Duration of the reproductive period decreases the frequency of preovulatory luteinizing hormone surges in heavy weight-sire line turkey hens.

摘要: Abstract The frequency of preovulatory luteinizing hormone (LH) surges is an important determinant ovulation and oviposition rates in turkeys. Egg production rate relatively poor heavy weight-sire line type turkey hens declines with advancing duration the reproductive period. purpose this study was to measure characteristics LH a early, at peak egg (Early), late, after had declined (Late), Early were photostimulated continuous photoperiod [24 h light (L):0 h dark (D)] 40 weeks age sampled during about 47 age. Late long day (14L:10D). After 27-week period, switched 24L:0D 74 Continuous lighting used blood sampling allow rhythm free run. All cannulated 3–5 days before starting hourly samples collected for 200 h. necropsied ovarian oviductal morphologies measured serial bleeding. longer interval between intra-clutch than hens, higher incidence atretic follicles. baseline surge amplitude concentrations but lower progesterone (P 4 ) hens. surges, “blind” P concentrations, overall estradiol-17β (E 2 not different In conclusion, follicles, concentration associated decline late period