The objective of this study was to examine the effect of donor breed on pronuclear-stage embryo yield to be used for DNA microinjection in a transgenesis goat program. Twelve Canindé and twelve Saanen goats were heat synchronized using a progestagen-cloprostenol treatment. Forty-eight hours before the sponge removal, superovulation was induced with a total administration of 4.4 mg/kg bodyweight NIH-FSH-P1, given twice daily in decreasing doses over 3 days. In addition, goats received 100 μg of GnRH and they were hand-mated at 36 and 48 h after progestagen removal. Embryo recovery was performed by oviduct flushing at 72 h after sponge removal. Embryos were microinjected with a DNA construct and noticeable swelling of the nuclei was the criterion for successful microinjection. The total diameter, cytoplasm diameter, zona pellucida thickness and pronuclei diameter were measured for each microinjected embryo. A higher (p < 0.05) percentage of fertilized ova was observed in Canindé (89.9%) than Saanen (36.2%) goats. In addition, Canindé donors produced a higher percentage of pronuclear embryos when compared with Saanen: 72.5% vs 20.6% (p < 0.05), respectively. Successful microinjection was verified in 96.7% and 73.3% of times in Canindé and Saanen embryos, respectively (p < 0.05). Significant differences were observed for all morphometric parameters except for cytoplasm diameter. In conclusion, under our study experimental conditions, Canindé were more efficient than Saanen goats concerning the pronuclear embryo yield and manipulation. The use of Canindé goats in transgenesis programs could be increase the interest in their breeding and could be contribute to saving them from extinction.

This study was aimed at developing a hormonal treatment protocol in order to optimize the proportion of pronuclear-stage embryos to be used for DNA microinjection in a goat transgenic founder production programme. A total of 46 adult BELE and 47 adult standard goats (1-5 years old) were used as donors and recipients, respectively. They were heat-synchronized using intravaginal sponges containing 60 mg medroxyprogesterone acetate for 10 days with an injection of 125 microg cloprostenol on the morning of the eighth day. Recipients were injected with 400 IU eCG at the time of sponge removal while donors received a total of 133 mg NIH-FSH-P1 (Folltropin-V) given twice daily in decreasing doses over 3 days starting 48 h before sponge removal. Ovulation was induced in donors by injecting 100 microg of GnRH at 24 h (GnRH24) or 36 h (GnRH36) after sponge removal. Embryo recovery was performed by oviduct flushing following a standard mid-ventral laparotomy procedure. The proportion of embryos in the pronuclear stage of development was higher in the GnRH36 group (90% vs 34%, p < 0.01). Embryos were microinjected with a DNA expression cassette followed by transfer to the oviduct of synchronized recipients. A higher, yet not statistically significant, pregnancy rate was found in the recipients transferred with pronuclear-stage embryos compared with those transferred with 2-cell-stage embryos (64% vs 37%, chi-square p = 0.06). One transgenic female founder was produced from the group of recipients transferred with pronuclear-stage microinjected embryos.

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.

The objectives of this study were 1) to compare pregnancy rates resulting from 2 methods of insemination using low sperm numbers and 2) to compare pregnancy rates resulting from hysteroscopic insemination of 5 x 106 nonsorted and 5 x 106 spermatozoa sorted for X- and Y-chromosome-bearing populations (flow sorted). Semen was collected with an artificial vagina from 2 stallions of known acceptable fertility. Oestrus was synchronised (June to July) in 40 mares, age 3-10 years, by administering 10 ml altrenogest orally for 10 consecutive days, followed by 250 microg cloprostenol i.m. on Day 11. All mares were given 3000 iu hCG i.v. at the time of insemination to induce ovulation. Mares were assigned randomly to 1 of 3 treatment groups: mares in Treatment 1 (n = 10) were inseminated with 5 x 10(6) spermatozoa deposited deep into the uterine horn with the aid of ultrasonography. Mares in Treatment 2 (n = 10) were inseminated with 5 x 10(6) spermatozoa deposited onto the uterotubal junction papilla via hysteroscopic insemination. Mares in Treatment 3 (n = 20) were inseminated using the hysteroscopic technique with 5 x 10(6) flow sorted spermatozoa. Spermatozoa were stained with Hoechst 33342 and sorted into X- and Y-chromosome-bearing populations based on DNA content using an SX MoFlo sperm sorter. Pregnancy was determined ultrasonographically at 16 days postovulation. Hysteroscopic insemination resulted in more pregnancies (5/10 = 50%) than did the ultrasound-guided technique (0/10 = 0%; P<0.05) when nonsorted sperm were inseminated. Pregnancy rates were not significantly lower (P>0.05) when hysteroscopic insemination was used for sorted (5/20 = 25%) and nonsorted spermatozoa (5/10 = 50%). Therefore, hysteroscopic insemination of low numbers of flow sorted stallion spermatozoa resulted in reasonable pregnancy rates.

