Besides, he argues, there's no available data to establish reproductive qualities. MacNeil agrees scrotal circumference alone is not enough to predict fertility. Other means of gauging reproductive performance need to be developed, he says. He suggests it may be possible to predict fertility by looking at carcass traits. Previous studies, he says, have tended to err toward the low estimates for safety's sake.
Reproduction is heritable enough to include.
He also says some studies have indicated reproduction may be five to 20 times more important to profitability than growth characteristics. Newer selection indexes are placing more emphasis than before on carcass characteristics. The experts agree the end point of the bull's progeny makes a difference. For example, producers of terminal-cross calves will place more emphasis on marbling and eliminate the consideration of milk production. MacNeil cautions cow-calf producers who sell soon after weaning not to ignore carcass traits.