Disorder of sexual development in a Holstein Friesian calf: Clinical, genetic, MRI and pathological findings

Abstract A 25‐day‐old Holstein Friesian singleton calf was presented with ambiguous external genitalia suggestive of a disorder of sexual development (DSD). Clinical examination revealed an abnormally positioned urogenital orifice caudal to the mammary complexes, with a palpable tubular structure resembling a hypoplastic penis. At 3 months of age, ultrasonography and magnetic resonance imaging identified bilateral ovaries with small follicles, uterine horns, a uterine body, cervix and a subcutaneous tubular structure of uncertain origin extending towards the perineal region. Endocrine evaluation at 6 months showed low testosterone (<25 pg/mL) and progesterone concentrations of 0.1–0.4 ng/mL during one oestrous cycle. Cytogenetic analysis revealed a normal female karyotype (60, XX) with a concurrent Robertsonian translocation, rob(1;29). Postmortem examination at 7 months confirmed a normal female reproductive tract, with the vagina narrowing into a tubular structure extending to the perineal region. The rob(1;29) translocation was considered unlikely to be causative, and the aetiology of the DSD remained undetermined.