福岡県農業総合試験場研究報告

肥育前中期における乾燥ビール粕の飼料混合割合が乳用種去勢牛の産肉性に及ぼす影響

　乳用種去勢牛18頭（約８ヵ月齢）を用い、肥育前期および中期の混合飼料中の乾燥ビール粕割合が、産肉性に及ぼす影響について検討した。肥育期を前期、中期および後期に分け、試験区として、ビール粕を肥育前期に10％、中期に10％混合した10％区、ビール粕を前期に20％、中期に10％混合した20％区を設定し、対照区としてビール粕を全期間混合しない０％区を設定した。各試験区のＴＤＮ水準は前期71％、中期78％および後期82％とした。終了時体重（19.6ヵ月齢）は３区とも700～720㎏と同程度で仕上がった。増体量、乾物摂取量およびＴＤＮ摂取量についても試験区における差は認められなかった。枝肉成績では20％区は、０％区および10％区と比較して枝肉重量は同程度であったが、枝肉の特徴としてロース芯面積が広く、バラが厚く、肉質では脂肪交雑、肉の色沢および締まり・きめ等の評価が高い良質肉生産に効果が認められた。

　Eighteen Holstein steers were divided into three groups to investigate the effect of dry brewers' grain supplementaion in their diet on fattening performance. Fattening periods were divided into three stages with the early one being for steers 8 to 12 months old, the middle one for those from 12 to 15 months and the last for steers 15 to 20 months old. Group A was fed a fattening diet without the brewers' grain for all periods. Group B was fed the fattening diet supplemented with 10% brewers' grain (content of the total mixed rations) in the early and middle periods. Group C was fed the fattening diet supplemented with 20% brewers' grain in the early and 10% in the middle period. All the steers were fed the same diet in the last period. The content level of TDN( % on DM) for the three groups was the same : 71% in the early stage, 78% in the middle and 82% in last fattening period. The final body weight before slaughter ranged from 700kg to 720kg.　 Daily gain, DM intake and TDN intake were not different among the three groups in each period. There were no statistical differences among the three groups for the average daily gain and the carcass weight. Compared to groups A and B, Group C showed tendencies for a wider rib eye area and thicker ribs along with higher beef marbling standard numbers and firmness grades B. These results suggested that the total mixed rations supplemented with the dry brewers' grain could be an improvement factor in fattening Holstein steers.