Effects of Concentrate on Barley Silage and Nitrogen Utilization by Lactating Cows Fed Large Amounts of Urea

Associative effects between the digestibility of barley silage and concentrate and the effect of concentrate feeding on nitrogen utilization were determined. Barley (41% dry matter) was ensiled with 0.5% urea. Concentrate contained protein and urea similar to barley silage on a dry basis. Concentrate was fed to lactating cows (8 per group) to provide either 0, 25, 50 or 75% of the estimated total digestible nutrient requirements for 40 days. Silage was available ad libitum. A digestibility and nitrogen balance trial with 5 cows per group began on Day 32. Silage intake decreased linearly (P