This article focuses on the role that genetic progress may play in improving milk quality. Despite important genetic advances in dairy production, the absence of genetic records in farm management databases has precluded empirical production models from explicitly accounting for differences in genetics across herds. The influence of genetics on milk composition is analyzed by splitting milk production into protein, fat, and other components. The article explores some modeling issues associated with the specification of the effect of genetics in this multi-output technology framework. In particular, genetic indexes are considered as allocable inputs and the remaining inputs as nonallocable. Our results show that genetics have a significant impact on milk composition. In particular, we find that farmers’ income increases by 6.6% when genetic indexes are augmented by one sample standard deviation.