Decreased pulsatile LH secretion in heifers superovulated with eCG or FSH

This study was designed to test the hypothesis that treatment with super-ovulatory drugs suppresses endogenous pulsatile LH secretion. Heifers (n=5/group) were superovulated with eCG (2500 IU) or FSH (equivalent to 400 mg NIH-FSH-P1), starting on Day 10 of the estrous cycle, and were injected with prostaglandin F(2alpha) on Day 12 to induce luteolysis. Control cows were injected only with prostaglandin. Frequent blood samples were taken during luteolysis (6 to 14 h after PG administration) for assay of plasma LH, estradiol, progesterone, testosterone and androstenedione. The LH pulse frequency in eCG-treated cows was significantly lower than that in control cows (2.4 +/- 0.4 & 6.4 +/- 0.4 pulses/8 h, respectively; P<0.05), and plasma progesterone (3.4 +/- 0.4 vs 1.8 +/- 0.1 ng/ml, for treated and control heifers, respectively; P<0.05) and estradiol concentrations (25.9 +/- 4.3 & 4.3 +/- 0.4 pg/ml, for treated and control heifers, respectively; P<0.05) were higher compared with those of the controls. No LH pulses were detected in FSH-treated cows, and mean LH concentrations were significantly lower than those in the controls (0.3 +/- 0.1 & 0.8 +/- 0.1, respectively; P<0.05). This suppression of LH was associated with an increase in estradiol (9.5 +/- 1.4 pg/ml; P<0.05 compared with controls) but not in progesterone concentrations (2.1 +/- 0.2 ng/ml; P>0.05 compared to controls). Both superovulatory protocols increased the ovulation rate (21.6 +/- 3.9 and 23.0 +/- 4.2, for eCG and FSH groups, respectively; P>0.05). These data demonstrate that super-ovulatory treatments decrease LH pulse frequency during the follicular phase of the treatment cycle. This could be explained by increased steroid secretion in the eCG-trated heifers but not in FSH-treated animals.     

Preovulatory LH profiles of superovulated cows and progesterone concentrations at embryo recovery

Forty-two Holstein cows were randomly assigned to three superovulatory treatment groups of 14 cows each. Cows in Group I received follicle stimulating hormone (FSH; 50 mg i.m.); those in Group II received FSH (50. mg i.m.) along with GnRH (250 ug in 2 % carboxymethylcellulose s.c.) on the day of estrus; and cows in Group III were infused FSH (49 mg) via osmotic pump implants. FSH was administered over a 5-d period for cows in Groups I and II (twice daily in declining doses). Cows in Group III received FSH over a 7-d period (constantly at a rate of 7 mg/day). All cows received 25 mg PGF(2)alpha (prostaglandin F(2)alpha) 48 hours after initiation of the FSH treatment. Blood samples were collected from seven cows from each group at 2 hour intervals on the fifth day of superovulation for serum luteinizing hormone (LH) concentration analysis by radioimmunoassay, and blood samples were collected from all cows on the day of embryo recovery for plasma progesterone determination. The LH profile was not altered (P>0.05) by either GnRH administration or by the constant infusion of FSH as compared to FSH treatment alone. Plasma progesterone concentrations were highly correlated with the number of corpora lutea (CL) palpated (r=0.92; P<0.01) and with the number of ova and/or embryos recovered (r=0.88; P<0.01). The accuracy of predicting the number of recoverable ova and/or embryos by the concentration of plasma progesterone was 86%.     

Effect of treatment with recombinant bovine somatotropin on responses to superovulatory treatment in swamp buffalo (Bubalus bubalis)

