The effect of feeding management during the growing and laying periods on productivity and the characteristics of adipose tissue of the broiler breeders

The present experiment was undertaken to study the egg production and abdominal fat accumulation of broiler breeder female chickens which had been subjected to different feeding management procedures. Broiler breeder female chicks (1022) were divided into two populations. One population was fed between 8 and 10 a.m. using conventional feeders. The other population was fed twice daily the same amount of feed as the feeder-fed population but given feed broadcast on the litter between 8 a.m. and 10 p.m. and between 3:30 p.m. and 4:30 p.m. Physical activity and the extension of feeding time of the floor-fed population were therefore greater than was the case with the feeder-fed population. The floor-fed brids were lighter in weight under ad libitum feeding from 2 to 4 weeks of age. Thereafter the floor-fed birds were heavier under quantitative feed restriction. At 18 weeks of age each population was divided into four groups, heaviest, upper medium, lower medium and lightest, based on body weight. The birds of the lighter groups subsequently grew faster than those of the heavier groups and by 47 weeks of age the weights were not significantly different. The amount and proportion (% of body weight) of abdominal fat in the floor-fed pullets at 26-27 weeks of age were higher than in the feeder-fed pullets. Abdominal fat increased with increased body weight in those groups of pullets which gained up to 1200 g in body weight after the division at 18 weeks of age, but decreased in proportion to body weight in those groups of pullets which gained in excess of 1200 g. The data suggested that the more vital parts of the body, such as the muscle and skeletal tissues, developed at a faster rate than the abdominal fat pad in the lightest group of pullets. Floor feeding did not affect the age at which the pullets reached sexual maturity. Egg production, calculated on hen-day basis, was similar in all groups. When egg production was calculated on a hen-housed basis, however, the feeder-fed pullets showed a higher rate of egg production than did the floor-fed pullets. Furthermore, the birds of the heavier groups within both feeding systems had a higher rate of production than did the birds in the lighter groups. Floor-fed pullets laid significantly larger eggs than feeder-fed pullets. Egg weight was not significantly different among the four weight-groups of pullets in each feeding system. Birds fed on the litter had lower mortality during the brooding period but thereafter had a higher mortality than did the birds fed from feeders. The major cause of death was gizzard impaction with litter material. Mortality was the highest in the lightest groups on both feeding systems during the laying period.Land and Food Systems, Faculty ofGraduat