Potassium Excretion of Dry, Pregnant and Lactating Cows Fed Forage

Abstract

Sixty two balance trials were conducted to clarify the potassium excretion of dry, pregnant and lactating cows fed forages. The ratio of feeding forage ranged from 60 to 100%, and daily potassium intake of cows ranged from 81 to 555g. According to the regression equation of potassium absorption on potassium intake, the rates of potassium absorption in dry, pregnant and lactating cows were 95.6 to 99.9%, and most of potassium absorbed was excreted in the urine. Urine volume of cows increased with the increased urine excretion of potassium, and the increase of 1g of urine potassium excretion was estimated to increase 70g of urine volume in dairy cows. Feeding corn silage decreased potassium excretion and urine volume of cows due to the low potassium intake.