A study of traits other than production in the New Zealand dairy industry National Breeding Objective

The selection goal of the New Zealand dairy industry National Breeding Objective (NBO) is to identify animals whose progeny will be the most efficient converters of feed into farmer profit. Desired traits and their relative importance in the form of an economic value are combined to produce an index known as Breeding Worth (BW). This provides a method of ranking bulls and cows on their expected ability to breed replacements which will fulfill the national objective. This study sought to challenge some of the assumptions in the current index and investigates the value of an extra lactation and the value of liveweight in the NZ dairy herd using economic models. The models were informed by industry data for both economic and farm systems analysis.