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PubMed1997

Ovarian response and endocrine changes in buffalo superovulated at midluteal and late luteal stage of the estrous cycle: a preliminary report.

A study was designed to determine whether superovulatory and endocrine responses in buffalo differ when gonadotropin treatment is initiated at midluteal and late luteal stages of the estrous cycle. Twenty-eight buffalo were randomized into 4 groups (A, B, C and D). Buffalo in Groups A and B (n = 8 each) were superovulated with Folltropin (total dose 25 mg) and Lutalyse. Treatments in Group A were initiated between Days 8 to 10 (midluteal group) and in Group B between Days 13 to 15 (late luteal group) of the estrous cycle. Buffalo in Groups C and D (n = 6 each) were not superovulated and served as controls. Blood samples from all groups of buffalo were collected daily for plasma progesterone and estradiol determinations. The number of corpora lutea (CL) and unovulated follicles was recorded (following per rectum palpations) 5 or 6 d post-estrus. Buffalo in Groups A and B exhibited estrus in larger proportions and earlier (49.33 +/- 3.82 h and 46.67 +/- 2.46 h, respectively) than the control Groups C and D (77.33 +/- 5.33 h and 78.0 +/- 3.83 h, respectively). Mean number of CL was higher in Group B (3.38 +/- 0.46) than in Group A (2.25 +/- 0.75), however,the difference was not significant (P > 0.05). Plasma progesterone concentrations on the day of treatment were higher in late luteal superovulated and control groups than in midluteal superovulated and control groups. In both Groups A and B progesterone levels were significantly related (r = 0.78,0.76; P < 0.05) to the number of CL palpated after the superovulatory estrus. Progesterone levels on the day of estimation of ovarian response were approximately 4 times higher in Groups A and B than in Groups C and D. Peak estradiol concentrations were approximately twice as high in superovulated groups as in control groups.

Journal Article↗

PubMed1997

Induction of superovulation in cyclic rats by administration of decreasing doses of recombinant follicle stimulating hormone (Org32489).

The objective of this study was to set up a superovulation protocol in adult cyclic rats by using recombinant human follicle stimulating hormone (rhFSH; Org32489). Good results were obtained by treatment with decreasing doses of rhFSH (2.5 to 0.5 IU) during the dioestrus period. The number of corpora lutea (CL) found in rats treated with this protocol was 43.5 +/- 3.4; this is more than three times the number in saline-treated control rats (13.0 +/- 0.4). Fertilization of oocytes after superovulation was as good as after normal ovulation in terms of number of 2-cell stage embryos found 2 days after mating. The absolute number of implantations was twice the number observed in saline-treated control rats (23.3 +/- 1.8 versus 10.6 +/- 0.5); therefore the number of implantations per CL was lower in superovulated rats. The serum concentrations of luteinizing hormone (LH), endogenous FSH and oestradiol-17beta were decreased during rhFSH treatment, while the inhibin serum concentration was increased. The progesterone serum concentration was increased on the days of pro-oestrus and oestrus after treatment. No difference was observed in the testosterone serum concentration. Pretreatment with 10 IU rhFSH at oestrus before giving the decreasing doses of rhFSH during dioestrus reduced the ovulatory response. Finally, treatment with a constant low dose of rhFSH instead of a decreasing dose of rhFSH did not result in spontaneous ovulation. However, ovulation induction by means of a human chorionic gonadotrophin bolus resulted in superovulation in six out of eight rats. It is concluded that superovulation in cyclic rats can be achieved using rhFSH treatment. However, it was found that the type of rhFSH regimen was very important to achieve appropriate stimulation. The optimal protocol was treatment with decreasing doses of rhFSH during dioestrus. The oocytes retrieved could be fertilized as well as oocytes of saline-treated control rats. The results also indicate that treatment with higher doses of rhFSH might induce a desensitization for FSH and LH.

Animals↗

PubMed2003

Optimization of superovulation induction by human menopausal gonadotropin in guinea pigs based on follicular waves and FSH-receptor homologies.

