Influence of Dietary Sodium Bicarbonate on the Potassium Metabolism of Growing Dairy Calves

¹ Department of Animal Science, University of Kentucky, Lexington 40546 and Animal Science Department, Oklahoma State University, Stillwater 74078

We evaluated the influence of supplemental dietary NaHCO₃ on K metabolism of young dairy calves. Thirty-two Holstein and Jersey male and female calves were blocked at 56 to 70 d after birth according to breed, sex, and age and assigned randomly to a 2 x 2 factorial arrangement of dietary treatments for 8 wk: .4% K with 0% NaHCO₃, .4% K with 2% NaHCO₃, .6% K with 0% NaHCO₃, and .6% K with 2% NaHCO₃. Feed intake was not affected by dietary KCl or NaHCO₃ supplementation, but average daily gain increased with increased K and tended to be reduced by dietary NaHCO₃. Plasma K was elevated by increased dietary K but generally was unaffected by NaHCO₃. Urinary Ca excretion appeared to be reduced by NaHCO₃; urine pH increased with supplemental NaHCO₃. Results indicate 1) the K requirement of the growing calf is between .40 and .55% of diet DM, 2) because urinary K excretion was elevated by dietary NaHCO₃, the K requirement may be increased when the diet is supplemented with NaHCO₃, and 3) average daily gain and plasma K are sensitive indicators of dietary K in the growing calf.

Key Words: potassium • sodium • dairy calf growth • feed intake

Submitted on July 23, 1990
Accepted on December 6, 1990