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1.
A preliminary trial was performed to evaluate the ability of sustained release preparations of estradiol-17β or progesterone plus estradiol-17β to synchronize estrus in cyclic mares. Group 1 mares were treated with a 50 mg intramuscular (IM) injection of sustained release estradiol-17β, while group 2 mares were treated with estradiol plus 1.5 g of sustained release progesterone. All mares received an IM injection of 10 mg of prostaglandin-F2α (PGF2α) 10 days after steroid treatment. Mares were examined by transrectal ultrasonography on Days 1 and 10 of treatment and then at ≤2 day intervals to monitor follicle size. Once a follicle ≥30 mm diameter and uterine edema were detected, 0.5 mg of the GnRH analog histrelin was administered IM. Mares were examined daily thereafter to detect ovulation. Group 1 mares did not exhibit ovulation synchrony (ovulations occurred 12-22 days after steroid treatment), whereas ovulation synchrony was satisfactory in group 2 mares (interval to ovulation being 20.4 ± 1.5 days, range 17-22 days). Using sustained release preparations of progesterone plus estradiol-17β, with PGF2α administered on Day 10, could eliminate the need for daily injections of steroid preparations in oil when synchronizing estrus and ovulation.  相似文献   

2.
Soon after Ovuplant™, the sustained-release implant containing the gonadotropin releasing hormone (GnRH) agonist deslorelin, was approved for commercial use in the United States for induction of ovulation in mares, anecdotal field observations were reported that some Ovuplant™—treated mares that did not become pregnant experienced a delayed return to estrus and prolonged inter-ovulatory interval. Although those observations have been subsequently confirmed, further data on how mares respond to Ovuplant™ compared to human chorionic gonadotropin (hCG) during the post-treatment period is needed. The objective of this study was to further evaluate the clinical use of Ovuplant™ by comparing the reproductive performance of commercial broodmares treated with hCG or Ovuplant™. This retrospective study was completed by examining the 1999 reproductive records of 106 mares treated with hCG during 134 estrous cycles and 117 mares treated with Ovuplant™ during 151 estrous cycles. There were no differences (P > 0.10) in follicle size at the time of treatment (39.4 ± 0.5 vs. 38.9 ± 0.5 mm), interval from treatment to ovulation (2.2 ± 0.1 vs. 2.2 ± 0.1 days), proportion of mares that failed to ovulate after treatment (3.0 vs. 4.6 %), or per-cycle pregnancy rate (47.7 vs. 51.4 %) between hCG-and Ovuplant™-treated mares, respectively. The interval from ovulation to return to estrus (25.8 ± 1.3 vs. 15.5 ± 0.6 days) and the inter-ovulatory interval (30.4 ± 1.5 vs. 20.8 ± 0.6 days) were longer (P<0.001) for Ovuplant™-compared to hCG-treated mares, and the proportion of non-pregnant mares that failed to return to estrus within 30 days after ovulation (31.4 vs. 1.5 %) was higher (P<0.001) for Ovuplant™-compared to hCG-treated mares, respectively. For Ovuplant™—treated mares, follicle size at the time of treatment tended (P<0.1) to be smaller for mares that failed to return to estrus within 30 days compared to mares that returned to estrus within 30 days (37.1 ± 1.1 vs. 40.1 ± 0.6 mm, respectively). Also, the average date of ovulation during the calendar year was later (P < 0.05) for Ovuplant™—treated mares that failed to return to estrus within 30 days compared to those that returned to estrus within 30 days (May 15 ± 4 vs. April 30 ± 4 days). The results of this study confirm previous reports that although the ovulatory response and fertility were not different for hCG- and Ovuplant™—treated mares, mares treated with Ovuplant™ that did not become pregnant had a significantly delayed return to estrus and prolonged inter-ovulatory interval. Based on recently published information, it appears this effect is due to Ovuplant™—induced down-regulation of the pituitary gland, which suppresses subsequent follicular growth and development. This study also demonstrated that follicle size and/or season may influence the probability that Ovuplant™—treated mares would experience a delayed return to estrus/ovulation; therefore, further work is needed to determine whether these or other factors are related to this specific outcome following Ovuplant™—treatment.  相似文献   

3.
The use of equine FSH (eFSH) for inducing follicular development and ovulation in transitional mares was evaluated. Twenty-seven mares, from 3 to 15 years of age, were examined during the months of August and September 2004, in Brazil. Ultrasound evaluations were performed during 2 weeks before the start of the experiment to confirm transitional characteristics (no follicles larger than 25 mm and no corpus luteum [CL] present). After this period, as the mares obtained a follicle of at least 25 mm, they were assigned to one of two groups: (1) control group, untreated; (2) treated with 12.5 mg eFSH, 2 times per day, until at least half of all follicles larger than 30 mm had reached 35 mm. Follicular activity of all mares was monitored. When most of the follicles from treated mares and a single follicle from control mares acquired a preovulatory size (≥35 mm), 2,500 IU human chorionic gonadotropin (hCG) was administered IV to induce ovulation. After hCG administration, the mares were inseminated with fresh semen every other day until ovulation. Ultrasound examinations continued until detection of the last ovulation, and embryo recovery was performed 7 to 8 days after ovulation. The mares of the treated group reached the first preovulatory follicle (4.1 ± 1.0 vs 14.9 ± 10.8 days) and ovulated before untreated mares (6.6 ± 1.2 vs 18.0 ± 11.1 days; P < .05). All mares were treated with prostaglandin F2α (PGF2α), on the day of embryo flushing. Three superovulated mares did not cycle immediately after PGF2α treatment, and consequently had a longer interovulatory interval (22.4 vs 10.9 days, P < 0.05). The mean period of treatment was 4.79 ± 1.07 days and 85.71% of mares had multiple ovulations. The number of ovulations (5.6 vs 1.0) and embryos (2.0 vs 0.7) per mare were higher (P < 0.05) for treated mares than control mares. In conclusion, treatment with eFSH was effective in hastening the onset of the breeding season, inducing multiple ovulations, and increasing embryo production in transitional mares. This is the first report showing the use of FSH treatment to recover embryos from the first cycle of the year.  相似文献   

