| Three experiments were conducted to determine effects of corn grain processing on lactational performance and nutrient utilization in dairy cows; and to evaluate feeding value of Amaferm (a culture of Aspergillus oryzae) for lactating cows.;In trial 1, 40 lactating Holstein cows were allotted to five Dietary treatments containing 40% corn grain as finely-ground (FG), coarsely-ground (CG), steam-flaked (SFL, 309 g/L), steam-flaked (SFM, 361 g/L), or steam-rolled (SR, 490 g/L). The SFM increased milk yield 1.6 kg/d more than FG, and an average 2.5 kg/d more than CG, SFL, or SR. Diets with FG increased efficiency of feed utilization 16% because of the lower DMI. Diets with SFL had lower milk fat content than CG or SR. Starch digestibility in the total digestive tract was higher for FG, SFL, or SFM than for CG or SR.;In trial 2, 32 Holstein cows were used in a 2 x 2 factorial arrangement of treatments for 70d. The four diets were: (1) steam-flaked corn (SFC, 361 g/L) + 3 g/d Amaferm, (2) SFC without Amaferm, (3) steam-rolled corn (SRC, 490 g/L) + 3 g/d Amaferm, and (4) SRC without Amaferm. Intake was not affected by processing of grain or addition of Amaferm. Compared with rolled, flaked corn increased milk yield 2.1 Kg/d, milk protein percentage.09%, milk protein yield 8.5%, lactose yield 5.4%, and efficiency of feed utilization 8%. Addition of Amaferm had no significant effects on lactational performance, rectal temperatures or respiration rates of lactating cows during the hot summer conditions of the study.;In trial 3, 5 cannulated lactating Holstein cows were used in a 5 x 5 Latin square design. Dietary treatments were: (1) FG; (2) CG; (3) SFL; (4) SFM; and (5) SR. Diets with SR had lower DMI than CG. Diets with FG, SFL, or SFM had lower ruminal pH than CG or SR. Rumen NH... |
