Influence of boar seminal plasma on the distribution of spermatozoa in the genital tract of gilts.

The main purpose of the present study was to investigate whether boar seminal plasma affects the transport of spermatozoa in the genital tract of oestrous pigs or not, with special reference to the sperm transport into the oviducts. Altogether 17 gilts were used in three experiments. Experiment I. In nine gilts one uterine horn was injected surgically with 10 spermatozoa suspended in seminal plasma and the other uterine horn with 10 spermatozoa suspended in TESNaK-glucose buffer solution. The sperm deposition was performed under general anaesthesia. The gilts were slaughtered 1–2 or 4–6 h after insemination. The genital tract was removed and the numbers of spermatozoa determined in oviducts and in uterine horns. Experiment II. The insemination doses were prepared exactly as in Experiment I. Approx. 24 h before insemination Polyvinylchloride cannulas were inserted into the uterine lumen of the horns, drawn via the midventral incision at linea alba subcutaneously to cutaneous incisions ventral to the vulva opening. One cannula was placed in each uterine horn. At standing heat the insemination doses were slowly injected through the cannulas. The gilts were slaughtered 1 h after insemination and the numbers of spermatozoa within the genital tract were counted. Experiment III. In three gilts under general anaesthesia the uterine horns were ligated 10 cm from the uterotubal junction. The semen doses (containing 2 × 10 spermatozoa), prepared as in Experiment I, were deposited into the uterine horns anterior to the ligatures through a cannula. The gilts were slaughtered 1 h after insemination, and the numbers of spermatozoa within the oviducts and ligated part of the uterine horns were counted. In all three experiments more spermatozoa were, on average, recovered in the oviducts connected to uterine horns inseminated with spermatozoa suspended in seminal plasma. In Experiments I and II this was the case for 10 of 14 gilts and in Experiment III for all the three gilts. It is therefore suggested that boar seminal plasma pro¬motes sperm transport into the oviduct of oestrous pigs. The back¬ground mechanism for this is discussed.