EFFECT OF LINECROSS AND DELAYED CASTRATION ON GROWTH AND CARCASS TRAITS IN BOARS AND BARROWS

Abstract

The effects of linecross, castration treatment, and linecross × castration treatment interaction on live animal growth and carcass attributes were determined on data from 212 male pigs. The linecrosses were derived from randomly mating Landrace boars to Yorkshire control, Yorkshire select, and Hampshire select (LHs) sows and castration treatments were: no castration (IB, intact boars), early castration (EC, mean of 12 d, range from 10 to 14 d of age), and late castration (LC, mean of 100 d, range from 97 to 104 d of age). The traits studied were subdivided into general carcass traits, loin traits, hindleg traits, cooked semitendinosus traits, and interactions. Linecross differences were (LYc = LHs) < LYs — carcass length and percent pressed fluids in cooked semitendinosus; LYs < (LHs = LYc) – percent cooking loss; LHs < LYs < LYc – backfat thickness and leaf fat weight; LHs < LYc < LYs – percent biceps femoris weight and moisture in cooked semitendinosus; LHs<(LYc=LYs) – pH and percent protein; LYc < (LHs = LYs) – hindleg weight; (LHs = LYs) < LYc – percent gastrocnemius weight; (LYc = LYs) < LHs – percent foot and skin of the hindleg; LHs < LYc – loin weight; LHs < LYs – percent absorption and moisture in the longissimus muscle; and LYs < LHs – percent ether extract in the longissimus muscle, average shear, and percent semimembranosus. Differences among castration treatments were: IB < (EC=LC) – backfat thickness, leaf fat and loin weights, percent fat weight of the hindleg, and percent ether extract in cooked semitendinosus; (EC = LC)<IB – carcass length, kidney and hindleg weights, carcass shrink, weights of foot, skin, bone, and lean tissue as percents of hindleg, and lean/fat separation, marbling, firmness, and odor scores; LC < IB – loin eye area and average shear; EC < IB – texture score and percent semimembranosus weight; IB < EC – percent cooking loss; and LC < EC – percent pressed fluids in cooked semitendinosus. Linecross × castration treatment interactions were found for postweaning average daily gain, percent lean in the ham face, two-tone score of the ham, and percent semitendinosus weight. Key words: Pigs, boar, linecross, castration, carcasses, growth