Induction of double ovulation in mares using deslorelin acetate

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Ovarian activity reversibility after the use of deslorelin acetate as a short-term contraceptive in domestic queens

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Induction of multiple ovulations in mares using low doses of GnRH agonist Deslorelin Acetate at 48 hours after luteolysis

This study was aimed to test low doses of a GnRH agonist, deslorelin acetate (DA), for induction of multiple ovulations in mares and to determine its impact upon their reproductive efficiency. Seven mares aging from 8-20 years were used in three consecutive reproductive cycles. Mares were initially monitored by ultrasound irrespectively of cycle stage, inseminated and submitted to embryo collection (EC) (T1). Immediately after, mares received 7.5 mg dinoprost tromothamine (DT) and were monitored by ultrasound twice a day until larger follicle reached 23-25mm and the second >18mm (T2). At this time point, mares received 100 mu g DA and ovulation was induced with 1000 mu g DA and 1000IU hCG when largest follicle reached 33-35mm in diameter, followed by EC. Mares were further allocated to T3 when received 7.5 mg DT after EC on 12 and 100 mu g DA 48 h later. DA treatment was performed until dominant follicle reached 34 +/- 1 mm or 6 days of application. All EC were performed 8 days after ovulation. Mares with multiple ovulations in T1, T2 and T3 were 14.28% (1/7), 100.00% (7/7) and 0.00% (0/7), respectively, and averaged 0.43 +/- 0.53 in T1, 0.86 +/- 0.38 in T2 and 0.00 in T3 embryos per donor, respectively. Embryo recovery rate was 43.00% in T1, 85.71% in T2 and 0.00% T3. In conclusion, use of DA in mares with follicles larger than 25mm enhanced dominant and co-dominant follicle growth, that ultimately increased the incidence of multiple ovulations and embryo recovery rate.

Evaluación del folículo preovulatorio y efecto del deslorelin como inductor de la ovulación en 12 yeguas silla argentina en el municipio de Facatativá, Cundinamarca

Tesis (Médico Veterinario). -- Universidad de La Salle. Facultad de Ciencias Agropecuarias. Programa de Medicina Veterinaria, 2013

Long-term treatment of familial male-limited precocious puberty (testotoxicosis) with cyproterone acetate or ketoconazole

Background Familial male-limited precocious puberty (FMPP) or testotoxicosis is a rare gonadotrophin-independent form of sexual precocity caused by constitutively activating mutations of the LH receptor. Several clinical therapeutic approaches have been reported for this disorder, but with a paucity of long-term outcome data. Objective To evaluate the long-term treatment of testotoxicosis with cyproterone acetate or ketoconazole. Design A multicentric retrospective clinical study. Patients Ten boys from eight unrelated Brazilian families who carried known LH-receptor activating mutations were treated with 70 mg/m(2) cyproterone acetate (n = 5) or 10 mg/kg ketoconazole (n = 5) for a mean period of 5 and 8 years, respectively. Measurements Chronological and bone ages, bone age/chronological age ratio, target height (TH) range, adult height, basal and GnRH-stimulated gonadotrophin levels and basal testosterone levels were assessed. Results Growth velocity decreased significantly during treatment with cyproterone acetate or ketoconazole when compared to pretreatment value in each group (P < 0.05). Bone age/chronological age ratio decreased significantly after cyproterone acetate or ketoconazole therapy. Basal testosterone levels were significantly lower in patients undergoing ketoconazole compared to cyproterone acetate treatment [0.6 +/- 0.3 nmol/l (42 +/- 21 ng/dl) vs. 5.6 +/- 4.0 nmol/l (392 +/- 280 ng/dl); P < 0.05], as expected. Secondary gonadotrophin-dependent precocious puberty occurred at a similar frequency (40%) in both groups. Five patients have attained adult height and two patients have already reached 90% of their adult height. Two of them achieved their TH range and one patient, for whom TH was not available, had an adult height of 0.3 SDS. Four boys (two in each group) did not attain their TH range. Conclusion Long-term treatment with cyproterone acetate or ketoconazole resulted in similar outcomes without important side-effects in boys with testotoxicosis. However, both therapies showed limited efficacy in attaining normal adult height.

