Responses in Molt and Lay of Fowl to Progestins and Gonadotrophins. ∗

Summary

Progesterone, appropriately administered, has the capacity to a) induce proliferation of the feather papilla with consequent molt, and b) interrupt a laying period. Several compounds with known or suspected progestational activity were tested to ascertain their effectiveness in these respects. De-soxycorticosterone acetate interrupted lay; molt was initiated soon thereafter. Testosterone propionate similarly interrupted lay but molt was evident only after considerable delay. Cortisone acetate was ineffective in either process. Other experiments examined the action of several gonadotrophins given in 10-fold difference of dosage, alone and in conjunction with a constant progesterone dosage. Pregnant mares' serum, follicle stimulating hormone, or luteinizing hormone in adequate dosage diminished or interrupted lay for 3 weeks or more beyond the actual time of treatment. Progesterone augmented all such effects. Molt occurred if lay ceased. Pro-lactin affected lay very slightly and counteracted interference by progesterone. Molt occurred very early with prolactin alone and was brief and light with progesterone given simultaneously. At the higher dosage level, some molt appeared even though lay was not entirely suppressed.