The present study analyzed the participation of the left and right superior ovarian nerves (SON) in regulating progesterone, testosterone, and estradiol serum levels in unilaterally ovariectomized rats on each day of the estrous cycle. For this purpose, ovarian hormone concentrations in serum were measured in animals with either sham-surgery, unilateral ovariectomy (ULO), unilateral sectioning of the SON, or sectioning of the SON innervation of the in situ ovary in rats with ULO.This investigation results show that the right and left ovaries have different capacities to maintain normal hormone levels, that such capacity varies during the estrous cycle, and that it depends on the integrity of the SON innervation. In rats with only one ovary, the effects of ovarian denervation on hormone levels varied according to which ovary remained in situ, the specific hormone, and the day of the estrous cycle when treatment was performed. Present results support the idea that the ovaries send and receive neural information that is processed in the central nervous system and we propose that this information participates in controlling the secretion of gonadotropins related to the regulation of ovarian functions.

Bilateral ovariectomy or adrenalectomy are experimental tools used to understand the mechanisms regulating the hypothalamus-pituitary-ovarian and the hypothalamus-pituitary-adrenal axis. There is evidence that acute unilateral perforation of the dorsal peritoneum in rats results in significant changes in progesterone, testosterone and estradiol serum concentrations. Because different surgical approaches for unilateral or bilateral ovariectomy or adrenalectomy, sectioning the superior ovarian nerve or the vagus nerve are used, we compare the acute effects on hormone serum concentrations resulting from the unilateral or bilateral dorsal approach to performing bilateral ovariectomy or adrenalectomy with those obtained when an unilateral incision is performed in the ventral abdomen. In general, the progesterone, testosterone and estradiol serum concentrations were higher in animals with ventral approach than in those with dorsal surgery, the effects varying depending on the day of the estrous cycle when surgery was performed. The results suggest that the neural signals arising from different zones of the peritoneum and/or the abdominal wall play different roles in the mechanisms regulating steroid hormones concentrations.

The objective of the present study was to evaluate the quantity and quality of oocytes collected when using 2 methods for ovum pick-up and 2 different regimens for ovarian stimulation in live alpaca donors. Thirty-four non-pregnant female alpacas of 3 to 5 years of age maintained at 4100 m elevation in southern Peru were randomly distributed into 4 experimental groups. Groups 1 (n = 8) and 3 (n = 9) received an intravaginal device containing 0.78 mg of progesterone (Cue-Mate�, Bioniche Animal Health, Belleville, Ontario, Canada) plus an i.m. injection of 1 mg of estradiol benzoate on Day 0; the intravaginal device was removed on Day 7. Groups 2 (n = 7) and 4 (n = 10) received an i.m. injection of 3.1 mg of LH (Lutropin�, Bioniche Animal Health) on Day 0. Females received 700 IU of eCG (Pregnecol�, Bioniche Animal Health) i.m. on Day 7 (Groups 1 and 3) or Day 2 (Groups 2 and 4). In all groups, oocyte collection was done 2 days after the injection of eCG. Groups 1 and 2 were subjected to ventral laparotomy aspirating the oocytes from follicles >3 mm in diameter using a 10-mL hypodermic syringe containing 1 mL of aspiration media (Ringer's lactate solution plus 10% bovine serum) and connected to an 18 G � 1 inch aspiration needle. After collection, the follicular fluid was searched and the COC were graded. Groups 3 and 4 were subjected to ovum pick-up by transvaginal recovery using an ultrasound scanner (Parus 240�, Pie Medical, Maastricht, the Netherlands) equipped with a vaginal probe of 7.5 MHz (MEVA�, Pie Medical) and a 17G � 55 cm aspiration needle introduced through a needle guide. Follicles >3 mm in diameter were aspirated into 50-mL centrifuge tubes containing 5 mL of aspiration media with 75 IU mL–1 of heparin. The aspirated fluid was filtered and rinsed using an embryo filter (EmCon�, Immunosystems, Menomonie, WI), and COC were searched and graded under a microscope based on the intactness of the cumulus cell layers. Data were analyzed by ANOVA. There were no differences (P > 0.05) between groups in the mean number of follicles aspirated per donor (11.0, 13.8, 9.4, and 9.1 for Groups 1 to 4 respectively), and in the mean number of COC recovered per donor (7.6, 7.0, 6.0, and 6.1 respectively for Groups 1 to 4). The proportions of good quality COC were significantly (P < 0.01) different between surgical (81.0 and 79.5% for Groups 1 and 2) and transvaginal/ultrasound-guided (7.4% for Group 3) methods of collection; however, they were similar to the proportion in Group 4 (64.9%) retrievals. The results show that in the absence of an intravaginal device, a similar quantity and quality of alpaca oocytes can be collected when using a surgical approach or minimally invasive ultrasound-guided transvaginal follicular aspiration.

