For about fifty years New Zealand dairy farmers have relied on the traditional methods of population genetics, with intensive selection on three of the four genetic selection pathways, to improve the genetic ability of their cows to convert grazed pasture into milksolids. They have complemented selection within breeds with selection across breeds and crossbreeding. These methods have delivered predictable improvements in the profit-related traits of their cows. The rate of genetic improvement in converting feed into net income is increasing as breeding goals are more precisely specified, more data to support trait selection becomes available, genetic evaluation techniques improve, and new reproductive technologies have an impact on selection intensities. In future improved genetic evaluation techniques will be available to control any associated tendency for functional traits to deteriorate as a consequence of genetic selection for higher milksolids yields. Over the next ten years it is expected that new techniques in biotechnology will supplement rather than replace the traditional methods of genetically improving dairy cattle on commercial dairy farms in New Zealand. Accelerating rates of genetic gain in the milkfat and protein traits result inincreased feed demand at the individual cow level, so increased feed supply per-cow needs to proceed in tandem with genetic improvement.
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