Technical note: Artificial vagina vs a vaginal collection vial for collecting semen from rams.

Abstract

The time required to train rams to an artificial vagina (AV) makes collecting semen from large numbers of rams difficult. To manage this problem, we developed a glass, round-bottomed, 1.9-cm i.d. x 9.8-cm long vaginal collection vial (VCV). Three experiments were conducted to determine whether the VCV affected 1) semen volume per collection, 2) percentage of motile spermatozoa, 3) forward progressive motility score before and after extension and after freezing and thawing, and 4) our ability to collect semen from untrained rams. A soft rubber cap with a hole in the center was used to cover the VCV. A VCV was inserted into the vagina of an estrual ewe, and a monofilament line attached to the VCV was clipped to the wool near the vulva. Rams were joined with unrestrained ewes in a pen until they ejaculated into the VCV. In Exp. 1, five rams trained to an AV were used in a switchback design with four collection periods. During each period (1 d), semen was collected with an AV and a VCV. Immediately after collection, semen volume and sperm motility were quantified. Semen was extended with an aloe vera gel-based diluent at a 1:4 dilution rate, motility was quantified again, and semen was frozen. At 1 h after freezing, semen was thawed and sperm motility was quantified. Ejaculate volume (mean = 0.7 mL) and all measures of motility after collection were similar (P > 0.05) for the two collection methods. In Exp. 2, 10 rams trained to an AV were used in a switchback design with five collection periods (period = 3 d). On d 1 and 3 of each period, an AV and a VCV were used to collect semen. Collection method did not affect (P > 0.05) ejaculate volume (mean = 1.0 mL), percentage of motile cells, or forward progressive motility score. In Exp. 3, 51 untrained rams were used in a switchback design with a single collection period (2 d). Semen was collected with an AV and a VCV. Ability to collect an ejaculate and time required for collection were recorded. The likelihood of collecting semen from untrained rams was greater (P < 0.01) using a VCV (mean = 31.4%) than using an AV (mean = 9.8%). Collection method did not affect (P > 0.05) ejaculate volume (mean = 0.8 mL), percentage of motile cells, or forward progressive motility score. We concluded that a VCV could be used to collect semen from rams that are not trained for semen collection without decreasing ejaculate volume or sperm motility.