PRODUCTIVE AND ECONOMIC RESPONSE OF DAIRY BULL PRODUCTION UNDER TWO FEEDING SYSTEMS

Abstract

In order to evaluate the productive and economic response of dairy bull production under two feeding systems, 16 Holstein-Friesian young bulls, born in Autumn of 2011 were evaluated. After a rearing period under pasture as a unique group, the animals with 14 months of age and on average 340 ± 20 kg LW were assigned to two feeding treatments, T1: pasture silage and 2% LW concentrate per animal per day, in confinement; T2: pasture silage and 1% LW concentrate and access to kale, on pasture. Eight bulls were assigned to each treatment. Treatments were isoproteic (14% CP) and isoenergetic (2.6 Mcal ME kg-1), dry matter basis. The study finished at 21 months of age, when the bulls reached an average of 550 kg LW. No statistical differences (P > 0.05) were found between treatment in daily liveweight gain, dressing percentage and carcass weight. However, significant differences (P < 0.05) were found in kidney fat with 4.44 kg an-1 (T1) and 2.61 kg an-1 (T2) and pH of 5.72 and 5.46, respectively. Intramuscular fat content of 1.94 and 0.90 (P < 0.05) were determined for T1 and T2, respectively. It was concluded that it is possible to finish dairy bulls at 21 months of age with adequate fat cover, and carcass quality; gross income was better from animals fished on pasture.