Effect of dietary electrolytes, sodium and chloride on physiological and production responses of lactating dairy cows and growing pigs in hot weather

Abstract

Different dietary sodium and chloride concentrations were evaluated in lactating dairy cows and growing pigs in the summer of 1980. Twelve Holsteins and 12 Jerseys were divided into six equivalent groups and assigned to one of three dietary treatments: control (corn-cottonseed-corn silage complete diet), control with high-chloride (2.28% CaCl2) and control with high-sodium bicarbonate (1.7% NaHCO3). The trial was a repeated measures design with five periods. Blood pH and HCO3 concentration were lowest (p < .01) for the high-chloride group. This group showed a partially compensated metabolic acidosis, in contrast to the control and high-NaHCO3 groups which exhibited a non-compensated respiratory alkalosis. Base excess was normal (3.14) for the high-NaHCO3 cows; higher for the control (4.50) the lower for the high-chloride cows (-4.31 mEq/l). Blood glucose was highest (p < .01) in the high-NaHCO3 group. The high-chloride group had the lowest respiration rate (p < .01), and consumed the least feed (p < .01). These data agree with previous work showing the acidogenic properties of excess dietary chloride. They also suggest that computer-formulated diets should include restrictions on macroingredients and that dietary electrolyte research should consider water composition and ambient temperature.