Low to moderate||Mostly hay||30-60 g||60-90 g||90-120 g|
|Low to moderate||Mostly pasture||30-60 g||60-90 g||90-120 g|
|Moderate to high||Mostly hay||60-90 g||90-120 g||120-150 g|
|Moderate to high||Mostly pasture||90-120 g||120-150 g||150-180 g|
|Container Size||Servings per container|
|1.25 kg (2.76 lb)||10 - 20|
|7.2 kg (15.84 lb)||60 - 120|
|18 kg (39.6 lb)||150 - 300|
- EquiShure Technical Review Article
- Industry research on equine hindgut pH
- Industry research on equine hindgut acidosis
What is subclinical acidosis?
When excessive starch makes its way into the hindgut, the production of volatile fatty acids (VFA) and lactic acid increases, causing a significant decrease in the pH. This shift in pH provides an unfavorable environment for some of the many beneficial microorganisms that normally inhabit the hindgut and aid digestion.
These changes in the pH of the hindgut due to alterations in the microbial populations and acid profiles cause a condition known as subclinical acidosis.
Why does subclinical acidosis occur?
Subclinical acidosis is thought to result from overconsumption of either high-starch concentrates or pasture grasses rich in fructans.
What are the clinical signs of subclinical acidosis?
Signs of subclinical acidosis may include:
- Decreased feed intake or complete inappetence in severe cases
- Mild to moderate colic signs of unexplained origin
- Poor feed efficiency and subsequent weight loss
- Loss of performance
- Development of stereotypies such as wood-chewing, weaving, and stall-walking
Additionally, horses with subclinical acidosis are more susceptible to colic and laminitis.
What is a hindgut buffer?
A time-released buffer helps moderate gut conditions by preventing the drastic drop in pH associated with high lactate production and supports lactic-acid-utilizing bacteria to enhance the natural production of VFA from starch and cellulose. While VFA are weak acids and will reduce pH, the dramatic effects of lactic acidosis are moderated and the associated problems attenuated by the time-released buffer EquiShure.
Does it work?
Research trials at Kentucky Equine Research (KER) were designed to test the efficacy of EquiShure on hindgut acidosis in horses fed a high-grain ration. Fecal examination indicated that nonsupplemented horses had decreased fecal pH (were more acidic) after feeding when compared to horses supplemented with EquiShure.
KER also tested the efficacy of EquiShure against a challenge of fructan. Results showed that EquiShure-supplemented horses had less fecal lactate when compared to control horses, which, like in the grain study, indicates that lactate is being converted into VFA by lactic-acid-utilizing bacteria.
These significant results suggest that EquiShure prevented the decrease in pH associated with rapid starch and sugar fermentation, enabling lactate-utilizing bacteria to thrive and convert lactate into VFA.
Joe Pagan, Ph.D., founder and president of KER, presented “Feeding Protected Sodium Bicarbonate Attenuates Hindgut Acidosis in Horses Fed a High-Grain Ration” to the American Association of Equine Practitioners. Read this paper.
The resulting accumulation of lactic acid in the hindgut is one of the most direct causes of colic and laminitis in horses on pasture.