One hundred and eleven 5-month-old Belgian Blue double-muscled bulls were divided into three feeding management groups. Group I was turned out on pasture with a daily supplement of 2 kg of beet pulp during the summer period and was fed grass silage to appetite and 2 kg of concentrate during the winter period. The other groups stayed permanently indoors and were fed on maize silage and concentrate (67:33 dry matter basis). Intake was limited for group II to have a daily liveweight gain of 0.85 kg, while the feeds were freely available for group III. From 400 kg onwards, all animals were finished indoors on a diet of maize silage and concentrate (50:50). Within each group, half of the animals were slaughtered at either 650 or 725 kg. Below 400 kg, the daily liveweight gain averaged 0.76, 0.83 and 1.16 kg, respectively (P <0.05). Above 400 kg, the animals of groups I and II gained faster and gain was more efficient in comparison with group III. Slaughtering at 725 kg tended to decrease daily liveweight gain during the finishing period (P = 0.13) and had a negative effect on feed conversion (P = 0.013) in comparison with 650 kg. Overall daily liveweight gain was lower in groups I and II and these animals needed more time to achieve the same finishing weight (P <0.001) compared to group III. The bulls, which grazed during the growing period, showed a lower dressing percentage and a tendency for a lower meat content in the carcass. Slaughtering at a heavier live weight also increased fat content of the carcass. Furthermore, significant interactions were found between feeding management and slaughter weight for total number of experimental days, overall daily liveweight gain, dressing, carcass composition and meat production coefficient. It is concluded that animal performance of double-muscled bulls is affected by feeding management during the growing period and liveweight range during the finishing period. Reduced growth rate during the growing period was not fully compensated afterwards, and it did not result in a reduction of carcass fat content. Double-muscled animals mostly behave in a similar way as non-double-muscled animals with regard to compensatory gain. Energy supplementation of light animals at pasture should be advised. (C) 2002 Elsevier Science B.V. All rights reserved.
|Vertaalde titel van de bijdrage
|Performance of double-muscled bulls affected by grazing or restricted indoor feed intake during the growing period followed by finishing up to two different slaughter weights
|Livestock Production Science
|Gepubliceerd - 1-okt.-2002