PROSTAGLANDIN INDUCTION OF ABORTION IN PREGNANT BITCHES AFTER MISALLIANCE

Of 48 privately-owned bitches evaluated 30 to 35 days after a single, unplanned breeding, 30 (62%) dogs were determined not to be pregnant b y abdominal ultrasonography and 18 dogs were confirmed to be pregnant. Each pregnant dog was hospitalized, allotted to a treatment group, an d given prostaglandin F2alpha, sc, at 1 of 3 dosages: group 1, 0.1 mg/ kg of body weight, every 8 hours; group 2, 0.25 mg/kg, every 12 hours; and group 3, 0.1 mg/kg, every 8 hours for 2 days and then 0.2 mg/kg e very 8 hours thereafter. Plasma from each dog was assayed for progeste rone concentration before treatment and daily until abortion was compl eted. Physical examinations and abdominal ultrasonography were perform ed every 12 and 48 hours, respectively. Treatment was continued until abortion was complete as determined by results of abdominal ultrasonog raphy. Ultrasonography was performed earlier than the scheduled 48 hou rs if abdominal contractions, fetuses, or bloody or dark colored vagin al discharge was observed. Dogs of 14 breeds were treated; body weight ranged from 5.4 to 37.7 kg. All dogs aborted all fetuses within 9 day s of beginning treatment. Abdominal palpation was not satisfactory in confirming whether the abortion process had been completed; however, r esults of ultrasonography were a reliable indicator. Plasma progestero ne concentrations prior to treatment were typical of the middle phase of gestation, with all concentrations > 6.0 ng/ml. The plasma progeste rone concentration decreased significantly in each dog after the first 48 hours of therapy. None of the bitches aborted any fetal material u ntil at least 24 hours after the plasma progesterone concentration was < 2.0 ng/ml. Side effects of the initial injection of prostaglandin F 2alpha included panting (n = 14), excess salivation (n = 13), vomiting (n = 12), defecation (n = 10), and urination (n = 3). Side effects we re not life threatening, lasted < 30 minutes in all but 2 dogs, and we re less severe with each subsequent treatment. Prostaglandin F2alpha p rovided a safe, reliable, effective, and practical abortifacient in pr egnant bitches treated at 30 to 35 days after an unplanned breeding. T he results of all 3 protocols were satisfactory.