摘要
A study (factorial design) was conducted to evaluate RFI reranking between growing and finishing phases of production using two nutritional management regimens (MR). One-hundred and eight non-implanted British and Continental crossbred steers (±353 kg) were fed an alfalfa/corn silage growing diet for ~90 days. RFI classification was calculated with steers classified as high, medium, and low (RFI) based on 0.5 SD from the mean. Cattle were allocated to two MR (MR1, MR2) based on RFI, breed, and weight. MR1 cattle were finished on an 84.7% concentrate diet while MR2 cattle were backgrounded on pasture for ~112 days and subsequently finished on the high concentrate diet. Steers were slaughtered at ~750 kg BW. Carcass and meat quality data were collected, and finishing phase RFI calculated to evaluate reranking. Average daily gains (ADG, kg/d) and gain:feed (G/F) respectively included: growing (±1.28; 0.178), MR1 finishing (±1.74; 0.152) and MR2 finishing (±1.92; 0.149). ADG differed between MR (P 0.05), while G/F differed between MR and RFI class (P0.05) while positively correlated with ribeye area (cm2) (P<0.001) and quality grade (P=0.02). Ribeye area was also smaller (P<0.05) for medium RFI steers when compared to either high or low RFI classification. Ultimately, management regimen did not affect reranking of RFI classification for cattle fed a common diet in the growing phase of production.
摘要译文
进行了一项研究（阶乘设计），以评估使用两种营养管理方案（MR）在生产和生产阶段之间的RFI重新融合。一百八个未植入的英国和大陆杂交牛排（±353 kg）被喂食约90天。根据平均值为0.5 SD，使用将转向器分类为高，中和低（RFI）的转向分类。根据RFI，品种和体重，将牛分配给两个MR（MR1，MR2）。 MR1牛以84.7％的浓缩饮食结束，而MR2牛在牧场上进行了约112天的背景，然后以高浓缩饮食完成。大约750千克bw被屠宰。收集了car体和肉质质量数据，并计算出旨在评估重读的RFI。平均每日增益（ADG，kg/d）和增益：分别包括：饲料（g/f）包括：增长（±1.28; 0.178），MR1饰面（±1.74; 0.152）和MR2完成（±1.92; 0.149）。 MR之间的ADG不同（P 0.05），而MR和RFI类别之间的G/F差异（P0.05），而Ribeye区域（CM2）（P <0.001）和质量等级（P = 0.02）正相关。与高RFI分类相比，中等RFI转向的Ribeye区域也较小（P <0.05）。最终，管理方案不会影响在生产阶段增长饮食的牛的RFI分类的重新分类。
N Ferriman; C Campbell; K Wood; A Edwards; ; I M;ell. 79 Residual Feed Intake (RFI) Reranking in Beef Steers Fed Growing and Finishing Diets under Two Management Regimens.[J]. Journal of Animal Science, 2018,96(Sup3)