Previous studies have demonstrated the facilitating effect of a single cloprostenol treatment postinsemination on ovulation and pregnancy rate in dairy cattle and Italian buffalos. This study was conducted to test the effects of 500 microg cloprostenol given intramuscularly immediately postinsemination to 55 primiparous and 60 multiparous Holstein cows (Bos taurus; TR) of a typical dairy operation in East Germany and to compare them with 57 primiparous and 48 multiparous saline-treated cows (CON). Animals of the TR and CON groups did not differ or only differed marginally for age at treatment, interval calving-treatment, lactation number, milk production on the day of treatment, body condition score, and their peri- and postparturient case histories. All animals were clinically and reproductively healthy on the day of treatment. They were inseminated once 12h after the onset of estrus, scanned 24h after insemination to confirm ovulation, and tested for pregnancy by transrectal palpation between Days 42 and 48 postinsemination. Treatment did not affect the number of cows ovulating. The overall combined pregnancy rate (PR) was 47.3%. Pregnancy rate did not differ statistically between TR and CON (46.1% vs. 48.6%; P>0.05). In conclusion, this study failed to demonstrate beneficial effects of a postinsemination treatment of primiparous and multiparous cows with cloprostenol on ovulation and PR in a typical dairy cattle operation in East Germany.

This study investigated the effects of pregnant mare se-rum gonadotropin (PMSG) and cloprostenol (CLO) on estrus induc-tion and synchronization, uterine development, and follicle-stimulating hormone receptor (FSHR) expression in mice. A total of 105 Kunming pre-puberty mice were divided into seven subgroups. Three PMSG sub-groups were injected intraperitoneally with 10, 20, and 40 IU PMSG twice (on days 0 and 4), and three CLO subgroups were injected intra-peritoneally with 10, 15, and 20 μg cloprostenol acetate twice (on days 0 and 4). The results showed that 93.33 and 66.67% of synchronized mice displayed estrus within 18.68-37.59 h following CLO and PMSG exposure, respectively. Estrus numbers, estrus onset time, and estrus rates in CLO and PMSG groups were greater than in control groups (CG) (P < 0.05). Uterine weights of the PMSG group were higher than that of CLO and CG groups, and the uterine horn longitudinal diameters in experimental mice were greater than CG. Expression levels of FSHR proteins in CLO and PMSG groups increased slightly when compared to CG. In conclusion, CLO and PMSG administration did not clearly af-fect the expression of uterine FSHR proteins in mice. Moreover, PMSG and CLO treatments synchronized estrus and enhanced the uterine de-velopment of mice. The efficacy of CLO on estrus synchronization was greater than PMSG, and the effects of PMSG on uterine development were stronger than CLO. These results have important significance re-garding the modulation of animal reproductive functions.

The goal of the present study was to compare the ovarian response, oocyte yields per animal, and the morphological quality of oocytes collected by ultrasound guided follicular aspiration from Holstein cows treated either with FSH or eCG. Twenty four normal cyclic, German Holstein cows were randomly divided into two groups. Fourteen cows received 3000 IU eCG on day-4 prior to ovum pick-up (OPU) (day 0), 2 days later (day-2), 625 microg cloprostenol was administered. On day-1 GnRH was administered i.m. and 24h later OPU (day 0) was performed. In ten cows a total dose of 500 IU follicle stimulating hormone (Pluset) was administered intramuscularly in a constant dosage for 4 days with intervals of 12h, starting on day-5. Luteolysis was induced by application of 625 microg cloprostenol on day-2. On day-1 (24h after the last FSH treatment) GnRH was administered i.m. and 24h later OPU (day 0) was performed. Ovarian follicles were visualized on the ultrasound monitor, counted and recorded. All visible antral follicles were punctured. Recovered oocytes were graded morphologically based on the cumulus investment. Average follicle number in ovaries was higher in FSH group than eCG group (p<0.05). Oocyte yields per animal did not differ between FSH and eCG groups. The proportion of grade A oocytes was higher in the FSH group in the than eCG group (p<0.05). Likewise, rate of grade C oocytes in FSH group were lower than eCG group (p<0.05). In conclusion, these results suggest that ovarian response, follicle number in ovaries and oocyte quality are affected by the type of gonadotropin and FSH is better alternative than eCG for OPU treatment.

