title: Influence of egg shell embryonic incubation temperature and broiler breeder flock age on posthatch growth performance and carcass characteristics.
abstract: A study was conducted to examine the posthatch growth performance of high-yielding broilers when eggs were incubated at 3 different embryo temperatures from 2 flocks of breeders at different ages (different egg size). Two thousand, four hundred eggs from 2 broiler breeder flocks (29 and 57 wk of age) of the same high-yielding strain (Cobb x Cobb) were incubated in the same incubator for 16 d at 37.5 degrees C. Following candling, the eggs from the 2 flocks were transferred into 3 hatcher cabinets at starting temperatures of 36.5 degrees C (low, L), 37.6 degrees C (middle, M), and 38.7 degrees C (high, H) and adjusted to achieve a shell temperature of 37.5 degrees C (L), 38.6 degrees C (M), and 39.7 degrees C (H) using an infrared thermometer. All chicks were taken off at 21 d of incubation, randomized into floor pens, and reared for 44 d. Body weights, feed intake, and feed conversion were determined at 21, 35, and 44 d of age. Body weight of birds from the H treatment was significantly less at 21, 35, and 44 d compared with the M birds. Birds in the L group weighed significantly less at 35 and 44 d compared with the M birds. Progeny from the older breeder flock had significantly greater BW at 1, 21, and 35 d of age, but had only numerically greater BW at 44 d when compared with birds from the younger flock. Feed conversion for the H birds was significantly higher from 0 to 21 d of age compared with the M and L birds. Broilers from the 29-wk-old breeder flock had lower cumulative feed conversion values than the birds from the 57-wk-old flock. No significant differences in mortality were observed. Posthatch performance appears to be affected by hatcher environment as determined by embryo shell temperature.
authors.affiliation: Department of Poultry Science, 222 Henning Bldg., Penn State University, University Park, PA 16802, USA. mrh4@psu.edu
authors.forename: R
authors.initials: R
authors.lastname: Hulet
authors.forename: G
authors.initials: G
authors.lastname: Gladys
authors.forename: D
authors.initials: D
authors.lastname: Hill
authors.forename: R
authors.initials: R
authors.lastname: Meijerhof
authors.forename: T
authors.initials: T
authors.lastname: El-Shiekh
mesh_terms: D000375:Aging / Q000502:physiology*; D000818:Animals; D001823:Body Composition; D002642:Chick Embryo; D002645:Chickens / Q000254:growth & development*; D004528:Egg Shell; D005260:Female; D010063:Ovum / Q000254:growth & development*; D013696:Temperature; D015430:Weight Gain / Q000502:physiology*