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1.
To test whether inhibin A assays can be used for the prediction of yields in embryo programmes in goats, 50 does were treated with 45 mg FGA sponges (Chronogest) for 16 days plus a single dose of 100 microg i.m. cloprostenol on Day 14, just before the start of administration of eight doses of 1.25 ml of Ovagen twice daily for 4 days. At first FSH injection, the number and size of all follicles > or =2 mm was assessed by transrectal ultrasound and plasma inhibin A levels were measured by specific dimeric assay. There was a positive correlation between number of follicles > or =6 mm (8.8 +/- 0.5) and inhibin A levels at first FSH dose (193.2 +/- 14.5 pg/ml, P<0.05). The mean number of corpora lutea on Day 7 after sponge removal was related to the total number of follicles with a diameter of 2-6 mm at the onset of the FSH treatment (15.3 +/- 0.7, P<0.05). The total number of embryos recovered was related to the number of follicles with 4-6 mm in size (6.2 +/- 0.5, P<0.05) and to the inhibin A levels at first FSH dose (P<0.05). These results suggest that follicles > or =4 mm are the source of inhibin prior to FSH stimulation and are the main source of oocytes resulting in the number of viable embryos recovered after a superovulatory treatment. Hence, the response to superovulatory treatments in goats in terms of the number of embryos can be predicted from either the population of follicles determined by ultrasound or the plasma inhibin A levels at start of the superovulatory FSH treatment.  相似文献   

2.
The effect of pulsatile infusion of gonadotropin-releasing hormone (GnRH) on follicular function was evaluated in nutritionally induced anovulatory beef cows. After 4 (short; n = 12) or 18 wk (long; n = 12) of anovulation, cows were randomly assigned within anovulatory group to either 2 microg of GnRH treatment or saline (control; i.v.) every hour for 5 d. Ovarian structures were monitored by daily ultrasonography. Growth rate of the largest follicle (P < 0.01) and maximal size of the largest follicle during treatment were greater (P < 0.01) for GnRH vs control cows. At exsanguination after 5 d of GnRH treatment, the size of the second-largest follicle was greater (P < 0.05) in short (i.e., 4 wk) anovulatory cows than in long (i.e., 18 wk) anovulatory cows and the largest follicle tended (P < 0.10) to be larger in long vs short anovulatory cows. Short anovulatory GnRH-treated cows had more small follicles than short anovulatory control cows or long anovulatory GnRH-treated or control cows (anovulation x GnRH; P < 0.10). Follicular fluid (FFL) concentrations of estradiol (P < 0.01) and androstenedione (P < 0.05) were greater in GnRH vs control cows. Concentrations of insulin-like growth factor-I were greater (P < 0.10) in large vs small follicles in cows that were anovulatory for 4 wk, but not in cows that were anovulatory for 18 wk. The amount of insulin-like growth factor-binding protein (IGFBP)-3 in FFL was greater (P < 0.05) in 4- vs 18-wk anovulatory cows. Amounts of IGFBP-2, -4, and -5 were greater (P < 0.001) in FFL of small (< 5 mm) vs large (> or = 5 mm) follicles regardless of treatment. We conclude that pulsatile treatment with GnRH for 5 d stimulates similar growth of the largest follicles in short- and long-term anovulatory beef cows, and that the duration of anovulation is not a major factor that limits follicular growth w hen anovulatory cowsare treated with GnRH. The primary intrafollicular factors associated with increased follicular size were increased concentrations of estradiol, progesterone, and insulin-like growth factor-I,and decreased concentrations of IGFBP-2, -4, and -5. Increased duration of anovulation was associated with decreased concentrations of IGF-I and IGFBP-3 in FFL.  相似文献   

3.
The effects of pregnant mare serum gonadotrophin (PMSG) dose and PMSG antiserum on superovulation in crossbred beef cows were studied. In experiment I, three groups were treated with 1200, 2400 or 3600 IU of PMSG and 48 h later with prostaglandin (PGF). The mean numbers of corpora lutea (CL), unovulated follicles, and total ova/embryos collected increased as the PMSG dose increased. The percent of fertilized ova and transferable embryos was lowest in the highest dose group (p < 0.05). In experiment II, all cows received 2500 IU of PMSG; groups 1 and 2 were treated with sheep anti-PMSG serum at 48 h or 60 h after PGF; group 3 cows were PMSG-only controls. The number of CL was lowest and the number of unovulated follicles highest in the PMSG-only group (p < 0.05). The number of CL was higher in group 2 (anti-PMSG at 60 h) than in the control group, with the anti-PMSG at 48 h not different from the other groups. Numbers of total ova/embryos, fertilized ova, and transferable embryos were higher (p < 0.05) in both antiserum-treated groups relative to the PMSG-only group. We conclude that superovulation of beef cows with PMSG and treatment with PMSG antiserum will induce a higher superovulatory response and will result in higher CL numbers and fewer unovulated follicles. Further, the variability in the superovulatory response to PMSG treatment was still evident when PMSG antiserum was administered.  相似文献   

