title: Sex selection of sperm in farm animals: status report and developmental prospects.
abstract: Pre-selection of spermatozoa based on the relative DNA difference between X- and Y-chromosome bearing populations by flow cytometry is an established method that has been introduced into commercial cattle production. Although several important improvements have increased the sort efficiency, the fertilising ability of sexed spermatozoa based on offspring per insemination is still behind farmers' expectations. The main stress factors, especially on mitochondria, that reduce the lifespan of spermatozoa are described, and new technical as well as biological solutions to maintain the natural sperm integrity and to increase the sorting efficiency are discussed. Among these methods are the identification of Y-chromosome bearing spermatozoa by bi-functionalised gold nanoparticles and triplex hybridisation in vivo as well as new laser-controlled deflection system that replaces the deflection of spermatozoa in the electrostatic field. Additionally, as well as a new nonsurgical transfer system of spermatozoa into the oviduct of cows has been developed and allows a significant reduction of spermatozoa per transfer. Altogether, the improvements made in the recent years will allow a broader use of sex-sorted spermatozoa even in those species that require more cells than cows and sheep.
authors.affiliation: Institute of Farm Animal Genetics, Friedrich-Loeffler-Institut, Hoeltystrasse 10, 31535 Neustadt-Mariensee, Germany. rath@tzv.fal.de
authors.forename: D
authors.initials: D
authors.lastname: Rath
authors.forename: S
authors.initials: S
authors.lastname: Barcikowski
authors.forename: S
authors.initials: S
authors.lastname: de Graaf
authors.forename: W
authors.initials: W
authors.lastname: Garrels
authors.forename: R
authors.initials: R
authors.lastname: Grossfeld
authors.forename: S
authors.initials: S
authors.lastname: Klein
authors.forename: W
authors.initials: W
authors.lastname: Knabe
authors.forename: C
authors.initials: C
authors.lastname: Knorr
authors.forename: W
authors.initials: W
authors.lastname: Kues
authors.forename: H
authors.initials: H
authors.lastname: Meyer
authors.forename: J
authors.initials: J
authors.lastname: Michl
authors.forename: G
authors.initials: G
authors.lastname: Moench-Tegeder
authors.forename: C
authors.initials: C
authors.lastname: Rehbock
authors.forename: U
authors.initials: U
authors.lastname: Taylor
authors.forename: S
authors.initials: S
authors.lastname: Washausen
mesh_terms: D000818:Animals; D000829:Animals, Domestic; D001947:Breeding / Q000379:methods*; D002417:Cattle; D004247:DNA / Q000032:analysis; D005260:Female; D005434:Flow Cytometry / Q000379:methods; D007315:Insemination, Artificial / Q000379:methods*; D008297:Male; D053768:Metal Nanoparticles; D012743:Sex Preselection / Q000379:methods*; D034561:Sheep, Domestic; D013094:Spermatozoa / Q000166:cytology*; D014960:X Chromosome / Q000737:chemistry; D014998:Y Chromosome / Q000737:chemistry
chemical_list: D004247:DNA