Effect of addition of autologous prostatic fluid on the fertility of frozen-thawed dog semen after intravaginal insemination.

Vaginal insemination of frozen-thawed dog semen usually gives a highly unpredictable fertility rate with poor pregnancy rates in most bitches. This study was designed to establish whether litter size, pregnancy rate and conception rate could be improved by the addition of autologous prostatic fluid to the frozen-thawed semen before insemination. Twenty German shepherd bitches that were free of any clinical reproductive abnormality or suspect breeding history were used. The bitches were stratified according to their ages and randomly assigned within strata to treatment (group T, n = 10) or control groups (group C, n = 10). All bitches were inseminated daily with frozen-thawed semen for the duration of that stage of vaginoscopic oestrus during which the vaginal folds were shrunken and angular. Bitches in group T were inseminated with semen to which 7-10 ml of frozen-thawed sperm-free autologous prostatic fluid has been added immediately before insemination. No prostatic fluid was added to the semen used to inseminate the bitches in group C. Each inseminate contained 100 x 10(6) progressively motile spermatozoa after thawing. Semen was deposited in the vaginal fornix using a disposable plastic bovine artificial insemination pipette. For groups T and C the mean number of conceptuses per cycle (litter size), the mean ratio of conceptuses to corpora lutea (conception rate), and the pregnancy rate were 5.2 +/- 3.01 and 2.4 +/- 2.84, 0.577 +/- 0.35 and 0.23 +/- 0.27, and 100% and 60%, respectively. The addition of autologous prostatic fluid to frozen-thawed canine spermatozoa significantly improved the litter size (P = 0.023), the conception rate (P = 0.0127) and pregnancy rate in bitches (P = 0.043).(ABSTRACT TRUNCATED AT 250 WORDS)