4.
To determine if specific binding of 125I-labeled gonadotropins to granulosa and thecal cells, or concentrations of steroids in ovarian follicles change during the postpartum anovulatory period, 21 suckled beef cows were slaughtered on d 7, 14, 28, 42 or 56 after parturition (n = 4 to 6 per d). After slaughter, 10 to 15 follicles were dissected from each pair of ovaries and categorized by diameter: small (1.0 to 3.9 mm), medium (4.0 to 7.9 mm) or large (greater than or equal to 8 mm). Progesterone (221 to 612 ng/ml), androstenedione (48 to 94 ng/ml) and estradiol (2.7 to 23.9 ng/ml) did not change (P greater than .10) in fluid of small or medium follicles from d 7 to 42 to 56 after parturition. Similarly, specific binding of human chorionic gonadotropin (125I-hCG) or follicle stimulating hormone (125I-oFSH) to homogenates of small, medium or large follicles did not change (P greater than .05). In contrast, progesterone in fluid of large follicles increased (P less than .05) 3.4-fold between d 7 and 14, but decreased (P less than .05) 55% between d 14 and 28. Concentrations of androstenedione in fluid of large follicles did not change (P greater than .10) from d 7 to 42 to 56. Concentrations of estradiol in fluid of large follicles remained constant between d 7 and 14, but increased (P less than .05) 4.2-fold between d 14 and 28. We conclude that during the postpartum anovulatory period, there is no change in steroidogenic capabilities of small or medium follicles, both of which predominantly produce progesterone.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

5.
Plasma progesterone was measured in 14 normally cycling heifers and cows subjected to non-surgical recoveries of embryos. A radioimmunoassay (RIA) method was used for progesterone determination. The average progesterone concentration increased from 7.5 to 11.6 ng/ml in 8 of the animals following treatment with PMSG on day 8–12. Six animals had a decrease from 5.0 ± 2.1 to 3.9 ± 2.5 ng/ml. The overall increase was from 6.4 ± 2.7 ng/ml to 8.3 ± 4.8 ng/ ml. Prostaglandin F2a-analogue (cloprostenol) treatment resulted in a sharp decrease in plasma progesterone followed by a rapid increase to an average of 46.8 ng/ml on day 16. A high degree of variability in this peak value was observed, and it was not correlated with the number of corpora lutea. The superovulatory cycle was generally prolonged. The heat following the superovulatory treatment was silent, and a typical ovarian resting period was observed during which the progesterone concentration remained low and the ovaries small.  相似文献   

6.
Changes in sizes and numbers of ovarian antral follicles, uterine size and weight, serum hormones, and frequency and duration of suckling were examined during the postpartum anovulatory period in primiparous, suckled beef cows. Twenty-one anovulatory, suckled cows (n = 4 to 6/d) were slaughtered on d 7, 14, 28 and 42 to 56 after parturition. In addition, a total of 11 postpartum cows that had begun cyclic activity were slaughtered on d 28, 42 or 56. Blood was collected at 10-min intervals for 6 h 1 d before slaughter for measurement of prolactin, cortisol and progesterone in serum. Numbers of medium (4.0 to 7.9 mm) follicles increased fourfold (P less than .05) between d 7 and 42 to 56 in anovulatory cows, whereas numbers of small (1.0 to 3.9 mm) and large (greater than or equal to 8.0 mm) follicles did not change (P greater than .10). Uterine involution was complete by d 28. In anovulatory cows, a higher (P less than .05) proportion of largest (but not second-largest) follicles was opposite the ovary containing the corpus albicans from pregnancy (CAP). In addition, 90% of these largest follicles opposite the CAP had concentrations of estradiol greater than progesterone. In cyclic cows, however, first ovulations occurred with equal frequency on either ovary. Concentrations of prolactin or cortisol in serum or duration of suckling were not associated with changes in uterine or ovarian measurements. In conclusion, growth and function of the largest (but not second-largest) follicle were reduced when located on the ovary containing the CAP.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

