The comparison of two forms of sodium and potassium and chloride versus sulfur in the Dietary Cation-Anion Difference equation: Effects on acid-base status and mineral balance in sedentary horses

Summary Six mature geldings were randomly assigned treatments within a 6×6 latin square design experiment to study the effects of the Dietary Cation-Anion Difference equation (DCAD) on acid-base status and mineral balance in sedentary horses. Dietary Cation-Anion Difference was calculated as: meq ((Na+K)-(Cl+S))/kg diet DM. High (H) diets were formulated with the addition of sodium citrate (H:NaC), sodium bicarbonate (H:NaB), potassium citrate (H:KC), and potassium bicarbonate (H:KB). Low (L) diets were formulated with the addition of magnesium sulfate (L:S) and ammonium chloride (L:Cl). Experimental diets consisted of a pelleted base concentrate fed in a 60:40 ratio with native prairie grass hay, and were fed for a 12-day adjustment period followed by a 72-h sample collection period. Post-feeding venous blood samples were analyzed for the determination of pH and HCO 3 . Post-feeding urine samples were analyzed for the determination of urine pH. Representative samples of feed, feces, and urine were analyzed for mineral content and apparent mineral balances were calculated by difference. Horses consuming L:Cl and L:S had lower (P 3 values as compared to those consuming L:S at 6 of 12 intervals measured, and had lower (P 3 values as compared to those consuming all H diets at all intervals measured. Horses consuming H:NaB and H:NaC excreted more Na in the urine (P