The objective of this study was to determine the effect of treatment with recombinant bovine somatotropin (rBST) on the response to superovulatory treatment in swamp buffalo. Estrous cycles of 16 buffalo cows were synchronized by intravaginal administration of progesterone and estradiol benzoate, and the cows were then randomly divided into 2 groups. The rBST-treated group received 250 mg of a sustained-release formula of rBST on Day 4 after progesterone implantation, whereas the control group did not receive rBST. Both groups were then given a superovulatory regimen of twice daily injections of FSH for 3.5 d (total dose of 260 mg, i.m.), between Days 9 and 11 after administration of progesterone. The cows were bred naturally 1 d after the last FSH injection, then 6 d after breeding they were slaughtered, and their reproductive tracts were removed. The numbers of corpora lutea (CL) and follicles were recorded, and embryos were flushed out of the uterine horns. There were no significant differences between the rBST-treated and control cows for the mean numbers (+/- SEM) of CL (6.0 +/- 2.2 vs 4.3 +/- 1.1), follicles (15.9 +/- 4.1 vs 19.8 +/- 2.9), or total embryos recovered per collection (4.5 +/- 1.6 vs 2.3 +/- 1.0). However, there were significant differences between rBST-treated and control cows for the numbers of transferable embryos per collection (3.0 +/- 1.0 vs 0.8 +/- 0.3; P < or = 0.05) and the overall proportion of transferable embryos (75 vs 33%; P < or = 0.01). The results of this study show that pretreatment of swamp buffalo with rBST significantly increases the production of transferable embryos in response to superovulation.     

Follicular growth, ovulation and embryo recovery in dairy cows given FSH at the beginning or middle of the estrous cycle

Variability in the superovulation response is an important problem for the embryo transfer industry. The objective of this study was to determine whether FSH treatment at the beginning of the cycle would improve the ovulation rate and embryo yield in dairy cows. Twenty-eight postpartum cyclic dairy cows were allocated at random to 4 treatment groups (A, B, C and D). Group A cows (n = 10) received FSH (35 mg) at a decreasing dose, starting on Day 9 (Day 0 = day of estrus) for 5 days followed by PGF(2alpha) (35 mg) on Day 12. Cows assigned to Groups B, C and D (n = 6 cows each, respectively) were given 35 mg FSH at a decreasing dose from Days 2 to 6 followed by PGF(2alpha) on Day 7. Group C and D cows received PRID inserts from Day 3 to Day 7. Cows in Group D additionally received 1000 IU hCG 60 hours after PGF(2alpha) treatment. Ovaries were scanned daily using a real time ultrasound scanner from the beginning of FSH treatment until embryo recovery, to monitor follicular development, ovulation and the number of unovulated follicles. Embryos were recovered from the uterus by a nonsurgical flushing technique 7 days after breeding. There were no differences (P>0.01) in the number of follicles > 10 mm at 48 hours after PGF(2alpha) treatment among the 4 groups. The mean numbers of follicles were 10.6 +/- 1.2, 9.3 +/- 1.3, 12.2 +/- 1.3 and 15.0 +/- 2.9 for Groups A, B, C and D, respectively. A significantly (P<0.001) higher number of ovulations was observed and a larger number of embryos was recovered in Group A than in the other groups. The results of this study indicate that superovulation with FSH at the beginning of the cycle causes sufficient follicular development but results in very low ovulation and embryo recovery rates.     

Factors affecting the yield of viable embryos by superovulated Holstein-Friesian cows

GnRH treatment (250 ug) 48 h after prostaglandin F(2alpha) in 40 superovulated cows induced a release of LH (increment > 5 ng/ml) in only 13 of the older cows. Eleven of these cows did not yield viable embryos. Thirty-two of 75 cows had preovulatory surge levels of LH 48 h after prostaglandin treatment. Plasma progesterone concentrations were determined in 140 cows at the time that superovulation was initiated. Eighty-four of these donors were superovulated with 40 mg of FSH and 56 donors with 48 mg of FSH. There was no relationship (P > 0.05) between the concentration of progesterone at the start of superovulation with either ovulation rate determined by palpation per rectum or the number of viable embryos per flush. These parameters were also unaffected (P > 0.05) by age of the donor or the dose of FSH. In another group of donors, treatment with 40 mg FSH was compared over a 3-d (n = 28) and a 4-d (n = 18) interval. The donors treated with FSH over a 3-d period had similar ovulation rates but yielded less viable embryos (1.5 v 5.8, P < 0.05). The fertility rate of 33 cows, inseminated 60 and 72 h after prostaglandin, was comparable to the fertility rate of 18 cows inseminated at 60, 72 and 84 h after prostaglandin treatment.     