4.
Thirty reproductively sound mares were divided into treatment and control groups. In the treatment group, consisting of 14 mares, 2500 I.U. of human chorionic gonadotropin (hCG) was administered intravenously during estrus, in the presence of a 35 mm follicle over five successive cycles in 1987, and at least two cycles in 1988. Beginning with the second cycle of treatment in 1988, these mares were bred to a fertile stallion. The control group, consisting of 16 mares, was followed for two to five cycles in either the 1987 or 1988 season and six of these mares were bred to fertile stallions. Throughout the study period, blood was collected from the mares in the treatment group for analysis of anti-hCG antibodies and cross reactivity of the antibody to purified equine lutenizing hormone (eLH) and equine chorionic gonadotropin (eCG).In 1987, after the first three injections of hCG, mean duration of estrus in treated mares tended to be shorter than in control mares (P<.10). After all five hCG injections in 1987, mean ovulation time for treated mares was shorter than in control mares (P<0.01). However, after two to five hCG injections in 1987, seven treated mares (50%) had some individual ovulation times that did not differ from the control mares.Initially, following the first three injections of hCG in 1988, mean duration of estrus tended to be shorter (P<0.1) in treated mares compared to control mares. A reduction in mean ovulation time was observed after the first two hCG injections of 1988 (P<0.01). However, after one to four hCG injections in 1988, eight treated mares (57.1%) had some individual ovulation times that did not differ from controls.In 1987, all 14 treated mares developed significant levels of antibodies to hCG after one to four injections, and again in 1988, were positive for anti-hCG antibodies after one to three injections. However, no correlation was observed between magnitude of the immune response and duration of ovulation time or pregnancy rate. In cross reactivity studies, no significant binding of plasma anti-hCG antibodies to either eLH or eCG was observed in vitro.Overall, pregnancy and foaling rates of treated (85.7%) and control mares (83.3%) did not differ. Additionally, no difference was observed in number of inseminations per estrus between treated and control mares. In this study, with successive injections of hCG, the expected shortened time to ovulation was not elicited consistently in all mares. However, mares continued to ovulate, conceive and foal in the presence of significant levels of anti-hCG antibodies.  相似文献   

5.
Deslorelin acetate (Ovuplant™, Fort Dodge), a GnRH agonist, is commonly used to induce ovulation in cycling mares. Although its efficacy in hastening ovulation has been previously reported, the effects of age of mare and month of administration on percent of mares responding and interval to ovulation have not been studied.Data was gathered from reproduction records of 376 mares receiving deslorelin acetate at the Equine Reproduction Laboratory, Colorado State University, from 1995 to 1999. Age of mare, date of administration, size of largest follicle at treatment, and interval to ovulation were recorded. Age of mare was categorized into five groups: 2–4, 5–9, 10–14, 15–19, and greater than or equal to 20 years. Date of administration was divided into four groups: March and April, May and June, July and August, and September and October.A higher (p < 0.05) percentage of mares aged 10–14 (98.5%) ovulated in response to deslorelin acetate than mares aged 2–4 or 5–9 (90.2% or 91.0%, respectively) or mares aged 15–19 or ≥ 20 (87.9% or 83.8%, respectively). Mares ≥ 20 had the lowest ovulation rate (83.8%). However, mares ≥ 20 that responded to deslorelin acetate had a shorter (p < 0.05) interval from treatment to ovulation (1.7 ± 0.1 days) than mares 2–4 and 5–9 years of age (1.9 ± 0.1 and 1.9 ± 0.0 days, respectively).Deslorelin acetate was more effective in inducing ovulation in the July and August (95.4%) (p < 0.01) and September and October (95.7%) (p = 0. 04) than in the March and April (81.1%). Mares treated in May through October also experienced shorter (p < 0.05) intervals to ovulation than mares treated in March and April.  相似文献   

6.
Our aim was to compare Corpus luteum (CL) development and blood plasma concentration of progesterone ([P4]) in thoroughbred mares after spontaneous (Control: C) or human chorionic gonadotrophin (hCG)‐induced ovulation. Lactating mares (C = 12; hCG = 21) were daily teased and mated during second oestrus post‐partum. Treated mares received 2500 IU hCG i.v. at first day of behavioural oestrus when dominant follicular size was >35, ≤42 mm and mated 12–24 h after. Control mares in oestrus were mated with dominant follicular size ≥45 mm. Dominant follicle before ovulation, CL and gestational sac were measured by ultrasound and [P4] by radioimmunoassay (RIA). Blood sampling and ultrasound CL exams were done at days 1, 2, 3, 4, 8, 12, 16, 20, 25, 30, 35, 40, 45, 60 and 90 after ovulation and gestational sac from day 12 after ovulation in pregnant (P) mares; non‐pregnant (NP) were followed until oestrus returned. Data analyses considered four subgroups: hCG‐P, hCG‐NP, C‐P and C‐NP. Preovulatory follicular size was smaller in hCG mares than in C: 39.2 ± 2.7 mm vs 51.0 ± 1.8 mm (p < 0.0001). All hCG mares ovulated 24–48 h after treatment and presented similar oestrus duration as controls. C. luteum size in P mares showed the same pattern of development through days 4–35, presenting erratic differences during initial establishment. Thus, on days 1 and 3, CL was smaller in hCG‐P (p < 0.05); while in hCG‐NP, CL size was greater than in C‐NP on day three (p = 0.03). Corpus luteum size remained stable until day 90 in hCG‐P mares, while in C‐P a transient and apparently not functional increase was detected on days 40 and 45 (p < 0.05) and the decrease from day 60 onwards, made this difference to disappear. No differences were observed in [P4] pattern between P, or between NP subgroups, respectively. So, hCG‐induced ovulation does not affect CL development, neither [P4] during early pregnancy. One cycle pregnancy rate tended to be lower in hCG mares while season pregnancy rates were similar to controls.  相似文献   