In a large Croatian commercial unit, 1204 of parity 2-7 late pregnant sows were from January till Mai 2002 randomly assigned to four farrowing groups and treated as follows: Group one (n = 302 sows) received a single perivulvar injection of 175 g cloprostenol at day 113 of pregnancy. The remaining animals have received a treatment as group one and were additionally treated with 10 IU of oxytocin intramuscularly 6 hours after prostaglandin application (Group two, n = 311), or with 10 IU of oxytocin 6 and 12 hours later (Group three, n = 291), or 10 IU of oxytocin 6, 12 and 18 hours later (Group four, n = 300). Onset of farrowing, duration of parturition, total born litter size and stillbirth rate were evaluated. Except total born litter size, combined oxytocin + cloprostenol treated sows revealed significantly (p < 0.01) better results as the only with cloprostenol treated ones. Multiple oxytocin application increased the predictability of farrowing. The application of multiple oxytocin injections following prostaglandin partusinduction are recommended for batch farrowing of sows in large production units.

Four experiments were carried out in Merino ewes during a period of 4 years to determine the long-term effects of immunization against different synthetic peptides mimicking the amine terminal of the alpha subunit of porcine inhibin. Peptides were conjugated to human serum albumin and 100-200 micrograms emulsified in Freund's complete adjuvant for the primary immunization. Usually two booster injections were given at monthly intervals with 50-100 micrograms conjugated peptide using either incomplete Freund's adjuvant or Montanide:Marcol. In some experiments a further immunization was carried in the next year. Blood samples were taken 10 days after each immunization, during the luteal phase, for estimation of gonadotrophin concentrations and determination of inhibin antibody titres. One day after blood sampling cloprostenol was used to induce luteolysis and laparoscopy was performed in the subsequent oestrous cycle. Immunization of ewes with synthetic peptides 1-32, 1-26, 7-26 and 8-30 resulted in large increases in the ovulation rate (OR). An approximately two-fold increase in OR was observed following the first booster immunization with these peptides and a three- to five-fold increase after the second booster immunization. Immunization with these large peptides resulted in a sustained increase in OR for a period of at least 1 year after the second booster immunization. Of the shorter peptides, peptides 10-26 and 13-26 gave a reasonable ovulatory response, although it was more difficult to obtain a response with peptides 1-16, 8-22, 13-25, 8-19 and 10-19; peptides 7-13 and 1-6 gave no response (but were examined for one breeding season only). The smaller peptides led to lower inhibin antibody titres that were not necessarily associated with increased follicle-stimulating hormone (FSH) or OR. More intensive blood sampling in one experiment showed that following primary immunization against peptide 1-32 there was a transient increase in plasma FSH, which did not lead to an increased OR. Moreover, a prolonged period of raised FSH after the first booster was significantly correlated with increased OR. In these animals antibody titres were only slightly increased after primary immunization, but after the first booster immunization higher titres were observed that were significantly correlated with trough FSH values and the subsequent OR. These results are interpreted as showing that (1) to obtain an increase in OR peptides 1-32, 1-26 and 7-26 are suitable as immunogens; (2) smaller peptides are less reliable, often require multiple injections, and the response may be delayed; and (3) an extended period of raised plasma FSH is needed to give a large ovulatory response.

