The Incorporation of Efficiency Traits into the Canadian Dairy Selection Index

Abstract

Feed efficiency and methane production traits have been highlighted as both economically and environmentally important due to the growing cost of feed and rising concern of the livestock industry’s environmental impact. Current genetic progress for these traits is restrained by an undefined breeding objective for these traits due to difficulty in measuring phenotypes, the various trait definitions available, and unknown responses to selection. Feed efficiency and methane production are strongly correlated; therefore, improving one has a favorable effect on the other. This relationship can be exploited to obtain both economic and environmental progress using genetic improvement. Determining the economic value of daily dry matter intake and associated methane production is key in including these novel traits in future breeding programs. In addition, the change in emission intensity (EI) per unit change in each trait undergoing genetic selection was calculated to determine the environmental impact of current and prospective index traits. Of the traits investigated, feed efficiency, milk yield, fat yield, protein yield, herd life and mastitis resistance had a considerable effect on EI. The results of this thesis suggest that the Canadian dairy system is continuing to increase sustainability and efficiency.