7.
Synchronization of estrus (SE) in mares has been achieved, but not of ovulation (SO). Progestins followed by PGF2a are useful for SE only. In the two studies reviewed here, SE and SO were attempted by using CIDR-B, an intravaginal (itv) progesterone (1.9 g) releasing device, alone (study 1) or accompanied by estradiol (10 mg) given also itv (study 2). In both studies, Ovuplant™ (OT), an implant containing 2.1 mg of the GnRH analog deslorelin was used for the control of ovulation. Eighty cycling Hanoverian mares, 40 each in studies 1 and 2, received CIDR-B itv for 12 days, with PGF2a given once at CIDR-B removal. In study 1, 15 mares each received OT when the lead follicle had reached 40 mm (A) or on Day 3 of estrus (B); 10 controls received no OT (C). In study 2, E2 was used in addition on Day 0 (CIDR-B insertion) (10 mares; group II), or on Days 0 and 7 (10; group III) or not (20; groups I and IV). Mares in groups I to III received OT as in study 1 (A); group IV (10) remained untreated. Ovaries were examined and blood samples were taken in studies 1 and 2 from all mares in 1, 2 or 4-day intervals, respectively, and concentrations of FSH, LH, progesterone and estradiol were determined by RIA. In study 1, CIDR-B treatment achieved SE, but not SO as shown by a wide spread of days on which follicles were reaching 40 mm; OT treatment assured ovulations in 48 hours in 93.3% of treated mares vs. 44.4% in controls (P<0.05. In study 2, SE was achieved and SO, but only when estradiol was given once (itv) on Day 0 (group II) but not twice on Days 0 and 7 (group III). In both studies, CIDR-B prevented estrus but stimulated follicle growth: 8 mares in study 1 ovulated with CIDR-Bs in place and 2 in trial 2, respectively. Only when estradiol was used together with CIDR-B, follicle growth was retarded (group II) or suppressed (group III: P<0.05 vs. groups I and IV). The pregnancy rate in study 2 from a single breeding at the first estrus was 52.8% with no significant differences between groups. FSH rose until Day 4 or 8 and had dropped sharply at Day 12; after CIDR-B removal FSH rose most quickly in group II, study 2. LH declined slightly until Day 12 and rose thereafter, reaching peak levels by Day 18 or 20, respectively. In both studies, estradiol had dropped slightly by Day 4 but increase steadily thereafter until ovulation had occurred. Preovulatory rise and postovulatory drop was seen earlier in group II, study 2. Values for progesterone had risen uniformly by Day 4, had declined slowly by Day 12 and precipitously in response to PGF2a by Day 14. Treatment of cyclic mares with CIDR-B for 12 days, followed by PGF2a at the day of CIDR-B removal and by Ovuplant™ a deslorelin implant when a follicle had reached 40 mm, resulted in synchronization of estrus. Adding to this scheme a single dose of estradiol (10 mg, intravaginal) on Day 0 resulted also in synchronization of ovulation.  相似文献   

8.
Thirty-one mares were used in an experiment to evaluate the effectiveness of three sustained-release injectable formulations of altrenogest and one formulation of medroxyprogesterone acetate (MPA) for long-term suppression of estrus and ovulation. Luteolysis was induced by injection of prostaglandin-F2α (Lutalyse) on day 0 (6th day after the previous ovulation) and was immediately followed by treatment with 1) no injection (controls; n = 7), 2) 1.5 mL of an altrenogest solution in sustained-release vehicle (LA 150, 1.5 mL; 225 mg altrenogest; n = 6), 3) 3 mL (450 mg altrenogest) of the same solution (n = 6), 4) 500 mg altrenogest in lactide-glycolide microparticles suspended in 7-mL vehicle (MP 500; n = 6), or 5) 1.0 g MPA as a 5-mL suspension. Mares were checked for estrus daily, and their ovaries scanned every other day until a 25-mm or greater follicle was detected, after which they were scanned daily. Control mares returned to estrus an average of 3.9 days after Lutalyse administration; all the single-injection altrenogest formulations increased (P < .05) the days to return to estrus, with the greatest increase occurring in mares receiving MP 500. Return to estrus was not affected by MPA treatment. Time of ovulation was determined by serial ultrasound scans and confirmed by daily plasma luteinizing hormone (LH) and progesterone concentrations. Control mares ovulated an average of 8.8 days after Lutalyse administration. Treatment with 1.5 or 3 mL of LA 150 increased (P < .05) the mean days to ovulation to 16.5 and 21.2 days, respectively; MP 500 increased (P < .05) the days to ovulation to 33.5 days. Administration of MPA did not affect (P > .1) days to ovulation relative to control mares. The MP 500 treatment provided long-term suppression of estrus and ovulation and could prove useful for that purpose. Treatment with the LA 150 solutions provided shorter-term suppression, and a relatively tight grouping of the individual mares around the mean days to ovulation; these one-shot formulations could be useful for synchronizing ovulation in cyclic mares and inducing normal estrous cyclicity in vernal transitional mares exhibiting erratic, anovulatory estrous periods.  相似文献   

9.
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.