Follicular development and reproductive endocrinology during and after superovulation in heifers and mature cows displaying contrasting superovulatory responses

To understand the causes for poor response to superovulation in mature cows of high genetic potential, endocrine and follicular events during and after superovulation were compared in heifers (<2 yr old) yielding large numbers of embryos and cows (9 to 13 yr old) known to be poor embryo donors. Follicular development was monitored by daily ultrasonography. Blood samples were taken 2 to 3 times a day for the measurements of P4, E2, FSH and LH by RIA. Intensive blood collections at 15-min intervals for 6 h were also performed during preovulatory and luteal phases. The number of embryos produced in the heifers (15.2 +/- 2; mean +/- SEM) and the cows (0.6 +/- 0.4), was similar to the number of ovulatory follicles derived from ultrasonographic observations in the heifers (16.2 +/- 3.7), but not in the cows (7.8 +/- 2.8). Contrary to that observations in heifers, there was no increase in the number of 4- to 5-mm follicles in cows during superovulation. The number of larger follicles (>5 mm) increased during superovulation in both cattle groups, but it was significantly lower in cows than in heifers. During superovulation, the maximal E2 concentration was greater (P < 0.0001) in heifers than in cows. One cow showed delayed luteolysis during superovulation, while another had abnormally high FSH (>10 ng/ml) and LH (>3 ng/ml) concentrations following superovulation. All the cows had a postovulatory FSH rise which was not detected in the heifers. The results showed that attempts to improve superovulatory response in mature genetically valuable cows are hampered by a number of reproductive disorders that are not predictable from the study of the unstimulated cycle.     

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 +/- SEM) 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.     

Superovulation of a low fecundity sheep breed using a porcine gonadotrophin extract with a defined LH content (Pluset)

The aim of this study was to determine the efficiency of a porcine pituitary gonadotrophin extract with a defined pLH content in the superovulation of sheep. Estrus was synchronized in 61 Polish Mountain ewes with intravaginal fluorogestone acetate sponges. Twenty-four hours before the sponges were removed, the ewes underwent different superovulatory treatments: Group I 250 IU of pFSH with 250 IU of pLH (n=19); Group II 500 IU of pFSH with 500 IU of pLH (n=19); and Group III 750 IU of pFSH and 750 IU of pLH (n=18). Gonadotrophine was administered intramuscularly twice a day over a 3-day period in decreasing dosages. A control group of ewes (n=5) was treated with saline. In most of the ewes estrus began about 20 hours after sponges were removed. All the ewes were bred naturally every 12 hours. Superovulation was confirmed in 75% of the treated animals. The ewes receiving 250 IU each of pFSH and pLH produced an average of 7.6 +/- 3.1 corpora lutea (CL), 6.3 +/- 2.4 ova and 4.3 +/- 4.1 transferable embryos. Group II (500 IU of pFSH and pLH) produced 8.5 +/- 4.0 CL, 7.6 +/- 4.1 ova, and 4.1 +/- 2.9 transferable embryos. Group III (750 IU each of pFSH and pLH) produced 8.3 +/- 5.2 CL, 7.5 +/- 5.5 ova and 5.2 +/- 5.1 transferable embryos. The mean embryo recovery rate was 87% for all three groups. Differences in superovulatory response and embryo recovery rate among the groups were not statistically significant (P>0.05).     

LH surge in Nelore cows (Bos indicus), after induced estrus or after ovarian superestimulation

