Factors affecting broiler breeder performance. 7. Effect of varying levels of dietary protein on the development and reproductive performance of the dwarf broiler breeder.

Vedette dwarf broiler breeder female chicks were raised in floor pens and fed a standard starter ration. At 3 wk of age, 1,032 pullets were divided into four dietary treatment groups (258 bird/treatment). Birds were transferred into individual cages at 18 wk of age and at 21 wk of age assigned to one of four laying rations. Dietary treatments consisted of a 4 X 4 factorial design with four developer diets (12, 14, 16, and 18% protein) and four layer diets (12, 14, 16, and 18% protein). Body weight was determined at 6, 12, and 17 wk of age and thereafter at 4 wk intervals. Hen-day egg production was determined weekly from 21 to 58 wk of age. Specific gravity and egg weights were measured at 4-wk intervals on eggs collected over 4-day periods. Fertility and hatchability were measured at 32, 34, and 44 wk of age on the one-half of the birds in each treatment that had been artificially inseminated weekly with .05 mL of semen from Ross males. Embryonic mortality and chick weights of offspring were recorded when the breeder flock was 32 and 44 wk of age. Dietary treatment had a significant effect on body weight (P greater than .05) at Week 12, (12% and 14% vs. 16% and 18%) but by Week 17 differences were no longer significant. Significant differences in body and egg weights during the laying cycle were detected (P less than .05), with hens receiving the higher protein (16% and 18%) laying diets exhibiting heavier body and egg weights.(ABSTRACT TRUNCATED AT 250 WORDS)