Introduction

Induction of multiple ovulations or superovulation has been an elusive goal in the mare. Superovulation would potentially increase the efficiency and decrease the cost of embryo transfer by increasing embryo collection rates.[1 and 2] Superovulation also has been suggested as a critical requirement for other types of assisted reproductive technology in the horse, including oocyte transfer and gamete intrafallopian transfer. [2 and 3] Unfortunately, techniques used successfully to superovulate ruminants, such as administration of porcine follicle stimulating hormone and equine chorionic gonadotropin have little effect in the mare. [4 and 5]The most consistent therapy used to induce multiple ovulations in mares has been administration of purified equine pituitary gonadotropins. Equine pituitary extract (EPE) is a purified gonadotropin preparation containing approximately 6% to 10% LH and 2% to 4% FSH.[6] EPE has been used for many years to induce multiple ovulations in mares [7, 8 and 9] and increase the embryo recovery rate from embryo transfer donor mares. [10] Recently, a highly purified equine FSH product has become available commercially.The objectives of this study were to evaluate the efficacy of purified eFSH in inducing superovulation in cycling mares and to determine the relationship between ovulation rate and pregnancy rate or embryo collection rate in superovulated mares.

Materials and methods

Experiment 1

Forty-nine normally cycling mares, ranging in age from 3 to 12 years, were used in a study at Colorado State University. Group 1 (control) mares (n = 29) were examined daily when in estrus by transrectal ultrasonography. Mares were administered an implant containing 2.1 mg deslorelin (Ovuplant, Ft. Dodge Animal Health, Ft. Dodge, IA) subcutaneously in the vulva when a follicle 35 mm in diameter was detected. Mares were bred with frozen semen (800 million spermatozoa; minimum of 30% progressive motility) from 1 of 4 stallions 33 and 48 hours after deslorelin administration. The deslorelin implants were removed after detection of ovulation.[11] Pregnancy status was determined at 14 and 16 days after ovulation.Group 2 mares (n = 10) were administered 25 mg of eFSH (Bioniche Animal Health USA, Inc., Athens, GA) intramuscularly twice daily beginning 5 or 6 days after ovulation was detected. Mares received 250 g cloprostenol (Estrumate, Schering-Plough Animal Health, Omaha, NE) intramuscularly on the second day of eFSH treatment. Administration of eFSH continued until a majority of follicles reached a diameter of 35 mm, at which time a deslorelin implant was administered. Mares were subsequently bred with the same frozen semen used for control mares, and pregnancy examinations were performed as described above.Group 3 mares (n = 10) received 12 mg of eFSH twice daily starting 5 or 6 days after ovulation and were administered 250 μg cloprostenol on the second day of treatment. Mares were randomly selected to receive either a deslorelin implant (n = 5) or 2500 IU of human chorionic gonadotropin (hCG) intravenously (n = 5) to induce ovulation when a majority of follicles reached a diameter of 35 mm. Mares were bred with frozen semen and examined for pregnancy as described above.

Experiment 2

Sixteen cycling light-horse mares were used during the physiologic breeding season in Brazil. Reproductive activity was monitored by transrectal palpation and ultrasonography every 3 days during diestrus and daily during estrus. On the first cycle, mares were administered 2500 IU hCG intravenously once a follicle 35 mm was detected. Mares were subsequently inseminated with pooled fresh semen from 2 stallions (1 billion motile sperm) daily until ovulation was detected. An embryo collection procedure was performed 7 days after ovulation. Mares were subsequently administered cloprostenol, and eFSH treatment was initiated. Mares received 12 mg eFSH twice daily until a majority of follicles were 35 mm in diameter, at which time hCG was administered. Mares were inseminated and embryo collection attempts were performed as described previously.

Statistical analysis

In experiment 1, 1-way analysis of variance with F protected LSD was used to analyze quantitative data. Pregnancies per ovulation were analyzed by x2 analysis. In experiment 2, number of large follicles, ovulation rate, and embryo recovery rate were compared by Student,'s t-test. Data are presented as the mean S.E.M. Differences were considered to be statistically significant at p < .05, unless otherwise indicated.

Results

In experiment 1, mares treated with 25 mg eFSH twice daily developed a greater number of follicles 35 mm in diameter (p = .001) and ovulated a greater number of follicles (p = .003) than control mares (Table 1). However, the number of pregnancies obtained per mare was not significantly different between the control group and the group receiving 25 mg eFSH (p = .9518). Mares treated with 12 mg eFSH and administered either hCG or deslorelin to induce ovulation also developed more follicles 35 mm (p = .0016 and .0003, respectively) than untreated controls. Mares receiving eFSH followed by hCG ovulated a greater number of follicles (p = .003) than control mares, whereas the number of ovulations for mares receiving eFSH followed by deslorelin was similar to that of control mares (p = .3463). Pregnancy rate for mares induced to ovulate with hCG was higher (p = .0119) than that of control mares, whereas the pregnancy rate for eFSH-treated mares induced to ovulate with deslorelin did not differ from that of controls (p = .692). Pregnancy rate per ovulation was not significantly different between control mares (54.5%) and mares treated with eFSH followed by hCG (52.9%). The lowest pregnancy rate per ovulation was for mares stimulated with 25 mg eFSH and induced to ovulate with deslorelin. The mean number of days mares were treated with 25 mg or 12 mg of eFSH was 7.8 ± 0.4 and 7.5 ± 0.5 days, respectively. Overall, 80.0% of mares administered eFSH had multiple ovulations compared with 10.3% of control mares.  相似文献   

