THE EXPERIMENTAL ERROR OF FEULGEN CYTOPHOTOMETRY IN THE ANALYSIS OF BULL SPERMATOZOA OVER AN EXTENDED PERIOD OF TIME

Feulgen cytophotometry has been applied over a period of about two years to the analysis of the deoxyribonucleic acid content of 658 samples of spermatozoa from 275 Santa Gertrudis bulls of the King Ranch, most of which were under two years of age. A system of correction for smear to smear and slide to slide staining variation due to experimental error is presented that restricts the total maximum experimental error of a single determination to 15%, and to 10% in 80% of samples, when 18-25 sperm are measured per smear. Refinements of technique are described by which the maximum error can be reduced to 7% in 95% of samples and to 5% by increase in the number of sperm measured per sample smear.