title: Relationship between sperm-zona pellucida binding assays and the 56-day nonreturn rate of cattle inseminated with frozen-thawed bull semen.
abstract: Assays based on sperm-zona pellucida binding have been developed as diagnostic tests to predict the fertilizing potential of mammalian spermatozoa. Recently, we reported on the development of a sperm-zona pellucida binding assay (SZBA) for bull spermatozoa. The aim of the present study was to develop a hemi-zona assay (HZA) for bull spermatozoa and to investigate the relationship between SZBA and HZA outcomes and in vivo fertility. Frozenthawed semen samples from 8 fertile Swedish Red and White bulls (one ejaculate per bull) designated as the test semen samples and a single ejaculate from a fertile Holstein-Friesian bull designated as the control semen sample were used in this study. In the SZBA, 2 groups of 20 oocytes per semen test sample and in the HZA a minimum of 6 matching pairs of hemizonae were used for comparison of sperm binding with control semen. Sperm binding to matching hemi-zonae of individual semen samples was equal, and clearly demonstrated the feasibility of the HZA for cattle. A significant correlation was found between the SZBA and the HZA indices obtained from the different semen test samples (r = 0.42, P < 0.001; n = 67). There was no significant relation between the SZBA indices and the 56-d nonreturn rate of the test samples. However, the HZA indices of the semen test samples and the 56-d nonreturn rate were significantly correlated (r = 0.46, P < 0.0001; n = 67). It is concluded that HZA can be regarded as a potential assay for predicting the fertilizing ability of bovine semen samples. However, further studies using more semen samples are necessary to confirm this view.
authors.affiliation: Department of Herd Health and Reproduction University of Utrecht, Utrecht, The Netherlands. ARFAZELI@UCL.AC.UK
authors.forename: A R
authors.initials: AR
authors.lastname: Fazeli
authors.forename: B R
authors.initials: BR
authors.lastname: Zhang
authors.forename: W
authors.initials: W
authors.lastname: Steenweg
authors.forename: B
authors.initials: B
authors.lastname: Larsson
authors.forename: M M
authors.initials: MM
authors.lastname: Bevers
authors.forename: J
authors.initials: J
authors.lastname: van den Broek
authors.forename: H
authors.initials: H
authors.lastname: Rodriguez-Martinez
authors.forename: B
authors.initials: B
authors.lastname: Colenbrander