Welfare Status in Dairy Cows during Confined and Grazing Periods in the North American Pacific Northwest using Blood Parameters and Visual Assessments

Grazing is usually associated with higher well-being in dairy cows. However, current research on the welfare of grazing cows lacks validation via blood profiling. We monitored four dairy farms that seasonally graze in the temperate North American Pacific Northwest, USA, to address this gap. We collected blood and hair samples and scored the animals for welfare-related visual evaluations during the dry period and early and late lactation stages during the confined and grazing periods. Over 20 blood parameters were analyzed, plus cortisol in the tail hair as a stress indicator. Blood profiling indicated that cows during the grazing period had a more stable metabolism across the stages of lactation, a more robust immune system, and slightly greater inflammation than during the confined period. The amount of cortisol in the hair was lower in cows during the grazing vs. confined period. Only a few direct animal measurements were affected, including a better body condition and cleanliness score compared to the confined period. Overall, our data indicate better welfare conditions in cows during the grazing period compared to the confined period.

放牧通常可提升奶牛的福利水平。然而，当前针对放牧奶牛福利的研究尚缺乏通过血液谱分析（blood profiling）开展的验证。为填补这一研究空白，我们对美国太平洋西北温带地区的4家季节性放牧奶牛场开展了监测。我们分别在圈养期与放牧期的干奶期、泌乳早期及泌乳晚期阶段，采集了奶牛的血液与毛发样本，并针对与福利相关的外观评估指标对奶牛进行了评分。本次研究共分析了20余项血液参数，并将尾毛中的皮质醇作为应激检测指标。血液谱分析结果显示，相较于圈养期，放牧期奶牛在各泌乳阶段的代谢更为稳定，免疫系统更为强健，但炎症水平略高。放牧期奶牛尾毛中的皮质醇含量低于圈养期奶牛。仅有少量直接体况测量指标受到放牧的影响，其中包括相较于圈养期更优的体况评分与清洁度评分。综上，本研究数据表明，相较于圈养期，放牧期奶牛的福利状况更佳。