Maternal weaned calf value ($M) is the most maternally-focused selection index
currently available to Angus members and commercial users of Angus genetics. $M,
expressed in dollars per head, aims to predict 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.
$M places greater emphasis on the cost side of commercial cow-calf production than
any tool available in the past. Increased selection pressure on $M aims to decrease
overall mature cow size while maintaining weaning weights consistent with today’s
production. Under $M selection, less emphasis is placed on maternal milk, while
heifer pregnancy and docility have an increased emphasis, and foot traits start
to improve. The index finds cattle that are most profitable when producers receive
no economic benefit for traits affecting post-weaning performance.
For example if Bull A has a $M of +75 and Bull B has a $M of +55 and both are mated
to a comparable set of females, one would expect, on average, for Bull A’s progeny
to be $20 more profitable per head for the cow/calf producer.
EPDs directly influencing the index include: calving ease direct and maternal, weaning
weight, maternal milk, heifer pregnancy, docility, mature weight as well as foot angle
and claw set.