2. Materials and methods
2.1. Overview
Embryos were produced in vitro at Colorado State
University and the University of Florida using similar, albeit
not identical procedures. Embryos were transferred at two
dairies in Colorado and three dairies in Florida and Georgia.
There was variation among dairies in synchronization of
reproductive cycles, personnel doing the commercial ET,
and the specific bulls that provided semen. These differences
were accounted for statistically by having dairy as
a factor in all statistical analyses. Some analyses involved all
five dairies, whereas others involved only dairies within
a geographical region.
Exact sperm sexing procedures for semen were proprietary,
but likely did not deviate substantively from those
described by Seidel and Garner [9].