Data collected from two controlled breeding field trials involving 561 Bos indicusxBos taurus cows and heifers were analyzed for estrous and fertility response following a cloprostenol ICI-80, 996 (CLP) synchronization regime. Fertility data were discussed in a companion paper (1). In Trial 1, 128 animals were assigned to four treatments: 1) controls which were inseminated at the naturally occurring estrus; 2) Animals artificially inseminated at approximately 72 hr and 96 hr following a second CLP; 3) Animals artificially inseminated at approximately 72 hr following a second CLP; and 4) Animals artificially inseminated approximately 12 hr after detection of estrus post-second CLP. Trial II included 391 heifers distributed among six treatments: 1) Artificially inseminated between 70 and 90 hr post-second CLP; 2) Sham inseminated between 70 and 90 hr post-second CLP; 3) Processed with no manipulation of the genital tract between 70 and 90 hr post-second CLP; 4) Artificially inseminated approximately 12 hr after the detection of estrus following a second CLP; 5) Artificially inseminated at the naturally occurring estrus and 6) Non-treated heifers exposed to fertile bulls. Cloprostenol ICI-80996 was effective (P<.01) in synchronizing estrus in comparisons of treated vs non-treated controls in Trials I and II (82 vs 29%; 57 vs 19%, respectively). However, a significant reduction in the expression of estrus was observed following Timed AI when compared to heifers bred 12 hr after detection of CLP-induced estrus in Trial II (37 vs 54%, P<.05). The authors conclude that a single timed insemination of Brahman crossbred heifers suppresses the behavioral expression of estrus. Other evidence (1) indicates that the fertility during this period is similarly reduced.

The present study was developed to assess possible effects on ovulatory response and embryo yields arising from the presence of a corpus luteum (CL) at the time of initiation of the progestagen treatment used in superovulatory protocols in sheep. In breeding season, estrus was synchronized in 25 Manchega ewes using 40 mg FGA sponges for 14 days, together with a single dose of 125 microg of cloprostenol on Day 12, with Day 0 as day of progestagen insertion. Superovulatory treatment consisted of eight decreasing doses (1.5 x 3 ml, 1.25 x 2 ml, and 1 x 3 ml) of Ovagen twice daily from 60 h before to 24 h after sponge removal. The presence or absence of corpora lutea was assessed by transrectal ultrasonography at progestagen insertion and at first FSH dose. Number and size of all follicles>> or = 2 mm were also evaluated at first FSH dose. The number of corpora lutea and the number and viability of recovered embryos in response to the treatment were evaluated 7 days after sponge removal. No significant effect on ovarian response of the presence of a CL at sponge insertion in 21 of the 25 ewes (84%) was detected. However, ewes with a CL at first FSH dose (16 ewes, 64%) yielded a higher number of transferable embryos (7.2 +/- 1.4 versus 2.7 +/- 0.7, P < 0.05), since the embryo degeneration rate was increased in sheep without a CL (42.5% versus 12.7%, P < 0.01). Analysis of possible effects derived from the presence of a large presumptively dominant follicle >> or = 6 mm) at first FSH dose showed that both recovery and viability rates were lowest (P < 0.05) in ewes bearing a large follicle in the absence of a CL (40.5 and 50.6%, respectively), and highest in ewes that did not show a large follicle but in which a CL was present (73.9 and 85.2%). The final number of transferable embryos was very different between groups (10.2 versus 1.8, P < 0.01). These results indicate that the number and quality of embryos obtained from superovulated ewes is affected by the presence of a CL prior to the first FSH dose (i.e. by the stage of the estrous cycle at progestagen insertion) and also by an interaction with suppressive effects from large dominant follicles. This finding suggests the existence of some effects on follicular population prior to the FSH treatment that may compromise follicle and oocyte developmental competence. It seems reasonable to hypothesize that superovulatory yields would be increased by beginning the treatment during the early-luteal phase of the estrous cycle, allowing for the presence of a CL along with the progestagen treatment.

The effects of fenprostalene, cloprostenol sodium and prostaglandin F2 alpha (PGF2alpha) on estrus, conception rate, pregnancy rate, and the interval from Day 1 of the breeding season to calving were studied on 135 purebred Angus cows and heifers. The cows and heifers were randomly allotted within age to the three estrus synchronization treatments and a control group. The calving percentages (for cows and heifers combined) that resulted from artificial insemination (AI) were 32.3, 31.4, 43.6, and 51.1% for the control, fenprostalene, cloprostenol sodium, and PGF2alpha groups, respectively. The calving percentage during the AI period by ages of dam at breeding were 54.2% for yearling heifers, 30.5% for two-year-olds, 47.6% for three-year-olds, and 26.1% for four-year-old or older cows. The percentage of cows and heifers detected in estrus and the percentage that conceived after the first injection for control, fenprostalene, cloprostenol sodium, and PGF2alpha groups were 51.6 and 22.3%, 59.3 and 32.1%, 76.8 and 44.1%, and 66.6 and 50.2%, respectively. The intervals from Day 1 of the breeding season to calving and from Day 1 of the calving season within each treatment to the birth of each calf were control, 285.9 and 23.8 d; fenprostalene, 283.6 and 13.4 d; cloprostenol sodium, 285.5 and 6.5 d; and PGF2alpha, 284.0 and 11.1 d.

