A method for deriving the genetic matrix needed for selection across combinations of breeds.

A method is described for deriving the genetic matrix G needed for breeders to select across breeds for any breeding objective. The matrix comprises partitions among selection criteria (G ), between selection criteria and the breeding objective traits (G ), and among the breeding objective traits (G ). A weighting procedure is used to combine the G matrix of individual breeds with known breed differences.

Methods and consequences of including reduction in greenhouse gas emission in beef cattle multiple-trait selection.

Background: Societal pressures exist to reduce greenhouse gas (GHG) emissions from farm animals, especially in beef cattle. Both total GHG and GHG emissions per unit of product decrease as productivity increases. Limitations of previous studies on GHG emissions are that they generally describe feed intake inadequately, assess the consequences of selection on particular traits only, or examine consequences for only part of the production chain.

Methods and consequences of including feed intake and efficiency in genetic selection for multiple-trait merit.

Methods are presented for including feed intake and efficiency in genetic selection for multiple-trait merit when commercial production is from any combination of pasture or concentrates. Consequences for the production system and for individual animals are illustrated with a beef cattle example. Residual feed intake at pasture (RFI-p), residual feed intake in the feedlot (RFI-f), and cow condition score are additional traits of the breeding objective.