Abstract
In the bovine heart, chondrification of the fibrous tissue occurs just after birth and proceeds to bony tissue. The ossification appears first in the right fibrous trigonum three months after birth and then in the left trigonum twelve months after birth. During ossification, the bone marrow structure appears to form a narrow space within the bony tissue and develops during the subsequent year. Light and electron microscopic examinations revealed development of typical hematopoiesis in the heart bone marrow. Hemoglobin was estimated in various erythroid cells by cytospectral analysis. The hematopoietic activity was retained for about 10 years in the heart bone.
