EFFECT OF VARYING DOSES OF UNDILUTED SEMEN ON FERTILITY AND HATCHABILITY IN THE DOMESTIC FOWL

Abstract

An experiment was conducted with chickens to investigate the relationship between the volume of a single insemination of undiluted semen and fertility and hatchability. The fifteen doses of semen ranged from 0.0002 to 0.15 ml. Semen samples were collected with a minimum amount of cloacal fluid dilution and pooled within strain. Twelve White Leghorn hens were inseminated with each of the fifteen doses of semen from each of three strains of males. Although some fertility resulted from the smallest dose, most of the hens were infertile. Only when doses 0.004 ml and larger were used did nearly all hens lay some fertile eggs. There were highly significant differences among strains and doses in the duration of fertility observed. From forty to seventy million spermatozoa per insemination were required for high fertility. Doses larger than this (0.006 to 0.01 ml) increased fertility very slightly but the difference was not significant. The number of "skipped infertile eggs" per bird (defined as the number of infertile eggs laid between the 2nd day after insemination, and the day the last fertile egg was laid) decreased gradually as the semen dosage was increased from 0.0006 to 0.15 ml. There were no significant differences among strains in number of skipped infertile eggs, although the most fertile strain (Strain A) had relatively more skipped infertile eggs per bird than each of the other two less fertile breeds (Strains B and C). The interval (days) between the day insemination and the day the first fertile egg was laid was longer for hens inseminated with the smaller doses than for those inseminated or by the strain of male used to produce the semen.