Cryopreservation of Bovine Semen in Egg Yolk Based Extenders

................................................................................................................................... ii ACKNOWLEDGEMENTS ........................................................................................................... iv TABLE OF CONTENTS ................................................................................................................ v LIST OF TABLES ....................................................................................................................... viii LIST OF FIGURES ....................................................................................................................... ix LIST OF ABBREVIATIONS ......................................................................................................... x 1 General Introduction ............................................................................................................... 1 1.1 History of artificial insemination in cattle........................................................................ 2 1.2 Sperm plasma membrane ................................................................................................. 3 1.2.1 Composition of sperm plasma membrane................................................................. 4 1.2.2 Role of plasma membrane in sperm function ........................................................... 4 1.2.2.1 Sperm Motility ................................................................................................... 5 1.2.2.2 Changes during capacitation .............................................................................. 5 1.2.2.3 Changes during acrosome reaction and fertilization ......................................... 6 1.3 Sperm plasma membrane changes during cryopreservation ............................................ 6 1.4 Composition and features of extenders for bovine semen cryopreservation ................... 8 1.5 Egg yolk and egg yolk extenders ..................................................................................... 9 1.5.1 Composition of egg yolk ........................................................................................... 9 1.5.2 Mechanism of protection by egg yolk low-density-lipoproteins ............................ 10 1.5.3 Use of whole egg yolk, clarified egg yolk and low-density-lipoproteins extenders10 1.5.4 Preparation of clarified and low-density-lipoprotein extenders .............................. 11 1.6 Fresh and cryopreserved semen evaluation .................................................................... 12 1.6.1 Initial semen evaluation .......................................................................................... 12 1.6.2 Sperm morphology.................................................................................................. 13 1.6.3 Sperm motility and sperm motion........................................................................... 14