Relationship of sperm migration in anterior vaginal fluid and embryo quality in superovulated dairy heifers.
Anterior vaginal fluid samples from 26 superovulated dairy heifers at insemination were classified into 2 grades: 1) with abnormal sperm penetration ability when vanguard sperm migration was randomly oriented; and 2) with normal sperm penetration ability when vanguard sperm migration was parallel and unidirectional. Vanguard sperm behavior and vanguard sperm migration distances were evaluated for their effects on fertilized ova recovery rates and transferable embryo recovery rates. Twelve vaginal fluid samples (46%) showed abnormal sperm penetration ability (Grade 1) and the mean +/- sem distance traveled by the vanguard spermatozoa into these samples (7.3 +/- 0.9 mm) was different (P<0.0001) from the remainder of the samples (48 +/- 3.4 mm) in which sperm penetration was registered as normal (Grade 2). In heifers in which anterior vaginal fluid samples were Grades 1 and 2, the fertilized ova recovery rates were 78.3% and 80.2%, respectively (P=0.91). Transferable embryo recovery rates were 54.2% and 32% for Grades 1 and 2, respectively (P<0.001). Using correlation and linear regression analysis, the sperm migration distance in Grade-2 samples was not related to fertilized ova (P=0.77) or to transferable embryo recovery rates (P=0.97). These results indicate that vanguard sperm movement into capillary tubes varied qualitatively and was related to subsequent embryo quality.
López-Gatius
F
F
Departamento de Producción Animal Escuela Técnica Superior de Ingeniería Agraria Universidad de Lleida Avda. Alcalde Rovira Roure, 177 25006 Lleida, Spain.