Fertility of fresh and frozen -thawed semen of the angora goat

Abstract

In six experiments, involving a total of 954 does, fresh and frozen-thawed semen processed in a Tris-based diluent was used for artificial insemination. There was an improvement in fertility with increasing depth of insemination into the genital tract (up to 1 · 0 cm, 1· 5-3 · 0 cm into the cervix, into uterus), but the effect was more pronounced for frozen-thawed than for fresh-diluted semen. The two types of semen yielded indistinguishable kidding results after intra-uterine insemination. When the insemination was made at the second oestrus after synchronization with intravaginal sponges, the fertility for the categories of depth of insemination was not improved by double insemination and deposition of twice the total number of fresh motile spermatozoa (120 × 106 + 120 × 106) than by single insemination, or by the increase of fresh or frozen-thawed motile sperm numbers (60 × 106 Å. 120 × 106) in the single inseminate. When at the synchronized oestrus the depth of insemination was not recorded and equal total numbers of frozen-thawed motile spermatozoa (60 × 106 Å. 120 × 106) were deposited by both single and double inseminations, the latter method of insemination was of no advantage within either sperm dose. Further, the rates of kidding were not different for single insemination of frozen-thawed semen 48 or 59 h after removal of intravaginal sponges, for washed (seminal plasma removed) or nonwashed spermatozoa, and for does injected with 75 or 300 i.u. pregnant mare serum gonadotrophin at sponge removal. © 1983 ASEG.