10.
The objective of this study was to evaluate various equine follicle-stimulating hormone (eFSH) treatment protocols and the effect of “follicle coasting” on ovulation and embryo recovery rates in mares. Cycling mares (n = 40) were randomly assigned to one of four groups 7 days after ovulation: (1) 12.5 mg eFSH twice daily until follicles were 35 mm or larger; (2) 12.5 mg eFSH twice daily until follicles were 32 mm or larger; (3) 12.5 mg eFSH twice daily for 3.5 days followed by 12.5 mg eFSH enriched with luteinizing hormone (LH) twice daily until follicles were 35 mm or larger; and (4) 25 mg eFSH once daily until follicles were 32 mm or larger. Mares in groups 1 and 3 were injected with human chorionic gonadotropin (hCG) (2500 IU intravenously) at the end of eFSH treatment, whereas mares in groups 2 and 4 were given hCG approximately 42 and 54 hours, respectively, after the last eFSH treatment (“follicle coasting”). Nonsurgical embryo collection was performed 6.5 to 7.5 days after ovulation. Each mare experienced a nontreated estrous cycle before being reassigned to a second treatment. Ovulation rates for mares in treatment groups 1 to 4 were 3.3 ± 0.4, 4.1 ± 0.4, 3.5 ± 0.4, and 2.8 ± 0.4 (mean ± SEM; P < .05), respectively. One or more embryos were recovered from more than 80% of mares in each treatment group, and embryo recovery rate per flush was similar among treatment groups (1.9 ± 0.3, 2.6 ± 0.3, 1.9 ± 0.3 and 1.9 ± 0.3, respectively; P > .05). The overall embryo recovery rate was 2.1 ± 1.5 embryos per flush. In summary, ovulation rate was higher for mares treated with eFSH (3.4 ± 0.4) compared with non-treated controls (1.1 ± 0.2). Ovulation rate in mares in which hCG was delayed (follicle coasting) was higher (P < .05) when treatments were given twice per day versus once per day. Administration of equine luteinizing hormone (eLH) in conjunction with eFSH did not have an advantage over mares treated only with eFSH.  相似文献   

11.
Breeding records of 48 Thoroughbred and Standardbred mares treated with native GnRH (500μg im, bid) during February—April, 1999 or 2000, on 7 farms in central Kentucky were retrospectively examined. Treated mares were classified as being in anestrus or early transition (n=42; if no signs of estrus occurred within 31/2 weeks and the largest follicle remained ≤25 mm in diameter or the first larger follicle(s) of the season regressed without ovulating), or were classified as being in late transition (n=6; if follicular growth achieved 30-40 mm diameter but ovulation had not yet occurred during the breeding season). Thirty-eight mares (38/48; 79%) ovulated in 13.7 ± 7.4 days. Interval to ovulation was negatively associated with size of follicles at onset of native GnRH therapy (P < 0.01). Per cycle pregnancy rate was 53% (19/36 mares bred). Ovulation inducing drugs were administered to 32 of the native GnRH treated mares (2500 units hCG intravenously, n = 20; deslorelin implant [Ovuplant™] subcutaneously, n=12), while 6 mares were not administered any additional drugs to induce ovulation. Per cycle pregnancy rate did not differ among mares treated only with native GnRH (2/5 mares bred; 40% PR), mares treated with native GnRH plus hCG (12/19 mares bred; 63% PR), or mares treated with native GnRH plus Ovuplant™ (5/12 mares bred; 42% PR) (P > 0.10). Additional treatment with either hCG or Ovuplant™ did not alter mean follicle size at ovulation or interovulatory interval (P > 0.10). The proportion of interovulatory intervals > 25 days was not different between mares receiving no additional treatment to induce ovulation (0/4; 0%) compared to mares receiving hCG to induce ovulation (3/8; 38%) (P > 0.10), but the proportion of interovulatory intervals > 25 days was greater for mares receiving Ovuplant™ to induce ovulation (5/7; 71%) compared to mares receiving no additional treatment to induce ovulation (P < 0.05). The proportion of mares with extended interovulatory intervals (i.e., > 25 days) did not differ between mares with follicles < 15 mm diameter (4/8, 50%) and those with follicles > 15 mm diameter (3/11, 27%) at onset of native GnRH treatment (P > 0.10). While concurrent untreated controls were not used in this study, the 79% response rate to twice daily administration of native GnRH is in agreement with other reports using pulsatile or constant infusion as methods of administration, confirming therapy can hasten follicular development and first ovulation of the breeding season. As with previous reports, follicle size at onset of treatment is an important determinant of interval from onset of native GnRH therapy to ovulation. Use of hCG or Ovuplant™ did not enhance ovulatory response in native GnRH treated mares. Use of Ovuplant™ during native GnRH therapy may increase the incidence of post-treatment anestrus in mares not becoming pregnant.  相似文献   

12.
We studied the effects of gonadotrophins and prostaglandin (PG) F2α on ovulation in gilts. Twenty-eight gilts were induced to ovulate using 750 IU pregnant mares serum gonadotrophin (PMSG) and 500 IU human chorionic gonadotrophin (hCG), administered 72 h apart. At 34 and 36 h after hCG, gilts received injections of either 500 μg or 175 μg PGF2α (cloprostenol), or had no injections. Laparotomies were performed at 36 h (cloprostenol gilts) or 38 h (controls) after hCG injection. The ovaries were examined and the proportion of preovulatory follicles that had ovulated (ovulation percent) was determined at 30 min intervals for up to 6 h. The number of gilts in which ovulation was initiated and the ovulation percent increased (p<0.001) with time, but was not affected by treatment. Many medium sized follicles (≤6 mm) were also observed to ovulate, or to exhibit progressive luteinization without overt ovulation, during the surgical period. A discrepancy between numbers of preovulatory follicles and corpora lutea suggests that luteal counts may not be an accurate assessment of ovulation rate following gonadotrophic stimulation.  相似文献   