7.
The aims of this study were to evaluate the chronology of periovulatory events (oestrus behaviour, LH surge and ovulation) in 16 superovulated Manchega sheep and to determine whether follicular status at start of the FSH supply might affect their occurrence. Mean timing for onset of oestrus behaviour was detected at 28.1 +/- 0.7 h after sponge withdrawal; the preovulatory LH surge and ovulation started at 37.2 +/- 0.7 h and 65.4 +/- 0.7 h after progestagen withdrawal, respectively. The intervals between oestrus, LH surge and ovulation were affected by a high individual variability, which might be the cause for reported decreased efficiency in embryo production. Current results also addressed the role of follicular status at start of the superovulatory treatment on the preovulatory LH surge and the ovulation. The interval LH surge-ovulation was increased in ewes with a growing dominant follicle at starting the FSH treatment (32.3 +/- 0.9 vs 28.6 +/- 0.5 h, p < 0.05). The developmental stage of the largest follicle at starting the superovulatory treatment also affected occurrence of LH surge and ovulation; follicles in growing phase advanced the occurrence of the LH surge and ovulation when compared to decreasing follicles (33.0 +/- 1.0 vs 43.5 +/- 1.1 h, p < 0.05, for LH peak and 60.7 +/- 1.1 vs 72.8 +/- 1.2 h, p < 0.05, for ovulation). Thus, only ewes with growing follicles ovulated prior to 55 h after sponge withdrawal; conversely, no sheep with decreasing follicles ovulated earlier than 67 h, when an 85.7% of the ewes bearing growing follicles has ovulated at 63 h.  相似文献   

8.
The objective of the present studies was to determine the effect of cytokines on FSH-induced estrogen production by granulosa cells from small (1–5 mm) and large (≥ 8 mm) bovine follicles. FSH-induced estradiol production by granulosa cells from large follicles (expressed as pg estradiol/105 cells/24 hr) was not affected (P>.05) by 10 or 100 ng/ml of interleukin (IL)-1β, 10 or 100 ng/ml of tumor necrosis factor-α (TNFα) or 100 ng/ml of IL-2. In contrast, 100 ng/ml of IL-1β, IL-2 or TNFα inhibited (P<.05) FSH-induced estradiol production by 31%, 55% or 72%, respectively in cells from small follicles. Interferon-α (IFNα; 100 U/ml) inhibited (P<.05) FSH-induced estradiol production by 61% and 20% in cultures of cells from small and large follicles, respectively. Interferon-β (IFNβ; 100 U/ml), interferon γ (IFNγ; 100 U/ml) and bovine trophoblast protein-1 (bTP-1; 100 U/ml) inhibited (P<.05) estradiol production by 47%, 71% and 28%, respectively in cells from small follicles, but had no effect (P>.05) on FSH-induced estradiol production in cells from large follicles. TNFα binding protein-I blocked (P<.05) the inhibitory effect of TNFα on FSH-induced estradiol production by cells from small follicles. Viability of granulosa cells was not affected (P>.05) by the various cytokines. In summary, cytokines have little or no effect on FSH-induced estradiol production by bovine granulosa cells collected from large follicles, whereas cytokines (bTP-1 ≤ IL-1β < IL-2 = IFNβ < IFNα < IFNγ = TNFα) have potent inhibitory effects on FSH-induced estradiol production by granulosa cells collected from small follicles. Thus, it appears that less differentiated granulosa cells (small follicles) are more responsive to cytokines than are highly differentiated granulosa cells (large follicles).  相似文献   

