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

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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.