Performance and Carcass Characteristics of Feeder Heifer Calves Fed Different Amounts of Concentrates with Urea-Limestone Treated Corn Silage

Two feeding trials, one in 1967-68 and the other in 1968-69, were conducted at the University of Tennessee's Blount Farm to determine the effect of feeding different amounts of concentrates with urea-limestone treated corn silage on the performance and carcass characteristics of feeder heifer calves. A total of 288 animals were involved in the study. Treatments included delaying the feeding of a 6 lb. concentrate supplement for 0 (control), 56, 84, 112, 140 and 168 days during a period of high roughage feeding. Two other treatments involved the feeding of 2 or 4 lb. of concentrate during the entire roughage phase. After the roughage phase all animals were given a full feed of concentrate until they graded high-Good to low-Choice. They were then slaughtered at local packing plants.

Daily gains were highest when the heifers were fed 4 or 6 lb. of concentrate during the entire roughage phase. Delaying the feeding of the concentrate supplement for as long as 84 days resulted in gains slightly less in magnitude but not significantly (P > .05) lower than those of the two highest gaining groups of heifers. The amount of feed required per hundred pounds of gain was lowest for the heifers fed 2 or 4 lb. of concentrate. Average daily dry matter consumption decreased with increased delay of concentrate feeding. Dressing percent and percent kidney fat was highest for the heifers fed 4 or 6 lb. of concentrate. Fat thickness, marbling scores, and U.S.D.A. carcass grades were highest for heifers fed 6 lb. of concentrate during the entire roughage phase. The treatments had little or no effect on ribeye area. Final condition grades generally decreased with decreases in total amount of concentrate fed. Feed cost per hundred pounds of gain was lowest for heifers fed 6 lb. of concentrate for the entire roughage phase.