A three-year study on three northern-California ranches says a bull that breeds a lot of cows and sires a lot of calves will produce more value than a bull that doesn't ... period.
This is regardless of genetics for carcass merit, weaning weight or method of marketing.
"Prolificacy was the main driver of total income per sire, irrespective of whether the calves were marketed as feeder or retained ownership," say the researchers.
Bulls in this study sired an average of 20 calves per season, although some bulls averaged 40 calves per season for several seasons. Some sired no calves and never improved. Some began to sire more in successive seasons. Parentage was determined using DNA tests.
Typically, every breeding season produced a range of 0 to more than 40 calves per bull, yet all the bulls had equal opportunity with a ratio of about 25 cows per bull.
Further, as has been the case in Missouri and Nebraska research more focused on cows, calving earliness made profit. In this study, calving was divided into four, 21-day periods. Calves from the first 21 days of calving returned about 40% of the total feeder calf or retained ownership value to the ranch, and those from the first two periods combined accounted for about 72% of the total income.
Researchers studied EPDs for answers and found the primary indicator was a slight difference in scrotal circumference EPDs, with the larger-indexed bulls siring more calves. All the bulls were subjected to breeding soundness exams prior to breeding and no problems or differences were detected in that hands-on evaluation, says Alison Van Eenennaam, extension genomics and biotechnology specialist at the University of California-Davis.
Van Eenennaam thinks a key lesson here may be to include scrotal circumference EPDs and perhaps minimum scrotal circumference measurements in your selection criteria for bulls.
Remember, too, that plenty of evidence says heifers sired by more prolific bulls and those with larger scrotal circumference tend to cycle earlier and to be more productive cows, says Van Eenennaam.
In the end the most profitable bull is still much like the most profitable cows. He produces calves, although many of them, and does so early in the breeding season.
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