Secretion patterns of oxytocin and PGF2α-metabolite in response to cervical dilatation in cyclic mares

Abstract We conducted the present study to establish a standardized method for cervical stimulation without affecting the endometrium, and to investigate the effect on estrous cycle pattern and concentrations of progesterone, oxytocin and PGF2α-metabolite of cervical dilatation in the mare. Six healthy Haflinger mares underwent three different treatments (control, insertion, dilatation) on Days 5 and 7 of the cycles in different orders according to a Latin square design. During dilatation, the balloon of the catheter was inflated stepwise every 30 s with warm physiological saline to a maximum of 50 ml. At this stage the size of the balloon was 4.5 cm in diameter and 6 cm in length. Estrous cycle length was significantly shortened by dilatation when compared to controls (control: 22.8±1.7, insertion: 21.8±2.5, dilatation: 20.0±1.3 days; P P P