BROILER YIELDS USING CHICKS FROM EXTREMES IN BREEDER AGE AND DIETARY PROPIONATE

Chicks originating from 27- and 62-wk-old breeder flocks were evaluate d beyond live performance to carcass characteristics. One half of each sources and sex received 3% ammonium propionate in the first week's f eed; thereafter; a common regiment was given to 7 wk of age. Birds fro m the older breeders showed superior live gain and survival, but birds from younger breeders had better feed conversion. Supplemental propio nate decreased live gain while it was being fed but improved ultimate feed conversion for all birds and survival in birds from the young bre eder flock. Proportion of abdominal fat was similar, with regardless o f breeder age and supplemental propionate; however, additional carcass yield with broilers from the old breeders provided further advantage in chilled weight. Few differences in carcass defects associated with downgrading were detected. Proportions of cone deboned parts were simi lar among treatments.