A Simplified Technique to Determine the Ability of Spermatozoa to Penetrate the Estrous Cervical Mucus in Japanese Beef Cattle

Abstract

This study was carried out to simplify the previous method for the mucus penetration test in Japanese beef cattle. Frozen-thawed semen was brought into contact with frozen-thawed estrous cervical mucus loaded in a rectangular capillary tube under the following conditions for placement of the tube and temperature of incubation: 1) horizontal/38 C (the previous method, Horizontal 38 C), 2) upright/38 C (Upright 38 C), or 3) upright/room temperature (Upright RT). The previous method included fixing the capillary tube with a mixture of vaseline and paraffin and a cover of semen with paraffin oil and a cover slip on a glass slide. This procedure was simplified by use of a small vial, in which semen was placed and covered with paraffin oil in Upright 38 C and Upright RT. Mucus penetration, expressed as the distance travelled by the sperm cell that penetrated the mucus the farthest in 10 min, was similar to Horizontal 38 C and Upright 38 C but was significantly lower with Upright RT. Intra-assay and inter-assay coefficients of variation in Upright 38 C were below 5%. Thus this study simplified the technique of the mucus penetration test using Upright 38 C