In recent days dog owners frequent request is to terminate pregnancy with usual reasons that include unintended mating, mating at too young or old age. Regardless of what treatment is used for pregnancy termination it is most important to diagnose that the bitch is actually pregnant before treating for her mismatings. It has been shown that only 40% of bitches presented for misalliance were actually pregnant which means 60% of bitches will be treated unnecessarily if pregnancy diagnosis is not confirmed [1]. Hence administration of estrogen immediately after mating can be avoided which has major side effects as permanent bone marrow suppression or destruction resulting in severe anemia, leukopenia, thrombocytopenia and death [2]. Present report shows the result of the successful pregnancy termination with Mifepristone to a mismated dog.

A 3 year old female dog was brought to the Veterinary Hospital, Teaching Veterinary Clinical Complex, College of Veterinary Science, Proddatur with mating history of three days. All vital parameters of the animal were found to be normal. Faecal samples and blood was collected for laboratory analysis. Owner was asked to come after one month to confirm the pregnancy. Upon clinical examination dog had slight rise in temperature (103.2ºF), elevated heart rate (150/min), respiratory rate (38/min), with normal ECG parameters, alterations in the blood pressure (164/82) was recorded. Dog had normal haemoglobin (11.8 g/dl), packed cell volume (36.4 per cent), total erythrocyte count (6.8 x 106/cumm), total leucocyte (9198/cumm), absolute neutrophil count (6825/cumm), absolute eosinophil count (122/cumm), monocytes (51/cumm) and lymphocytes (2200/cumm). Faecal sample examination revealed presence of ancylostoma spp. eggs. Owner had brought the same dog after one month. Abdominal palpation revealed spherical masses. Ultrasound scanning was done and four embryos were identified. Length of gestational sac diameter was found to be 1.5 cm and gestational age was calculated as 29 days based on G A= (6X GSD)+20 [3].

On the first day of presentation to eliminate the internal warm burden dog was treated with dewormer (Eazypet, Intas animal health, Ahmedabad) (one tablet). After pregnancy confirmation, as per the owners request it was decided to abort the bitch by using an antiprogesterone drug, Mifepristone (Termipil, Alkem Laboratories Ltd.) given at dose rate of 3mg/kg body weight in in twice daily orally, 250 ml of DNS I.V., chlorpheniramine maleate (Anistamin, Intas animal health, Ahmedabad) 0.5@ mg/kg body weight, Cefpodoxime (Cefpet, Intas animal health, Ahmedabad) 5@ mg/kg body weight and melonex (Melonex Suspension, Intas animal health, Ahmedabad) 0.5@ mg/kg body weight is given orally five days. Antibiotic was stopped after day 5 and nutritional supplements (Intacal Pet, Intas animal health, Ahmedabad) were given and animal became normal within one week. On first day of treatment animal was dull and there was no signs of any discharge from vulva of animal. On second day animal showed lowered appetite with slight discharge from vulva. One aborted foetus was expelled with frequent licking of animal near vulva and few drops blood mixed discharge was seen following day. On 4th, 5th and 6th days there was no evidence of fetal expulsion but much reduced appetite was observed.

In the present case even though four foetuses were seen during ultrasound scanning only one foetus was expelled and the remaining might had undergone resorption [4]. Cefpodoxime was used in this treatment to eliminate any secondary bacterial infection [5]. Mifepristone is a progesterone and glucocorticoid antagonist. It is more potent as antiprogestin than as anti-corticoid. The drug act as a progesterone receptor antagonist at the level of the uterus independent of any additional effects on luteal function [4]. Premature cessation of luteal function might have occurred secondary to termination of pregnancy. Dog had all the haematological parameters under the reference values mentioned in the local area [6].

Galac et al. reported that during a treatment in a pregnant bitch with aglepristone, a similar progesterone antagonist, pregnancy termination resulted in premature luteal function and interestrous interval was shortened [7]. These effects may be the consequence of actions of progesterone receptor antagonist at the hypothalamus-pituitary level. Concannon et al. suggested that cessation of luteal function in antiprogestagen treated animals secondary to termination of pregnancy may represent a luteolytic effect of treatment independent of pregnancy status [8]. Luteolysis secondary to abortions or resorptions could be related to an uterine release of luteolytic amounts of prostaglandin F-2α normally occurring at parturition. Mifepristone can induce endometrial prostaglandin secretion in vitro [9]. A pituitary effect could also be involved since mifepristone has antigonadotrophic in non pregnant women, a direct ovarian effect cannot be completely ruled out [10]. Mifepristone suppress 3β-hydroxysteroid dehydrogenase and 17-hydroxylase activities of human ovarian tissue in vitro [11].

In conclusion administration of antiprogestagens such as mifepristone terminates pregnancy in dogs and no adverse effects were noticed after treatment.

Corresponding author expressed his thankfulness to Dr.A.Sardamma, Assistant Director and Heads of clinical Departments for their cooperation for completion of this work. Special thanks to the reviewers of this manuscript.

Dr. S. Sivajothi from Sri Venkateswara Veterinary University and Dr. R. Venkatasivakumar from College of Veterinary Science, Andhra Pradesh recommend publication of this article.