9.
The aim of the present in vivo study was to monitor real-time fluctuations of cortisol (Cr) in the wall of preovulatory follicles using a microdialysis system (MDS) implanted in the theca layer as well as changes in ovarian venous plasma (OVP) and jugular venous plasma (JVP). Seven cows were superovulated using FSH and prostaglandin F2alpha injections. Dialysis capillary membranes were surgically implanted into the theca layer of mature follicles and connected to a microdialysis system. Fractions of the perfusates were collected from Day -1 (Day 0=LH surge) to Day 3. No difference in the concentrations of Cr between JVP and OVP was detected throughout the experiment. Circulating concentrations of Cr ranged from 20 to 35 ng/ml 8 h after surgery in ovulatory and anovulatory cows. In five ovulatory cows, the Cr concentration decreased to basal levels (<10 ng/ml) between 12 and 24 h after surgery, however, two anovulatory cows retained high Cr levels (>10 ng/ml) up to 42 h after surgery. There was a clear increase in the local concentration of Cr from 13.3+/-2.1 pg/ml at -24 h to 27.5+/-1.7 pg/ml at 0 h (peak of the LH surge) within the wall of ovulatory follicles. This increase was not detected in anovulatory follicles. This transient increase in Cr occurred only in the follicle wall, but not in the OVP or JVP, indicating that the presence of a local regulatory mechanism for Cr production/conversion in ovulatory follicles, and this mechanism may modulate the inflammatory-like reaction induced by LH surge in the follicle wall. The present results demonstrate that the glucocorticoid environment in the follicular wall adjusts at the local level in bovine ovulatory follicles. This mechanism may protect follicles from the adverse effects of glucocorticoid, and it may prevent excess inflammatory reactions associated with ovulation by temporarily increasing local concentrations of glucocorticoid, thus forming an integral part of the regulatory mechanism in ovarian physiology.  相似文献   

10.
Factors that affect ovarian follicular dynamics in cattle.   总被引：1，自引：0，他引：1  
Studies of ovarian follicular dynamics in cattle may lead to methods for improving fertility, for synchronizing estrus with more precision, and for enhancing superovulatory responses. Within an estrous cycle, two or three large (> 10 mm) follicles develop during consecutive waves of follicular growth. The last wave provides the ovulatory follicle, whereas preceding wave(s) provide follicles that undergo atresia. The life span of large follicles seems to depend on the pulsatile secretion of LH; decreased frequency of LH pulses results in atresia of large follicles. Aromatase activity in the walls of the largest follicles is greatest during the first 8 d of the estrous cycle and decreases by d 12. Steroidogenesis of the largest and second-largest ovarian follicles differs on d 5, 8, and 12 of the estrous cycle. Follicular dynamics are altered by negative energy balance and lactation. The number of large follicles and concentration of estradiol during the preovulatory period differs between postpartum lactating and nonlactating cows. Dietary fats stimulate follicular growth when they are fed to increase energy balance. Administration of bovine somatotropin decreases energy balance and has a differential effect on ovarian follicular responses; growth of the largest follicle does not change, but growth of the second-largest follicle is stimulated by somatotropin. Studies of follicular dynamics in lactating cows demonstrate changes in ovarian function associated with energy balance that may be related to inefficient reproductive performance of cows producing high yields of milk.  相似文献   

11.
Thirteen beef cows were superovulated using 4,000 i.u. of pregnant mare serum gonadotrophin (PMSG) on days 9 to 14 of the estrous cycle, followed by two injections of 500 micrograms prostaglandin F2 alpha analogue (PGF2 alpha) 48 and 55 hrs later. Seven of them were injected intramuscularly with bovine anti-PMSG serum 12 hrs after the first signs of estrus. The remaining 6 cows were served as controls and received no antiserum. Peripheral blood concentrations of progesterone (P) and estradiol-17 beta (E2) were compared in relation to the superovulatory responses. The injection of anti-PMSG serum did not significantly affect the numbers of the corpora lutea (CL), the anovulatory follicles and the transferable embryos at 7 to 8 days after superovulatory estrus, but increased the ratio of embryos classified as excellent or good quality. Although the plasma P concentration showed no significant differences between the anti-PMSG-treated and control cows, the plasma E2 concentration displayed a characteristic difference, suppressing the second E2 peak in the anti-PMSG-treated cows. It is concluded that the use of bovine anti-PMSG serum for PMSG/PGF2 alpha-treated cows at 12 hrs after the beginning of the estrus improves the quality of embryos recovered, probably due to inhibition of high estrogenic environment following ovulation.  相似文献   

