| Autor: |
Dinkel, C. A., Busch, D. A., Schafer, D. E., Tuma, H. J., Minyard, J. A., Costello, W. J. |
| Zdroj: |
Journal of Animal Science; March 1969, Vol. 28 Issue: 3 p316-323, 8p |
| Abstrakt: |
Data from three different experiments involving 530 steers of two breeds were used in evaluating the growth curve of trimmed retail cuts in relation to animal weight. One experiment was a time-constant study with all animals fed a constant length of time post-weaning while other experiments were weight constant with individual animals assigned slaughter weights and marketed individually at that weight.The growth of trimmed retail cuts in relation to animal weight in the weight range of 206 to 329 kg. carcass weight was essentially straight line with a tendency toward increasing slope at higher weights. This was true in three different experiments over varying weight ranges with two breeds, and was also true in data supplied by K. E. Gregory from the Fort Robinson Research Station involving three breeds. The data from all studies indicate that for each kg. gained the increase in trimmed retail cuts will be the same regardless of the weight at which that kilogram of gain is added from about 300 to 600 kg. liveweight. This does not agree with expectations. It is postulated that the lack of agreement is due to expectations based on (1) growth with respect to age rather than weight, (2) previous growth curves expressed as a percent rather than in kilograms and (3) slaughter occurring at a different point in the growth curve due to modern management practices.Nearly every growth curve examined indicated a plateau in growth of trimmed retail cuts near the middle of the weight range.Although no significant departure from linearity is indicated by statistical test the plateau effects appear important. The tendency for the slope to increase following the plateau is unexpected and unexplained.Sire within ranch effects were highly significant (P<.01) for days on feed (daily gain), weight of removed bone, significant (P<.05) for marbling and percent fat trim and nonsignificant for weight of trimmed retail cuts, weight of trimmed fat, percent trimmed retail cuts and dressing percent. Ranch effects were highly significant for days on feed, significant for marbling and nonsignificant for the remainder of the traits. The sire-weight groups interaction (P<.05) was significant for dressing percent and nonsignificant for the remainder of the traits. This is particularly important from a breeding standpoint since this indicates that sires tended to be ranked the same regardless of the weight at which their progeny were slaughtered, for all traits except dressing percent. Dressing percent was the only trait for which the year-weight group (P<.01) and the ranch-weight group (P<.05) interactions were significant. |
| Databáze: |
Supplemental Index |
| Externí odkaz: |
|
