Correlations Between Osteocytes and Bone Density in Bovine Bony Pelvic Floor: A Pilot Study.

The functional morphology of the bovine bony pelvic floor has been studied little. This is a fascinating anatomical region as female animals have to adapt to various tensions caused by the reproduction cycle. In this study, based on the bony pelvic floors of five heifers and five cows, the average number of round and flat bone cells was detected in four pelvic floor regions, and correlations were calculated between the number of osteocytes and bone density. The number of flat cells per sample (33.0 ± 10.8) was significantly higher than the number of round cells (3.7 ± 1.7; p < 0.001). Cranially, the number of flat cells was the same in heifers and cows, while caudally, the number of flat cells was higher in cows. In both heifers and cows, bone mineral density was the lowest at the ischiopubic junction. However, while in heifers it was the same level caudally, in cows the bone mineral density was significantly higher (in heifers 0.55 g/cm2 and cows 1.53 g/cm2). Thus, bone adaptation was location-specific; in cows, the load was the greatest in the region of the ischia where dense bone mass accumulated, but in heifers, the tension was distributed more equally across the pelvic floor. Due to adaptation, multiparity did not lessen the bone density of the cows' pelvic floor. The correlation between bone density and the presence of bone cells in the bovine pelvic floor was weak and not significant and was surprising. Further studies with other histological methods may help to clarify these findings.