Reproductive patterns and reproductive pathologies of stray bitches in the tropics.

The objectives of this study were to determine the annual reproductive pattern and to estimate the frequency of reproductive pathologies in female mongrel stray dogs under tropical conditions. The genital tracts of 300 mongrel bitches from a municipal dog pound were examined post-mortem from January to December 2003. Season of the year, age, size, and body condition score (BCS) were recorded for each dog. The year was divided into three seasons: warm-dry (March-June), warm-humid (July-October), and fresh-humid (November-February). Distribution of estrus periods was not influenced by any of the factors studied (i.e. season, age, size, BCS). A significantly lower number of pregnancies were recorded during the warm-dry season, probably as a consequence of embryo resorption. Underweight animals had a significantly lower percentage of pregnancies than bitches of ideal BCS. More ovulations per bitch occurred during the warm-humid season than during the other seasons of the year, probably due to climatic factors. Bitches of medium and large size had more ovulations than those of small size. Of the 300 bitches examined, 43.5% had one or more genital pathologies. The most frequent pathologies found in the ovary, uterus, and vagina were epoöphoron cysts (6.7%), serosal inclusion cysts (5.0%), and transmissible venereal tumors (15.3%), but the capacity of the females to come into estrus or to become pregnant was not affected by these conditions. We concluded that stray domestic bitches in the tropics were not seasonal breeders, but their reproductive pattern was apparently modified by environmental factors such as temperature and probably photoperiod. Although several bitches in the present study had reproductive pathology, the most prevalent pathologies did not adversely reproductive capacity.