The study involved 44 primiparous, 2-yr-old heifers and 74 multiparous cows, 3 or 4 yr old, bred to a single Charolais bull. Variables were dam age (heifer, H; or cow, C), restricted (RE) or forced (FE) exercise for the last 90 d precalving, and natural (NP) or induced (IP) parturition. The RE dams were held in drylots; FE dams were on range until d 260 to 267 and walked 3.2 km/d for feed and w...

An extended and variable period of anovulation and anestrus occurs in suckled beef cows following parturition. This imposes both biological and economic constraints on the efficiency of beef production. A large body of knowledge has linked these phenomena to an attenuation of neuroendocrine signals that subserve gonadal function. During late gestation, high concentrations of placental estrogen ...

Reproductive traits are economically important for beef cattle production; however, these traits are still a bottleneck in indicine cattle since these animals typically reach puberty at older ages when compared to taurine breeds. In addition, reproductive traits are complex phenotypes, i.e., they are controlled by both the environment and many small-effect genes involved in different pathways. ...