Effect of a Combination of Diethylstilbestrol and Methyltestosterone, Sex and Dietary Protein Level on Performance and Carcass Characteristics of Finishing Swine
Four hundred forty-eight finishing pigs were utilized in three experiments to evaluate efficacy of a dietary combination of diethylstilbestrol (DES) and methyltestosterone (MT). The effects of sex and dietary protein level upon response to the hormonal combination were also evaluated. Regardless of sex or dietary protein level, carcass leanness was improved by DES + MT, but improved feed efficiency resulted only at the higher levels of dietary protein. Feed efficiency and carcass leanness response to DES+ MT tended to be greater in barrows than in gilts. Rate and efficiency of gain were maximized at a dietary protein concentration of 12% in barrows but 14% in gilts. For maximal carcass leanness, 14% protein was required by barrows and 16% protein by gilts. Protein level had no effect on backfat thickness or carcass length, but the remaining criteria of carcass leanness were improved additively by both DES + MT and increased dietary protein.