Comparison of sorghum and corn grains in early and midlactation diets for dairy cows.

Two trials were conducted to compare the effects of corn and sorghum grains on performance of early and midlactation Holstein dairy cows. In trial 1, 36 multiparous midlactation cows were assigned to one of four diets in a 2 x 2 factorial arrangement for 10 wk: 1) grain mixture containing 77% rolled corn fed in a TMR, 2) same grain fed separately from forage, 3) grain mixture containing 77% finely ground sorghum fed in a TMR, and 4) same grain fed separately from forage. Grain source and feeding methods had similar effects on milk yield, milk fat percentage, SNF, SCM, and BW. Cows fed sorghum had higher DMI; cows fed corn had greater efficiency of milk yield. In trial 2, 36 multiparous early lactation cows were assigned to one of four TMR in a 2 x 2 factorial arrangement for 9 wk: 1) TMR containing 35.5% rolled corn, 2) TMR containing 35.5% finely ground corn, 3) TMR containing 35.5% rolled sorghum, and 4) TMR containing 35.5% finely ground sorghum. Grain source produced no differences in DMI, milk yield, milk fat percentage, SCM, and BW. Cows fed finely ground grain yielded more milk than those fed rolled grain. Finely ground sorghum promoted higher milk protein and SNF percentages than did finely ground corn. Total tract starch digestibility was greater for corn than for sorghum. These two trials indicate that sorghum grain, when finely ground, supports milk yield and composition similar to that of corn.