Considering that there is limited information about the preovulatory LH surge in Zebu cattle (Bos indicus), the purpose of the present work was to assess the LH surge in Nelore cows during the estrous cycle and after ovarian superestimulation of ovarian follicular development with FSH. This information is particularly important to improve superovulatory protocols associated with fixed-time artificial insemination. Nelore cows (n=12) had their estrus synchronized with an intravaginal device containing progesterone (CIDR-B) associated with estradiol benzoate administration (EB, 2.5 mg, i.m., Day 0). Eight days later all animals were treated with PGF2alpha (Day 8) in the morning (8:00 h) and at night, when CIDR devices were removed (20:00 h). Starting 38h after the first PGF2alpha injection, blood sampling and ovarian ultrasonography took place every 4h, during 37 consecutive hours. Frequent handling may have resulted in a stress-induced suppression of LH secretion resulting in only 3 of 12 cows having ovulations at 46.7+/-4.9 and 72.3+/-3.8 h, respectively, after removal of CIDR-B. Thirty days later, the same animals received the described hormonal treatment associated with FSH (Folltropin), total dose=200 mg) administered twice a day, during 4 consecutive days, starting on Day 5. Thirty-six hours after the first injection of PGF2alpha, to minimize stress, only seven blood samples were collected at 4h interval each, and ultrasonography was performed every 12 h until ovulation. In 11 of 12 cows (92%) the LH surge and ovulation were observed 34.6+/-1.6 and 59.5+/-1.9 h, respectively, after removal of progesterone source. The maximum values for LH in those animals were 19.0+/-2.6 ng/ml (mean+/-S.E.M.). It is concluded that, in Nelore cows submitted to a ovarian superstimulation protocol, the LH surge occurs approximately 35 h after removal of intravaginal device containing progesterone, and approximately 12h before the LH surge observed after an induced estrus without ovarian superstimulation.     

Recovery rates and embryo quality following dominant follicle ablation in superovulated cattle

To determine the association between dominant follicle ablation and the outcome of a superovulatory regimen, two data sets were constructed from records of 171 recoveries from non-ablated cows and 1214 recoveries from cows that underwent follicular ablation prior to FSH treatment. Data set 1 included all cows with 2 or more records (n = 1385). Data set 2 included paired data for 87 cows which had at least 2 records of both ablated and non-ablated superovulatory attempts. Dominant follicle ablation was performed by use of transvaginal, ultrasound guided aspiration 48 hr prior to the start of FSH. The same FSH protocols were used for both ablated and non-ablated cows. For all cows (data set 1), more total ova/embryos were recovered from the ablation group (12.1+/-0.3 vs 10.5+/-0.8; P=0.06). This difference could be accounted for by greater numbers of non-transferable embryos in the ablation group (6.5+/-0.2 vs 5.3+/-0.6; P>0.01). For the paired data (data set 2), greater numbers of total ova/embryos recovered from the ablation group (12.8+/-1.0 vs 9.7+/-0.7; P=0.01) could also be accounted for by higher numbers of nontransferable embryos in this group (7.8+/-0.8 vs 4.5+/-0.4; P>0.01). There were no differences between groups for high quality embryos, percent cows producing no ova/embryos or percent cows producing no transferable embryos. These data support the premise that synchronization of follicular waves following dominant follicle ablation increases total ova/embryo output. However, the additional embryos were primarily nontransferable thereby negating potential economic gains.     

Superovulatory responses in dairy cows following ovulation of the dominant follicle of the first wave

In the present study we investigated the effect of hCG administration on Day 7 (Day 0 = day of standing estrus) to ovulate the dominant follicle of the first wave and the associated increase in progesterone concentration on subsequent superovulatory response in dairy cows. Twenty cyclic lactating cows were allocated at random to 2 groups: control (n = 10) and hCG-treated (n = 10). The ovaries of each cow were scanned using an ultrasound scanner on Day 7, to confirm the presence of the dominant follicle and thereafter every other day until embryo recovery. All cows received a total dose of 400 mg Folltropin-V in decreasing amounts for 5 days (Days 9 to 13) and 35 mg PGF(2alpha) on Day 12. In addition, the treated cows received 1000 IU hCG on Day 7. All cows were inseminated twice during estrus, and the embryos were collected 7 days later by a nonsurgical procedure. Blood smaples were taken at different times of the treatment period for progesterone determination. All cows possessed a dominant follicle at Day 7, and all but one of the hCG-treated cows ovulated the dominant follicle and formed an accessory corpus luteum. Plasma progesterone concentrations were significantly higher (P<0.01) in hCG-treated cows than control cows on the first day of Folltropin treatment and on the day of PGF(2alpha) injection. The mean number of follicles at estrus, the number of ovulations, the total number of embryos and the number of transferable embryos were not different (P>0.05) between control and hCG-treated cows.     

