Effects of sex and reproductive state on the mechanical properties of bovine cardiovascular tissues

Effects of sex and reproductive states on the mechanical properties of bovine cardiovascular tissues were investigated. It was hypothesized that hemodynamic changes during pregnancy trigger structural remodeling of the aorta. Vessels from pregnant cows at several gestation states, heifers, dairy cows and male steers were harvested for the study. Vessel mechanical properties were examined using servo-hydraulic stress-strain tests and opening angle measurements. Aortic opening angles were found to increase by 50% at late gestational state, while mean aortic opening angle in the heifer was not significantly different from that of steers or dairy cows. It was concluded that structural remodelling occurs that alters the residual stresses in the aortic wall.