The guinea pig represents an excellent animal model for the study of reproduction in humans and most domestic animals because unlike the mouse and rat, it undergoes a complete estrous cycle. In this study, we investigated the availability of ovarian oocytes during the estrous cycle, and the follicle stimulating hormone (FSH) receptor (FSH-R) homologies between guinea pigs and other species, in order to identify an effective gonadotropin and optimal time-of-application for the induction of superovulation in the guinea pig. The number of collectable ovarian oocytes showed biphasic changes with peaks at the midluteal and pre-ovulatory stages. On the other hand, the number of oocytes that matured in vitro remained constant ( approximately 10 oocytes) until day 14 post-ovulation and increased thereafter. The deduced amino acid sequence of the guinea pig FSH-R showed greater similarity to the primate FSH-R than to the rodent FSH-R, which suggests that commercially available human menopausal gonadotropin (hMG) may be a better inducer of superovulation in guinea pigs. Indeed, significantly more oocytes (5.4 +/- 1.6, range 0-17, n = 10) were obtained from hMG-treated guinea pigs at the pre-ovulatory stage than during spontaneous ovulation (3.6 +/- 0.1, n = 96; P < 0.05), whereas guinea pigs that received hMG at the midluteal stage (n = 3) did not ovulate. These results indicate that hMG is an effective, albeit stage-dependent, inducer of superovulation in the guinea pig, and that FSH-R homologies should be taken into account when choosing hormones for superovulation.

Amino Acid Sequence↗

PubMed1980

Inhibitory effect of progesterone on follicular growth and induced superovulation in the rat.

We investigated the effect of exogenous progesterone on follicular growth and pregnant mares' serum gonadotropin and human chorionic gonadotropin (PMS-HCG) induced superovulation in intact and hypophysectomized immature rats. Although the administration of progesterone during PMS-HCG injections had no effect on superovulation, the administration of progesterone beginning 3 days before PMS injection inhibited superovulation in both intact and hypophysectomized rats. In order to study the mechanism of inhibition of superovulation by pretreatment with progesterone, an autoradiographic study using tritiated thymidine was done in hypophysectomized rats just before PMS injection. The labelling indices of granulosa cells were significantly decreased by the administration of progesterone (p < 0.001). Treatment with progesterone resulted in an increase of the follicles in early stages of atresia with pycnotic nuclei in granulosa cells surrounding apparently normal oocytes. Ovarian histology and serum and ovarian tissue concentrations of estradiol were then examined in hypophysectomized rats 20 h after HCG injection. Large Graafian follicles and corpora lutea were rarely seen in rats previously given progesterone, whereas many large Graafian follicles and corpora lutea were observed in the control rats. The concentrations of estradiol in the progesterone-pretreated rats were significantly reduced in serum (p < 0.02) and slightly reduced in ovarian tissues when compared with controls.

Animals↗

PubMed1994

Optimization of superovulation in the reproductively mature mouse.

Optimum gonadotropin doses and chronology were established for the induction of superovulation in sexually mature hybrid mice (BALB/cBy x C57BL/6By). A regime of 12 IU pregnant mares' serum gonadotropin (PMSG), followed 48 hr later by 20 IU human chorionic gonadotropin (hCG) administered 1 hr before the midpoint of the light cycle (1200), gave the maximum ovulatory response. There was no evidence that endogenous luteinizing hormone influenced the superovulation response to exogenous gonadotropins. Fewer than 50% of zygotes reached the blastocyst stage (90-93 hr post hCG), with the greatest rate of loss at the two- to four-cell stage. Litter size following superovulation was 19.6 +/- 0.9. There was no significant difference between the number of blastocysts observed and litter size. Similarly, counts of mature follicles in ovaries prior to hCG stimulation were not significantly greater than the number of secondary oocytes that subsequently ovulated. These data indicate that standard superovulation protocols may require fine-tuning to maximize productivity and confirm that embryo loss is greatest between the first cleavage division and blastocyst formation.

