| Popis: |
Experiments were conducted to compare dietary and hormonal techniques for molting broiler breeder hens. In the first experiment, production dropped to 5% 3 wk after hens were restricted to an intake of one half of their calculated energy requirement (FR). Egg production levels of hens given a single i.m. injection of the Lupron Depot formulation of leuprolide acetate (LA) in a dose intended to provide 10 micrograms/kg BW per d for 30 d dropped to 9.5% whereas production dropped to 33% in hens receiving 5 micrograms and was unchanged by 2.5 micrograms. Postmolting fertility and hatchability of eggs from the FR and the 10-micrograms LA groups were not different. In the second experiment, postinjection egg production, oviduct weight, and uterus weight were depressed, in a dose-related manner, when hens received 0, 10, or 22 micrograms LA/kg per d. In a third experiment, egg production dropped to zero within 2 wk when hens were deprived of feed (FD) or deprived of feed and light (FD+LR), whereas it reached zero in 4 wk in hens fed only 30 g of wheat shorts per d (FR). Lupron Depot at a dose intended to deliver 30 micrograms/kg BW per d, reduced egg production to 9.5% by the 3rd wk. Twenty-eight weeks postmolting, egg production ranged from 84 to 98 eggs per hen in the molted groups and 56 eggs per hen in the unmolted controls. Fertility ranged from 82.1% in the FD+LR groups to 69.8% in the unmolted controls, whereas chick production averaged 36, 50, 59, 60, and 68 chicks per hen in the unmolted controls and in hens molted by LA, FR, FD, or FD+LR, respectively. |
