Advancing knowledge of feeding behaviour to enhance cow health and milk quality

为了确保以有效的方式生产出充足的优质牛奶，已经进行了大量的研究。尽管产奶量有所增加，主要是由于奶牛的遗传和营养得到改善，但这些动物的代谢状况持续高发。其中一种情况是亚急性瘤胃酸中毒（SARA），它给乳制品行业造成了巨大的经济损失。此外，最近的研究表明，患有SARA的奶牛在牛奶中产生的共轭亚油酸（CLA）的反式-10，顺式-12异构体水平升高，这种化合物对乳制品消费者的葡萄糖稳态有潜在的负面影响。有经验证据表明，SARA可能与奶牛的摄食行为直接相关。进食行为模式被认为受到经历的影响，包括生命早期的学习。因此，在过去的5年里，我们的研究主要集中在对受营养和饲养管理影响的年轻奶牛喂养行为的个体发生有一个基本的了解。虽然在这方面已经取得了很大的进展，但我们的研究也表明，当动物经历生理和环境变化时，习得的行为模式并没有始终保持不变。因此，这项拟议研究计划的长期目标是对影响成熟奶牛摄食行为表达的因素及其后果有一个基本的了解。为了解决这个问题，我的具体短期目标是确定喂养行为，包括膳食模式和饮食选择，是如何：1)与奶牛健康和牛奶的营养质量有关；2)因生理需要而改变；3)适应环境刺激，4)适应社会刺激。在这个项目中，我提出了一系列的实验，这些实验将实现我的短期目标，并共同实现我的长期目标。通过研究，我预测可以通过短期经验修改奶牛的喂养行为模式和策略，以改善奶牛的健康和牛奶的营养质量。在每项研究中，将根据所调查的各种因素（包括与哺乳期和妊娠相关的营养需求变化，以及社会和管理刺激）监测奶牛的喂养行为（包括进食时间、膳食模式和日粮选择）。行为模式的变化也将与奶牛的健康状况（通过生理和行为观察来测量）以及所产牛奶的产量和成分（脂肪酸谱）有关。该研究项目将为影响奶牛摄食行为表达的因素及其对奶牛健康和牛奶营养质量的影响提供新的生物学见解。本研究不仅对乳制品生产企业具有经济效益，而且具有社会效益。食品的营养质量仍然是影响消费者选择食品的主要因素。此外，动物的福利，特别是用于食品生产的动物的福利，是一个日益受到社会关注的领域。因此，这项研究不仅有助于为消费者生产健康的食品，而且还满足了消费者购买以人道方式饲养的动物产品的兴趣。

Much research has been done to ensure that a sufficient supply of high-quality milk is produced in an efficient manner. Despite increases in milk production, due largely to improved genetics and nutrition of dairy cattle, these animals continually experience a high incidence of metabolic conditions. One of these conditions, sub-acute ruminal acidosis (SARA), is responsible for large economic losses to the dairy industry. Further, recent research has shown that cows with SARA produce elevated levels of the trans-10, cis-12 isomer of conjugated linoleic acid (CLA) in milk, a compound with potential negative effects on the glucose homeostasis of consumers of milk products. There is empirical evidence that SARA may be directly linked to the feeding behaviour of dairy cows. Feeding behavior patterns are believed to be influenced by experiences, including learning early in life. As such, our research during the past 5 years has focused on developing a fundamental understanding of the ontogeny of feeding behaviour in young dairy cattle, as affected by nutritional and housing management. While much advancement has been made in this understanding, our research has also shown that learned behaviour patterns are not consistently retained when the animal experiences physiological and environmental changes. Thus, the long-term objective of this proposed research program is to develop a fundamental understanding of the factors influencing the expression of feeding behaviour in mature dairy cattle and the consequences of that behaviour. To address this, my specific short-term objectives are to determine how feeding behaviour, including meal patterning and diet selection, are: 1) related to cow health and nutritional quality of milk; 2) altered in response to physiological needs; 3) adapted in response to environmental stimuli, and 4) adapted in response to social stimuli. For this program I propose a series of experiments that will address my short-term goals and collectively address my long-term objective. Across studies, I predict that the feeding behaviour patterns and strategies of dairy cattle can be modified through short-term experiences to improve cow health and nutritional quality of milk. In each study the feeding behaviour (including time course of eating, meal patterning, and diet selection) of individual cows will be monitored in response to various factors under investigation (including changing nutrient requirements associated with lactation and pregnancy, and social and management stimuli). Changes in behavioural patterns will also be related to health status of cows (measured through physiological and behavioural observations) and the yield and composition (fatty acid profile) of the milk produced. This research program will provide novel biological insights into factors affecting the expression of feeding behaviour in dairy cattle and the implications this has on cow health and nutritional quality of milk. This research not only has economic benefits to dairy producers, but also societal benefits. Nutritional quality of food products remains a primary factor influencing food choices by consumers. Further, the welfare of animals, especially those used in food production, is an area of increasing social concern. Thus, this research will not only contribute to production of a healthful food product for the consumer, but also satisfy the consumers’ interest in purchasing products obtained from animals that have been raised in a humane manner.