Analysis of Variance↗

PubMed1981

Superovulation-induced intrauterine growth retardation in mice.

Existing animal models for inducing intrauterine growth retardation (IUGR) involve severe maternal compromise or acute fetal insult. We postulated that superovulation would produce IUGR gradually by enhancing fetal competition for nutrients. Mice were superovulated with pregnant mare serum and human chorionic gonadotrophin and killed on day 19 of gestation. Compared to controls, the mean number of fetuses was significantly increased; body, brain, liver, and placental weights were reduced; and brain/liver weight ratios were increased. Additional mice underwent partial unilateral oophorectomy before superovulation. Marked asymmetry in the number of fetuses in the two uterine horns of the same mother was produced, and the fetuses on the more crowded side manifested smaller brains and livers an increased brain/liver ratios. In the mouse, superovulation is a simple, preconceptual method for achieving IUGR and may be combined with partial unilateral oophorectomy to permit comparisons between fetuses with different growth characteristics within the same mother.

Animals↗

PubMed1985

Biochemical and morphologic effects of ethanol on fetuses from normally ovulating and superovulated mice.

To further our understanding about the teratogenicity of ethanol, we studied the changes produced by this compound in the incorporation of glucose 14C into several tissue fractions of 12-day mice fetuses and the morphologic alterations present at day 19 of gestation. Furthermore, to determine if the fetal toxicity of ethanol was modified by changes in the characteristics of the pregnancy, we performed similar biochemical and morphologic observations in fetuses from superovulated mice. Maternal ethanol administration caused biochemical alterations in the fetal tissues of both normally ovulating and superovulated mice, but it caused morphologic alterations predominantly in fetuses from superovulated animals. The prevalent morphologic alteration found in ethanol-treated animals was a hemorrhagic lesion dorsal to the lumbar or dorsal vertebrae. These results suggest that superovulation increases the susceptibility of the fetal mice tissues to the teratogenic effects of ethanol.

Abnormalities, Drug-Induced↗

PubMed1995

Superovulation, IGFBP-1 and birth weight.

In this study, the effect of superovulation on the circulating levels of insulin-like growth factor binding protein-1 (IGFBP-1) has been investigated. IGFBP-1 levels were measured in singleton pregnancies achieved either naturally (n = 203) or following superovulation, in-vitro fertilisation and embryo transfer (IVF-ET) with either pituitary desensitisation with buserelin and superovulation with human menopausal gonadotrophin (b/hMG) followed by IVF-ET (n = 15) or with clomiphene citrate and hMG (CC/hMG) followed by IVF-ET (n = 15, 1st trimester only). The circulating levels of IGFBP-1 were similar in all three groups during the first trimester, and in both normal and b/hMG pregnancies in the second, but were significantly higher during the third trimester in b/hMG pregnancies than in normal pregnancies (P = 0.0002). The birth weights were significantly lower in the b/hMG group (P = 0.04), but not in the CC/hMG group compared with natural conceptions. Gestational age at delivery was similar in control and b/hMG pregnancies, but significantly reduced in CC/hMG pregnancies (P = 0.04). These data suggest that pregnancies achieved following superovulation with b/hMG are associated with elevated levels of IGFBP-1 during the third trimester of pregnancy and reduced birth weight.

Adult↗

PubMed1986

Effects of superovulation, arachidonic acid or endometrium on release of prostaglandins and synthesis of proteins by bovine trophoblast.

