Effects of the age at castration in beef steer production of Holstein and Montbéliard breeds

Abstract

Beef steer production in the dairy livestock systems of the east of France implements an enhanced value of pastures and a simplification of livestock managements. Traditionally, the animals are castrated before they are one-year-old. Sometimes, the animals are castrated later on, so that they can benefit from bull growth superiority. Three trials with 83 animals (41 sevenmonth-old weighing 265 kg, castrated before they first went out to pasture ; 42 sixteen-month-old weighing 458 kg, castrated before they went out a second time to pasture) showed the effects of castration age on animal growth, carcass and meat features. Twenty sevenmonth-old beef steers weighing 700 kg after trough feeding were slaughtered. The age at the castration did not change growing performances up to 16 months of age and no bull growth superiority was observed in these trials. Trough feeding with a grass silage and hay diet (for 65 to 95 days) permitted weight gains of 1000 to 1500 g per day. The age at castration had little effect on slaughter weight of the carcass (380 kg on the average), tissue composition and conformation. Holstein carcasses were, however, better classified for animals castrated at sixteen months of age than at seven months of age. Castration at 16 months of age did modify certain physicochemical muscular characteristics : the total collagen or haeminic iron contents were higher. These trials confirmed the better meat production abilities of the Montbéliard breed.