Sexual Dimorphism in Body Weight, Morphometric and Growth Traits of Japanese Quails (Coturnix coturnix japonica) Reared in Southern Nigeria

This present study was carried out to determine sexual dimorphism in body weight, morphometric traits and growth parameters of Japanese quails (Coturnix coturnix japonica). Data on body weight (BW), body length (BL), wing length (WL), thigh length (TL) and Shank Length (SL) were obtained on a weekly basis (week 1 to 7) from 120 Japanese quails. The female weights of 14.90 g and 30.39 g were significantly (P<0.05) superior than 10.53 g and 21.48 g of their male counterpart recorded at weeks 1 and 2, respectively. Similarly, sex exerted significant effects (P<0.05) on all linear body measurements from week 1 to week 3 except on thigh length where the influence of sex was not significant in week 3. The males grew faster than the females at all ages except between 6 – 7 weeks. The body weight gain was highest in 3 – 4 weeks (4.80 g/day for males and 4.05 g/day for females) before it started to decline. The least body weight gain was recorded between week 6 and 7 and the males value (1.37±0.32 g/day) was significantly lower (P<0.05) than the female recorded (2.22±0.19 g/day). The female birds showed higher variability in body weight (17.15% - week 1, 20.40% - week 2, 14.93% - week 6 and 12.32% - week 7) than their male counterparts (7.90%, 11.48%, 10.93% and 10.85%) respectively in the same duration. From the findings, it has been concluded that sex exerts influence on morphometric traits for the first 3 weeks but these effects wane with age. The male Japanese quails grew faster than the females at all ages except between the period of 6 to 7 weeks. It is recommended that genetic parameters for male and female Japanese quails should be estimated separately.