294 EFFECT OF SPERMATOZOA MOTILITY ON TRANSFERABLE EMBRYO RATE OF SUPEROVULATED JAPANESE BLACK CATTLE

Abstract

Sperm motility is known to affect fertilization; however, little is known about the relationship between frozen–thawed sperm motility and in vivo fertilization following superovulatory treatment. The objective of this study was to evaluate a sperm function test as potential predictors of embryo production following superovulatory treatment in cattle. Two to five batches of semen (Japanese black bull, n = 4, A to D) were diluted with egg york-citrate-glycerol in 0.5 mL plastic straws, and they were stored in liquid nitrogen until analyzed. Frozen–thawed spermatozoa were evaluated for motility {motile sperm concentration (MSC, million mL–1), progressive MSC (PMSC, million mL–1) and velocity (μm s–1)} using a sperm quality analyzer for bulls (SQA-Vb, Medical Electronic Systems, Caesarea, Israel). Each sample of 20 μL aspirated into the disposable capillary, was inserted into SQA-Vb. Measurements were displayed within 75 s. Intra-assay CVs of MSC, PMSC, and velocity were 14.2, 7.3 and 7.5%, respectively. Inter-assey CVs of them were 13.5, 3.9 and 4.3% respectively. Superstimulated donors (Japanese black cows, n = 161) were artificially inseminated with one dose of frozen–thawed semen (bull A = 74, B = 46, C = 21 and D = 20). The proportion of transferable embryo (IETS grade 1 to 3) was examined on day 7 (day 0 = estrus). Data were analyzed using ANOVA followed by Scheffe multiple comparison test, and Fisher’s z-transformation. MSC, PMSC and velocity values differed significantly among each bull. The values of bull A were much lower than those of the other bulls. The proportion of transferable embryos produced by bull A was significantly lower than that of other bulls (P < 0.05, Table 1). Correlations showed significant association between MSC and proportion of transferable embryos (r = 0.99, P < 0.01). We conclude that bovine sperm motility using a SQA-Vb is a useful predictor of embryo production following superovulatory treatment. Table 1.Relationship between sperm motility and proportion of transferable embryo