RESUMO
Two studies were conducted to evaluate the use of medical ozone (O3) in commercial extenders for equine semen cryopreservation. In the first study (Study 1), 0, 5, and 15 µg/mL of O3 were added to diluents of refrigerated or frozen semen. Samples were evaluated for sperm kinematics at different time points for the chilled samples and after a thermoresistence test for the frozen/thawed samples. In the second study (Study 2), 0, 5, and 10 µg/mL of O3 were added to an antibiotic-free diluent for refrigerated semen for comparison with the control group in which semen was diluted in the same diluent enriched with antibiotics. Semen sample kinematics were analyzed and an aliquot was collected after ozonification for bacteriological analyses. For Study 1 no difference was found comparing all the kinematic parameters analyzed over time, in the various treatments (P > 0.05). In Study 2 the absence of antibiotics did not affect the kinematic parameters compared to the control (P > 0.05). However when antibiotics were added, a smaller number of bacterial colony-forming units were detected compared to samples without antibiotics and without or with different O3 supplementations. In conclusion, O3 treatment at low dosages did not affect the semen kinematics, although it was ineffective in preventing bacterial overgrowth. Higher O3 concentrations should be evaluated to explore the possibility of reducing the use of antibiotics in equine sperm conservation.
RESUMO
Most of the northern hemisphere donkey breeds are faced with the risk of extinction, thus donkey reproduction is considered an emerging branch of theriogenology, and the management of artificial insemination and induction of ovulation is a crucial point in setting up preservation protocols. For four consecutive cycles, six jennies' ovarian activity was routinely monitored; an ultrasound examination was performed daily from the evidence of a follicle diameter ≥27 mm until ovulation. Upon reaching a follicular diameter ≥32 ± 2 mm (Hour 0), oestrous jennies were treated alternatively with 0.1 mg triptorelin acetate, sc, (TRIP), 0.4 mg/sc of buserelin acetate (BUS) or saline, sc, (CTRL) and examined ultrasonographically at Hours 14, 24, 38, 42, 48, 62 and every 24 h until ovulation. Induction of ovulation was considered successful if ovulation occurred from 24 to 48 h after treatment. 11/12 cycles resulted in ovulation for TRIP and 12/12 for BUS and CTRL groups, respectively. Mean ± SD ovulation time after treatment was 37.3 ± 8.3, 47.1 ± 21.0 and 66.8 ± 25.9 h for BUS, TRIP and CTRL, respectively (p = .0032). Ovulation rates between h24 and h48 were 10/12 (83.3%) for both TRIP/BUS and 2/12 (16.7%) for CTRL, respectively (p = .003). Buserelin and triptorelin-treated jennies had a 25 times higher probability to ovulate between Hours 24 and 48 than controls (p = .003), while there were no jenny and cycle effects on the ovulatory rate. The results of this study show how triptorelin successfully induced ovulation in jennies, like other GnRH analogues previously evaluated.