This study was conducted in vitro to examine factors that may regulate prostaglandin release by bovine trophoblast and endometrial slices. Trophoblastic tissues and endometrial slices were recovered from superovulating and normally-ovulating cattle on day 16 or 20 of pregnancy and incubated for 24 h. Release of PGF2 alpha and 13,14-dihydro-15-keto-PGF2 alpha (PGFM), and incorporation of [14C]-leucine into proteins were quantified and expressed per microgram DNA, which gives a measure of cellular activity. Activity of trophoblastic tissue for synthesizing protein was decreased (P less than .05) and for releasing PGFM was increased (P less than .05) on day 20 compared to day 16 of pregnancy. Neither superovulation nor day of pregnancy altered trophoblastic activity for releasing PGF2 alpha. Superovulation increased (P less than .05) endometrial release of PGF2 alpha. Endometrial release of PGF2 alpha was less (P less than .05) on day 20 than on day 16 of pregnancy. When arachidonic acid (0, 100, 200 or 400 micrograms) was added at the start of incubation, trophoblastic release of PGF2 alpha changed (P less than .05) quadratically with dose of arachidonic acid. When arachidonic acid was added 8 h after the start of incubation, trophoblastic release of PGF2 alpha increased linearly (P less than .01) with dose of arachidonic acid. Adding arachidonic acid to incubation medium did not affect trophoblastic or endometrial protein synthesis. Endometrial slices suppressed (P less than .05) trophoblastic protein synthesis and release of PGF2 alpha. Apparently, endometrium can modulate trophoblastic release of prostaglandins and synthesis of proteins in vitro, and trophoblastic tissue from superovulated cattle 16 or 20 days pregnant can be used to study trophoblastic synthesis of prostaglandins and proteins.

Animals↗

PubMed1989

Maternal factors influencing development of embryos from mice superovulated with gonadotropins.

In NMRI mice superovulation with pregnant mare serum gonadotropin (PMSG) and human chorionic gonadotropin (hCG) increased mating rate, number of implantation sites, rate of advanced and delayed resorptions, as well as retarded sternebral ossification and cleft palate. On day 3 of gestation in preimplantation embryos, cell number and mitotic index were lower after superovulation than after spontaneous ovulation. However, when preimplantation embryos from superovulated and control females were transferred on day 3 of pregnancy to pseudopregnant recipients (10 embryos per female) no differences could be detected between the two groups of fetuses at term. The results of the embryo transfer experiments indicate that abnormal embryonic development after superovulation with gonadotropins is predominantly induced by effects of the hormone treatment on the maternal uterine environment.

Abnormalities, Drug-Induced↗

PubMed2006

Embryo production from superovulated sheep inseminated with sex-sorted ram spermatozoa.

An experiment was undertaken to assess the fertilizing capacity of sex-sorted, frozen-thawed ram spermatozoa, artificially inseminated into superovulated ewes, and the quality and survivability of the resultant pre-sexed embryos. Synchronized (intravaginal progestagen pessary and GnRH) donors were superovulated using PMSG and repeat ovarian stimulation with FSH before insemination. Ewes (n=67) were inseminated with either 30x10(6) or 15x10(6) motile non-sorted (control) or 15x10(6) motile sex-sorted (sorted) frozen-thawed spermatozoa (control: C30 or C15; sorted: S15, respectively) and the resultant embryos transferred immediately into synchronized recipients (n=160). The percentage of transferable embryos, pregnancy rate and embryo survival were similar (P>0.05) across all treatments. Oocyte cleavage rate was higher for ewes inseminated with S15 (172/230; 74.8%; P<0.05) than for C15 (97/151; 64.2%) or C30 (89/141; 63.1%) spermatozoa. Of the lambs resulting from embryos produced with sex-sorted spermatozoa, 86/93 (92.5%) were born of the predicted sex. This study demonstrated for the first time that pre-sexed offspring derived from superovulated sheep can be produced following transfer of embryos. Furthermore, sex-sorting by flow cytometry did not compromise the in vivo fertilizing capacity of ram spermatozoa in superovulated sheep, nor did it affect the quality or survivability of the resultant embryos.

Animals↗

PubMed1996

In vitro fertilization, gamete intrafallopian transfer, and superovulation with intrauterine insemination: efficacy and potential health hazards on babies delivered.

