Yield and quality grade outcomes as affected by molecular breeding values for commercial beef XXXX .

@entity5685 @entity291
Although genetic tests for many economically important beef @entity291 traits are commercially available, additional information is needed to help the industry better understand how the results from these tests translate into phenotypic outcomes. This information has important implications for marker-assisted management. The objective of this research was to determine the relationship between molecular breeding values ( @entity5685 ) characterizing yield grade and marbling and distributions of phenotypic outcomes for yield grade and quality grade. Using data collected from commercially-fed @entity291 , mixed-model regression equations were estimated for yield grade and quality grade outcomes for both the full sample of commercial @entity291 (n= 8,995) and a subsample of black-hided steers (n = 4,790). Significant yield grade (P < 0.01) and marbling (P < 0.01) @entity5685 effects were found. However, the yield grade @entity5685 held up better at predicting phenotypic outcomes than the marbling @entity5685 . Estimated conditional probability mass functions of yield and quality grade outcomes for the general population and black-hided steers were similar. Since distributions for black-hided steers were expected to be more applicable from a management perspective, we focused our analysis on these animals. For example, black-hided steers with "low" genetic potential for yield grade and marbling had about a 29% chance of achieving the base price or better on a price grid (yield grade 3 or lower and quality grade Low Choice or better). Increasing genetic potential for marbling increased the likelihood of achieving this same outcome. However, increasing genetic potential for yield grade was unlikely to increase overall carcass quality given its large deleterious effect on quality grade outcomes. Instead, simultaneous improvements in genetic potential for yield grade and marbling offered much more reliable improvements in overall carcass quality. For example, an animal with "moderate" genetic potential for both yield grade and marbling had a 46% chance of achieving the base price or better on a price grid, and an animal with the maximum observed @entity5685 for these traits had a 66% chance of achieving this same outcome. Although the yield grade @entity5685 held up better at predicting phenotypic outcomes, shifts in the distributions of yield grade and quality grade suggested that these increases were largely determined by the marbling @entity5685 .
