| − | Oxytocin is a naturally secreted [[hormone]] that is important in milk letdown and the contraction of the smooth uterine muscles during the birthing process in [[cow]]s. | + | Oxytocin is a naturally secreted [[hormone]] that is important in milk letdown and the contraction of the smooth uterine muscles during the birthing process in [[mammal]]s, including [[cow]]s and [[human]]s. |