OBJECTIVE: The purpose of this article was to review the efficacy and potential hazards of assisted conception. STUDY DESIGN: A review of pertinent scientific articles published in English was done. RESULTS: There are no adequate prospective, randomized, controlled, or comparative studies of sufficient power on the efficacy of in vitro fertilization, gamete intrafallopian transfer, and superovulation with intrauterine insemination in well-defined infertile couples. In vitro fertilization can overcome tubal sterility. The pregnancy per cycle is 19.8% and delivery per cycle is 16.0% for in vitro fertilization (all indications) and 29.5% and 19.8%, respectively, for gamete intrafallopian transfer. In limited prospective studies, in vitro fertilization, gamete intrafallopian transfer, and superovulation with intrauterine insemination have similar fecundity. Multiple births from in vitro fertilization and gamete intrafallopian transfer are increased, whereas preterm labor and low-birth-weight babies are significantly more common, even in singletons. CONCLUSION: The efficacy or relative superiority of IVF, gamete intrafallopian transfer, and superovulation with intrauterine insemination in nontubal subfertility remains to be shown by properly designed, prospective, randomized, controlled, or comparative studies. Therefore less invasive and less expensive methods such as expectant management or superovulation with intrauterine insemination should be used before embarking on in vitro fertilization and gamete intrafallopian transfer. Further studies on the outcome of babies delivered after assisted conception are required.

Female↗

PubMed1996

Menotropins alone are superior to a clomiphene citrate and menotropin combination for superovulation induction among clomiphene citrate failures.

OBJECTIVE: To examine the difference in efficacy between two protocols of superovulation induction with IUI among infertile couples. DESIGN: A prospective randomized trial. SETTING: Normal human volunteers in an infertility clinic. PATIENTS: Consecutively treated patients attending our infertility clinic for superovulation induction with IUI who had been unsuccessfully treated by clomiphene citrate (CC). INTERVENTIONS: Infertile couples were randomized to undergo one of two controlled ovarian hyperstimulation protocols. Group A patients received daily hMG beginning on cycle day 3, whereas group B patients were administered CC days 3 through 7, followed by hMG from day 7 onward. Randomization was performed using a random numbers table. In both groups, ovulation was triggered by 5,000 IU hCG and IUI was performed by 36 hours. MAIN OUTCOME MEASURES: Studied cycle performance parameters included peak E2, number of dominant and intermediate-sized follicles recruited, endometrial thickness and pattern, and frequency of monitoring. RESULTS: Data analysis demonstrated no significant difference between the two groups with respect to patient age, parity, weight, indication for superovulation and IUI, number of dominant follicles recruited, peak E2, or mean number of total motile sperm inseminated. Endometrial thickness and pattern differed between treatments, however, with group A demonstrating relatively thicker and proportionately more trilaminar patterns than group B. Group A had significantly more serum E2 measurements, as well as transvaginal sonograms performed, when compared with group B. Pregnancy rates for groups A and B were 0.192 and 0.091, respectively. Of 25 pregnancies in group A, 7 (0.28) were multiples, whereas there were no multiple gestations in group B. CONCLUSION: For patients undergoing superovulation with IUI, a menotropin-alone protocol yields significantly higher pregnancy rates than one using a combination of menotropin with CC. These differences could not be explained by patient characteristics. Among cycle performance parameters, endometrial thickness and pattern differed significantly between the two groups.

Adult↗

PubMed1998

Comparison of intrauterine insemination with timed intercourse in superovulated cycles with gonadotropins: a meta-analysis.

OBJECTIVE: To compare timed intercourse and IUI with the husband's sperm in patients with unexplained infertility who are undergoing superovulation with gonadotropins. DESIGN: Meta-analysis. All published reports of randomized, prospective studies with an English-language abstract extracted from MEDLINE were analyzed. A crossover search was done from the papers obtained. SETTING: Academic center. PATIENT(S): Couples with unexplained infertility. INTERVENTION(S): Meta-analysis of studies evaluating patients superovulated with gonadotropins and randomized for timed intercourse or IUI. MAIN OUTCOME MEASURE(S): Pregnancy rates (PRs) were obtained. The common odds ratio (OR) and 95% confidence intervals (95% CI) were calculated. RESULT(S): There were 49 pregnancies in 431 cycles of timed intercourse (11.37%), whereas there were 110 pregnancies in 549 cycles of IUI (20.04%). The PRs for IUI were significantly increased compared with those for timed intercourse in superovulation cycles (common OR = 1.84; 95% CI = 1.30-2.62). CONCLUSION(S): On the basis of the meta-analysis of 980 cycles in randomized and prospective studies, a patient's chances of becoming pregnant are greater with IUI with her husband's sperm than with timed intercourse in cycles superovulated with gonadotropins.

