the etiological factors behind these processes are believed to include a reduction in the resistance of bulls due to long-lasting consumption of feeds contaminated with the fungus aspergillus fumigatus , insufficient movement and bad zoo-hygienic practices , all this combined with the secondary action of the infectious germs of mycoplasma bovigenitalium , which were revealed by cultivation tests in 50 % of the ejaculates of the bulls ;
C0004034
fungus aspergillus
C0004037
fumigatus