Use of GnRH agonist implants for long-term suppression of fertility in extensively managed heifers and cows

The ability of gonadotrophin releasing hormone (GnRH) agonist implants to suppress ovarian activity and prevent pregnancies, long-term, was examined in heifers and cows maintained under extensive management. At three cattle stations, heifers (2-year-old) and older cows (3- to 16-year-old) were assigned to a control group that received no treatment, or were treated with high-dose (12 mg, Station A) or low-dose (8 mg, Station B and Station Q GnRH agonist implants. The respective numbers of control and GnRH agonist-treated animals (heifers + cows) at each station were: Station A, 20 and 99; Station B, 19 and 89; Station C, 20 and 76. Animals were maintained with 4% bulls and monitored for pregnancy at 2-monthly intervals for approximately 12 months. Pregnancy rates for control heifers and control cows ranged from 60-90% and 80-100%, respectively, depending on the study site. The respective number of animals (heifers + cows) treated with GnRH agonist that conceived, and days to first conception, were: Station A, 9 (9%) and 336 3 days; Station B, 8 (10%) and 244 +/- 13 days; Station C, 20 (26%) and 231 +/- 3 days. Treatment with high-dose GnRH agonist prevented pregnancies for longer (similar to300 days) than treatment with low-dose GnRH agonist (similar to200 days). In the majority of heifers and cows treated with GnRH agonist, ovarian follicular growth was restricted to early antral follicles (2-4 mm). The findings indicate that GnRH agonist implants have considerable potential as a practical technology to suppress ovarian activity and control reproduction in female cattle maintained in extensive rangelands environments. The technology also has broader applications in diverse cattle production systems. (C) 2002 Elsevier Science B.V. All rights reserved.

Cryopreservation and fertility of ejaculated and epididymal stallion sperm

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Embryo Transfer Efficiency of Quarter Horse Athletic Mares

This study was designed to compare embryo recovery rates and pregnancy rates of athletic and breeding Quarter Horse mares in a tropical warm climate. Thirty-nine barrel racing mares in training and 135 breeding mares as control donors were included. During the training period, the ambient temperature ranged from 31 degrees C to 36 degrees C and the average humidity from 70% to 90%. After the detection of a 35-mm follicle by ultrasound, ovulation was induced with 1 mg of deslorelin acetate (i.m), and insemination was performed 24 hours later with cooled and fresh semen from different fertile stallions. Embryos were collected on day 8 postovulation. The body temperature (rectal) was evaluated from eight athletic donor mares randomly selected from the same studied group. A total of 138 and 657 embryo collections were carried out on training and breeding mares, respectively, with a total of 105 (76%) and 466 (71%) embryos collected (P > .05). Similarly, no differences (P > .05) were observed for the pregnancy rates on day 15 (82/105, 78% vs. 370/466,79%), and day 40 (73/105, 69% vs. 328/466,70%) between the training and breeding donor mares. Just after training, the body temperature increased to an average of 39.4 degrees C and the respiratory rate from 14.5 to 35.3 breaths per minute. The results of the present study showed that embryo production from appropriately trained donor mares in good condition were similar to non-athletic broodmares. (C) 2011 Published by Elsevier B.V.

Embryo recovery and pregnancy rates after the delay of ovulation and fixed time insemination in superstimulated beef cows

The aim of this study was to evaluate the effect of delaying ovulation subsequent to superstimulation of follicular growth in beef cows (Bos indicus) on embryo recovery rates and the capacity of embryos to establish pregnancies. Ovulation was delayed by three treatments using either progesterone (CIDR-B®) or a GnRH agonist (deslorelin). Multiparous Nelore cows (n = 24) received three of four superstimulation treatments in an incomplete block design (n = 18 per group). Cows in Groups CTRL, P48 and P60 were treated with a CIDR-B device plus estradiol benzoate (EB, 4 mg, i.m.) on Day-5, while cows in Group D60 were implanted with deslorelin on Day-7. Cows were superstimulated with FSH (Folltropin-V® 200 mg), from Day 0 to 3, using twice daily injections in decreasing amounts. All cows were treated with a luteolytic dose of prostaglandin on Day 2 (08:00 h). CIDR-B devices were removed as follows: Group CTRL, Day 2 (20:00 h); Group P48, Day 4 (08:00 h); Group P60, Day 4 (20:00 h). Cows in Group CTRL were inseminated at 10, 20 and 30 h after first detected estrus. Ovulation was induced for cows in Group P48 (Day 4, 08:00 h) and Groups P60 and D60 (Day 4, 20:00 h) by injection of LH (Lutropin®, 25 mg, i.m.), and these cows were inseminated 10 and 20 h after treatment with LH. Embryos were recovered on Days 11 or 12, graded and transferred to synchronized recipients. Pregnancies were determined by ultrasonography around Day 100. Data were analyzed by mixed procedure, Kruskal-Wallis and Chi-square tests. The number of ova/embryos, transferable embryos (mean ± S.E.M.) and pregnancy rates (%) were as follows, respectively: Group CTRL (10.8 ± 1.8, 6.1 ± 1.3, 51.5), P48 (12.6 ± 1.9, 7.1 ± 1.0, 52.3), P60 (10.5 ± 1.6, 5.7 ± 1.3, 40.0) and D60 (10.3 ± 1.7, 5.0 ± 1.2, 50.0). There were no significant differences among the groups (P > 0.05). It was concluded that fixed time AI in association with induced ovulation did not influence embryo recovery. Furthermore, pregnancy rates in embryos recovered from cows with delayed ovulation were similar to those in embryos obtained from cows treated with a conventional superstimulation protocol. © 2002 Elsevier B.V. All rights reserved.