Adult↗

PubMed2003

Improvement in recovery of embryos/ova using a shallow uterine horn flushing technique in superovulated Holstein heifers.

The aim of this study was two-fold: (1). to compare recovery of embryos/ova from superovulated Holstein heifers by flushing the uterine horns through insertion of the catheter very close to the tip of the horn (deep) or just after the uterine bifurcation (shallow) and (2). to evaluate the hormonal and superovulatory response to estradiol benzoate (EB) treatment prior to superovulation. Ten Holstein heifers (12-16 months) underwent two superovulatory treatments in a cross-over design. Heifers were treated with decreasing doses of FSH from Days 8 to 12.5 of a synchronized estrous cycle. At 4 days prior to superovulation, half of the heifers received EB (5mg, i.m.) or served as Controls, followed by the alternative treatment in the subsequent superovulation. At embryo recovery, one uterine horn was flushed with deep ( approximately 7 cm caudal to the tip of the horn) and the other with shallow ( approximately 5 cm cranial to the beginning of the uterine bifurcation) flushing techniques. Embryos/ova were recovered, counted, and scored. Number of ovulations was estimated by ultrasound. Pretreatment with EB reduced circulating FSH and regressed the first wave dominant follicle with no change in number of large follicles, number of ovulations, number of embryos/ova recovered, or number of transferable embryos. The shallow flushing technique was superior to the deep technique for number of embryos/ova recovered per horn (5.4+/-1.1 versus 3.9+/-0.8) or percentage of embryos/ova recovered per CL (63.9+/-8.6% versus 37.4+/-6.5%). Thus, flushing the entire uterine horn increased recovery of embryos/ova.

Administration, Intravaginal↗

PubMed1999

Effects of superovulation on endogenous LH secretion in cattle, and consequences for embryo production.

Stimulation of follicular growth during superovulation is achieved by the injection of FSH or compounds with high FSH-bioactivities. However, some LH-activity is required for follicle maturation. It is of relevance to evaluate, therefore, the effect of superovulatory treatments on endogenous LH secretion. Luteinizing hormone is secreted in discrete pulses, and the pattern of pulsatile LH secretion during superovulation is reviewed. Four of five published studies have shown that LH pulse frequency is significantly reduced by injection of eCG or FSH preparations. This suppression appears within 8 h of treatment Effects of superovulation on LH pulse amplitude are less consistent. The reasons for the decrease in pulse frequency have been investigated, and although the answer is not definitive, it would seem that increased follicular estradiol, acting perhaps in synergism with progesterone, may play a role. Changes in plasma progesterone concentrations are not related to changes in LH pulse frequency. What is the significance of decreased LH pulse frequency? We attempted to investigate this by inducing LH pulses during superovulation, but the result was a major reduction in ovulation rate. More research is required to determine if modification of endogenous LH secretion can improve superovulatory responses.

Animals↗

PubMed2003

Differences between Brahman and Holstein cows in response to estrus synchronization, superovulation and resistance of embryos to heat shock.

