Arbor Acres broiler breeder hens, 21 to 61 wk of age, were given the daily ME level recommended by the primary breeder for their age and level of production (100% AA) or were given 94 or 88% of that amount. The reduction in daily energy allotment had no effect on age at 50% or age at peak production, but there was a highly significant linear decrease in the eggs per hen from 165 +/- 2.8 in hens given 100% AA to 149 +/- 3.2 and 141 +/- 3.8 in hens given 94 and 88% AA. The percentage of nonlaying hens between 44 and 60 wk of age was substantially increased as daily energy allotment was reduced. The percentage settable eggs was significantly lower in the 100% AA group, but no differences in fertility or hatchability were seen. Chicks per hen fell from 123 +/- 2.4 to 116 +/- 2.4 to 102 +/- 2.6 as energy allotment was progressively reduced. Dietary energy allotment had no effect on egg weight, shell weight, shell characteristics, or proportion of albumen and yolk. Chick weight was unaffected but chicks' liver weight increased with increasing dam energy intake. Percentage lipid in hens' carcasses increased with increasing energy intake and percentage protein and percentage ash decreased.

The effects of daily energy intake on reproductive performance of Arbor Acres males and on growth of their offspring was studied. In Experiment 1, 21 males were placed in individual pens with 12 females. Three rations, differing in energy, were fed from 24 to 57 wk of age with seven males receiving either 300, 340, or 380 kcal ME/d. In Experiment 2, 32 individually caged males were given daily allotments of 280, 320, 360, or 360 kcal ME/d from 26 to 32 wk of age and 300, 340, 380, or 380 kcal ME/d from 32 to 38 wk. Rations of the two groups of males fed the highest energy level differed in formulation, one being the same wheat short-based basal ration as fed to the two lower energy groups, only with additional fat, and the other being a corn-soybean-based ration. Body weight and testes weight were increased with increased energy allotment in both experiments but carcass composition was unaltered. There were no significant effects of energy intake on fertility or hatchability in either experiment. Even though mean differences were not significant, fertility in two pens dropped to near zero at 38 wk in Experiment 1. Semen characteristics and plasma testosterone concentrations were unaffected by energy intake in Experiment 2. There was a significant linear increase in 6-wk BW of broilers associated with the increase in sire energy intake in each of three batches of broilers grown in Experiment 1 and in one of two batches of broilers grown in Experiment 2.

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.

Ross broiler breeder males, housed in floor pens with females and fed from separate feeders, were given 125 g/day of isonitrogenous diets formulated to provide 300,340, and 380 kcal per male per day between 28 and 60 wk of age. Males given 300 kcal/day maintained their initial BW and were consistently lighter than those fed the two higher energy levels; BW of males given the two higher energy allotments did not differ from each other. Fertility levels, over the whole experiment, averaged 80.1, 91.1, and 83.0% for the low-, intermediate-, and high-energy groups, respectively. Fertility dropped slightly over time in all groups but showed a precipitous fall in the low-energy group between 48 and 60 wk. Hatchability of fertile eggs showed a significant decrease over time but no treatment differences were found. Hatchability of eggs set, like fertility, showed a significant quadratic regression on energy allocation.A significant linear effect of energy level on 60-wk testes weights was found but carcass composition at 60 wk was unrelated to dietary energy allocation. Males fed 300 kcal/day had less severe pododermatitis than males in other groups, but the correlation between BW and pododermatitis score was not significant. Average 6-wk BW of approximately 500 offspring of males fed the low-energy diet, raised comingled with those from other male treatments in three separate growth trials, were consistently and significantly lower than those of offspring of males fed 380 kcal/day. (

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