The effect of diethylstilbestrol and methyltestosterone on the growth, carcass characteristics, and nitrogen retention of growing swine / by Ernest William Lucas.

Abstract

Investigated as potential feed additives, as v/eJl as numerous androgenic compounds. Recently, work using cornbinatlons of estrogen and androgen has l^ecn done. Research with hormones as cliemothei-apeut Ics for svyine has been conducted since the early ISSO's, v/lth varying results. Evidence pro and con has been collected for several different hormones. Including diethyl st 1 1 best rol and inethyl testosterone, the tr^^st vndely used estrogen and androgen, respectively. Recent v/ork indicates tliat a combination of these two compounds fed to grov;ing-f inishlng sv/lne Is more effective in stimulating efficiency, carcass quality, and leanness than either one alone. The purpose of this study was to Investigate the effects of a dietary combination of d iethylst 1 1 best rol (DES) and methyl testosterone (MT) , fed at 2,2 mg each per kg of feed, on the grcvjth, carcass characteristics, and nitrogen retention of growing-finishing pigs. REVIEW OF LITERATURE The Effects cf Sex on the urOWtii di";u i^diCdSS i^udHty Or ov/iiic Sex has been recognized for many years as a factor which affects the performance of meat animals. Differences in growth, efficiency, and carcass characteristics between the genders are common In most species. Swine are prone to show sex differences in performance and carcass qual i ty. Blair and English (1965) reported on an experiment designed to measure sex differences in growth and carcass quality in growingfinishing pigs. These workers fed boars, gilts, and barrows on a similar ration from weaning to market weight and measured carcass parameters and feedlot performance. They reported significant differences among sexes in the various standard carcass parameters. Boars had significantly less backfat than either barrows or gilts. In addition, boars and gilts showed a significantly larger loin eye area than barrows. Wallace (I965) reviewed the effects of sex influences (barrows vs. gilts) on finishing swine and concluded that gilts gained more slowly but more efficiently than barrows, and that gilts were superior to barrows in all aspects relating to carcass leanness. Kolaczyk and Kotik (I966) compared muscle properties of barrows and gilts. The meat of gilts had a significantly higher percentage of