Equine chorionic gonadotropin increases fertility of grazing dairy cows that receive fixed-time artificial insemination in the early but not later postpartum period - Prata, Alexandre B; Pontes, Guilherme C. S; Monteiro Júnior, Pedro Leopoldo J; Drum, Jéssica N; Wiltbank, Milo C; Sartori Filho, Roberto (Theriogenology, 2017)