Produced by Bryan Ness, Harry Lame and the Online Distributed Proofreading Team at http://www.pgdp.net (This file was produced from images generously made available by The Internet Archive/American Libraries.) +------------------------------------------------------------------+ | TRANSCRIBER'S NOTES: | | | | * Transcription used in this e-text: | | _text_ indicates italics; | | =text= indicates bold-face text; | | ^{text} indicates superscript text; | | _{text} indicates subscript text. | | * Lettered footnotes (with anchors [A], [B], etc.), explaining | | the text, have been moved to directly below the paragraph or | | table they refer to. Footnotes with anchors [1], [2], etc. | | refer to references, that are listed towards the end of the | | text. | | * The original text has not been modified, except that some minor| | typographical errors have been corrected silently. | | | +------------------------------------------------------------------+ PRESERVATION OF BULL SEMEN AT SUB-ZERO TEMPERATURES By N. L. VanDemark W. J. Miller W. C. Kinney, Jr. Carlos Rodriguez M. E. Friedman Bulletin 621 UNIVERSITY OF ILLINOIS AGRICULTURAL EXPERIMENT STATION 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