Surgical intrauterine insemination with cat semen cryopreserved with Orvus ES paste or sodium lauryl sulfate.

The mean post-thaw sperm motilities of feline frozen semen prepared with 1% OEP or 3 g/ml SLS as a cryoprotective agent, in addition to 7% glycerin, were 35.0 ± 2.4 and 37.0 ± 2.5%, respectively, showing no significant difference. On unilateral intrauterine insemination (UIUI) using these semen samples at a sperm number of 40 × 10(6), the conception rate was 70.0% (7/10) in the OEP group and 30% (3/10) in the SLS group, showing that the rate was higher in the OEP group, but the difference was not significant. It was suggested that sperm in frozen semen showing the above qualities were transferred to the contralateral uterine horn on UIUI.

Changes in qualities and quantities of consecutively ejaculated feline semen.

Cats show repeated copulation, but changes in semen qualities and quantities with repetition of ejaculation have not previously been clarified. We collected semen 4 times consecutively from 5 cats using the artificial vagina method and observed the semen qualities and quantities. No significant changes were noted in the semen volume, frequency of abnormal sperm or incidence of immature sperm, but the number of sperm and sperm motility and viability decreased with repetition, and in particular, the number of sperm in the first semen accounted for 55.0% of the total number in the 4 consecutive ejaculations, showing a significant difference from those in the 2nd-4th semen (P<0.01).

The qualities of cryopreserved epididymal sperm collected from feline epididymides stored at low temperature.

We observed the influences of low-temperature storage of the feline epididymis on the epididymal semen qualities before and after cryopreservation to identify the optimal duration for low-temperature storage of the epididymis. After excision, the feline epididymis was stored at 4 degrees C for 0-72 hr and then subjected to epididymal sperm collection. When sperm from the refrigerated cauda epididymis were frozen and thawed, there was no significant difference in sperm motility between the 0- and 24-hr low-temperature storage groups, but sperm motility was significantly decreased in the 48-hr storage group. The above findings suggested that low-temperature storage of the epididymis until 24 hr is useful for frozen sperm collected from the feline cauda epididymis.

Usefulness of addition of Orvus ES paste and sodium lauryl sulfate to frozen feline semen.

It has been shown that addition of the surfactant Orvus ES paste (OEP) and its main component sodium lauryl sulfate (SLS) to boar or dog semen before freezing improves post-thaw sperm motility and protects acrosome caps. In this study, we investigated the usefulness of the addition of OEP (0, 1, 2 and 4%) or SLS (0, 1, 2, 3 and 4 mg/ml) to cat ejaculates before freezing and their concentrations. Among the OEP addition groups, the 1% OEP group showed higher sperm motility than the other groups. Among the SLS addition groups, the 3 mg/ml SLS group showed slightly higher sperm motility and viability than the other groups. Comparison between the 1% OEP and 3 mg/ml SLS addition groups suggested a higher percentage of sperm with an acrosome cap in the 1% OEP group. The other sperm properties did not significantly differ between the 2 groups. These results indicate that addition of 1% OEP or 3 mg/ml SLS is effective for freezing of cat ejaculated semen.

Effects of liquid nitrogen vapor sensitization conditions on the quality of frozen-thawed dog spermatozoa.

The freezing conditions for preparation of frozen canine semen by the plunging method were investigated with regard to the period of sensitization in liquid nitrogen (LN2) vapor and the height from LN2, and the semen qualities after thawing were compared with those of canine semen prepared by the simple freezer method previously reported by us. In the plunging method, 9 semen straws were prepared under the same conditions, horizontally kept at 5, 7, and 10 cm above the LN2 surface in a styrene foam box for 5, 10, and 15 min, and then plunged into LN2. The semen qualities immediately after thawing were high in the 7 cm/10 min (cooling rate: -4 to -22 degrees C/min) and 10 cm/15 min groups (cooling rate: -6 to -10 degrees C/min). On comparison of frozen semen prepared by the plunging method (7 cm/10 min) with frozen semen prepared by the simple freezer method, sperm motility and viability were significantly higher for the frozen semen prepared by the plunging method. The cooling rate in freezing was higher for the simple freezer method (cooling rate: -6 to -50.9 degrees C/min) than the plunging method. Based on these findings, horizontal placement of canine semen straws above LN2 to reduce the temperature at a slow cooling rate of about -10 degrees C/min, followed by plunging into LN2 after sensitization for 10-15 min, provides good semen qualities after thawing.

Effects of addition of sodium lauryl sulfate on frozen-thawed canine spermatozoa.

The addition of Orvus ES paste (OEP) to extender may be essential for preparing frozen dog semen. The major ingredient of OEP is sodium lauryl sulfate (SLS). In this study, we compared the effect of SLS on frozen dog semen with that of OEP. There were no significant differences between the 2-mg/ml SLS group and OEP group concerning sperm motility, viability and the percentage of viable sperm with intact acrosomes after freeze-thawing. These results suggest that the effectiveness of frozen dog semen extender containing 2 mg/ml of SLS is similar effective to that demonstrated for OEP.