Effects of Roughage Feeding Type during the Growing and Early-Fattening Periods on Growth Performance, Feed Efficiency and Carcass Characteristics in Holstein Steers

Abstract

Twenty four Holstein steers fed commercial concentrates with rice straw (T1), mixed grass hay (T2), or wet brewer's grains based TMR ad libitum (T3) were used to investigate the effects of roughage feeding type during the growing and early-fattening periods on growth performance, feed efficiency and carcass characteristics. Growth performance and feed efficiency were investigated during the feeding trial conducted from 6 to 23 mo of age, and carcass characteristics were investigated after slaughter. Body weight at slaughter and daily gains were 751 to 802 kg (mean 782 kg) and 1.064 to 1.159 kg/d (mean 1.122 kg/d), respectively, showing that those for T2 were highest followed by T3. Compared with T1, the daily gain for T2 was improved by 8.9%. The TDN intakes per kg gain were 6.87, 7.17 and 7.15 kg for T1, T3 and T2, respectively, indicating that feed efficiency for T2 was improved (approx. 5%) compared with T1. The feeding treatments did not change dressing percentage (mean 60.8%), back fat thickness (6.68 mm) and rib-eye area (84.0 cm 2 ). Neither meat quality characteristics nor physicochemical properties were significantly different among the treatments. However, economic analysis accounting for 882.8, 991.7 and 943.8 thousand won per head for T1, T2 and T3, respectively, indicated that T2 and T3 increased (7~12%) total net income compared with T1. Therefore, it may be concluded that high quality meat of Holstein steers can be produced if they are fattened until 23 mo of age and that feeding mixed grass hay as roughage or TMR containing mainly wet brewer's grains during the growing and early-fattening periods can improve growth performance compared with feeding rice straw.