Superovulation in Cycling Mares Using Equine Follicle Stimulating Hormone (eFSH)

Superovulation would potentially increase the efficiency and decrease the cost of embryo transfer by increasing embryo collection rates. Other potential clinical applications include improving pregnancy rates from frozen semen, treatment of subfertility in stallions and mares, and induction of ovulation in transitional mares. The objective of this study was to evaluate the efficacy of purified equine follicle stimulating hormone (eFSH; Bioniche Animal Health USA, Inc., Athens, GA) in inducing superovulation in cycling mares. In the first experiment, 49 normal, cycling mares were used in a study at Colorado State University. Mares were assigned to 1 of 3 groups: group 1, controls (n = 29) and groups 2 and 3, eFSH-treated (n = 10/group). Treated mares were administered 25 mg of eFSH twice daily beginning 5 or 6 days after ovulation (group 2). Mares received 250 (of cloprostenol on the second day of eFSH treatment. Administration of eFSH continued until the majority of follicles reached a diameter of 35 mm, at which time a deslorelin implant was administered. Group 3 mares (n = 10) received 12 mg of eFSH twice daily starting on day 5 or 6. The treatment regimen was identical to that of group 2. Mares in all 3 groups were bred with semen from 1 of 4 stallions. Pregnancy status was determined at 14 to 16 days after ovulation. In experiment 2, 16 light-horse mares were used during the physiologic breeding season in Brazil. On the first cycle, mares served as controls, and on the second cycle, mares were administered 12 mg of eFSH twice daily until a majority of follicles were 35 mm in diameter, at which time human chorionic gonadotropin (hCG) was administered. Mares were inseminated on both cycles, and embryo collection attempts were performed 7 or 8 days after ovulation. Mares treated with 25 mg of eFSH developed a greater number of follicles (35 mm) and ovulated a greater number of follicles than control mares. However, the number of pregnancies obtained per mare was not different between control mares and those receiving 25 mg of eFSH twice daily. Mares treated with 12 mg of eFSH and administered either hCG or deslorelin also developed more follicles than untreated controls. Mares receiving eFSH followed by hCG ovulated a greater number of follicles than control mares, whereas the number of ovulations from mares receiving eFSH followed by deslorelin was similar to that of control mares. Pregnancy rate for mares induced to ovulate with hCG was higher than that of control mares, whereas the pregnancy rate for eFSH-treated mares induced to ovulate with deslorelin did not differ from that of the controls. Overall, 80% of mares administered eFSH had multiple ovulations compared with 10.3% of the control mares. In experiment 2, the number of large follicles was greater in the eFSH-treated cycle than the previous untreated cycle. In addition, the number of ovulations during the cycle in which mares were treated with eFSH was greater (3.6) than for the control cycle (1.0). The average number of embryos recovered per mare for the eFSH cycle (1.9 ± 0.3) was greater than the embryo recovery rate for the control cycle (0.5 ± 0.3). In summary, the highest ovulation and the highest pregnancy and embryo recovery rates were obtained after administration of 12 mg of eFSH twice daily followed by 2500 IU of hCG. Superovulation with eFSH increased pregnancy rate and embryo recovery rate and, thus, the efficiency of the embryo transfer program.

Estrus synchronization and fixed time artificial insemination (FTAI) in dairy buffaloes during seasonal anestrus

The aim of this work was to study estrus synchronization and fixed time artificial insemination (FTAI) in dairy buffaloes during season anestrus. One hundred thirty-nine dairy buffaloes in seasonal anestrus were divided in two groups as G1(n=66) and G2(n=73). The protocols for both the groups were the same until day (D)14:D0 administration of 2.0 mg estradiol benzoate and implantation of progesterone device (P4) for 14 days; D14 removal of P4 plus 150 mg of cloprostenol and 400 IU of equine chorionic gonadotropin. On D16, G1 received 10 mg of buserelin and G2 100 mg deslorelin acetate. On D17, both the groups were submitted to FTAI. Ultrasonographic examinations of ovaries were performed on D0, D14, D16 and D17. Results showed that pregnancy rates in G1 and G2 were 20 and 41% (p<0.05) and the ovulation rates were 16.6 and 37%, respectively (p<0.05). The dominant follicle (DF) diameter on D16 was 7.9 mm in G1 and 8.9 mm in G2 (p>0.05). Thirty-five percent of the animals in G1 and 54.1% in G2 showed a diameter DF greater than 8.0 mm on D16 (p>0.05). Thus, it could be concluded that the protocols synchronized the estrus, leading the concentration of the parturitions in the period of low milk production. Deslorelin was more efficient than buserelin due the higher percentage of DF ovulation and higher pregnancy rates.