Dollar value indexes, or $Values, are a tool used to select for several traits at once based on a specific breeding objective. An economic index approach takes into account genetic and economic values as well as the relationships between traits to select for profit. Read on for more information provided by the American Angus Association.
Maternal Weaned Calf Value ($M), an index expressed in dollars per head, predicts profitability differences in progeny due to genetics from conception to weaning. $M is built off of a self-replacing herd model where commercial cattlemen replace 25% of their breeding females in the first generation and 20% in subsequent generations. Remaining cull females and all male progeny are sold as feeder calves. Increased selection pressure on $M aims to decrease overall mature cow size and improve foot structure and fertility while maintaining weaning weights consistent with today’s production.
Weaned Calf Value ($W), an index expressed in dollars per head, provides the expected difference in future progeny pre-weaning performance from birth to weaning. $W assumes that producers retain 20% of their female progeny for replacements and sell the rest of their cull female and male progeny as feeder calves. Over time, increased selection pressure on $W will increase weaning and maternal milk traits while also continuing to increase mature cow size.
Feedlot Value ($F), an index expressed in dollars per head, is the expected average difference in future progeny performance for post-weaning merit compared to progeny of other sires. The underlying objective assumes commercial producers will retain ownership of cattle through the feedlot phase and sell fed cattle on a carcass weight basis with no considerations of premiums or discounts for quality and yield grade.
Grid Value ($G), an index expressed in dollars per carcass, is the expected average difference in future progeny performance for carcass grid merit, including quality and yield grade attributes, compared to progeny of other sires.
Beef Value ($B), an index expressed in dollars per carcass, facilitates simultaneous multi-trait genetic selection for feedlot and carcass merit. $B represents the expected average differences in the progeny postweaning performance and carcass value compared to progeny of other sires. This index assumes commercial producers wean all male and female progeny, retain ownership of these animals through the feedlot phase and market these animals on a quality-based carcass grid.
Combined Value ($C), an index expressed in dollars per head, includes all traits that make up both $M and $B with the objective that commercial producers will replace 20% of their breeding females per year with replacement heifers retained within their own herd. The remaining cull heifer and steer progeny are then assumed to be sent to the feedlot where the producers retain ownership of those cattle and eventually sell them on a quality-based carcass merit grid.