EFFECTS OF DIETARY CATION-ANION BALANCE ON PH, ELECTROLYTES, AND LACTATE IN STANDARD-BRED HORSES

Fifteen Standardbred racehorses were utilized in a 3 x 3 Latin square experiment replicated five times to evaluate the effects of dietary ca tion-anion balance (DCAB) on whole venous blood values for pH, pCO(2), HCO3-, lactate, Na+, K+, Cl-, and Ca2+. The horses were matched accor ding to racing ability and history and randomly allotted to the treatm ent groups (High, Low, and Basal DCAB). Horses were allowed a 21-day a djustment period on the diets between each rotation. On the last day o f each feeding period, blood samples were drawn for determination of t he previously mentioned parameters before and after a one-mile warm-up and race and at 60 minutes of recovery. Due to health related problem s and complications beyond our control, seven of the original fifteen horses were unable to complete the trial and thus were removed from th e data set prior to statistical analysis. This study demonstrated that DCAB did not significantly alter acid-base status of the horse. The p H, pCO(2) and HCO3- values were not different (p > .05) across treatme nts. Furthermore, whole blood values for Na+, K+ and Ca2+ did not diff er significantly between treatments. Chloride was not significantly di fferent between diets but was found to be consistently higher in horse s fed the low DCAB diet versus those fed the high DCAB diet. No change (p > .05) was observed in plasma lactate concentrations across treatm ents. These data suggest that horses were able to maintain normal acid -base status regardless of the dietary cation-anion balance of the die t.