In two field trials, the parturition inducing and MMA preventing effects of the prostaglandin F(2alpha) analog (PGFA), K 11941, were explored. In trial 1, 100 sows were treated with 2 mg and 30 with 3 mg of K 11941 i.m. on day 112 of gestation; 125 sows treated on day 112 with 175 mcg cloprostenol (Planate, ICI) served as positive controls, and 248 sows treated with saline on day 112 of gestation were used as negative controls. Both PGF analogs were equally effective in inducing early parturiton: 84.6% and 83.2% of the sows had farrowed between 20 and 30 hours after treatment. Both treatments reduced stillbirth rate and piglet losses during the first 10 days of life, and lowered the incidence of MMA significantly (6.2 and 5.6% vs 27.3 and 24.2%; p<.001). In a second trial, parturitions were induced in four groups of 60 sows each with 2 mg K 11941, housed in farms with either a chronic high incidence of MMA (A: 45 to 65% or only a seasonal rise in MMA during summer (B: 10 to 50%). Groups were treated either in April/May or August/September; 240 salinetreated, control sows were used. K 11941-induced parturition reduced MMA incidence in farm A during both seasons and prevented the summer rise in farm B (p<.01). Fertility after weaning was impaired in herds with an increased incidence of MMA.

BACKGROUND

The study was conducted to compare the efficacy and acceptability of second-trimester induction termination using vaginal misoprostol to hypertonic saline and d-cloprostenol, a prostaglandin F(2alpha) (PGF) analogue, in Tashkent, Uzbekistan.

METHODS

Eleven clinics providing second-trimester induction terminations were randomized to provide one of two regimens for second-trimester induction termination: vaginal misoprostol 400 mcg every 3 h or hypertonic 10% saline intrauterine instillation plus an intravenous PGF analogue, d-cloprostenol, 2.5 mg/h. Demographic information, and obstetric and medical history data were collected, and interviewers administered questionnaires to measure procedural pain and satisfaction. Differences in procedure time and complication rate, the primary outcomes, were analyzed with survival analysis and chi(2) tests.

RESULTS

Of 228 participants, 120 received misoprostol and 108 received hypertonic saline and d-cloprostenol; the groups did not significantly differ by age, parity or gestational age. Both misoprostol and saline procedures were effective, with 99.2% and 100% successful abortion rates, respectively. Median procedure time (13.1 vs. 29.2 h, p<.001), and number of women with retained placenta (2 vs. 70, p<.001) or hemorrhage (3 vs. 19, p=.001) were lower for the misoprostol group. Both provider (p<.001) and patient (p<.001) procedural satisfaction scores were higher for the misoprostol group.

CONCLUSIONS

While equally effective, vaginal misoprostol had a shorter time to abortion, was more acceptable to providers and patients and had fewer complications than saline instillation plus intravenous administration of a PGF analogue in Tashkent. This evidence supports change of the existing standard of care for second-trimester induction termination in Uzbekistan.

