Symp., Vol 2, 2008 FEEDING PROTECTED SODIUM BICARBONATE ATTENUATES HINDGUT ACIDOSIS IN HORSES FED A HIGH GRAIN RATION J.D.
LawrenceA and P.J.
HuntingtonB A B Kentucky Equine Research, Versailles, Kentucky, USA Kentucky Equine Research, Brighton, Vic, Australia Hindgut acidosis (HGA) is a common problem in horses consuming either large quantities of grain or fructan-rich forages and a survey of racehorses in NSW found that 27% were suffering HGA (1).
When large grain meals are fed to horses, a portion of the starch may escape digestion in the small intestine and be rapidly fermented in the caecum and colon.
Volatile fatty acid (VFA) and lactic acid production increases, causing a significant decrease in pH.
Horses suffering from HGA may develop loose droppings, anorexia, colic, or laminitis or display stereotypical behaviors such as wood chewing and stall weaving.
This study tested the effectiveness of a protected sodium bicarbonate (PSB)1 that survives transit through the stomach and small intestine of the horse on HGA in horses fed a high grain ration.
Blood pH, pCO2, HCO3-, Na+, K+, Cl-, and tCO2 and faecal VFAs, pH, and L- and D-lactate concentration were measured in 6 Thoroughbred horses in training fed a high grain diet in 2 feeds with hay and 168g/d protected sodium bicarbonate using a switchback design.
Feeding 2 to 3 kg of sweet feed in a single meal resulted in a significant drop in faecal pH 6 h post feeding (Fig 1).
This drop was the result of a combination of microbial production of VFAs and lactic acid in the hindgut.
Addition of PSB to the diet attenuated the drop in faecal pH and reduced the concentration of faecal lactic acid (Fig 1), but it had no effect on VFA suggesting that its primary action was related to either lactate producing or utilizing microorganisms. Figure 1.
Fecal pH (L) and Fecal D-lactate (R) concentration on day 15 Addition of PSB to the diet attenuated the drop in faecal pH and reduced the concentration of faecal lactic acid.
The dose rate of PSB used in this study did not significantly elevate tCO2.
Feeding a protected sodium bicarbonate (PSB) is a safe and effective method of attenuating HGA without producing a metabolic alkalosis. 1.
Richards N, Hinch GN and Rowe JB. (2006).
Aust Vet J 84:402-407 1 EquiShureTM, Kentucky Equine Research, Inc., Versailles, KY, USA 40383 26 Proc.
Symp., Vol 2, 2008 BIOELECTRICAL IMPEDANCE MEASUREMENTS FOR PREDICTING BODY COMPOSITION OF HORSES K.
Van der Aa KuhleA, A.J.
WardB and W.L.
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