Serum Anti-Müllerian Hormone Levels and Estrous Monitoring of GnRH Agonist Deslorelin-Induced Estrus in Bitches: A Pilot Study

This study was performed to monitor estrous patterns and, more importantly, changes in anti-Müllerian hormone (AMH) concentrations during the peri-ovulatory period in deslorelin-induced estrous bitches. Healthy anestrous bitches (n = 4) were used. Estrus and ovulation were monitored after deslorelin implantation. Blood samples were collected for analysis of progesterone, estradiol-17ß and AMH concentrations before implantation (day 0) and on days 6, 8, 10, 12, 14, 16, 18, 20 and 22 after implantation. Six days following treatment, all bitches showed estrus signs. Ovulation took place between days 12 and 15. Circulating AMH concentrations varied among bitches from 0.12 to 3.08 ng/mL. However, no significant differences in AMH levels (mean ± SD) were observed between day 0 and days following post-implantation (p > 0.05). There were no significant correlations between AMH and estradiol or AMH and progesterone (p > 0.05). Ultrasonographically, the number of clearly identifiable ovarian follicles was higher before ovulation and the area of ovaries increased after ovulation (p < 0.05). Except for AMH, changes in vaginal cytology, estradiol-17ß and progesterone levels observed in our study were similar to naturally occurring estrus. Large intra- and inter-individual variation in AMH were observed suggesting that AMH is currently not suitable as a canine fertility marker to monitor ovarian response to deslorelin treatment for estrus induction.

Ovum Pick-up in Cycling and Lactating Postpartum Swamp Buffaloes (Bubalis bubalis)

The objective of this study was to evaluate the efficiency of Ovum Pick Up (OPU) in cycling (n = 5) and lactating, postpartum, swamp buffaloes (n = 6) with and without gonadotropin stimulation. The OPU was performed every two weeks in all groups of animals, for a total of six sessions. Thirty collections were performed in five cycling buffaloes and 36 collections in six lactating postpartum buffaloes. Buffaloes that received hormonal stimulation were given a total of 400 mg, follicle stimulating hormone (FSH), administered twice daily over 3 days in decreasing doses, together with 100 microg of GnRH, 24 h after the last FSH injection. Following a resting period of 1 month, the two groups of buffaloes, were subjected to the same OPU regimen, but without any hormonal treatment for an additional six OPU sessions. The number of aspirated follicles recorded from the hormonal stimulated, cycling animals and lactating, postpartum buffaloes was not significantly different, 7.2 +/- 3.7 and 9.0 +/- 3.2, respectively (p > 0.05). Recovered oocytes collected from the two groups of hormonally stimulated animals were also not statistically different: 3.7 +/- 2.7 in the cycling and 5.9 +/- 3.5 in the lactating postpartum group (p > 0.05). In the two groups of buffaloes not receiving hormonal stimulation, the number of aspirated follicles was not significantly different: 2.1 +/- 1.4 and 1.4 +/- 0.7 in cycling and lactating postpartum buffaloes respectively (p > 0.05). Recovered oocytes in the non-treated groups were also similar: 1.4 +/- 1.3 vs 0.7 +/- 0.8 in cycling and lactating buffaloes (p > 0.05). Among stimulated buffaloes, most aspirated follicles were small in size (< or =5 mm), whereas they were mostly medium and large sizes in the non-treated buffaloes. The oocyte recovery rate in both the groups, cycling and lactating postpartum, were 51.6% and 69.5% in stimulated groups and 55.0% and 53.1% in non-stimulated groups (p > 0.05). The majority of recovered oocytes were single- and multi-layered, and the number was greater in the cycling than in the lactating, postpartum buffaloes. The number and quality of recovered oocytes was similar in all groups of buffaloes whether they were received or did not receive hormonal stimulation. Moreover no difference was found in multi- and single-layered oocytes between cycling and lactating, postpartum buffaloes. In conclusion, OPU can be performed successfully in swamp buffalo in different reproductive status and FSH administration was shown to increase the number of aspirated oocytes in both cycling and lactating, postpartum buffaloes.

339 ULTRASOUND GUIDED OVUM PICK UP (OPU) IN PREPUBERTAL SWAMP BUFFALO USING THREE DIFFERENT VACUUM PRESSURES

Our group successfully developed ovum pick-up in prepubertal swamp buffalo, however the quality of the oocytes that were collected was poor especially those without a cumulus mass (Techakumphu et al. 2003 Theriogenology 61, 1705–1711). The vacuum pressure used for oocyte collection was one of the factors influencing oocyte quality (Bols et al. 1997 Theriogenology 47, 1221–1236). The objective of this study was to compare the effect of three vacuum pressures on both the recovery rate and oocyte quality in prepubertal swamp buffaloes. Oocyte recovery and oocyte quality were using different groups of aspiration vacuum pressures. The maturation stages of the recovered oocytes were immediately assessed by fixation and rapid staining with basic carbol fuchsin. Twelve prepubertal calves, aged 1.5 yrs were a total of 180 mg FSH given, twice a day, in divided doses over 3 d (40/40, 30/30, 20/20). The animals were randomized into 3 groups, according to the different vacumm pressures, 100 (n = 8), 80 (n = 8) and 60 mmHg (n = 8). Two sets of treatments, carried out, with a 2 month interval between them. The oocyte recovery rates using 100 and 80 mmHg, were not different at 78.4% (29/37) and 83.6% (61/73). The 60 mmHg gave a lower rate, 65.7% (23/35) which was statistically different from the 80 mmHg group (P < 0.05). The oocytes recovered per donor showed no significant difference among the groups; 5.8 ± 4.9 for 100 mmHg, 7.6 ± 8.6 for 80 mmHg and 3.3 ± 2.1 for 60 mmHg respectively. The percentage of cumulus-oocyte complex (COC), single layered+partial cumulus oocytes (S + P) and expanded cumulus oocytes (EXP) showed no differences for any of the pressures, being 79.3, 65.5 and 82% of the total recovered. The experiment showed that follicles with a size of 2–6 mm were dominant after FSH treatment, being around 80% of the total number. Furthermore, the maturation stages of these oocytes were at prophase I and metaphase I. In conclusion, the vacuum pressure used for the oocyte retrieval technique influenced the recovery rate but not the oocyte quality. This study was supported by Rajadapisek Sompoj Fund, Chulalongkorn University year 2002. AP was PhD candidate under Royal Golden Jubilee, Thailand Research Fund.