[Becoming pregnant and maintaining pregnancy]

To begin with, a brief historical review of a number of features of bovine fertility is presented in the present paper which is part of the series 'Papers of Yesterday and Today'. This is followed by a discussion of the current situation. All this is done on the basis of a paper by Stockfleth which appeared in 1878. As a result of the eradication of venereal infections and brucellosis, becoming pregnant as well as pregnancy run a course associated with less problems than it was one hundred years earlier. Errors of herd management are immediately reflected in fertility. When animals fail to stay pregnant (abortion), a large number of possible causes may be suggested. Infections are among the most important of these causes. Finally, attempts are made to look into the future. Becoming pregnant will probably run a more difficult course in view of the fact that getting the cycles going post-partum in highly productive cows gives rise to additional problems. As regards staying pregnant, considerable changes are not anticipated.