| Autor: |
Woody, H. D., Fox, D. G., Black, J. R. |
| Zdroj: |
Journal of Animal Science; September 1983, Vol. 57 Issue: 3 p717-728, 12p |
| Abstrakt: |
Two experiments were conducted to study the effect of grain level in the diet on performance of growing and finishing cattle. A total of 144 steers were fed corn silages of various grain contents as an all corn silage diet, or with various levels of added grain. Regression analyses of the pooled results were used to estimate feedlot performance and carcass characteristics. Average daily gains increased (P<.0005) and feed required per unit of gain decreased (P<.0005) as percentage grain in the diet increased. As grain content in the all silage diets increased from 30 to 50%, gains increased 17.4% (.99 vs .82 kg/d) and feed efficiency improved 12.3% (8.38 vs 9.55 kg DM/kg gain). Steers fed the high concentrate diet with 90% grain gained 6.6% faster (1.24 vs 1.16 kg/d) and required 16.0% less feed per unit of gain (6.05 vs 7.22) than those fed 70% grain. Carcass characteristics were adjusted to an equal carcass weight. Percentage of grain in the diet influenced carcass fat, fat thickness and dressing percentage (P<.05). Marbling, quality grade, yield grade, rib eye area and kidney, heart and pelvic fat were not influenced by diet grain content. Steers fed in a two-phase system had similar gains (1.09 vs 1.10 kg/d) but 6.5% better feed efficiency (6.80 vs 7.27 kg DM/kg gain) than those fed a constant percentage grain diet. Steers fed in the two-phase system had larger rib eye areas (P<.05), but poorer yield grades (P<.0005) than those fed a constant percentage of grain diet; no differences were found for other carcass characteristics. |
| Databáze: |
Supplemental Index |
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