title: Presumed myelopoiesis in spinal dura mater of normal bovine foetuses.
abstract: In the course of a study of normal bovine foetal development, the brain and spinal cord of 24 newborn calves and 81 foetuses, all of the Jersey breed and ranging in age from 60 to 280 days gestation, were examined histologically. This examination revealed cellular aggregates in the spinal dura mater of all newborn calves and all foetuses over 119 days gestation. The cells had the appearance of blood leucocytes (granulocytes, monocytes) and their precursors; and also, in the foetuses only, giant cells identified as megakaryocytes were also seen. It is suggested that in the second half of gestation and for at least 2 days after birth, the spinal dura mater of cattle, in the Jersey breed at least, acts as a site of myelopoiesis. The importance of this finding to veterinary pathologists is emphasized.
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001854:Bone Marrow Cells; D002417:Cattle / Q000196:embryology*; D004388:Dura Mater / Q000166:cytology* / Q000196:embryology; D005260:Female; D005333:Fetus / Q000033:anatomy & histology; D005865:Gestational Age; D011247:Pregnancy