The high fertility cycle
Over the past 2 decades, a reproduction revolution has occurred in the dairy industry in which average 21-d pregnancy rates have more than doubled from around 14% to more than 30% in many herds. Much of this increase in reproductive performance has been driven by development and adoption of fertility programs. Despite the dramatic increase in 21-d pregnancy rates, substantial variation exists among herds using the exact same reproductive management, suggesting that factors other than fertility programs can affect fertility. Change in body weight or body condition score postpartum or during the periparturient period dramatically affects embryo quality, reproductive outcomes, and transition cow health. Although some cows lose body weight or body condition score after calving, some cows maintain, whereas some cows even gain body weight or body condition score during this time period. Surprisingly, milk production during early lactation is not affected based on body condition score change during the first 3 weeks postpartum; however, peak milk measured near 60 DIM was less in both primiparous and multiparous cows that either gained or maintained compared to cows that lost body condition during the 1st 30 DIM. The high fertility cycle coupled with the dramatic increases in reproductive performance due to the development and adoption of fertility programs is a new paradigm that we can now use to explain much of the variation in reproductive performance among herds. The high-fertility cycle: how timely pregnancies in 1 lactation may lead to less BCS loss, fewer health issues, greater fertility, and reduced early pregnancy losses in the next lactation.