Abstract
Cytological, endocrinological, and histological analyses of a Japanese Black calf with abnormal external genitalia revealed sex-chromosome chimerism in the karyotype. In the PMSG-hCG administration test, the calf remained low in both estradiol-17β and progesterone concentrations, although both hormones increased in a normal control female calf. Necropsy showed male-like internal genitalia. Histological examination, however, revealed no spermatogenesis. On the basis of these findings, we determined this calf to be a single-birth freemartin.
