Optimizing energetic efficiency in cold adapted beef cattle

在过去的十年中，冬季对牛的管理已经从限制在干地围栏中转变为使用储存的饲料和草捆放牧，在冬季的很长一段时间里，牛都在牧场上。在这些广阔的环境中越冬的牛暴露在长时间的寒冷和波动的天气模式中。早期对冷暴露牛的开创性工作是在受控条件下进行的，例如环境室或室外禁闭围栏，其中环境温度很少低于-10 ℃。虽然对我们理解牛的冷生理至关重要，但我们对先前结果的解释和应用存在局限性。这种理解的基础是测量个体动物干物质摄入量的能力。拟议的研究将使我们能够验证使用粪便近红外光谱作为一种可行的，非侵入性的方法来测量牛在自由放养环境（越冬和牧场）中的个体动物摄入量。使用这种和其他新技术，包括行为生物测定和近红外热成像技术，将使我们能够提供有关牛在广泛的，非封闭的越冬环境中的行为和代谢反应的新信息。这项工作将为制定更好的口粮配方和寒冷天气下的动物管理战略提供所需的基本信息。研究结果还将提高我们在寒冷气候下减少养牛系统环境足迹的能力。该计划的一个主要组成部分将是开发高素质的人员，他们将利用他们对基本行为和生理过程的理解，将更好的实践和技术融入肉牛生产，特别是当他们涉及到广泛的（牧场或牧场）系统时。

In the last decade, management of cattle during the winter months has shifted from confinement in drylot pens to use of stock-piled forage and bale grazing where cattle are kept on pasture for significant periods of time during the winter months. Cattle wintered in these extensive environments are exposed to long periods of cold and fluctuating weather patterns. The early groundbreaking work on cold exposed cattle was conducted in controlled conditions such as environmental chambers or outdoor confinement pens in which ambient temperatures were rarely less than -10 degrees C. While critical to our understanding of cold physiology in cattle, there are limitations to our interpretation and application of previous results to current production systems. Fundamental to this understanding is the ability to measure individual animal dry matter intake. The proposed research will enable us to validate the use of fecal NIR spectra as a viable, non-invasive method for measurement of individual animal intake in cattle in free-ranging environments (overwintering and pasture). Use of this and other novel techniques including behavioural biometrics and near infrared thermography will enable us to provide new information regarding the behavioural and metabolic responses of cattle in extensive, non-confined overwintering environments. This work will provide the fundamental information required to develop better ration formulations and animal management strategies for cold weather. The results will also improve our ability to reduce the environmental footprint for cattle production systems in cold climates. A major component of this program will be the development of highly-qualified personnel who will use their understanding of basic behavioural and physiological processes to integrate better practices and technologies into beef cattle production, particularly as they relate to extensive (pasture or range-based) systems.