“…Daily administration of oxytocin to heifers during the first week after oestrus markedly shortens the ensuing dioestrus, and the subsequent oestrus occurs 8-12 days, instead of the usual 21 days, after the preceding oestrus (Armstrong & Hansel, 1959;Anderson & Bowerman, 1963;Anderson, Bowerman & Melampy, 1965 ;Black & Duby, 1965). Premature oestrus is also induced when oxytocin is administered on Days 3 to 6 (Hansel & Wagner, 1960;Black & Duby, 1965;Auletta, Currie & Black, 1972) or Days 3 to 7 after oestrus (Harms & Malven, 1969).…”