Involon DS 20-21 English

Uterus is considered the “organ of the pregnancy” because it houses, protects, and nourishes the calf throughout the pregnancy. During pregnancy, the diameter of the uterus expands to allow the growth of the calf and all the fluids that protect it. The uterus has many functions in the reproductive process. During the pregnancy, it provides an environment conducive to fetal growth and development. The uterine walls are composed of several layers including contractile muscles that will help expel the fetus and fetal membranes during the calving process. The fetal membranes are part of the placenta, an organ that develops only during the pregnancy and is composed of both maternal and fetal components. The major role of the placenta is to contain the fluids in which the fetus swims, produce hormones that regulate pregnancy, and exchange nutrients between the cow and the fetus. More specifically, the nutrient transfer and physical connection between fetal and maternal tissues occurs at the placentome (“buttons”), which are composed of cotyledons from the fetal membranes attached to caruncles from the uterus. During normal delivery of a calf, the placenta ruptures and once the calf has been delivered, the cotyledons and caruncles disconnect allowing the placenta to be expelled from the cow (a process called “cleaning”).