EFFECTS OF CASTRATION AND EXOGENOUS ESTRADIOL OR TESTOSTERONE ON LIMB BONE GROWTH AND SOME PERFORMANCE TRAITS IN YOUNG MALE PIGS

Abstract

A total of 57 male pigs were randomly allocated at 1 wk of age to one of four treatments: castrated and implanted with estradiol −17β; castrated and implanted with testosterone; castrated and not implanted; not castrated and not implanted. The pigs were weaned at 3 wk of age and raised under conventional commercial conditions to 2, 4 or 6 mo of age. Within age group, treatment had no effect (P > 0.05) on average daily gain, feed efficiency, backfat thickness or the growth coefficients of individual organs relative to body weight. Weights, lengths and circumferences of limb bones (humerus, scapula, tibio-fibula, patella, femur and pelvis) did not differ significantly among treatments within age groups. However, the radio-ulnae were thicker (P < 0.05) in boars than in the other three groups. No significant treatment differences in the rate of radiosulfate incorporation into the tibial or radial growth plates or on the rate of linear bone growth during the last 16–26 d of the study were detected. It is concluded that neither estradiol −17β nor testosterone therapy of young castrated male pigs is likely to influence their growth or bone development up to 6 mo of age. Key words: Swine, boar, barrow, sex steroids, castration, bone growth