CARCASS TRAITS AND REPRODUCTIVE DEVELOPMENT AT THE ONSET OF LAY IN 2 LINES OF FEMALE TURKEYS

A study was conducted comparing ovary and oviduct development followin g photostimulation in two lines of turkey breeder stocks (female Line and male Line). Birds were euthanatized for assessment of reproductive organ morphology at 3-d intervals following photostimulation (203 d o f age) to 245 d and on the day following their first oviposition. The age at first oviposition was similar for both lines. Male line birds w ere 3 to 4 kg heavier than female Line birds throughout the study, but had lower abdominal fat pad weights when expressed as a percentage of BW. Female Line birds had significantly more total carcass Lipid as a percentage of BW than male Line birds (24.76 vs 22.79%, respectively) . Male line birds had significantly more large ovarian follicles with a greater proportion in a triple or greater hierarchical arrangement a t first egg. To determine the incidence of unreconciled ovulations (pr esumed to be internally ovulated follicles and defined as ovulations o ccurring prior to first oviposition), postovulatory follicles on the o vary were reconciled with observed ovipositions and the developing egg s that were in the oviduct at the time of study. On average, male line hens had 3.0 unreconciled postovulatory follicles at first egg, where as the female Line hens had 1.6. The incidence of birds with physical remnants of internal ovulation was correlated (r = 0.44) to the number of unreconciled ovulations. The developing oviduct of the female line birds reached its mature weight (84.8 g) 3 d earlier than the ovary d id. The developing ovary and oviduct of the male line hens reached the ir mature weights on the same day. The development of the male Line ov iduct is seemingly accelerated relative to that of the ovary, resultin g in lost ovulations early in lay.