摘要
The aim of this study was to evaluate growth, ruminal and metabolic parameters and feeding behavior of young Nellore males classified based on postweaning residual feed intake (RFI). Fifty-nine Nellore males (290 ± 20 days of age and 294 ± 8.48 kg of body weight) were evaluated for 70 days in a feed efficiency test conducted with the GrowSafe System®, with automatic and daily measurement of individual feed intake and feeding behavior. The animals were weighed every 14 days. Body measures and blood samples were obtained at the beginning and end of the efficiency test. The RFI was calculated as the residual of the regression equation of dry matter (DM) intake on average daily weight gain and mid-test metabolic body weight. The animals were classified as low (n = 25), medium (n = 15), and high (n = 19) RFI. Six low RFI and six high RFI animals were used for determining ruminal parameters and microbial nitrogen. The data were analyzed considering the fixed effect of RFI class and initial age as linear covariate. Low RFI animals consumed less DM to achieve a performance similar to that of animals with medium and high RFI. The different RFI groups did not influence ruminal fermentation parameters, microbial nitrogen, blood metabolites, or body measures. Low RFI animals spent less time at the feed bunk when compared to animals with medium and high RFI for a similar amount of feed consumed per visit. Animals with low RFI are efficient in feed utilization as demonstrated by their good production potential despite lower feed intake, without losses in growth or ruminal and metabolic parameters.
摘要译文
本研究的目的是评估基于切换残留饲料摄入（RFI）的幼虫男性的生长，瘤胃和代谢参数以及饲养行为。在用GrowSafeSystem®进行的饲料效率试验中评估509个幼儿雄性（290±20天和294±8.48千克体重），在GROSEAFESystem®进行的饲料效率测试中，具有自动和每日测量单独的饲料摄入和饲养行为。每14天称重动物。在效率试验的开始和结束时获得身体措施和血液样本。将RFI计算为干物质（DM）的回归方程的残余物平均每日体重增加和中测代谢体重。将动物分类为低（n = 25），培养基（n = 15），高（n = 19）RFI。六个低RFI和六个高RFI动物用于确定瘤胃参数和微生物氮。考虑到RFI类和初始年龄作为线性协变量的固定效果分析了数据。低RFI动物消耗较少的DM，以实现类似于中高RFI的动物的性能。不同的RFI组不影响瘤胃发酵参数，微生物氮，血代谢物或身体措施。与中高RFI的动物相比，低RFI动物在饲料铺位时花了更少的时间，以获得每次访问消耗的类似饲料量。具有低RFI的动物在饲料利用中有效，尽管进料摄入量较低，但仍然良好的生产潜力所证明的，而不会损失生长或瘤胃和代谢参数。
N.Trevizan;R.C.Canesin;R.H.Branco;C.D.A.Batalha;J.N.S.G.Cyrillo;S.F.M.Bonilha;. Growth, ruminal and metabolic parameters and feeding behavior of Nellore cattle with different residual feed intake phenotypes - ScienceDirect[J]. Livestock Science, 2021,244