Induction of parturition in bitches with minimal side effects by two injections of a low dose of fenprostalene, a prostaglandin F-2 alpha analogue, and pretreatment with prifinium bromide

An experiment using 16 Beagle bitches (aged 11 months to 6 years and 2 mont hs) in their 56th to 58th day of pregnancy was carried out to investigate t he effects of two injections of a low dose of fenprostalene, a long-acting prostaglandin F-2 alpha analogue, and pretreatment with prifinium bromide, a parasympathetic nerve blocking agent, on the induction of parturition and severity of side effects. The bitches were divided into three treatment gr oups: one injection of 5 mu g/kg of fenprostalene (group I, n=5); one injec tion of 7.5 mg/head of prifinium bromide followed by one injection of 5 mu g/kg of fenprostalene at 5 min after prifinium bromide injection (group II, n=6); and one injection of 7.5 mg/head of prifinium bromide followed by tw o injections of 2.5 mu g/kg of fenprostalene, one injection at 5 min after prifinium bromide injection and the next at 1 hr after the fenprostalene fi rst injection (group III, n=5). Following the injection of fenprostalene, s ide effects such as salivation, vomiting, colic symptoms, and watery diarrh ea occurred most frequently (80-100% of cases) in group I bitches. Apart fr om colic symptoms, no side effects were observed in group III bitches. Grou p III bitches also showed the smallest increase in plasma cortisol concentr ation. No significant difference in the time to initiation of parturition w as found between the three groups. The one-week survival rate of newborn pu ppies was highest in group III. The results showed that pretreatment with p rifinium bromide and two injections of 2.5 mu g/kg of fenprostalene can all eviate side effects following fenprostalene administration and have no adve rse effect on the survival of newborn puppies, indicating that this method is a reliable and safe way of inducing parturition in bitches.