12.
Despite their continuous turnover, sheep antral follicles are always regularly innervated. The local production of neurotrophins is probably involved in the control of ovarian innervation. In this context the present investigation was designed to evaluate the ability of sheep antral follicles to produce neurotrophic factors. In the first part of the paper neurotrophic activity was measured in follicular fluid of sheep antral follicles of different size. Using an in vitro model the effect of gonadotrophins on neurotrophin production was then evaluated. The levels of neurotrophic activity in conditioned medium or follicular fluid and the kind of neurotrophin produced were determined by using the chicken embryo dorsal root ganglia test combined with an immunoneutralization step. Follicular fluid from medium-large follicles (>4 mm) contains high levels of NGF (240-250 ng/ml), whereas the factor is nearly undetectable in small follicles (<3 mm) and in early atretic follicles. Experiments in vitro based on the culture of follicle shells for 12 hr confirmed that medium-large follicles can produce NGF. The production is strictly dependent on gonadotrophin stimulation. When gonadotrophins were not added or were added separately, no detectable levels of neurotrophic activity accumulated in medium. By contrast, in the presence of both LH and FSH the production of NGF became apparent showing a clear dose-response behavior. In addition, this production increased progressively with increasing follicle size from 4 to >5 mm up to values of about 60 ng/follicle, whereas follicles with a diameter of less than 3 mm were insensitive to gonadotrophins stimulation and did not produce significant amount of NGF. The data presented demonstrate that sheep follicles produce relevant amounts of NGF as long as the correct hormonal milieu is provided. Under these conditions the production of the NGF increases with increasing follicle size. This may be responsible for the rapid innervation of the wall of growing follicles and/or take part in other non-neural processes that are generally attributed to gonadotrophin stimulation.  相似文献   

13.
To determine influences of insulin and body condition on follicular growth, prepuberal gilts (n = 16) treated with pregnant mare's serum gonadotropin (PMSG) were used in a 2 X 2 factorial experiment with main effects of insulin (0 or .4 IU/kg every 12 h beginning at 1800 on the day before PMSG) and backfat depth (moderate, 25 +/- .8; high, 32 +/- .7 mm; P less than .0001). Body weights were similar. Blood sampling was at 6-h intervals for analyses of LH, FSH, growth hormone (GH), glucagon, cortisol, insulin, insulin-like growth factor-I (IGF-I), plasma urea nitrogen (PUN), nonesterified fatty acids (NEFA), testosterone, estradiol-17 beta, and progesterone. Ovaries were removed 75 h after PMSG treatment, and visible small (less than or equal to 3 mm), medium (4 to 6 mm), large (greater than or equal to 7 mm), and macroscopically atretic follicles were counted. Administration of insulin increased IGF-I in fluid of medium follicles (108.8 vs 60.7 ng/ml; SEM = 13.3; P less than .05). Neither insulin nor fatness affected hCG binding by granulosa cells (12.5 +/- 1.6 ng/10(6) cells) or numbers of large (16.7 +/- 2.6) and medium (10.4 +/- 2.3) follicles. However, insulin increased the number of small follicles (58.9 vs 29.9; SEM = 9.7; P less than .05) and reduced the number of atretic follicles (3.8 vs 11.3; SEM = 1.1; P less than .05). The predominant effect of insulin on reducing number of atretic follicles was in the small size class (.6 vs 6.9; SEM = .6, P less than .01). Follicular fluid estradiol and progesterone were not affected by treatments; however, testosterone concentrations in large follicles were lower in gilts with higher backfat (32.5 vs 59.9 ng/ml; SEM = 4.0; P less than .05). Systemic LH, FSH, glucagon, cortisol, PUN, NEFA, estradiol, and testosterone were not affected by insulin or level of feeding. However, GH was lower in gilts that had higher backfat (overall average of 3.2 vs 2.8 ng/ml; SEM = .1; P less than .05). Insulin reduced atresia and altered intrafollicular IGF-I independently of body condition and without sustained effects on other hormones.  相似文献   

14.
奶牛不排卵状况的研究综述   总被引：2，自引：0，他引：2  
卵泡生长可分为三个阶段：卵泡出现；卵泡的选择优势化与闭锁分离；卵泡排卵。不排卵的情况可分为：①生长卵泡不能生长至“分离期”。原因可能是极度的营养缺乏。②卵泡可生长到“分离期”，但没有达到排卵体积。这方面研究得较多，认为这类牛比正常牛有更强的E2对GnRH／LH的负反馈，在营养不良或吮乳时可引起这类不排卵状况。③卵泡生长的最终体积大于排卵卵泡，这类牛的特征是下丘脑对E2的正反馈作用不敏感；高产奶牛常见。对于第一种情况，关键在于预防，提高育成期的饲管水平。后两种常见的不排卵状况是由于下丘脑对E2反应的敏感性改变；常用增加血液循环中P4的浓度改变GnRH／LH释放的脉冲以协助卵泡最后阶段的生长，或重新建立下丘脑对E2的正反馈来治疗。  相似文献   

