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Carcass composition traits and weights and lengths of organs relative to body weight were measured in females from a broiler-breeder parent stock segregating for early and late-feathering alleles maintained under four feeding regimens. Feeding regimens consisted of ad libitum (AL), ad libitum restricted (ALR, feed restricted daily), and skip-one-day and skip-two-days (SOD and STD, given two or three times ALR allowance on Day 1 and not fed on the next 1 or 2 days, respectively). At 160 days of age, pullets on SOD and STD were changed to ALR feeding; daily feed allowances were increased to 135 g by day 180 and to 138 g on day 250. Organ growth and carcass composition were generally similar for early and late-feathering genotypes. Restricted feeding increased relative weights and lengths of segments of the gastrointestinal tract (GIT) and pancreas and reduced relative weights of the abdominal fat depot (AFD) and lipid contents of the liver, AFD, and total carcass. Relative weights of legs, breast, feathers, heart, and liver and carcass protein composition were not affected by feeding regimen. Relative oviduct and ovary weights were not affected, but number of rapidly developing follicles was higher for AL than restricted-fed hens. Relationships of most organs to total body weight changed little after sexual maturity. Relative weights and lengths of GIT decreased whereas breast, legs, and AFD increased. Feed-restricted chickens adapted to fasts by retaining GIT contents longer. Feeding regimen x age interactions were significant for esophagus, proventriculus, gizzard, shank, breast, legs, feathers, and AFD weights; esophagus, duodenum, jejunum, ileum, and shank lengths; and lipid contents of AFD and liver.

Reproductive traits of females from a broiler-breeder parent stock segregating for early and late feathering were measured under four feeding regimens. Feeding regimens consisted of ad libitum (AL, feed was always available), ad libitum restricted (ALR, feed restricted daily to control body weight), and skip-one-day and skip-two-days (SOD and STD, given two or three times ALR allowance on Day 1 and not fed on the next 1 or 2 days, respectively). At 160 days of age, pullets on SOD and STD were changed to ALR feeding, and daily feed allowances were increased to 135 g by Day 180 and 138 g by Day 250. Early and late feathering chickens responded similarly, except that hen-day ovulation rates, relative egg shell weights, and incidences of extracalcified and compressed eggs were greater for the former than the later. For most traits measured, differences among restricted feeding regimens were minor, but considerable differences were noted between them and the AL regimen. Females fed AL reached sexual maturity approximately 60 days earlier than those whose feed intake was restricted. Also, body weights at onset of lay were about 1,200 g greater for AL than for feed-restricted females. Percentages of hen-day ovulation, normal egg production, and duration of fertility were lower, whereas incidence of defective eggs was higher for AL than for feed-restricted chickens.

Broiler-breeder females from a parent stock segregating for early and late feathering were fed ad libitum (AL, feed was always available), ad libitum restricted (ALR, feed restricted daily to control body weight), skip-one-day and skip-two-days (SOD and STD, given two or three times ALR allowance on Day 1 and not fed on the next 1 or 2 days, respectively). At 160 days of age, pullets on SOD and STD were changed to ALR feeding, and daily feed allowances were increased to 135 g by Day 180 and 138 g by Day 250. Responses of early and late-feathering females were similar for traits measured. Generally, body weights of AL chickens increased to 4,600 g at 130 days of age and then reached a plateau. Body weights of feed-restricted groups were less than half of that of AL chickens by 160 days of age. Controlled release from feed restriction enabled chickens to reach a weight of approximately 3,200 g by Day 210. Daily feed consumption for AL chickens increased to about 220 g by 140 days of age and then decreased to approximately 150 g by Day 250; it eventually decreased to approximately 120 g by Day 350, where it reached a plateau. Mortality, plasma glucose levels, and surface and cloacal temperatures were lower for females whose feed was restricted than for those fed AL. Plasma protein levels were greater for STD than for AL, ALR, and SOD groups whereas plasma lipids were higher for AL and SOD than for ALR and STD groups.(ABSTRACT TRUNCATED AT 250 WORDS)