Abstract
Seventy-two steers (36 each year) were randomly assigned to six treatments which included daily oral supplementation (mg.) of: (1) stilbestrol, 10; (2) chlortetracycline, 75; (3) penicillin, 32; (4) stilbestrol and chlortetracycline, 10 and 75; (5) stilbestrol and penicillin, 10 and 32; and (6) control. A modification of the paired-feeding technique was used to maintain equal feed intake among all cattle within years. Steers that received additives, alone or in combination, gained faster and were more efficient in feed conversion. Carcass measurements were not affected by treatments. There was a significant difference of the bulbourethral diameter among treatments. The interaction of antibiotics and stilbestrol indicates they cancelled out the effects of one another on bulbourethral size. Penicillin provided bloat protection when less mature alfalfa soilage was fed. Copyright © 1963. American Society of Animal Science . Copyright 1963 by American Society of Animal Science