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

The frequency of preovulatory luteinizing hormone (LH) surges is an important determinant of ovulation and oviposition rates in turkeys. Egg production rate is relatively poor in heavy weight-sire line type turkey hens and declines with advancing duration of the reproductive period. The purpose of this study was to measure frequency and characteristics of preovulatory LH surges in turkey hens of a heavy weight-sire line type early, at peak of egg production (Early), and late, after egg production rate had declined (Late), in a reproductive period.

Progesterone injection and egg production in turkey hens.

An arrest in laying associated with either a polyovarian follicle (POF) or a polycystic ovarian follicle (PCOF) syndrome has been reported in turkey hens photostimulated at an early age with a constant-light photoperiod. Hens expressing the POF or PCOF syndrome had stopped laying for several weeks, but the ovary contained an increased number of mature-size and larger follicles (POF hens), which were cystic (PCOF) in some of the hens. Hens with the POF or PCOF syndrome had plasma progesterone (P(4)) concentrations that were relatively high and without surges.

Temporal and spatial localization of proteoglycan decorin transcripts during the progression of cholesterol-induced atherosclerosis in Japanese quail.

The temporal and spatial distribution of decorin transcripts, endothelial cells, and smooth muscle actin-producing cells were determined during the progression of atherosclerosis in the dorsal aortas of Japanese quail selected for cholesterol-induced atherosclerosis. The quail were placed on either a control diet or a diet containing 0.5% added cholesterol at approximately 16 weeks of age.

Changes in plasma concentrations of luteinizing hormone, progesterone, and estradiol-17beta in peripubertal turkey hens under constant or diurnal lighting.

Possible circadian fluctuations and long-term changes in concentrations of reproductive hormones in peripubertal female birds is poorly documented in comparison with mammalian species. Our objective was to document changes in concentrations of several reproductive hormones the several days before and after initial pubertal preovulatory surges of LH in turkey hens photostimulated with either constant (24L:0D) or diurnal (14L:10D) lighting. The hens were cannulated for hourly blood sampling, starting 10 days after photostimulation and continuing until all hens had laid at least two eggs.