The Relative Usefulness of Combinations of Laboratory Tests for Predicting the Fertility of Bovine Semen

Open Access
Publisher Website
Google Scholar
Abstract
Statistically significant "gross" linear correlations were obtained between fertility of bovine ejaculates extended 1:100 and 1:300 and concentration of spermatozoa in the ejaculate, per cent of motile spermatozoa, methylene blue reduction time, pH, per cent of unstained spermatozoa, per cent of morphologically abnormal spermatozoa, livability of spermatozoa at 5[degree]C, and oxygen uptake of spermatozoa at 37.5[degree]C. Of the semen tests that may be performed quickly after the ejaculate is collected, spermatozoan concentration and per cent of abnormal spermatozoa make substantial contributions to the prediction of per cent nonreturns at extension rates of either 1:100 or 1:300. However, in routine examination of semen for large scale artificial breeding operations, culling of ejaculates on the basis of their predicted nonreturns from the number of motile spermatozoa per milliliter of extended semen appears more feasible. Rejecting 50% of the ejaculates by this procedure and extending the remaining ones 1:300 resulted in a predicted average nonreturn percentage equal to that predicted when no ejaculates were rejected and all were extended 1:100.