Birth of Bovine Twins at an Abnormally Prolonged Interval

Abstract

A holstein and a Japanese Black cow were conceived for the first time by one artificial insemination with frozen semen of the respective breeds. They were delivered of twins judged to be dizygotic. The Holstein twins were male and born at 271 and 296 days of gestation, respectively. The Japanese Black twins were male and female and born at 286 and 475 days of gestation, respectively. The male was small and weak, weighing about 20 kg. The female was normal in size. She was not a freemartin, but was fertile and bred normally.