Ovarian superstimulation after follicular wave synchronization with GnRH at two different stages of the estrous cycle in cattle

The objective of this study was to evaluate superovulatory programs based on synchronization of follicular waves with GnRH at 2 different stages of the estrous cycle. Sixteen Holstein cows were randomly assigned to 1 of 3 groups and administered GnRH (Cystorelin, 4 ml i.m.) between Days 4 and 7 (Groups 1 and 3) or between Days 15 and 18 (Group 2) of the estrous cycle (estrus = Day 0). Four days after GnRH treatment, > or = 7-mm follicles were punctured in Groups 1 (n = 6) and 2 (n = 6) or were left intact in Group 3 (n = 4). All cows were superstimulated 2 d later (i.e., from Days 6 to 10 after GnRH treatment) with a total of 400 mg NIH-FSH (Folltropin-V) given twice daily in decreasing doses. The GnRH treatment caused a rapid disappearance of large follicles (P < 0.005), rapid decrease in estradiol concentrations (P < 0.003), and increase in the number of recruitable follicles (4 to 6 mm; P < 0.04), indicative of the emergence of a new follicular wave within 3 to 4 d of treatment. Between 4 and 6 d after GnRH treatment, the mean number of 4- to 6-mm follicles decreased (4.7 +/- 1.8 to 1.5 +/- 3.3) in the nonpunctured group but increased (3.9 +/- 1.0 to 7.3 +/- 1.9) in the punctured group of cows (P < 0.05). In response to FSH treatment, the increase in the number of > or = 7-mm follicles was delayed by approximately 2 d in the nonpunctured group (P < 0.006). Moreover, the mean number of > or = 7-mm follicles at estrus was higher (16.9 +/- 1.7 vs 11.5 +/- 3.0; P < 0.1) in the punctured than the nonpunctured group. The increase in progesterone concentration after estrus was delayed in the nonpunctured group (P < 0.1) compared with the punctured follicles. Mean numbers of CL as well as freezable (Grade 1 and 2) and transferable (Grade 1, 2 and 3) embryos were similar (P > 0.1) in punctured and nonpunctured groups. Spontaneous estrus did not occur prior to cloprostenol-induced luteolysis in any group, and stage of the estrous cycle during which GnRH was given did not affect (P > 0.1) hormonal and follicular responses in the punctured groups. In conclusion, GnRH given at different stages of the estrous cycle promotes the emergence of a follicular wave at a predictable time. Puncture of the newly formed dominant follicle increases the number of recruitable follicles (4 to 6 mm) 2 d later and, in response to superstimulation with FSH, causes a greater number and faster entry of recruitable follicles into larger classes (> or = 7 mm) and a faster postovulatory increase in progesterone concentrations.     

Estradiol-induced blockade of ovulation in the cow: effects on luteinizing hormone release and follicular fluid steroids

Administration of 10 mg estradiol valerate (EV) to nonlactating Holstein cows on Days 16 of the estrous cycle prevented ovulation in 7 of 8 cows for 14 days post-injection. In these 7 cows, the timing of luteolysis and the luteinizing hormone (LH) surge was variable but within the normal range. At 14 days post-treatment, each of these cows had a large (greater than 10 mm) follicle, with 558 +/- 98 ng/ml estradiol-17 beta, 120 +/- 31 ng/ml testosterone, and 31 +/- 2 ng/ml progesterone in follicular fluid (means +/- SE). A second group of animals was then either treated with EV as before (n = 22), or not injected (control, n = 17) and ovariectomized on either Day 17, Day 18.5, Day 20, or Day 21.5 (24, 60, 96, or 132 h post-EV). Treatment with EV did not influence the timing of luteolysis, but surges of LH occurred earlier (59 +/- 8 h post-EV vs. 100 +/- 11 h in controls). The interval from luteolysis to LH peak was reduced from 44 +/- 6 h (controls) to 6.9 +/- 1.5 h (treated). Histologically, the largest follicle in controls tended to be atretic before luteolysis, but nonatretic afterwards, whereas the largest follicle in treated animals always tended to be atretic. Nonatretic follicles contained high concentrations of estradiol (408 +/- 59 ng/ml) and moderate amounts of testosterone (107 +/- 33 ng/ml) and progesterone (101 +/- 21 ng/ml), whereas atretic follicles contained low concentrations of estradiol (8 +/- 4 ng/ml) and testosterone (12 +/- 4 ng/ml), and either low (56 +/- 24 ng/ml) or very high (602 +/- 344 ng/ml) concentrations of progesterone. This study suggests that EV prevents ovulation by inducing atresia of the potential preovulatory follicle, which is replaced by a healthy large follicle by 14 days post-treatment.     

