SEX-DIFFERENCES IN WEIGHT OF TURKEY EMBRYOS

Wet and dry weights of 12-, 16-, and 20-d-old embryos from Hybrid strain and Nicholas strain commercial cross turkeys were determined, and the relationships between embryo weights and the preincubation weight of the eggs in which they were developing was determined by regression analyses. The wet weight of Hybrid strain male embryos was significantly greater than that of females at each age, whereas wet weight of male Nicholas embryos was greater than females at 16 and 20 d. Average dry weights of male embryos of both strains exceeded those of females at 16 and 20 d but differences were not significant. Significant linear regressions of embryo wet and dry weights on egg weight were present in the Hybrid strain males at 12 and 16 d of incubation and in females at 16 d only. The regression of Nicholas embryo wet weight on egg weight approached significance in 12-d-old males and 20-d-old females.