Morphometry of pectoral development in turkey breeding stock.

1. Musculo-skeletal development was measured in males and females of two genetic lines of turkey breeding stock: one line had been selected mainly for egg production (E-line) while the other had been selected for meat production as well as egg production (M-line). 2. The M-line had a more rapid growth of body weight and breast muscle weight than the E-line but breast muscle yield (breast muscle weight/body weight) did not differ between lines. 3. From an early age, breast length and keel length were longer in the M-line than in the E-line. 4. In older birds, keel depth was greater in the M-line than in the E-line. 5. No differences between lines were detected for depth of the pectoralis muscle, number of muscle fibres in the depth of the pectoralis, or muscle fibre cross sectional areas.