Twenty dairy cows were allotted to two treatment groups in a continuous feeding experiment over two lactation cycles. Cows in Group 1 were fed ad libitum to assure 5% orts, a constant 60:40 forage-to-grain ratio (dry basis) whereas Group 2 cows were fed 50:50, 63:35, and 85:15 ratios during early (Period 1, 21 wk) and late (Period 2, 23 wk) lactation, and the dry period (Period 3, 8 wk). There was no significant difference between Groups in the 2-yr average 308-day actual or 4% fat-corrected milk. The 4% fat-corrected milk production during lactations 1 and 2 for Group 1 was 6591, 6398 and for Group 2 was 6006, 6678kg. Fat test was higher during early lactation in Group 1; otherwise milk composition data were similar. The 2-yr average daily and yearly total dry matter intakes were not different between treatments. Digestible energy concentration of diets for Groups 1 and 2 during Periods 1, 2, and 3 were: 2.88, 2.93; 2.90, 3.08; and 2.99, 2.93 Mcal/kg dry matter. Cows in Group 2 had a more positive energy balance during early lactation, produced more actual milk, consumed more dry matter, lost less body weight, had higher blood glucose and lower ketone values, showed an earlier postcalving estrus, and recovered lost postpartum weight faster than cows in Group 1.

Redistribution of nitrogen, when isonitrogenous levels of urea (.5%) or diammonium phosphate (1.1%) were added with 0, .125, .25, .5 and 1.0% sodium bentonite to whole corn plants at ensiling, was studied in 33 pilot silos in Experiment I. In Experiment II, redistribution of 15N urea added to corn plant tissue harvested at 28.8 (low dry matter), 36.4 (medium dry matter) and 49.0% (high dry matter) dry matter was studied. Bentonite was added at 0, .25, .5 and 1.0% to the medium dry matter material. All treatments were ensiled in pilot silos designed to permit collection of gas and seepage fractions.