Measurement of Testicular Size and its Relation to Production of Spermatozoa by Bulls

The correlation between scrotal circumferences in situ and weight or volume of excised testes was .94. The correlation between scrotal circumferences and spermatozoan production was only .43 and .32 with bulls in routine service, but with four exhaustions at weekly intervals with each bull the correlation was .92 with 16 young bulls and --.53 with 6 aged bulls. It was estimated that nine young bulls the first year averaged 48.5 X 10 ~ spermatozoa per gram of testicular tissue per week; seven of these bulls a year later, 63.4 10 ~, and the aged bulls, 46.7 10 ~. Editor.