CONTENTS

Page
[EARLY WORK ON FREEZING SEMEN][5]
[SELECTION OF SEMEN FOR FREEZING][6]
[Predicting freezability][6]
[Freezability of first and second ejaculates][7]
[Freezability of several consecutive ejaculates][7]
[Freezability of epididymal sperm][9]
[Freezability of washed sperm][10]
[EXTENDERS FOR FREEZING BULL SEMEN][10]
[Proportion of egg yolk in final diluent][10]
[Citrate level in final diluent][11]
[Storing and freezing diluent][12]
[Other diluents][13]
[DILUTION RATES][14]
[Effect of further dilution and refreezing][14]
[GLYCEROL ADDITIONS][17]
[Effect of glycerol on sperm survival at 5° C.][17]
[Glycerol levels for freezing semen][18]
[Rate, temperature, and method of adding glycerol][18]
[Allowing sperm to equilibrate with glycerol][20]
[Sugar additions and equilibration time][20]
[Substitutes for glycerol][22]
[FREEZING RATE][22]
[Effect of freezing rate on sperm survival][22]
[Rate of cooling in plastic and in glass][23]
[STORAGE TEMPERATURE][24]
[Storage at -23° to -79° C.][24]
[Use of higher glycerol levels and storage at -20° C.][25]
[THAWING][26]
[Comparison of thawing at 5° C. and at 38° C.][27]
[Thawing rate in plastic and in glass][29]
[EFFECTS OF FREEZING PROCEDURES ON METABOLIC ACTIVITY OF SPERM][30]
[Effect of glycerol additions on oxygen uptake of diluted semen at 37° C.][30]
[Effect of glycerol-plus-catalase on oxygen uptake of diluted semen][32]
[Effect of freezing procedures on oxygen utilization][33]
[Effect of freezing procedures on methylene-blue reduction time][33]
[PRACTICAL FREEZING PROCEDURE][35]
[Collection of semen][35]
[Preparation of extender][35]
[Dilution after collection][36]
[Adding the glycerol][36]
[Equilibration][36]
[Freezing][37]
[Thawing][37]
[LITERATURE CITED][38]
[TEMPERATURE CONVERSION TABLE][39]
Urbana, IllinoisOctober, 1957
Publications in the Bulletin series report the results of investigations madeor sponsored by the Experiment Station