Ultrasonographic and histopathologic changes following injection of neutral zinc gluconate in dog’s ovaries

Different methods of fertility control are established in order to control the population of dogs and one of them is chemical methods. The effects of zinc gluconate on dog’s ovaries were studied. In this study, four female healthy and fertile dogs were selected randomly. Under general anesthesia and during laparotomy, the neutral sterile zinc gluconate was injected directly into the ovaries of five dogs. Changes in the size and appearance of the ovaries, leukocytes, and vaginal cytology were monitored before and after the start of the study twice a week. After 1 month, the uterus and ovaries were removed surgically and sent to laboratory for histopathologic examination. Except one dog which was in diestrus, the other dogs were in anestrus during the study. Based on ultrasonographic examination, zinc gluconate injection reduced the diameter of the ovaries after 1 month (P < 0.05). A significant reduction in the number of leukocytes occurred from the second day until the third day (P < 0.05). By the end of the study, decreases in the percentage of leukocytes were almost constant. In the histopathological examination, hyperemia was observed, and atretic, primordial, and primary follicles; fibrosis; and hemosiderin pigment were found in the ovaries. Consequently, the injection of neutral zinc gluconate did not destroy all ovarian structures after 1 month.