EFFECT OF STEAM FLAKING OF CORN AND SORGHUM GRAINS ON PERFORMANCE OF LACTATING COWS

The objective of this study was to compare the relative feeding value of sorghum versus com grain in rolled or steam-flaked forms in diets, for lactating dairy cows. Twenty-four Holstein cows (averaging 110 DIM ) were divided into four groups and fed diets of 40% grain as dry-roll ed sorghum, steam-rolled com, steam-flaked sorghum, or steam-flaked co m for 70 d. Compared with rolling, flaking of both grains increased yi elds of milk, milk protein and fat, and protein percentage of milk, bu t differences tended to be greater for sorghum than for com. Efficienc y of feed utilization was higher for steam-flaked than for dry-rolled sorghum but was unaffected by com processing. Flaking of both grains i ncreased total tract digestibilities of DM, OM, CP, starch, ADF, and N DF. Estimates for NE(L) were 21% higher for flaked than for rolled sor ghum and 6% higher for flaked than for rolled com. No differences in p erformance of cows existed between com and sorghum grains. Cows fed 40 % of their diet as steam-flaked sorghum or com yielded more milk and m ilk protein than those fed the rolled form of the grains, and no diffe rences existed between types of grain fed.