15.
We investigated the effect of the leukaemia inhibitory factor (LIF) alone or in association with FSH on the in vitro culture (IVC) of caprine preantral follicles. Preantral follicles >200 μm in size were isolated and cultured for 18 days in basic medium either alone (control) or supplemented with LIF (10 or 50 ng/ml) in the absence or presence of FSH. Every 6 days, follicular survival, growth and antrum formation were evaluated. At the end of the culture period, the oocytes underwent in vitro maturation (IVM), and their viability and chromatin configuration were assessed. Follicles of the control group and those cultured in 10 ng/ml LIF maintained the structural integrity (particularly the preservation of the basement membrane) when compared to the oocytes cultured in 50 ng/ml LIF, regardless the presence of FSH. In the absence of FSH, the percentage of antrum formation after 18 days of culture in the 50 ng/ml LIF group was significantly lower than in either the control group or the 10 ng/ml LIF group. However, this effect was not observed in the presence of FSH. The rate of resumption of meiosis was significantly higher in the 50 ng/ml LIF group in the absence of FSH in comparison with the control and 10 ng/ml LIF groups. Metaphase II was observed only when follicles were cultured in a combination of FSH and 50 ng/ml LIF. In conclusion, LIF alone does not interfere with antral formation and oocyte growth, but at concentration of 50 ng/ml and combined with FSH, it promotes oocyte maturation.  相似文献   

16.
The aim of this study was to improve the reliability of predicting the superovulatory response in Japanese Black cattle. Follicle counts and plasma anti-Müllerian hormone concentrations were analyzed within four days prior to the initiation of superovulation. The single nucleotide polymorphism (guanine or adenine) of the ionotropic glutamate receptor AMPA1 was determined. The plasma anti-Müllerian hormone concentration was positively correlated (P<0.001) with the numbers of all follicles and small (<5 mm) follicles and with the numbers of ova/embryos (P<0.001), fertilized embryos (P<0.001) and transferable embryos (P=0.005). There was no significant difference in follicle counts and superovulatory responses between donor cows bearing guanine/adenine or guanine/guanine alleles of AMPA1. Donor cows with a high plasma anti-Müllerian hormone concentration and homozygous for the guanine-containing allele of AMPA1 were most responsive to superovulation. The results suggest that physiological and genetic markers of superovulation have a synergistic effect on the accuracy of predictions of responsiveness.  相似文献   

17.
Two experiments were done using a two-by-two design to determine the effects of season and superstimulatory protocol on embryo production in wood bison. In Experiment 1 (in vivo-derived embryos), ovarian superstimulation was induced in female bison during the ovulatory and anovulatory seasons with either two or three doses of FSH given every-other-day (FSH × 2 vs. FSH × 3, respectively). Bison were given hCG to induce ovulation, inseminated 12 and 24 hr after hCG, and embryos were collected 8 days after hCG (n = 10 bison/group). In Experiment 2 (in vitro embryo production), ovarian superstimulation was induced in female bison during the ovulatory and anovulatory seasons with two doses of FSH, and in vivo maturation of the cumulus–oocyte complexes (COC) was induced with hCG at either 48 or 72 hr after the last dose of FSH. COC were collected 34 hr after hCG, and expanded COC were used for in vitro fertilization and culture. In Experiment 1, the number of follicles ≥9 mm, the proportion of follicles that ovulated, the number of CL, and the total number of ova/embryos collected did not differ between seasons or treatment groups, but the number of transferable embryos was greater (p < .05) in the ovulatory season. In Experiment 2, no differences were detected between seasons or treatment groups for any end point. The number of transferable embryos produced per bison was greatest (p < .05) using in vitro fertilization and was unaffected by season (1.5 ± 0.2 and 1.1 ± 0.3 during anovulatory and ovulatory seasons, respectively), in contrast to in vivo embryo production which was affected by season (0.1 ± 0.01 and 0.7 ± 0.2 during anovulatory and ovulatory seasons, respectively). Results demonstrate that transferable embryos can be produced throughout the year in wood bison by both in vivo and in vitro techniques, but the efficiency of embryo production of in vivo-derived embryos is significantly lower during the anovulatory season.  相似文献   

