A standard nigrosin-eosin staining method in current use has been said to differentiate between live (unstained) and dead (stained) spermatozoa. In the present work, the method is applied to rabbit semen. The general results are comparable with those already obtained in the larger domestic animals. The effects of several technical and biological factors on staining capacity are evaluated, and the validity of the method is examined experimentally. Some statistical aspects are presented. The percentage of stained spermatozoa varies widely between rabbit males. To a large extent, any particular male preserves a characteristic percentage from one ejaculate to another. The percentage of stained spermatozoa is inversely related to the fertility of males as measured by the birth rate after natural mating.
Concurrently, an investigation was made of the incidence of a class of morphologically abnormal spermatozoa seen in the preparations. The classifications of spermatozoa by morphology and by staining capacity are highly correlated. For assessing semen quality, the morphological classification is considered to be as useful as the classification by staining capacity, and perhaps more useful.
Nigrosin-eosin staining of rabbit spermatozoa is discussed; firstly, in comparison with other animals and in relation to sources of variation; secondly, as a means of differentiating between live and dead spermatozoa; thirdly, as a means of assessing the fertility of semen; and fourthly, in relation to the alternative classification of spermatozoa by abnormal morphology.