Germplasm evaluation in beef cattle - Cycle IV: Postweaning growth and puberty of heifers

Postweaning growth, puberty, and pregnancy traits were evaluated for 783 F- 1 heifers sired by Angus, Hereford, Charolais, Shorthorn, Galloway, Longhor n, Nellore, Piedmontese, and Salers bulls and out of Angus and Hereford dam s in Cycle TV of the Germplasm Evaluation (GPE) Program at the U.S. Meat An imal Research Center. The Hereford and Angus sires included a sample of bul ls born from 1982 to 1985 (1980s HA) as well as reference sires born from 1 963 to 1970 (REF HA) used in previous cycles of the GPE program. Breed grou p of sire had a significant (P < .01) effect on age and weight at puberty, on 200-, 400-, and 550-d weights, on ADG from 200 to 400 and from 400 to 55 0 d, and 550-d hip height, but it did not influence (P < .05) pregnancy rat e. Mean age and weight at puberty were predicted from the cumulative distri bution because of censoring of data in each tail of the distribution. Sire breed group rankings (and predicted means in days) for age at puberty were as follows: Piedmontese (332), Shorthorn (338), Charolais (348), REF HA (34 8), Galloway (351), 1980s HA (352), Salers (355), Longhorn (357), and Nello re (405). Sire breed group rankings (and predicted means in kilo-grams) for weight at puberty were Longhorn (283), Piedmontese (298), Galloway (305), REF HA(309), Shorthorn (329), 1980s HA (330), Salers (338),:Nellore (341), and Charolais (345). Sire breed group rankings (and least squares means in kilograms) for 200-d weight were Charolais (229), Salers (225), Nellore (22 1), Shorthorn (220), Piedmontese (215), 1980s HA (215), Galloway (209), REF HA (206), and Longhorn (197), with differences > 8.3 kg significant. Ranki ngs for 400-d weight (kilograms) were Charolais (390), Shorthorn (384), Sal ers (380), 1980s HA (374), Nellore (364), REF HA (356), Piedmontese (353), Galloway (348), and Longhorn (321), with differences > 11.5 kg significant. Rankings for 550-d weight (kilograms) were Charolais (445), Salers (430), Shorthorn (429), 80's HA (422), Nellore (420), Piedmontese (401), REF HA (3 98), Galloway (389), and Longhorn (371), with differences > 11.7 kg signifi cant. Rankings for 550-d hip height (centimeters) were Nellore (132.2), Cha rolais (131.9), Salers (129.9), Shorthorn (129.5), Piedmontese (126.7), 198 0s HA (126.1), Longhorn (125.3), Galloway (121.7), and REF HA (121.5), with differences > 1.35 cm significant. Breed of sire had sig nificant effects on growth and puberty traits of heifers.