Effect of Techniques of Preparing Semen Smears for Staining on The Morphology of Bull Spermatozoa

DETERMINATION of the proportion of morphologically abnormal spermatozoa in stained semen smears was formerly considered as one of the best means of estimating the potential fertility of a breeding male (Williams and Savage, 1925; and Moench and Holt, 193I). More recently, the reliability of this method has been questioned (Dougherty and Ewalt, 1941 ; Herman and Swanson, 1941; and Lasley and Bogart, 1943). Little recent evidence has been obtained to show direct correlation between the proportion of abnormals and relative fertility in the bull (Trimberger and Davis, 1942; and Mercier, 1946) but no proof is yet available that abnormals need no longer be considered in routine semen examination. Direct evidence on this question is needed. Before sound evidence can be obtained easy and precise methods by which the proportion of abnormal spermatozoa in bull semen can be determined routinely in any laboratory need to be developed. Work in this laboratory revealed that the procedures used in preparing smears for staining might have an influence on the proportion of tailless heads and abnormally-formed spermatozoa observed.