title: The usefulness of combining traditional sperm assessments with in vitro heterospermic insemination to identify bulls of low fertility as estimated in vivo.
abstract: To date, no single in vitro assessment can estimate bull fertility. This research was aimed at evaluating the ability of a series of laboratory assessments to assign 50 Holstein Friesian bulls grouped as low (ER-NRR<-1.5), medium (-0.5<ER-NRR<+0.5) and high (ER-NRR≥+1.5) fertility based on estimated relative non-return rates (ER-NRR), to the two categories of low and medium-high fertility. Heterospermic insemination with a Piedmontese reference bull was employed to define an index of competitive binding ability (CBI) to the zona pellucida using fluorochrome-labeled sperm, and a competitive fertility index (CFI) using embryo paternal assignment by single nucleotide polymorphism (SNP). Furthermore, kinetic parameters, membrane integrity and sperm DNA/chromatin integrity (% DFI) were assayed. Low fertility bulls had lesser (P<0.05) values for total motility and membrane integrity, and a greater value of % DFI as compared to medium and high fertility groups. A modest (P<0.001) correlation was reported among ER-NRR and total motility (r=0.30), progressive motility (r=0.26), membrane integrity (r=0.43) and % DFI (r=-0.26). While % DFI alone allowed the identification of 70% lowly fertile bulls, combining membrane integrity, average path velocity and CBI allowed for identification of 78% of the lowly fertile sires. Paternal assignment by SNPs resulted in 96% of successful assignments and could provide an alternative support to microsatellites for in vivo studies based on heterospermic fertilization for estimating fertility.
authors.affiliation: Istituto Sperimentale Italiano "Lazzaro Spallanzani", Rivolta d'Adda, CR, Italy. roberto.puglisi@istitutospallanzani.it
authors.forename: Roberto
authors.initials: R
authors.lastname: Puglisi
authors.forename: Anna
authors.initials: A
authors.lastname: Pozzi
authors.forename: Luciano
authors.initials: L
authors.lastname: Foglio
authors.forename: Marcello
authors.initials: M
authors.lastname: Spanò
authors.forename: Patrizia
authors.initials: P
authors.lastname: Eleuteri
authors.forename: Maria G
authors.initials: MG
authors.lastname: Grollino
authors.forename: Graziella
authors.initials: G
authors.lastname: Bongioni
authors.forename: Andrea
authors.initials: A
authors.lastname: Galli
mesh_terms: D000818:Animals; D002417:Cattle / Q000235:genetics / Q000502:physiology*; D002462:Cell Membrane / Q000502:physiology; D002843:Chromatin / Q000235:genetics / Q000502:physiology*; D004247:DNA / Q000235:genetics / Q000502:physiology*; D005260:Female; D005298:Fertility / Q000235:genetics / Q000502:physiology*; D005434:Flow Cytometry / Q000662:veterinary; D016015:Logistic Models; D008297:Male; D020641:Polymorphism, Single Nucleotide; D013081:Sperm Motility / Q000502:physiology; D013084:Sperm-Ovum Interactions / Q000502:physiology*; D013094:Spermatozoa / Q000502:physiology*; D015044:Zona Pellucida / Q000502:physiology*
chemical_list: D002843:Chromatin; D004247:DNA