1978 Volume 15 Issue 3 Pages 120-129
The collaborative experiment in 8 prefectural experiment stations was carried out to investigate the effect of restricted feeding in rearing period and induced moulting in laying period on prolonged egg production of hens.
Chicks were hatched in Spring and Autumn in this experiment. Eight experiment stations were divided into two groups and in Spring, hatching was assigned to Yamaguch, Ehime, Kumamoto and Miyazaki station and in Autumn, it was done to Tottori, Hiroshima, Oita and Kagoshima station, respectively. In each experiment station, chicks were divided into two groups at 4 weeks of age. One group was fed ad libitum and the other group was fed restricted, in which feed restriction rate was 60per cent feed of the control group from 4 weeks to 18 weeks of age. The ful-fed groups and the restricted feeding groups were divided into 4 sub-groups at 20 weeks of age, respectively. In two sub-groups, forced moulting was conducted only one time at 92 or 80 weeks of age and in the other two-sub groups, it was done twice at 68 and 96 or 56 and 96 weeks of age. They were reared until 128 weeks of age and production trait and economical trait were observed.
Age at the first egg was delayed in the restricted feeding group than in the fullfed group. But, the weight of first egg was havier in restricted feeding group than in full-fed group. Body weight of layer was lighter in restricted feeding groups than in the fullfed groups at 44 weeks of age. The rate of raising was lower in the restricted feeding group than in the full-fed group, but there was no significant differences between them.
In the full-fed group, egg production rate from 20 to 128 weeks of age was higher in earier forced moulting group than in later forced moulting one. And economical trait which were estimated by feed consumption from raising to laying period per kg of egg production was showed same tendency as the rate of egg production. On the other hand, the different result was observed in the restricted feeding groups. There was no significant relation between the age of forced moulting and egg production rate or economical trait. Furthermore, there were no significant differences in both traits among all restricted feeding groups and the full-fed group which was showed highest performance.
