315 Breeding for Efficiency: investigating dairy cattle efficiency traits and future implementation strategies.

摘要

Since the establishment of the Paris Agreement in 2016, external influence from consumers, government and society has placed increasing pressure on the global dairy industry to investigate new breeding strategies that focus on improving overall efficiency and sustainability. The Efficient Dairy Genome Project is a global initiative to improve feed efficiency and decrease methane emission using genomics. The project has enhanced genetic research by developing a centralized database to increase the reference population and enable the sharing of data for these expensive and difficult to measure efficiency traits through international collaboration. In Australia, breeding values for feed efficiency are available through the Feed Saved trait which uses a genomic prediction for residual feed intake. The economic benefit of including a feed efficiency trait in selection programs has been estimated using the proposed Canadian trait, Feed Performance. The economic gain due to Feed Performance was predicted after 10 years of selection at 0.25%, 0.5% and 1% annual genetic gain and had a value of $92.56, and $184.20 and $360.77 per cow, respectively. In addition, this resulted in an associated methane reduction of 1.75kg, 3.50kg, and 6.98kg per cow at the respective levels of genetic gain. Further environmental improvements have been considered by measuring the industry’s emission intensity and identifying index traits that strongly influence this value. It was determined that the Canadian dairy industry is currently reducing its environmental impact by 1% annually. The magnitude by which traits influence emission intensity may be utilized in a weighting scheme where traits are emphasized on an economic-environmental scale. However, inclusion of efficiency traits in routine national genetic evaluation is limited by the challenges associated with maintaining long-term phenotypic recording. Further investigation of easy to measure, inexpensive proxy traits will allow for large scale evaluation of efficiency traits and successful inclusion in breeding programs.