title: Sperm chromatin structure and sperm morphology: their association with fertility in AI-dairy Ayrshire sires.
abstract: Prognostic relations between sperm variables and sire fertility are yet elusive. A retrospective analysis of sperm morphology and chromatin stability (studied using sperm chromatin structure assay [SCSA]) and their relation to fertility after AI (as proportions of 60 days of nonreturn to estrous [NRR], corrected NRR, or calving rate) was studied with preselected frozen semen doses from a group (N = 43) of AI-sires of the Finnish Ayrshire breed composed of 50% subfertile bulls (<55% NRR) and 50% fertile sires (>55% NRR). Fertility, indicated by all three parameters, correlated significantly only with the percentage of morphologically normal spermatozoa, a variable which negatively correlated with the percentage of DNA fragmentation at the time of SCSA, thus confirming the value of always having high numbers of morphologically normal spermatozoa in AI-doses. Proportions of major sperm defects also related to fertility but only when considering corrected NRR, not with calving rate, indicating that proportions of normal spermatozoa, a value surpassing differences between sperm laboratory screening methods, might be valuable and could be easily made routine by the industry. Though SCSA as a method is being contested for DNA- and chromatin analyses in the light of epigenetic changes, a particular parameter, the High Green fluorescence, showed the highest values for sperm doses collected from bulls having meiotic problems and containing a high proportion of diploid spermatozoa (approximately 20%) and also in bulls having a reciprocal chromosomal translocation, thus suggesting such a parameter might be useable to discriminate which bulls ought to be studied in more detail, including cytogenetic analyses.
authors.affiliation: Georgikon Faculty, Department of Animal Sciences and Animal Husbandry, University of Pannonia, Keszthely, Hungary. nagy.szabolcs@georgikon.hu
authors.forename: S
authors.initials: S
authors.lastname: Nagy
authors.forename: A
authors.initials: A
authors.lastname: Johannisson
authors.forename: T
authors.initials: T
authors.lastname: Wahlsten
authors.forename: R
authors.initials: R
authors.lastname: Ijäs
authors.forename: M
authors.initials: M
authors.lastname: Andersson
authors.forename: H
authors.initials: H
authors.lastname: Rodriguez-Martinez
mesh_terms: D000818:Animals; D002417:Cattle; D048430:Cell Shape; D002843:Chromatin / Q000737:chemistry / Q000378:metabolism*; D053938:DNA Fragmentation; D003612:Dairying; D005260:Female; D005298:Fertility / Q000235:genetics / Q000502:physiology; D005434:Flow Cytometry / Q000379:methods / Q000662:veterinary; D007315:Insemination, Artificial / Q000662:veterinary*; D008297:Male; D011247:Pregnancy; D018873:Pregnancy Rate; D012189:Retrospective Studies; D013094:Spermatozoa / Q000166:cytology* / Q000378:metabolism*
chemical_list: D002843:Chromatin