Comparison of the performance of 1966- versus 2003-type turkeys when fed representative 1966 and 2003 turkey diets: growth rate, livability, and feed conversion.

Body weight, livability, and feed conversion of a randombred control turkey line (RBC2) started in 1966 at The Ohio State University was compared with that of modern commercial turkeys hatched in 2003 when fed representative 1966- and 2003-type diets from hatch (March 5, 2003) through 196 d of age. Each pen of modern turkeys consisted of 5 birds each of the Nicholas, British United Turkeys of America, and Hybrid strains. Eight groups (i.e., 2 strains (RBC2 vs. modern), 2 sexes, and 2 dietary regimens) were randomly assigned into each of 4 blocks of 8 litter floor pens (32 total) for growout. Using the BW performance of the 2 strains on the modern feed as the basis, the study showed that the 2003 turkeys were approximately twice as heavy as the 1966 RBC2 at the 4 slaughter ages and that tom weights have increased by 186, 208, 227, and 241 g/yr, and hen weights have increased by 164, 179, 186, and 205 g/yr at 112, 140, 168, and 196 d of age, respectively, over the past 37 yr. Cumulative feed conversion (kg of feed/kg of BW) was approximately 20% better in the 2003 tom turkey on the 2003 feed (2.638) than in the RBC2 tom on the 1966 feed (3.278) at 20 wk of age. Feed efficiency to 11 kg of BW in the 2003 toms (2.132 at 98 d of age) was approximately 50% better than in the RBC2 toms (4.208 at 196 d of age). The number of days to reach that weight was halved during this period of time. Growth performance during the different periods of the study appeared to be strongly affected by type of feed used and seasonal changes in ambient temperature. Overall livability was very good for all groups, but the mortality level of the RBC2 was consistently higher, although not significantly so, than for the modern birds.