The influence of processed corn and supplemental fat on digestion of limit-fed diets and performance of beef cows.

Trial 1, 135 crossbred cows with calves were used to compare limit-fed corn-hay diets with ad libitum hay and cracked with whole corn in limit-fed diets. Diets were to supply similar TDN intakes. Cow-calf pairs were fed treatment diets from 24 h after parturition until the beginning of the breeding season (62+/-13 d). Cow and calf performance was not affected (P > .05) by intake level or corn processing. In Trial 2, 48 crossbred primiparous cows with calves were used to determine the effect of adding 4% fat to a limit-fed corn-hay diet. Diets were to provide similar TDN intakes. Cow-calf pairs were fed treatment diets from 24 h after parturition until the breeding season started (79+/-14 d). Cow weight, condition score change, and calf gain were not affected (P > .05) by supplemental fat. Milk yield and composition were not different (P > .05) 52 d postpartum. At 92 d postpartum, milk production was 65% greater (P = .01) for cows that received supplemental fat. In Trial 3, four cannulated steers were used to evaluate the influence of corn processing and fat supplementation on digestion. Feeding cracked corn improved (P < .05) DM and OM digestion compared with whole corn. Adding 4% supplemental fat did not influence (P > .05) digestion. Limit-feeding a corn-hay diet is an alternative to feeding ad libitum hay that can accomplish similar cow and calf performance. Supplementation of 4% fat can be used in a limit-fed diet without detrimental effects on digestion, lactation, or cow and calf performance.