Superovulatory response of Sistani cattle to three different doses of FSH during winter and summer

Objective of the present study was to investigate the effect of season and dose of FSH on superovulatory responses in Iranian Bos indicus beef cattle (Sistani). Cyclic cows, in summer (n=16) and winter (n=16), were assigned randomly to three dose-treatment groups of 120 (n=10), 160 (n=12) and 200 (n=10) total mg of Folltropin-V with injections given twice daily for 4 days in decreasing doses. Estrous cycles were synchronized with two prostaglandin F2alpha injections given 14 days apart. From day 5 after the ensuing cycle, daily ovarian ultrasonography was conducted to determine emergence of the second follicular wave at which time superovulation was initiated. Relative humidity, environmental and rectal temperatures were measured at 08:00, 14:00 and 20:00 h for the 3 days before and 2 days after the estrus of superovulation. Non-surgical embryo recovery was performed on day 7 after estrus. The effects of season, dose, time of estrous expression and all two-way interactions were evaluated on superovulatory responses: total numbers of CL, unovulated follicles (10 mm), ova/embryo, transferable and non-transferable embryos. Season (summer or winter), doses of Folltropin-V (120, 160 or 200 mg NIH) and time of estrous expression (08:00, 14:00 or 20:00 h) did not affect the number of transferable embryos (3.1+/-0.58). When superovulatory estrus was detected at 08:00, a FSH dose effect was detected with the greatest numbers of CL (12.2+/-0.87) and total ova/embryos (12.2+/-1.46) occurring with 200 mg FSH (dosextime of estrous expression; P<0.01).     

Ovarian response to gonadotropin treatment initiated relative to wave emergence in ultrasonographically monitored ewes

Follicular recruitment and luteal response to superovulatory treatment initiated relative to the status of the first wave of the ovine estrous cycle (Wave 1) were studied. All ewes (n = 25) received an intravaginal progestagen sponge to synchronize estrous cycles, and ewes were monitored daily by transrectal ultrasonography. Multiple-dose FSH treatment (total dose = 100 mg NIH-FSH-P1) was initiated on the day of ovulation (Day 0 group) in 16 ewes. In the remaining 9 ewes, FSH treatment was started 3 d after emergence of the largest follicle of Wave 1 (Day 3 group). Ewes received PGF(2alpha) with the last 2 FSH treatments to induce luteolysis. Daily blood samples were taken to determine progesterone profiles and to evaluate the luteal response subsequent to superovulation. The ovulation rate was determined by ultrasonography and correlated with direct observation of the ovaries during laparotomy 5 to 6 d after superovulatory estrus when the uterus was flushed to collect embryos. Results confirmed that follicular recruitment was suppressed by the presence of a large, growing follicle. In the Day 0 and Day 3 groups, respectively, mean numbers (+/- SEM) of large follicles (>/= 4 mm) recruited were 6.4 +/- 0.6 and 2.7 +/- 0.7 (P < 0.01) at 48 h after the onset of treatment, and 6.7 +/- 0.5 and 5.1 +/- 0.6 (P = 0.08) at 72 h after the onset of treatment. Ovulation rates were 5.6 +/- 0.8 and 3.3 +/- 0.8 in the respective groups (P < 0.05). The number of transferable embryos was 1.8 +/- 0.5 and 0.3 +/- 0.2 in the respective groups (P < 0.05). Short luteal phases (相似文献   

Comparative studies on the superovulatory effect of PMSG and FSH in water buffalo (Bubalus bubalis )