13.
The aim of this study was to assess the efficacy of different doses of buserelin acetate and another GnRH agonist, triptorelin acetate, in saline solution in a single subcutaneous injection, to induce ovulation of growing pre-ovulatory follicle in mare and compare it with the classical treatment of a single injection of hCG. The study is split into 3 experiments over different breeding seasons in the same stud with a random distribution of treatment. The first one was to compare the injection of 6 mg of buserelin with 1,500 IU of hCG; the second one consisted of comparing different doses of buserelin (6 mg and 3 mg); and the third one compared three different doses of buserelin (3, 2 and 1 mg), 0.1 mg of triptorelin with 1,500 IU of hCG as a control group. The results of all experiments showed the same efficacy between all treatments with mares ovulating between 24 and 48 hr after injection: experiment 1: hCG (78% n = 41) and buserelin 6 mg (90% n = 50); experiment 2: buserelin 6 mg (78,1% n = 192) and buserelin 3 mg (78% n = 341); and experiment 3: hCG (87% n = 106), buserelin 3 mg (84,7% n = 137), buserelin 2 mg (82,7% n = 104), buserelin 1 mg (87% n = 54) and triptorelin 0.1 mg (84,7% n = 72). In conclusion, this study contributes to erasing the dogma that has been established since 1975 that a single injection in solution without any long-acting excipient of a GnRH agonist cannot induce ovulation in the mare. This study also shows that a injection of 0.1 mg of triptorelin in solution is a good alternative for ovulation induction and is comparable to small doses of buserelin acetate in solution (1 mg) and 1,500 IU of the gold standard trigger hCG, mainly in countries where human formulation of buserelin is not available.  相似文献   

14.
Natural GnRH and its analog have potential for hastening ovulation in mares. A study was conducted to evaluate the efficacy of a GnRH agonist given either as an injectable or s.c. implant for induction of ovulation in mares. Forty-five seasonally anestrous mares (March) were assigned to one of three groups (n = 15/group): 1) untreated controls; 2) i.m. injection of the GnRH agonist buserelin at 12-h intervals (40 micrograms/injection for 28 d or until ovulation) and 3) GnRH agonist administered as a s.c. implant (approximately 100 micrograms/24 h for 28 d). Six mares per group were bled on d 0, 7, 14 and 21 after injection or insertion of implant. Samples were taken at -1, -.5 and 0 h and at .5, 1, 1.5, 2, 4, 6 and 8 h after GnRH. Additional daily samples were drawn for 28 d after injection or until ovulation. Samples were assayed for concentration of LH and FSH. Progesterone concentrations were determined in samples collected on d 4, 6 and 10 after ovulation. Number and size of follicles and detection of ovulation were determined by ultrasonography. Number of mares induced to ovulate within 30 d was 0 of 15, 7 of 15 and 9 of 15 for groups 1, 2 and 3, respectively. During treatment, follicle sizes were smaller for mares in group 3 (implant). The LH response to GnRH agonist (area under curve) was similar among groups at d 0 but was greater (P less than .05) for mares in group 3 on d 7 and 14 and groups 2 and 3 on d 21 than for controls. A similar pattern was detected for peak concentrations of LH after GnRH on d 0, 7, 14 and 21. Daily concentrations of LH remained low in untreated control mares compared with GnRH-treated mares throughout the sampling period. Concentrations of LH for mares in group 3 that ovulated were elevated greatly above those for group 2 mares, whereas concentrations of FSH were similar in both treatment groups prior to ovulation.  相似文献   

15.
Strategies for Using eFSH for Superovulating Mares   总被引：1，自引：0，他引：1  
The standard treatment for superovulation of mares is to administer equine follicle-stimulating hormone (eFSH) for 4 to 5 days to stimulate multiple follicles and human chorionic gonadotropin (hCG) to induce synchronous ovulations. Objectives of this study were: (1) to determine whether a short-term (3-day) eFSH treatment protocol would result in similar ovulation and embryo recovery rates compared with the standard eFSH protocol; (2) to determine the efficacy of a decreasing dose of eFSH (step-down protocol) on ovulation rate and embryo recovery; (3) to compare the efficacy of hCG and recombinant equine luteinizing hormone (reLH) for inducing ovulation in FSH-treated mares; and (4) to compare embryo recovery rates and embryo size when mares are flushed at 6.5 or 7.0 days after ovulation. Forty light-horse mares were used in 2005 (experiment 1) and 20 different mares were used in 2006 (experiment 2). In experiment 1, mares were randomly assigned to one of three treatment groups: (1) untreated controls, (2) standard eFSH treatment (12.5 mg intramuscularly twice daily), and (3) 3-day eFSH treatment. In experiment 2, mares were randomly assigned to one of four treatments: (1) untreated controls, (2) standard eFSH protocol, (3) 3-day eFSH treatment, and (4) step-down eFSH treatment (12.5 mg twice daily day 1, 8.0 mg twice daily day 2, 4.0 mg twice daily day 3). Within each treatment, mares were given either hCG (2,500 IU) or equine LH (750 mg, EquiPure LH; reLH) to induce synchronized ovulations. Embryo recovery was performed either 6.5 or 7.0 days after ovulation. In experiment 1, numbers of preovulatory follicles and ovulations were less for mares in the 3-day treatment group than the standard group, but were greater than for controls. Embryo recovery per flush was higher in the standard group (2.6) than the 3-day eFSH treatment (0.8) or control groups (0.8). In experiment 2, the number of preovulatory follicles and number of ovulations were greater in the standard and 3-day treatment groups than in control and step-down groups. The percent embryo recovery per ovulation and mean embryo grade were similar for all groups; however, the embryo recovery per flush was higher for mares in the standard treatment than controls (1.3 vs 0.6) but was similar to the 3-day (1.1) and step-down (0.8) treatments. Embryo recovery was similar for flushes performed on days 6.5 and 7.0 post-ovulation. The percentage of control mares ovulating within 48 hours in response to hCG or reLH was similar. In contrast, a higher percentage of eFSH-treated mares ovulated within 48 hours in response to reLH than hCG (92% vs 71%). In both years, the 3-day eFSH treatment protocol resulted in a greater number of preovulatory follicles and a greater number of ovulations than untreated controls. Unfortunately, the increased ovulation rate for mares administered eFSH for 3 days did not result in a greater number of embryos recovered per flush in either year. Use of a step-down eFSH treatment protocol resulted in fewer preovulatory follicles, fewer ovulations, and fewer embryos as compared with the standard eFSH treatment. In conclusion, the standard eFSH treatment resulted in a greater embryo recovery rate per cycle than either the 3-day or step-down treatment protocols. Recombinant equine LH was more effective than hCG in causing ovulation in eFSH-treated mares.  相似文献   

