Mohammad Bolghanabadi - DVM Graduate, Faculty of Veterinary Medicine, Ferdowsi University of Mashhad, Mashhad, Iran
Hamideh Salari Sedigh - Department of Clinical Sciences, Faculty of Veterinary Medicine, Ferdowsi University of Mashhad, Mashhad, Iran
Pezhman Mirshokraei - Department of Clinical Sciences, Faculty of Veterinary Medicine, Ferdowsi University of Mashhad, Mashhad, Iran
Masoud Rajabioun - Department of Clinical Sciences, Faculty of Veterinary Medicine, Ferdowsi University of Mashhad, Mashhad, Iran

This study designed a protocol that would combine pregnant mare serum gonadotrophin (PMSG) and cabergoline (CAB) to induce estrus in bitches. Twenty clinically healthy adult and anestrous female dogs were randomly assigned into four groups. The first group was treated with ۵.۰۰ μg kg-۱ CAB until the onset of proestrus or for ۲۵ days. The second group was treated with ۲۰.۰۰ IU kg-۱ PMSG for ۵ days and ۵۰۰ IU human chorionic gonadotropin (hCG) on the ۵th day. The third group was treated with ۵.۰۰ μg kg-۱ CAB for ۱۰ days in combination with ۲۰.۰۰ IU kg-۱ PMSG for ۵ days and ۵۰۰ IU hCG on the ۱۰th day. The control group received ۱.۰۰ mL of normal saline. Ovarian changes were evaluated ultrasonographically, and the estrus cycle phase was examined by vaginal cytology. Respectively, three, three and four bitches showed clinical signs of proestrus in each treatment group. The intervals between treatment and proestrus for each group were ۳۰.۰۰ ± ۳.۰۵, ۷.۶۷ ± ۱.۲۰ and ۱۳.۰۰ ± ۱.۲۰ days, respectively. Two weeks after estrus, the progesterone mean was ۱۴.۵۱ ± ۶.۲۴, ۱۹.۹۶ ± ۱۷.۱۶ and ۱۹.۱۲ ± ۹.۲۶ ng mL-۱ for each group, respectively. In ultrasonography examination, the largest follicle was identified at ۱۵.۶۶ ± ۱.۳۳, ۱۱.۶۶ ± ۲.۴۰ and ۸.۷۵ ± ۲.۱۷ days after the onset of proestrus and the largest follicle’s size was measured ۶.۵۰ ± ۰.۵۵, ۴.۸۳ ± ۱.۶۴ and ۷.۰۷ ± ۱.۴۹ mm for each group, respectively. Although the combined use of CAB and PMSG reduced the duration of treatment, alteration of the duration or PMSG dosage can be helpful to improve the results.

Bitches, Cabergoline, Estrus induction, PMSG, Ultrasonography