Carcass traits and reproductive organ morphology in 62-week-old SCWL hens

The influence of body weight on reproductive organ morphology and the incidence of reproductive disorders was investigated with 324 Shaver Starcross 288-strain Single Comb White Leghorn hens at 62 wk of age. The hens were fed a typical laying ration (2720 kcal ME kg−1, 16.3%, CP, 3.5% Ca) ad libitum. All birds were housed two birds per cage in a windowless poultry house, with a photoperiod of 14L:10D. The total group of hens was separated into eight weight groups, on the basis of 62-wk body weight, ranging from 1100 to 2700 g, at 200-g increments. Birds were killed by cervical dislocation and dissected to observe carcass and reproductive organ traits. The length of the shank and the weights of the breast muscle, liver, fat pad, ovary and ovarian stroma increased significantly as hen weight increased. Ovary weight was increased because of an increase in the number of large follicles, as well as an increase in the weights of individual large follicles Ovarian regression occurred more often in hens weighing less than 1700 g than in hens weighing more than 1700 g. Internal oviposition occurred most often in hens near the population body weight (1803 g). Internal ovulation occurred more often in hens more than 1900 g in body weight than in hens less than 1900 g. These data suggest that hens that are heavier than average have increased follicular development, compared with low-weight hens. Key words: Single Comb White Leghorn, abdominal fat pad weight, breast-muscle weight, body weight, ovary morphology, reproductive disorders