The influence of genetic changes in body weight, egg production, and body conformation on organ growth of turkeys.

Measurements were made on the breast with bone (BWB), a demand organ, and various supply organs in mature turkeys (approximately 40 wk of age) from various lines of turkeys to determine the influence of selection for increased egg production, BW, and body conformation on resource allocation. Comparisons made were: 1) a line (E) selected long-term for increased egg production and its randombred control (RBC1); 2) a line (F) selected long-term for increased 16-wk BW and its control (RBC2); 3) the F line with a commercial sire line (C); and 4) the RBC1 line and a randombred control (RBC3) that was formed from the F and C lines. Data were analyzed on an absolute basis and after adjustment to a common BW by covariance analysis. The only major change in organ sizes that occurred that could not be accounted for by differences in BW was in the E line. The actual and relative weights of total supply organs decreased and the relative weight of the BWB increased in the E line when compared with its randombred control. Selection for increased BW in the F line did not result in a relative change in BWB. The BWB weight was relatively heavier in the C line than in the F line. The relative amount of BWB was slightly but significantly different in the two randombreds (RBC1 and RBC3) formed 29 yr apart. Weight of the gizzard did not increase at the same rate as BW in two large-bodied lines (F and RBC3).