Inconstant Skull Foramina in Bovine (Bos taurus) and Swine (Sus scrofa)

To inform about either presence or absence of inconstant foramina in bovine, swine, equine, ovine and canine species and give a description of them in case they were present, 35 bovine skulls, 33 swine skulls, 45 equine skulls, 10 ovine skulls and 20 canine skulls were examined. The inconstant foramina were located on the interparietal bone and on the nucal plane of the parietal bone in Bos taurus of Holstein breed and on the dorsal caudal region of the frontal bone in Sus scrofa, in the region where the outer bone plaque delimits the frontal sinus. No inconstant foramina were found in Equus caballus, Ovis aries or Canis familiaris. Since we found such perforations in adult livestock, mostly in old lactating cows, we suggest that they correspond to local osteoclastic resorption zones.