Animal Breeding and Genomics, Wageningen University & Research, PO Box 338, 6700 AH Wageningen, the Netherlands.
Animal Breeding and Genomics, Wageningen University & Research, PO Box 338, 6700 AH Wageningen, the Netherlands.
J Dairy Sci. 2022 Oct;105(10):8158-8176. doi: 10.3168/jds.2021-21532. Epub 2022 Aug 24.
Resilience is the ability of cows to be minimally affected by disturbances, such as pathogens, heat waves, and changes in feed quality, or to quickly recover. Obvious advantages of resilience are good animal welfare and easy and pleasant management for farmers. Furthermore, economic effects are also expected, but these remain to be determined. The goal of this study was to investigate the association between resilience and lifetime gross margin, using indicators of resilience calculated from fluctuations in daily milk yield using an observational study. Resilience indicators and lifetime gross margin were calculated for 1,325 cows from 21 herds. These cows were not alive anymore and, therefore, had complete lifetime data available for many traits. The resilience indicators were the natural log-transformed variance (LnVar) and the lag-1 autocorrelation (r) of daily milk yield deviations from cow-specific lactation curves in parity 1. Good resilience is indicated by low LnVar (small yield response to disturbances) and low r (quick yield recovery to baseline). Lifetime gross margin was calculated as the sum of all revenues minus the sum of all costs throughout life. Included revenues were from milk, calf value, and slaughter of the cow. Included costs were from feed, rearing, insemination, management around calving, disease treatments, and destruction in case of death on farm. Feed intake was unknown and, therefore, lifetime feed costs had to be estimated based on milk yield records. The association of each resilience indicator with lifetime gross margin, and also with the underlying revenues and costs, was investigated using analysis of covariance (ANCOVA) models. Mean daily milk yield in first lactation, herd, and year of birth were included as covariates and factors. Natural log-transformed variance had a significantly negative association with lifetime gross margin, which means that cows with stable milk yield (low LnVar, good resilience) in parity 1 generated on average a higher lifetime gross margin than cows that had the same milk yield level but with more fluctuations. The association with lifetime gross margin could be mainly attributed to higher lifetime milk revenues for cows with low LnVar, due to a longer lifespan. Unlike LnVar, r was not significantly associated with lifetime gross margin or any of the underlying lifetime costs and revenues. However, it was significantly associated with yearly treatment costs, which is important for ease of management. In conclusion, the importance of resilience for total profit generated by a cow at the end of life was confirmed by the significant association of LnVar with lifetime gross margin, although effects of differences in feed efficiency between resilient and less resilient cows remain to be studied. The economic advantage can be mainly ascribed to benefits of long lifespan.
奶牛的抗逆性是指奶牛受到病原体、热浪和饲料质量变化等干扰时受到的影响最小，或者能够快速恢复的能力。抗逆性的明显优势是良好的动物福利和易于管理，令农民感到轻松愉快。此外，预计还会产生经济效益，但这些仍有待确定。本研究的目的是使用使用观测研究中使用每日牛奶产量波动计算的抗逆性指标，来研究抗逆性与终生总利润之间的关系。为 21 个牛群的 1325 头奶牛计算了抗逆性指标和终生总利润。这些奶牛已经不在了，因此可以获得许多性状的终生数据。抗逆性指标是第 1 胎次牛的特定泌乳曲线中每日牛奶产量偏差的自然对数变换方差（LnVar）和滞后 1 自相关（r）。低 LnVar（对干扰的产量响应较小）和低 r（产量快速恢复到基线）表明具有良好的抗逆性。终生总利润是通过终生的所有收入减去所有成本的总和计算得出的。包括牛奶、犊牛价值和奶牛屠宰的收入。包括饲料、饲养、配种、产犊前后的管理、疾病治疗以及农场死亡时的销毁费用。饲料摄入量未知，因此必须根据牛奶产量记录估算终生饲料成本。使用协方差分析（ANCOVA）模型研究每个抗逆性指标与终生总利润的关系，以及与潜在收益和成本的关系。第一胎次、牛群和出生年份的平均每日产奶量被作为协变量和因子包含在内。自然对数变换方差与终生总利润呈显著负相关，这意味着第 1 胎次牛奶产量稳定（低 LnVar，抗逆性好）的奶牛的终生总利润平均高于具有相同产奶量水平但产量波动较大的奶牛。与终生总利润的这种关联主要归因于低 LnVar 奶牛的终生牛奶收入更高，这是因为它们的寿命更长。与 LnVar 不同，r 与终生总利润或任何基础终生成本和收入均无显著关联。然而，r 与每年的治疗成本显著相关，这对管理的便利性很重要。总之，由于 LnVar 与终生总利润显著相关，因此确认了抗逆性对奶牛终生产生的总利润的重要性，尽管抗逆性奶牛与非抗逆性奶牛之间的饲料效率差异的影响仍有待研究。经济优势主要归因于长寿命带来的好处。