The objective of the present study was to determine the ovarian response of alpacas to different treatments for follicular development and superovulation. Twenty-nine mature, lactating alpacas, between 31 and 56 days postpartum, managed in the Peruvian highlands (altitude = 4100 m) were randomly distributed into 4 experimental groups. Groups 1 (n = 7) and 3 (n = 8) received a homemade intravaginal sponge containing 60 mg of medroxyprogesterone acetate (MAP; Sigma Chemical Co., St Louis, MO, USA) plus 2 mL of PGF2α (IM; Illiren�; Intervet International, Boxmeer, The Netherlands) on Day 0. Groups 2 (n = 7) and 4 (n = 7) received 2 mL of PGF2α (IM) on Day 0, but did not receive a MAP sponge. All groups received 6 injections (IM) of FSH (Folltropin V�; Bioniche Animal Health, Beltsville, Ontario, Canada) in decreasing dosages of 50, 50, 30, 30, 20, and 20 mg, respectively, every 12 h (at 0700 and 1900 h each day), plus 300 IU of eCG (IM; Folligon�; Intervet International) at the time of the last FSH treatment, with the aim of increasing LH levels. The FSH treatments started on Days 7, 5, 9, and 7 (from Day 0) in groups 1–4, respectively. MAP sponges were removed at the time of the last FSH treatment in groups 1 and 3. All alpacas were naturally mated twice at 12 and 24 h after the last FSH treatment. Alpacas in groups 1 and 2 received 3000 IU of hCG (IM; Corulon�; Intervet International) and alpacas of groups 3 and 4 received 2.5 mL of GnRH (IM; Conceptal�; Intervet International) immediately after the first mating. Seven days after the first mating, ovaries of all alpacas were examined by transvaginal ultrasonography. Ovarian response was estimated by determining the number of CL present on each ovary. The numbers of follicles that were at least 8 mm in diameter were also counted. Data were analyzed as a complete randomized design with 4 treatments. The average number of CL per alpaca was 1.3, 1.00, 1.00, and 0.9 for groups 1 to 4, respectively (P &gt; 0.05). The average number of follicles that were at least 8 mm in diameter per alpaca was 9.4, 20.4, 0.9, and 3.9 for groups 1 to 4, respectively (P ≤ 0.05) with females in group 2 showing the highest response. We conclude that progestin treatment did not affect ovulatory response of lactating alpacas to exogenous gonadotropins. An effective ovarian stimulation strategy for achieving superovulation in alpacas remains to be developed.

The objective of the study was to evaluate 4 superovulatory regimes in terms of the quantity of transferable embryos recovered. A total of 48 female alpacas, 3 to 5 years of age and located at Malkini Alpacas Farm (4100 m elevation), were distributed into 4 treatments. In treatment 1, 13 female alpacas received on Day 0 an intravaginal device containing 0.78 mg of progesterone (Cue Mate®, Bioniche Animal Health, Belleville, Ontario, Canada) followed immediately by an i.m injection of estradiol (1 mg of estradiol benzoate) and an i.m. injection of PGF2α (Veyx®, 0.25 mg of cloprostenol). The intravaginal device was removed on Day 7, performing at removal time an i.m. injection of estradiol. From Days 8 to 16, the alpacas received an i.m injection twice per day and 12 hours apart of pFSH (FolltropinV®, Bioniche Animal Health) in decreasing doses totaling 420 mg of pFSH; on Day 16,300 IU of eCGi.m. (Pregnecol®, Bioniche Animal Health) was injected. In treatment 2, 13 alpacas received on Day 0 an intravaginal device of progesterone followed by an i.m. injection of PGF2; from Days 5 to 9, alpacas received injections twice per day of decreasing doses of pFSH (porcine FHS) totaling 320 mg; on Day 7, the intravaginal device was removed and 500 IU i.m. of eCG was injected. In treatment 3,13 alpacas received on Day 0 an intravaginal device of progesterone followed immediately by an i.m injection of GnRH (Conceptal®, 0.0042 mg of acetate of busereline); pFSH was injected i.m. from Days 5 to 9 in decreasing doses twice per day, totaling 440 mg; the intravaginal device was removed on Day 7. In treatment 4, 9 female alpacas received on Day 0 an i.m. injection of GnRH after verifying the presence of a preovulatory follicle (>8.0 mm diameter). On Day 2, the alpacas received 1000 IU i.m. of eCG followed on Day 7 by an i.m. injection of PGF2. In all cases, the donor alpacas were evaluated by ultrasonography. The matings for treatments 1, 2, and 3 were performed twice per donor alpaca at 12-hour intervals between Days 5 and 8 of the initiation of the pFSH treatments, whereas in treatment 4 the matings were made the following day after the application of the PGF2. In treatment 1, the donor alpacas received at time of first mating an i.m injection of 3.75 mg of LH (Lutropin®, Bioniche Animal Health); in treatments 2, 3, and 4, the donors received an i.m. injection of GnRH. In all treatments, embryo collection was performed by nonsurgical method 6.5 days after first mating. There were significant differences between treatments (P < 0.05) in the mean number of CL, with treatment 4 being the highest (4.7 ± 2.63, 4.1 ± 3.05, 1.8 ± 1.8, and 6.0 ± 3.16 for treatments 1 to 4, respectively). The total number of blastocysts recovered per treatment was 7, 16, 2, and 18 for treatments 1 to 4, respectively. The superovulatory strategy followed for treatment 4 showed to be the one resulting in the highest number of transferable embryos. Further comparative evaluations between FSH and eCG treatments are recommended. Research was partially funded by the contributions of Bioniche Animal Health.