Feeding Value of Dry Corn, Ensiled High Moisture Corn, and Propionic Acid Treated High Moisture Corn Fed with Hay or Haylage for Lactating Dairy Cows

Abstract

Trial I. Fifty lactating Holstein and Brown Swiss cows were assigned to six groups in a 3 X 2 factorial design and fed one of six diets for 16 wk: (1) dry corn q-hay, (2) dry corn q-haylage, (3) ensiled high moisture corn -4-hay, (4) ensiled high moisture corn + haylage, (5) propionic acid treated corn qhay, and (6) propionic acid treated corn + haylage. Quantities equal in dry matter of dry corn, ensiled corn, and acid treated corn were offered in the ratio of 1 kg concentrate (corn and supplement) for each 2.75 kg milk produced. Forage was fed free choice. Means adjusted by covarianee for cows fed diets 1 to 6 averaged: dry matter intake (kg/day), 16.7, 20.0, 17.4, 20.6, 17.1, 20.0; 4% fat-corrected milk (kg/day), 21.8, 21.1, 22.6, 23.5, 22.4, 23.4; milk fat percent, 3.54, 3.45, 3.63, 3.53, 3.62, 3.80; and acetate to propionate ratio 3. 53, 3.85, 3.73, 3.66, 3.13, 3.32. Cows fed ensiled corn and acid treated corn produced more 4% fat-corrected milk than did cows fed dry corn. The molar percent acetate to propionate ratio in rumen fluid of cows fed acid treated corn was lower than for cows fed dry corn or ensiled corn.