[Prevention of oestrus and/or pregnancy in dogs by methods other than ovariohysterectomy (author's transl)].

The present paper is based on findings reported in the literature and concerned with various possible methods of preventing heat and/or pregnancy without resorting to ovariohysterectomy. The drugs used to suppress and prevent oestrus, such as progestagens, testosterone and 19-nortestosterone derivates, are reviewed, the mechanism of action, mode of administration and advantages and disadvantages being discussed. Progestagens are particularly found to affect the uterus (CEH) and mammary glands (increased incidence of mammary tumours), and they may also induce diabetes mellitus and acromegaly. On the other hand, the untoward side-effects of 19-nortestosterone derivatives are found to be mainly due to their androgenic action, resulting in enlargement of the clitoris, vaginitis, changes of behaviour and masculinization of puppies when the drug is administered during pregnancy. Subsequently, those mechanical and surgical procedures which are less commonly employed, are discussed. The pros and cons of the various methods and drugs as well as the possible causes of the difference in gestagenic effect of a number of progestational agents are discussed in greater detail.