Embryos from Bos indicus are more resistant to elevated culture temperature (i.e. heat shock) than embryos from some Bos taurus breeds. The present experiment was designed to determine if Brahman embryos have greater resistance to heat shock than Holstein embryos at a stage in development before the embryonic genome was fully activated. A second objective was to test breed effects on estrus synchronization and superovulation responses. A total of 29 Brahman and 24 Holstein cows were subjected to estrus synchronization using gonadotropin releasing hormone (GnRH) and prostaglandin F2alpha (PGF2alpha) superovulation. Embryos were collected at 48 h and day 5 after insemination. There was a tendency for a lower proportion of Brahmans to be detected in standing estrus than Holsteins. There were no differences between breeds in the proportion of cows detected in estrus using both tailpaint and standing estrus as criteria or in interval from PGF2alpha to estrus. The degree of synchrony in estrus was greater for Brahmans. Superovulation response was generally similar between breeds. At 48 h after insemination, there was a tendency for a greater proportion of Brahman oocytes to have undergone cleavage. Uncleaved oocytes were cultured for an additional 24 h-at this time, cleavage rate was similar between breeds. When embryos reached the 2-4-cell stage, they were heat-shocked for 4.5 h at 41 degrees C. This heat shock reduced the proportion of embryos that developed to the blastocyst stage but there was no breedxtreatment interaction. At day 5 after insemination, the number of embryos recovered was too low to allow comparison of breed effects. In conclusion, genetic effects on cellular thermotolerance that make Brahman embryos more resistant to heat shock are not expressed at the 2-4-cell stage. There were few differences between Brahman and Holstein in response to estrus synchronization and superovulation. The fact that cleavage tended to occur earlier in Brahman than Holstein embryos suggests breed differences in timing of ovulation, fertilization or events leading to cleavage.

Animals↗

PubMed1997

Superovulation in cattle: effect of FSH type and method of administration on follicular growth, ovulatory response and endocrine patterns.

Although different FSH preparations and injection regimens are used to superovulate cattle, the optimum treatment regimen and blood concentrations of FSH to induce effective superovulatory responses are currently not known. The current objective was to evaluate the pattern of follicular growth, oestradiol-17 beta(E2) concentrations and yield of embryos in heifers following superovulation with two different pFSH preparations reportedly differing in LH content. In experiment 1, 90 synchronised heifers were superovulated at mid-cycle using a 2 x 2 factorial design comparing Folltropin (Vetrepharm; low LH) with Pluset (Serovet; FSH:LH ratio 1:1) administered either as a single or multiple (8 for Folltropin, MF and 10 for Pluset, MP) injections. Animals were inseminated during oestrus which was induced with prostaglandin F2 alpha analogue and embryos were recovered 7 days later. Overall, Pluset treatments compared with Folltropin resulted in more ovulations and unfertilized or degenerate embryos (P < 0.05). Multiple injections resulted in more (P < 0.05) freezable (MF = 55 +/- 1.2; MP = 3.8 +/- 1.0) and transferable embryos (MF = 2.68 +/- 0.9; MP = 2.71 +/- 0.9) than single injections (SF = 2.2 +/- 0.5 and 1.0 +/- 0.3 respectively; SP = 2.6 +/- 0.8 and 1.3 +/- 0.4 respectively); there was also a higher (P < 0.05) percentage embryo recovery rate. In two subsequent experiments, animals (n = 17) were superovulated with either single or multiple injections of Folltropin or Pluset as described and blood samples were collected and analysed for E2 concentrations. Ovarian scanning was carried out until 72 h after the first FSH injection, to count medium (5-9 mm) and large (> or = 10 mm) follicles. Heifers treated with SP had higher E2 concentrations in comparison with heifers treated with SF at 18, 36-48 and 84-96 h after the FSH injection. There were no differences in E2 concentrations in heifers treated with MF or MP treatments. Heifers treated with SP had greater numbers of follicles compared to SF treated heifers (21.0 +/- 3.1 vs 13.9 +/- 2.2; P = 0.089) on the third day after FSH injection. There were no differences between the numbers of medium and large follicles in heifers treated with MF or MP at any time throughout the experimental period. These data indicate that a single injection of Folltropin or Pluset can result in multiple ovulations and that the E2 profiles are different following single injections of either Folltropin or Pluset.

Animals↗