A total of thirty-eight lactating water buffalo cows were treated in four experiments simultaneously either with FSH (first group) or PMSG(second group). To the first group (half of the animals), a total dose of 40 mg FSH-P at 12-hr intervals was given i.m. within a 4-day period. The second group was treated i.m. with 3000 IU PMSG (Gestyl). Forty-eight hours after initiation of the superovulatory treatment all buffaloes were given 500 ug Cloprostenol. Fi seen buffaloes from the FSH-treated group (78.9%) and 17 from the second group (89.5%) came into heat at average PGF 2 alpha/standing heat intervals of 42.8+/-1.48 and 44.8+/-2.31, respectively. Superovulatory treatment resulted in meath number of 4.3+/-0.87 and 1.9+/-0.50 CL and 0.5+/-0.24 and 2.2+/-0.82 follicles for the first and second group. Twenty-five eggs were recovered after non-surgical flushing from 8 of 13 flushes in the first group and all except one were fertilized and classified as good embryos. Twelve eggs were recovered from 4 of 11 flushes in the second group and 11 of the eggs were fertilized and 10 of them classified as good ones.     

Superovulation of dairy and beef cows using porcine FSH with defined LH content

The results of the superovulation of dairy and beef cows using porcine pituitary FSH characterized by defined LH content are reported.

A total amount of FSH equivalent to 31 mg of Armour Standard and containing LH equivalent to 500 i.u. (HMG Standard), administered in 10 decreasing doses over a period of five days, induced 7.33 ± 4.67 (mean ± SD) ovulations in six lactating Friesian cows (group 1), and 2 ± 1.41 transferable embryos were collected nonsurgically.

Furthermore, the treatment with FSH equivalent to 62 mg of Armour Standard and containing 1000 i.u. LH induced 19.43 ± 9.25 ovulations in 16 lactating Friesian cows (group 2).

Similar results were obtained in seven Marchigiana and Chianina cows (group 3) using a total amount of FSH equivalent to 46.5 mg Armour Standard and containing 750 i.u. LH.

At the higher dose, 10.56 ± 6.39 transferable embryos were collected, their percentage was 73.47%, and none of the donors produced fewer than four transferable embryos.     

Superovulation induction in Japanese Black cattle by a single intramuscular injection of hMG or FSH dissolved in polyvinylpyrrolidone.

The efficacy of a single intramuscular dose of 450 or 600 international units (IU) of human menopausal gonadotropin (hMG) or 30 mg of follicle stimulating hormone (FSH), each dissolved in 30% polyvinylpyrrolidone K-30 (PVP), for superovulation treatment was compared to that of superovulation induction by administration of a total dose of 600 IU hMG given in declining doses twice daily over a 3-day period. A total of 48 Japanese Black cows were used for the investigation. Oestrus was observed within 60 h after PGF2alpha administration in all cows in the hMG groups. In the hMG group that received a single dose of 600 IU hMG (n = 12), oestrus was observed less than 36 h after treatment in one cow. In contrast, oestrus was not observed in 3 of the 12 cows (25%) in the FSH group. Neither the average number of recovered ova/embryos nor the number of transferable embryos per collection differed significantly among the hMG groups. However, the average number of transferable embryos was not significantly higher in cows treated with a single dose of 600 IU of hMG than in cows treated with a single 30 mg dose of FSH (7.5+/-4.5 vs. 2.1+/-2.8). The number of cows from which more than three excellent grade embryos were collected was highest in the group that received a single dose of 600 IU hMG (9/12, 75%) and lowest in the group that received a single 30 mg dose of FSH (2/9, 22%). The differences between groups in the percentages of cows with three or more excellent embryos between treatments were not statistically significant. The proportion of recovered ova/embryos classified as excellent was highest in the group that received 600 IU hMG in declining doses and lowest in the group that received a single 30 mg dose of FSH (55.2% vs. 30.2%; P < 0.05). The recovery rate of unfertilized ova was lowest in the group that received a single dose of 600 IU hMG and highest in the group received a single 30 mg dose of FSH (18.3% vs. 48.8%; P < 0.05). Although the differences in recovery results between the groups were not statistically significant, the recovery rates in hMG groups were higher than that the FSH group. These findings suggest that superovulation can be induced adequately in Japanese Black cows using one injection of 450 to 600 IU hMG dissolved in PVP.     

