生长阶段印度瘤牛的摄食行为、饲料效率和生长性状的遗传关联性。
Genetic association among feeding behavior, feed efficiency, and growth traits in growing indicine cattle.
机构信息
Beef Cattle Research Center, Institute of Animal Science, Sertãozinho, SP, Brazil.
Department of Animal Science, Federal University of Jequitinhonha and Mucuri Valleys, Diamantina, MG, Brazil.
出版信息
J Anim Sci. 2020 Nov 1;98(11). doi: 10.1093/jas/skaa350.
This study aimed to estimate genetic parameters, including genomic data, for feeding behavior, feed efficiency, and growth traits in Nellore cattle. The following feeding behavior traits were studied (861 animals with records): time spent at the feed bunk (TF), duration of one feeding event (FD), frequency of visits to the bunk (FF), feeding rate (FR), and dry matter intake (DMI) per visit (DMIv). The feed efficiency traits (1,543 animals with records) included residual feed intake (RFI), residual weight gain (RWG), and feed conversion (FC). The growth traits studied were average daily gain (ADG, n = 1,543 animals) and selection (postweaning) weight (WSel, n = 9,549 animals). The (co)variance components were estimated by the maximum restricted likelihood method, fitting animal models that did (single-step genomic best linear unbiased prediction) or did not include (best linear unbiased prediction) genomic information in two-trait analyses. The direct responses to selection were calculated for the feed efficiency traits, ADG, and WSel, as well as the correlated responses in feed efficiency and growth by direct selection for shorter TF. The estimated heritabilities were 0.51 ± 0.06, 0.35 ± 0.06, 0.27 ± 0.07, 0.34 ± 0.06, and 0.33 ± 0.06 for TF, FD, FF, FR, and DMIv, respectively. In general, TF and FD showed positive genetic correlations with all feed efficiency traits (RFI, RWG, and FC), ADG, DMI, and WSel. Additionally, TF showed high and positive genetic and phenotypic correlations with RFI (0.71 ± 0.10 and 0.46 ± 0.02, respectively) and DMI (0.56 ± 0.09 and 0.48 ± 0.03), and medium to weak genetic correlations with growth (0.32 ± 0.11 with ADG and 0.14 ± 0.09 with WSel). The results suggest that TF is a strong indicator trait of feed efficiency, which exhibits high heritability and a weak positive genetic correlation with growth. In a context of a selection index, the inclusion of TF to select animals for shorter TF may accelerate the genetic gain in feed efficiency by reducing RFI but with zero or slightly negative genetic gain in growth traits.
本研究旨在估计内罗尔牛的采食行为、饲料效率和生长性状的遗传参数，包括基因组数据。研究了以下采食行为性状（861 头有记录的动物）：在饲料槽的时间（TF）、单次采食持续时间（FD）、采食频率（FF）、采食速度（FR）和单次采食干物质采食量（DMIv）。饲料效率性状（1543 头有记录的动物）包括剩余采食量（RFI）、剩余体重增长（RWG）和饲料转化率（FC）。研究的生长性状包括平均日增重（ADG，n=1543 头动物）和选择（断奶后）体重（WSel，n=9549 头动物）。方差分量通过最大限制似然法估计，在两性状分析中，拟合动物模型包括（一步法基因组最佳线性无偏预测）或不包括（最佳线性无偏预测）基因组信息。对饲料效率性状、ADG 和 WSel 进行了直接选择反应的计算，并通过直接选择较短的 TF 对饲料效率和生长的相关反应进行了计算。TF、FD、FF、FR 和 DMIv 的估计遗传力分别为 0.51±0.06、0.35±0.06、0.27±0.07、0.34±0.06 和 0.33±0.06。一般来说，TF 和 FD 与所有饲料效率性状（RFI、RWG 和 FC）、ADG、DMI 和 WSel 均表现出正遗传相关。此外，TF 与 RFI（0.71±0.10 和 0.46±0.02）和 DMI（0.56±0.09 和 0.48±0.03）具有高且正的遗传和表型相关，与生长具有中弱的遗传相关（0.32±0.11 与 ADG 和 0.14±0.09 与 WSel）。结果表明，TF 是饲料效率的一个强指示性状，具有较高的遗传力和与生长的弱正遗传相关。在选择指数的背景下，选择 TF 较短的动物进行选择可能会通过降低 RFI 来加速饲料效率的遗传进展，但对生长性状的遗传进展为零或略有负值。
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