The advent of Genomic selection brought into view the two opposing approaches to selecting sires, both for new AI bulls and for how dairymen address mating their herds. Genomic sire selection is based totally on how bulls rank on the “in vogue” selection index. Over half of all dairymen, however, still base sire selection on a matrix (screening list) of desired traits.
Perceived competitive pressures have all major AI studs sorting their bulls (old and new) on the rankings for GTPI [Total Performance Index, Holstein USA] or GLNM$ [lifetime net merit value, AIPL-USDA]. This often makes it harder for those dairymen who have trait focuses to find their best sire choices. Useful sires get removed from promotion lists because some newer bull has a higher Index “rank” from Genomic estimation, but may be “better” than their replacements.
Comparing two “outlier” sires from International Protein Sires
The current high PTA Milk bull (ranking GTPI bull) at IPS is 566H1261 Jo Dandy. Still available (although not featured) from IPS is 566H1185 Barnstormer, who is among the highest of IPS bulls once Zoetis’ “Wellness Traits” are considered. As you follow down the following columns comparing these two, which would you use?