Department of Agricultural and Food Sciences, University of Bologna, Viale Fanin 48, 40127 Bologna, Italy.
Natural Resources Institute Finland (Luke), Production Systems Unit, Latokartanonkaari 9, PO Box 2 FI-00791 Helsinki, Finland.
Animal. 2020 Feb;14(2):418-424. doi: 10.1017/S1751731119001721. Epub 2019 Jul 31.
Heat stress is one of the most critical issues jeopardising animal welfare and productivity during the warm season in dairy cattle farms. The global trend of increase in average and peak temperatures is making the problem more and more serious. Many devices have been introduced in livestock farms to monitor and control temperature-humidity index, as well as animal behaviour and production parameters. The consequent availability of collected databases has increasingly enhanced the research aimed to understand the consequences of heat stress in cattle, in relation to genetic, reproductive, productive and behavioural features. Moreover, these investigations laid the foundations for the development, calibration, validation and test of numerical models quantifying the individual responses to heat stress conditions. In this work, a generalised additive model with mixed effects has been developed to analyse the relationship between milk production, animal behaviour and environmental parameters based on data surveyed in 2016 in an Italian dairy farm. Each cow has been characterised in terms of her response to heat conditions, and the results led to define three classes of susceptibility to heat stress within the herd. These attributes have then been related to the various phenotypic parameters collected by the precision livestock farming devices used in the farm. The study provides a model to understand the effects of heat stress conditions on individual animals in relation to the main parameters describing their rearing conditions; moreover, the results contribute to improve the herd management by lending indications to define targeted treatments according to the cow's characteristics.
热应激是奶牛养殖场在温暖季节中危害动物福利和生产力的最关键问题之一。全球平均和峰值温度上升的趋势使问题变得越来越严重。许多设备已被引入养殖场，以监测和控制温度-湿度指数，以及动物行为和生产参数。随之而来的是收集到的数据库的可用性越来越高，这使得研究人员能够深入了解热应激对奶牛的影响，包括遗传、繁殖、生产和行为特征。此外，这些研究为开发、校准、验证和测试量化个体对热应激条件反应的数值模型奠定了基础。在这项工作中，开发了一种带有混合效应的广义加性模型，以根据 2016 年在意大利一家奶牛场调查的数据来分析牛奶产量、动物行为和环境参数之间的关系。每头奶牛的热应激反应特征都已确定，结果表明牛群中有三种易感性类别。然后将这些属性与养殖场中使用的精准畜牧养殖设备收集的各种表型参数相关联。该研究提供了一种模型，可以根据描述其饲养条件的主要参数，了解热应激条件对个体动物的影响；此外，研究结果有助于通过根据奶牛的特征提供有针对性的治疗建议来改善牛群管理。
