The objectives of the present study were to estimate genetic parameters for several feeding behavior traits in growing cattle, as well as the genetic associations among and between feeding behavior and both performance and feed efficiency traits. An additional objective was to investigate the use of feeding behavior traits as predictors of genetic merit for feed intake. Feed intake and live-weight data on 6,088 growing cattle were used of which 4,672 had ultrasound data and 1,548 had feeding behavior data. Feeding behavior traits were defined based on individual feed events or meal events (where individual feed events were grouped into meals). Univariate and bivariate animal linear mixed models were used to estimate (co)variance components. Heritability estimates (± SE) for the feeding behavior traits ranged from 0.19 ± 0.08 for meals per day to 0.61 ± 0.10 for feeding time per day. The coefficient of genetic variation per trait varied from 5% for meals per day to 22% for the duration of each feed event. Genetically heavier cattle, those with a higher daily energy intake (MEI), or those that grew faster had a faster feeding rate, as well as a greater energy intake per feed event and per meal. Better daily feed efficiency (i.e., lower residual energy intake) was genetically associated with both a shorter feeding time per day and shorter meal time per day. In a validation population of 321 steers and heifers, the ability of estimated breeding values (EBV) for MEI to predict (adjusted) phenotypic MEI was demonstrated; EBVs for MEI were estimated using multi-trait models with different sets of predictor traits such as liveweight and/or feeding behaviors. The correlation (± SE) between phenotypic MEI and EBV for MEI marginally improved (P < 0.001) from 0.64 ± 0.03 to 0.68 ± 0.03 when feeding behavior phenotypes from the validation population were included in a genetic evaluation that already included phenotypic mid-test metabolic live-weight from the validation population. This is one of the largest studies demonstrating that significant exploitable genetic variation exists in the feeding behavior of young crossbred growing cattle; such feeding behavior traits are also genetically correlated with several performance and feed efficiency metrics. Nonetheless, there was only a marginal benefit to the inclusion of time-related feeding behavior phenotypes in a genetic evaluation for MEI to improve the precision of the EBVs for this trait.

中文翻译：

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杂交生长牛饲养行为的遗传变异性及其与生产性能和饲料效率的关系

本研究的目的是估计生长牛的几种摄食行为特征的遗传参数，以及摄食行为与生产性能和饲料效率性状之间的遗传关联。另一个目标是研究使用摄食行为特征作为采食遗传价值的预测因子。使用了 6,088 头生长牛的采食量和活体重数据，其中 4,672 头有超声波数据，1,548 头有采食行为数据。喂养行为特征是根据个体喂养事件或膳食事件（其中个体喂养事件被分组为膳食）定义的。单变量和双变量动物线性混合模型用于估计（协）方差分量。摄食行为特征的遗传力估计值 (± SE) 从每天进餐的 0.19 ± 0.08 到 0。每天喂食时间为 61 ± 0.10。每个性状的遗传变异系数从每天进餐的 5% 到每次饲料事件期间的 22% 不等。基因较重的牛、具有较高每日能量摄入量 (MEI) 的牛或生长较快的牛具有更快的采食率，以及每次采食事件和每餐的能量摄入量更多。更好的每日饲料效率（即较低的剩余能量摄入）在遗传上与每天较短的喂食时间和较短的进餐时间有关。在 321 头公牛和小母牛的验证群体中，证明了 MEI 的估计育种值 (EBV) 预测（调整后的）表型 MEI 的能力；MEI 的 EBV 是使用具有不同预测特征（如体重和/或摄食行为）的多特征模型估计的。当来自验证群体的摄食行为表型包含在已经包括表型中期测试的遗传评估中时，MEI 的表型 MEI 和 EBV 之间的相关性 (± SE) 从 0.64 ± 0.03 略微提高 (P < 0.001) 到 0.68 ± 0.03来自验证人群的代谢活重。这是最大的研究之一，表明年轻杂交生长牛的摄食行为中存在显着的可利用遗传变异；这种摄食行为特征在遗传上也与一些性能和饲料效率指标相关。尽管如此，在 MEI 的遗传评估中纳入与时间相关的摄食行为表型以提高 EBV 对该性状的精确度仅具有边际优势。001）从 0.64 ± 0.03 到 0.68 ± 0.03，当来自验证人群的喂养行为表型被纳入遗传评估时，该遗传评估已经包括来自验证人群的表型测试中代谢活重。这是最大的研究之一，表明年轻杂交生长牛的摄食行为中存在显着的可利用遗传变异；这种摄食行为特征在遗传上也与一些性能和饲料效率指标相关。尽管如此，在 MEI 的遗传评估中纳入与时间相关的摄食行为表型以提高 EBV 对该性状的精确度仅具有边际优势。001）从 0.64 ± 0.03 到 0.68 ± 0.03，当来自验证人群的喂养行为表型被纳入遗传评估时，该遗传评估已经包括来自验证人群的表型测试中代谢活重。这是最大的研究之一，表明年轻杂交生长牛的摄食行为中存在显着的可利用遗传变异；这种摄食行为特征在遗传上也与一些性能和饲料效率指标相关。尽管如此，在 MEI 的遗传评估中纳入与时间相关的摄食行为表型以提高 EBV 对该性状的精确度仅具有边际优势。03 当来自验证群体的喂养行为表型被包括在已经包括来自验证群体的表型测试中期代谢活重的遗传评估中时。这是最大的研究之一，表明年轻杂交生长牛的摄食行为中存在显着的可利用遗传变异；这种摄食行为特征在遗传上也与一些性能和饲料效率指标相关。尽管如此，在 MEI 的遗传评估中纳入与时间相关的摄食行为表型以提高 EBV 对该性状的精确度仅具有边际优势。03 当来自验证群体的喂养行为表型被包括在已经包括来自验证群体的表型测试中期代谢活重的遗传评估中时。这是最大的研究之一，表明年轻杂交生长牛的摄食行为中存在显着的可利用遗传变异；这种摄食行为特征在遗传上也与一些性能和饲料效率指标相关。尽管如此，在 MEI 的遗传评估中纳入与时间相关的摄食行为表型以提高 EBV 对该性状的精确度仅具有边际优势。这是最大的研究之一，表明年轻杂交生长牛的摄食行为中存在显着的可利用遗传变异；这种摄食行为特征在遗传上也与一些性能和饲料效率指标相关。尽管如此，在 MEI 的遗传评估中纳入与时间相关的摄食行为表型以提高 EBV 对该性状的精确度仅具有边际优势。这是最大的研究之一，表明年轻杂交生长牛的摄食行为中存在显着的可利用遗传变异；这种摄食行为特征在遗传上也与一些性能和饲料效率指标相关。尽管如此，在 MEI 的遗传评估中纳入与时间相关的摄食行为表型以提高 EBV 对该性状的精确度仅具有边际优势。