16.
The aim of this study was to predict the ovulation in mares by quantitative analysis of the echotextural changes of preovulatory follicular walls. Four mares of breeding age with 32 preovulatory follicles and 11 anovulatory follicles were observed by ultrasonography. The slope of the regression line of the follicular wall and the echogenicity score of granulosa layer (GL) and anechoic layer (AL) were measured from the images on Days -3 (Day 0 = ovulation), -2, and -1, respectively. GL was scored from 1 (anechoic) to 3 (echoic), and prominence of AL was recorded from 1 (gray and thin) to 3 (black and thick). The results indicated that the regression line of the follicular wall for 81.3% (26/32) of preovulatory follicles had the slope value ≥19.0 on Day -1, in which 4 of the 26 preovulatory follicles were ≥19.0 on Day -2 already. Mean slope value on Day -1 (21.9 ± 1.5) was significantly greater (P < .01) than on Day -2 (15.0 ± 1.4) and Day -3 (14.0 ± 1.1). All of the slope values for the 11 anovulatory follicles were <19.0 on any given day. GL and AL scores of preovulatory follicles were significantly greater (P < .01) than in anovulatory follicles on Days -3, -2 and -1; nevertheless, only 28.1% (9/32) of preovulatory follicles scored 3 for both GL and AL simultaneously on Day -1. All anovulatory follicles scored <2 for both GL and AL on Day -1. It was concluded that the slope of the regression line of the follicular wall is useful in predicting preovulatory follicles within 48 hours of ovulation when the value is ≥19.0. Of these follicles (N = 26), 84.6% (22/26) were predicted to ovulate within 24 hours, and 15.4% (4/26) within 24 to 48 hours.

Introduction

Insemination in mares by accurately predicting the time of ovulation may obtain maximum fertility with minimum use of semen, and therefore would definitely be a profitable advantage in the horse farming business. The optimal time for insemination with frozen-thawed semen usually include a shorter interval than if fresh semen or natural breeding is used. To achieve the maximal pregnancy rates with frozen-thawed semen, it is necessary to inseminate mares during a period between 12 hours pre- and 6 hours post-ovulation.[1] Therefore, if the timing of ovulation could be predicted, it would be helpful for the veterinarian to inseminate a mare only once per cycle if performed very close to the time of ovulation. [2] In recent years, many indicators have been reported for predicting impending ovulation in mares, including measurement of electrical resistance of the vaginal mucus, [3] the distinguishable endometrial folding pattern of uterus in estrus, [4] changes in size and shape of the preovulatory follicles, [5, 6 and 7] and the echotexture changes in the preovulatory follicular wall. [8] The latter has been more efficient for predicting the imminence of ovulation; nevertheless, their assessment of criterions was scored subjectively. The hypothesis for this study was based on the published report from Gastal et al in 1998 [8]; they found that 2 echotexture changes of the preovulatory follicle-increasing echogenicity of the granulosa layer and increasing prominence of an anechoic layer beneath the granulosa, were detected in the follicular wall as ovulation approached in mares. Computer-assisted image analysis is an advanced technology for diagnostic ultrasonography to improve the reproductive management of patients. [9, 10 and 11] The purpose of this study is to quantify the echotextural changes in the preovulatory follicular wall as ovulation approaches using computer-assisted image analysis, so that the quantified echotexture changes could serve as an indicator for prediction of ovulation in mares.

Materials and Methods

Animals and Ultrasonography

Four non-lactating and nonpregnant mixed mares between 4 and 14 years of age and weighing between 450 and 550 kg were studied from January to December 2001. The geographic area of the mares in this study was in subtropical Taiwan of the northern hemisphere. All mares were maintained on alfalfa/grass hay and had access to water and mineralized salt. A teaser stallion was introduced to detect the estrus signs of mares about 2 weeks after the end of the last estrus. Follicular changes were monitored with a real-time B-mode linear assay ultrasound scanner, equipped with a 7.5-MHz transrectal probe (Model Scanner 200 Vet, Pie Medical, The Netherlands). Upon detection of a preovulatory follicle, ultrasound examination was performed daily and continued until ovulation. A total of 32 preovulatory follicles and 11 anovulatory follicles were identified from a retrospective determination.Ultrasonographic images were recorded on Hi-8 MP videotape with a Sony DCR-TRV 120 Digital-8 camera. The brightness and contrast controls of the monitor and the time-gain compensation of the scanner were standardized to constant settings throughout the observation period.

Image Analysis

Still images were subsequently captured and saved as TIF files by computer using a digital image analysis program (Image-Pro Express V4.0 for Windows, Media Cybernetics, L.P., USA) with a resolution of 640 × 480 pixels and 256 shades of gray. Echotexture of the regions of interest was defined in terms of pixel intensity ranging from 0 (black) to 255 (white). Three ultrasonographic images of each preovulatory follicle at its distinctly discernible cross section were subsequently selected. To avoid the enhancement of through-transmission, sampling regions were located within the 10 or 2 o'clock position for measurement of pixel values (Fig 1). The pixel values were measured with the “Line Profile” tool, which involved sampling pixel values along a line traversing the follicle wall from the peripheral antrum, GL, AL, to the stroma. A graph of the pixel intensities along the line was produced ( Fig 2). The GL was defined as the highest pixel after which there was a sequential fall in gray-scale values. The pixel values along the curve (P0, P1, P2) were obtained as an average of 9 measurements (3 images per follicle and 3 lines per image) and were used to measure the slope of a regression line of the fall segment ( Fig 2).  相似文献   

