Persistent Müllerian duct syndrome (PMDS) in the Polish free-ranged bull populations of the European bison (Bison bonasus L.).

This study describes the diversity of vestigial male uteri of the European bison (Eb) examined for: (1) morphology, (2) glycoprotein localization, (3) total protein and glycoprotein profiles, (4) steroid concentrations, and (5) PMDS based on the mutation of AMH and AMHR2 genes. Uteri of adult bulls (5-12 years old) were compared to a uterus of a juvenile female (6 months old). Male uterine proteins were analyzed in parallel to secretory endometrial proteins of pseudo-pregnant pig (PsEND) and BSA used as profile-controls. Hematoxylin/eosin-staining revealed the diversity of male uterine morphology, including lumen size/shape, endometrial (END) gland density, luminal knob-like epithelial structures and multiple intrauterine cells proliferating within the lumen. PAS-staining revealed the presence of glycoproteins restricted to luminal epithelial cells and END glands. Heterologous total protein PAGE-profiles (20-66kDa) revealed two dominant fractions (66 and 45kDa), similar to PAS-profiles (67 and 47kDa) in male and female uterine tissues. In male uterine tissues, androstendione and progesterone, but not testosterone, estrone or estradiol concentrations were lower than in the female. Sequencing of AMH- and AMHR2-like amplicons allowed identification of these gene mutations in Eb. Our results provide novel data regarding PMDS, demonstrating the diversity of uterine morphology, glycoprotein mass/profile, steroid concentration and AMH/AMHR2 mutations in Eb bulls.

Persistent right aortic arch in a yearling captive wood bison (Bison bison athabascae).

An undersized, 16-mo-old, captive wood bison (Bison bison athabascae) was observed with dysphagia and postprandial regurgitation. The animal died shortly after anesthesia was initiated for diagnostic purposes. At necropsy, a persistent right aortic arch and aberrant left subclavian artery were diagnosed. The vascular ring structure around the esophagus and the trachea caused a megaesophagus with complete esophageal obstipation and ulcerative esophagitis. The aberrant left subclavian artery did not significantly compromise the esophagus. Persistence of the right aortic arch is relatively rare in ruminants and has not previously been reported in a bison.