Effect of the sex‐linked dwarf gene on circulating levels of 17/β‐estradiol, progesterone and luteinising hormone in the laying hen

Abstract

1. The sex‐linked dwarf gene did not appear to affect the LH, progesterone (P4) and oestradiol 17ß (E2) levels around the onset of lay in a sample of White Leghorn hens.

2. A longer interval between oviposition and subsequent ovulation was suggested in dwarf layers by a slower decrease in the P4 plasma concentration after the preovulatory peak and is consistent with the increased oviposition interval already described.

3. A higher ratio of E2/P4 basal levels was found in dwarf layers; this is consistent with their lower number of fast‐growing follicles and with their reduced laying rate.

4. Lipid mobilisation was modified in dwarf layers (as shown by their reduced abdominal fattiness); although plasma concentrations of tri‐glycerides were normal, unusual correlations between plasma trigly‐cerides, E2 basal concentrations and body weight were recorded.

Notes

To whom correspondence should be addressed.