17.
The objective of this study was to compare the rate of ovulation when deslorelin and/or human chorionic gonadotropin (hCG) was administered in mares in both the transition period and the ovulatory season. A total of 200 Paint Horses, Quarter Horses, and crossbred mares were used during the transition season (July to September) and the ovulatory season (October to February) of the southern hemisphere. The animals were divided into four groups. In the control group (n = 72), mares received 1 mL of saline; in deslorelin group (n = 171), 1.5 mg of deslorelin was administered by intramuscular (IM) injection; in hCG group (n = 57), 1,667 IU of hCG was administered IV; and in hCG + deslorelin group (n = 438), 1.5 mg of deslorelin (IM) and 1,667 IU of hCG (IV) were administered. The drugs were administered after follicles ≥35 mm in diameter were identified and grade III uterine edema was observed. At 48 hours after application, ultrasonography was performed to detect ovulation. During the transition period, the ovulation rates were 4.3% (control), 78.6% (deslorelin), 50% (hCG), and 73.3% (hCG + deslorelin). During ovulatory season, the ovulation rates were 16.4% (control), 68.8% (deslorelin), 60% (hCG), and 73% (hCG + deslorelin). There was no significant difference (P > .05) in the ovulation rate between the groups or the periods, except that the control group was lower than all others. Furthermore, both hCG and deslorelin are viable options for inducing ovulation during the transition period before ovulation season.  相似文献   

18.
A total of 88 thoroughbred mares were diagnosed with clinical ovarian quiescence and subjected to four treatment regimens. Using PMSG, hCG or combinations of both. A high dose combination of 5,000IU PMSG with 5,000IU hCG showed significantly higher rates of marked estrus and ovulation induction (P<0.01) as well as conception rates (P<0.05). In the present study, the administration of a high-dose combination of PMSG with hCG was shown to be an effective treatment of ovarian quiescence in light mares.  相似文献   

19.
In its first year of commercial availability in the United States, reports from the field indicated that Ovuplant™ (a deslorelin-containing slow-release implant for hastening ovulation in mares) was associated with a delayed return to estrus in mares not becoming pregnant. Supposedly this effect was particularly prevalent in mares subsequently administered PGF2α to cause luteal regression after embryo collection. The present experiment was conducted 1) to determine if the field observations were repeatable under controlled experimental conditions, and 2) to gather endocrine data that might yield information on the underlying cause(s) of this observation. Twenty-five light horse mares were used. Ovaries of each mare were examined by transrectal ultrasonography daily during estrus until ovulation. Once a follicle >30 mm was detected, the mare received either Ovuplant (treated group; N = 13) at the recommended dosage or a sham injection (controls; N = 12); treatments were administered in a manner to ensure that they were unknown to personnel involved with data collection. On day 7 after ovulation, each mare received a luteolytic injection of PGF2ð. Mares were examined every other day until return to estrus or development of a 30 mm follicle, at which time daily examination was performed until ovulation. Jugular blood samples were collected daily. Two mares receiving Ovuplant did not return to estrus within 30 days and their data were not included in the statistical analyses; in contrast, no control mare exhibited such an extended interovulatory interval. For all other mares receiving Ovuplant, the interval between the first and second ovulations was longer (P = .0001) than that of control mares by an average of 6.2 days. In addition, plasma LH concentrations were lower (P <.05) in the treated mares on days 0 through 4, 9, 11, 18, and 19 after the first ovulation. Plasma FSH concentrations were also lower (P = .017) in treated mares from days 4 to 11 and on days 6 and 5 prior to the second ovulation (P = .005). Differences in progesterone and estradiol were observed but were less consistent than for LH and FSH. Mares receiving Ovuplant had fewer small (P =.026), medium (P = .003) and large (P = .045) follicles prior to the second ovulation. In conclusion, Ovuplant treatment at the recommended dosage decreased follicular activity after ovulation and increased the interovulatory interval in mares short-cycled with PGF2ð. These effects appear to be mediated by a hyposecretion of LH and(or) FSH.  相似文献   

20.
The timing of ovulation is an important component to many equine breeding strategies. The action of luteinizing hormone on ovulation induction has been recognized; however, potential effects of follicle-stimulating hormone (FSH) have been less defined. Objectives of this study were to determine whether (1) mares could be induced to ovulate follicles ≤30 mm; (2) equine FSH (eFSH) has a positive effect on ovulation induction, and (3) ovulation of small follicles would affect embryo recovery. Light-horse mares (n = 12) between 4 and 10 years of age were assigned to treatments when they had a dominant growing follicle with a mean diameter of 24, 28, or 35 ± 2 mm and endometrial edema. Treatments were (1) H35, human chorionic gonadotropin (hCG) at 35 ± 2 mm; (2) F35, eFSH at 35 ± 2 mm; (3) H28, hCG at 28 ± 2 mm; (4) FH28, eFSH and hCG at 28 ± 2 mm; (5) D28, deslorelin (gonadotropin-releasing hormone [GnRH] analog) at 28 ± 2 mm; (6) FH24/H24, hCG or eFSH and hCG at 24 ± 2 mm. Mares’ reproductive tracts were scanned at 24 ± 2-hour intervals after treatment to detect ovulation. Mares were inseminated, and embryos were collected. Numbers of mares that ovulated within 48 ± 2 hours after treatment were: H35, 8/8 (100%); F35, 8/14 (57%); H28, 7/12 (58%); FH28, 9/12 (75%); D28, 3/7 (43%) and FH/H24, 4/14 (29%). The number of mares that ovulated in 48 ± 2 hours for H35 was not different from that for FH28 but was higher (P < .05) than all other groups. Embryo recovery rates, diameters, developmental stages, and morphology scores were not different for mares ovulating 48 hours or less versus more than 48 hours after treatment or among treatment groups. Results of this study demonstrate that follicles ≤30 mm can be induced to ovulate with no effect on embryo recovery or quality, as assessed by stereomicroscopy.  相似文献   

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