18.
To expand the breeding flock of Poll Dorset sheep in China, multiple ovulation and embryo transfer breeding program was applied to the limited number of imported Australian Poll Dorset sheep. This study investigated the effects of FSH from three different manufacturers, parity (nulliparous vs multiparous), repeated superovulation, oestrus induction, corpus luteum regression and oestrus delay on Poll Dorset superovulation. The results showed that gonadotropin FSH from Canada Folltropin‐V (Ca‐FSH) was successfully used for superovulatory treatment with 160 mg–200 mg dosage per ewe and recovered 12.91 ± 7.80 embryos. Multiparous ewes for superovulation treatment were significantly better nulliparous ewes (p < 0.05). The successive superovalution treatment reduced significantly embryo collection but did not affect transferable embryo number. Ewes with natural oestrus resulted in significantly higher number of embryos (13.83 ± 4.64) and of transferable embryos (12.00 ± 5.76) than ewes with induced oestrus (7.00 ± 4.92; 4.22 ± 3.42) and unknown oestrus cycle (5.94 ± 3.38; 3.19 ± 2.56, p < 0.05). The delayed oestrus ewes at 24 h after superovulatory treatment produced significantly fewer embryos and transferable embryos (0.92 ± 1.51 vs 0.42 ± 0.90) than those with normal oestrus (p < 0.01). Furthermore, the more transferable embryos were recovered from ewes with normal corpus luteum than those with corpus luteum regression (5.88 ± 5.09 vs 3.59 ± 4.30 and 8.83 ± 5.75 vs. 6.66 ± 5.41, p < 0.01). These results suggest that in our farm practice, a comprehensive treatment method by using the Canadian FSH (Folltropin‐V), plus choosing multiparous and natural oestrus ewes with normal corpus luteum might obtain an optimum embryo collection and embryos transfer in sheep.  相似文献   

19.
The aim of this study was to identify the occurrence of polyovular follicles in porcine ovaries. We investigated the presence of such follicles in relation to age, and compared the intrafollicular concentrations of steroid hormones between poly- and uniovular follicles. Then we measured the size, viability and the in vitro fertilizing ability of the oocytes from polyovular follicles. Histological examinations documented the occurrence of polyovular follicles in pigs at various stages of follicular growth. Within antral follicles, the number of polyovular follicles was higher in the ovaries of gilts than in sows ( P  < 0.01). We noticed differences in the viability and size of oocytes recovered from the same follicles. We noted a higher concentration of oestradiol-17β and a lower concentration of progesterone in polyovular follicles as compared with uniovular follicles ( P  < 0.01). The amount of embryos after in vitro -fertilization of oocytes from polyovular follicles was significantly lower than that from uniovular ones. Nevertheless, we found that some oocytes from polyovular follicles also have the capacity to be fertilized in vitro and be developed to the blastocyst stage.  相似文献   

20.
The effect of gonadotropin releasing hormone (GnRH) supplement was investigated in twenty eight FSH-treated buffalo cows. Animals were assigned to three groups; Group I: GnRH was given at standing heat (n=9), Group II: GnRH was given 8-12 hr after standing heat (n=8) and Group III: Control group with FSH alone (n=11). The responses (no. of corpora lutea and no. of anovulatory follicles), the number of recovered embryos and transferable embryos among the three groups were compared following slaughter of the animals on days 6 to 7 after first mating. The results indicated that the application of GnRH in FSH-treated animals gave no advantage by increasing in the number of ovulations or recovered embryos in all the treatment groups (P>0.05): 4.33 +/- 3.35 vs 3.88 +/- 4.09 vs 4.5 +/- 2.68 for corpora lutea, and 2.33 +/- 2.24 vs 2.0 +/- 3.20 vs 1.91 +/- 2.74 for recovered embryos respectively. GnRH treatment tended to reduce the number of anovulatory follicles but the finding was not significant; 6.11 +/- 3.3 vs 7.38 +/- 4.84 vs 10.18 +/- 2.74 follilcles (P>0.05). The supplementation of GnRH at 8-12 hr after standing heat seemed to produce more transferable embryos than those of treated at standing heat or the controls 1.63 +/- 2.77 vs 1.25 +/- 1.67 vs 1.36 +/- 1.69 embryos respectively.  相似文献   

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