Effects of Weaning Productivity, as Mediated Through Sire Selection, on Subsequent Pregnancy Rate of the Cow Herd 1 , 2: 1

The present study, conducted to determine the impact of level of weaning productivity on subsequent pregnancy rate of the cow herd, involved two locations in the Southern Region - University of Kentucky, Lexington and Hill Farm Research Station, Louisiana State University Agricultural Center, Homer. Differences in level of (WW ) productivity were created by producing calves sired by high and average bulls selected on the basis of direct WW expected progeny differences (EPD ) (Kentucky: low-accuracy yearling Limousin bulls, natural matings, 478 calvings, direct WW EPD between high and average bulls = 11.3 kg; Louisiana: high-accuracy Simmental bulls, AI matings, 120 calvings, direct WW EPD between high and average bulls = 9.2 kg). Realized differences for 205-d WW between high- and average-sired progeny were 13kg (P