Use of a GnRH agonist to prevent the endogenous LH surge and injection of exogenous LH to induce ovulation in heifers superstimulated with FSH: a new model for superovulation

A new protocol for superovulating cattle which allows for control of the timing of ovulation after superstimulation with FSH was developed. The preovulatory LH surge was blocked with the GnRH agonist deslorelin, and ovulation was induced by injection of LH. In Experiment 1, heifers (3-yr-old) were assigned to a control group (Group 1A, n = 4) or a group with deslorelin implants (Group 1B, n = 5). On Day -7, heifers in Group 1A received a progestagen CIDR-B((R))device, while heifers in Group 1B received a CIDR-B((R))device + deslorelin implants. Both groups were superstimulated with twice daily injections of FSH (Folltropin((R))-V): Day 0, 40 mg (80 mg total dose on Day 0); Day 1, 30 mg; Day 2, 20 mg; Day 3, 10 mg. On Day 2, heifers were given PGF (a.m.) and CIDR-B((R)) devices were removed (p.m.). Three heifers in Group 1A had a LH surge and ovulated, whereas neither of these events occurred in Group 1B (with deslorelin implants) heifers. In Experiment 2, heifers (3-yr-old) were assigned to 1 of 4 equal groups (n = 6). On Day -7, heifers in Group 2A received a norgestomet implant, while heifers in Groups 2B, 2C and 2D received norgestomet + deslorelin implants. Heifers were superstimulated with FSH starting on Day 0 as in Experiment 1. On Day 2, heifers were given PGF (a.m.) and norgestomet implants were removed (p.m.). Heifers in Groups 2B to 2D were given 25 mg LH (Lutropin((R))): Group 2B, Day 4 (a.m.); Group 2C, Day 4 (p.m.); Group 2D, Day 5 (a.m.). Heifers in Group 2A were inseminated at estrus and 12 and 24 h later, while heifers in Groups 2B to 2D were inseminated at the time of respective LH injection and 12 and 24 h later. Injection of LH induced ovulation in heifers in Groups 2B to 2D. Heifers in Group 2C had similar total ova and embryos (15.2 +/- 1.4) as heifers in Group 2A (11.0 +/- 2.8) but greater (P < 0.05) numbers than heifers in Group 2B (7.0 +/- 2.3) and Group 2D (6.3 +/- 2.0). The number of transferable embryos was similar for heifers in Group 2A (5.8 +/- 1.8) and Group 2C (7.3 +/- 2.1) but lower (P < 0.05) for heifers in Group 2B (1.2 +/- 0.8) and Group 2D (1.3 +/- 1.0). The new GnRH agonist-LH protocol does not require observation of estrus, and induces ovulation in superstimulated heifers that would not have an endogenous LH surge.     

Effect of recombinant bovine somatotropin (rBST) on follicular IGF-I contents and the ovarian response following superovulatory treatment in dairy cows: a preliminary study

Somatotropin and FSH act synergystically on insulin-like growth factor-I (IGF-I) synthesis in ovarian follicles; IGF-I regulates several granulosa cell specific functions and may thereby be beneficial in bovine superovulation. In a series of 3 experiments we investigated the effects of recombinant bovine somatotropin (rBST) on several parameters of the superovulatory response in dairy cows. A total of 81 Holstein Friesian crossbred dairy cows received either 640 mg rBST or the vehicle (controls) on Day 4 or 13 of the superovulation schedule. Superovulation was induced with 2500 IU PMSG on Day 9. The cows were artificially inseminated on Day 13. In Experiment 1, on Days 4, 8, 11, 13 and 17 4 to 5 animals each were slaughtered to obtain follicular fluid, endometrium and plasma. The rBST application increased IGF-I contents in plasma and follicular fluid on Days 8, 11 and 13 (P < 0.05) in the treated cows when compared with that of the controls. Plasma and follicular IGF-I contents were correlated closely (rBST: r = 0.90, n = 10; control: r = 0.94, n = 9). The number of antral follicles increased following rBST treatment, and on the day of artificial insemination (AI) twice as many follicles > 4 mm were counted in the rBST treated animals than in the control group. In Experiment 2, the flushing of 38 donors on Day 7 after AI resulted in more transferable embryos in the rBST group than in the control group (4.2 +/- 1.0 vs 2.5 +/- 0.7; P < 0.05). In contrast, in Experiment 3 involving 21 animals when rBST was administered at the time of AI the superovulation response was not altered. It is concluded that rBST increases follicular and plasma IGF-I contents and thereby has profound effects on follicular and early embryonic development.