Relationship between progesterone and egg production in pheasants.

A radioimmunoassay was developed to measure progesterone concentration in sera of immature and mature female pheasants. The antiserum to progesterone was produced against progesterone-3-carboxymethyloxime: bovine serum albumin in female rabbits. Crossreactivity of the antiserum with 17 different steroids was tested and was less than 2% for all steroids except 5 alpha-pregnane-3,20-dione (18%) and pregnenolone (9%). Sensitivity of the standard curve was 2.7 pg. The within and between assay coefficients of variation were 7% and 14%, respectively. Blood samples were collected weekly starting when the birds were 17 weeks of age and continued until they were 1 year of age. Progesterone concentration was measured in all serum samples. Egg production was recorded daily for the individual hens. The relationship between progesterone concentration and egg production was studied. Average progesterone concentration prior to sexual maturity was significantly lower than at subsequent ages. There was a significant positive correlation between average progesterone concentration and average percent egg production within individual birds. Furthermore, statistically a significant amount of the variation in percent egg production was explained by differences in progesterone concentration. These results indicate that progesterone is important for egg production in pheasants, as it is in chicken and turkey hens.