| Autor: |
Harris, J. M., Cash, E. H., Wilson, L. L., Stricklin, W. R. |
| Zdroj: |
Journal of Animal Science; September 1979, Vol. 49 Issue: 3 p613-619, 7p |
| Abstrakt: |
Ninety-six Hereford steers averaging 262 kg were utilized in a 6 × 2 × 2 factorial arrangement of treatments to determine effects of supplemental protein source, concentrate level and growth promoting implant on performance and carcass traits. The steers were randomly allotted by weight to 12 pens and fed six supplemental protein sources and two energy levels. All diets were formulated to be isonitrogenous. Steers within each pen were implanted with 36 mg zeranol4or 200 mg progesterone and 20 mg estradiol benzoate (EBP)5at trial initiation and 87 days later. The moderate energy (ME) diet consisted of ad libitumcorn silage (CS) for 87 days, then 60% CS and 40% shelled corn (SC, DM basis) until slaughter. The high energy (HE) diet consisted of 60% CS plus 40% SC for 87 days, then 40% CS plus 60% SC. Steers were slaughtered when they reached a pen average Choice live grade. Steers fed soybean meal and urea supplements gained faster (P<.01) than those supplemented with commercial urea-molasses supplements. HE steers gained faster during the first 87 days, required less days on feed and yielded carcasses with higher conformation scores, marbling scores and carcass quality grades (P<.01). Zeranol-implanted steers gained less (P<.05) during the first 87 days, exhibited less (P<.01) incidence of raised tailheads, yielded carcasses with less (P<.10) external fat, more (P<.10) kidney fat, and higher (P<.01) marbling scores. |
| Databáze: |
Supplemental Index |
| Externí odkaz: |
|