PART I PROSTAGLANDIN-INDUCED SYNCHRONIZATION OF ESTRUS IN BEEF CATTLE: Prostaglandin-induced regression of the mature cyclic corpus luteum in cows and heifers triggers a sequence of physiological events that results in a return to estrus in two to five days. There are several breeding management programs based on this premise. These programs range from attempts to synchronize estrus in entire herds with two injections of prostaglandin eleven days apart and breeding artificially, to simply shortening diestrus in responsive cattle with a single injection and bullbreeding. In this paper, several programs are discussed. No single program will be successful in all situations. Programs must be modified to fit each herd and its management. The factors that most commonly lead to program failure include inadequate nutrition, short postpartum interval, and mismanagement of heifers and first-calf heifers. PART II THE SYNCHRONIZATION OF ESTRUS IN EMBRYO TRANSFER RECIPIENTS USING VARIOUS SYNCHRONIZATION COMPOUNDS: Approximately 1800 recipient cows were synchronized for embryo transplants in three separate trials. The response rates, distribution of estrus, cull rates, and pregnancy rates of the synchronization products were compared. The pregnancy rates in prostaglandin-induced estrus in embryo transfer recipients were found to be no different from those in recipients that were used after natural noninduced estrus. The specific prostaglandin analog fenprostalene was tested for efficacy using various combinations of route of administration and antibiotic addition. There were no adverse reactions and neither the addition of oxytetracycline nor the route of administration had any effect on estrus rate, distribution, or pregnancy rates, which were not different from those achieved with the control prostaglandin analog cloprostenol. PART III TIMED BREEDING IN PROSTAGLANDIN-SYNCHRONIZED DAIRY HEIFERS: Five groups of 20 to 40 Holstein heifers were treated with two doses of cloprostenol eleven days apart. The control groups were bred 12 to 16 hours after first seen in standing estrus. Treatment groups were bred at either 64 or 72 hours postinjection (with no detection) or at more than 24 hours postdetection of estrus. Optimum results were achieved when heifers were bred within 16 hours of first observed estrus or 72 hours after the second synchronizing injection with no detection of estrus.

The induction of parturition in sows has been studied using prostaglandin F2 alpha or the analogue cloprostenol on day 112, 113 or 114 of gestation. No difference between treatments was found concerning the interval from injection to parturition, the incidence of stillborn piglets or the piglet viability during the first 48 hours. Whiel 58.3 per cent of the PGF2 alpha-treated sows demonstrated side effects, the corresponding percentage among cloprostenol-treated sows was 5.0. The dominating side effects were biting of cage bars and increased respiratory rate.

Although recent data for several species of primate, including human and marmoset, indicate that the corpus luteum secretes high levels of radioimmunoassayable inhibin, the nature of the immunoreactive (ir) inhibin detected has not been established. In this study, plasma ir-inhibin levels during the ovarian cycle of the marmoset (n = 12 animals) were measured by alpha-subunit-directed inhibin RIA, and values were compared with those estimated by a recently developed two-site immunoradiometric assay (IRMA) specific for inhibin alpha-beta dimer. Consistent with earlier data, plasma levels of ir-inhibin measured by RIA (overall mean value 133 +/- 7 ng/ml; n = 171) reached values 4-fold higher (p less than 0.001) during the luteal phase (222 +/- 20 ng/ml) than during the follicular phase (58 +/- 8 ng/ml), being directly correlated with plasma progesterone levels (r = 0.65; p less than 0.001). In contrast, plasma ir-inhibin levels estimated by IRMA were substantially lower than those measured by RIA (overall mean value 9.62 +/- 1.08 ng/ml; n = 171) and did not vary significantly during the cycle. Administration of a luteolytic dose of cloprostenol during the late luteal phase/early pregnancy led to an abrupt fall in plasma concentrations of progesterone (95%) and alpha-inhibin measured by RIA (82%), whereas dimeric inhibin levels remained unchanged. Analysis of marmoset luteal extracts (n = 5) by RIA, IRMA, and inhibin bioassay yielded inhibin estimates of 102.6 +/- 21.0, 0.632 +/- 0.103, and less than 2.0 ng/mg, respectively, thus confirming that only a very small proportion of the inhibin produced was dimeric (i.e., bioactive) in nature.(ABSTRACT TRUNCATED AT 250 WORDS)

Forty-two Holstein heifers were superovulated with FSH-P (total dose, 30 mg) and cloprostenol. Treatment was initiated on Day 3 (Group D3, n = 11), Day 6 (Group D6, n = 11), Day 9 (Group D9, n = 10) or Day 12 (Group D12, n = 10) of the estrous cycle. Heifers were bled daily for serum progesterone and estradiol-17beta determinations and every 6 h for a 48-h duration at the expected time of estrus for luteinizing hormone (LH) assay. Ova and embryos were flushed from the reproductive tracts and the number of corpora lutea (CL) were recorded after slaughter on Day 7 post-estrus. Mean (+/- SEM) numbers of observed CL were higher (P < 0.05) in Group D9 (33.3 +/- 4.8) than in Group D3 (15.3 +/- 3.8), with Group D6 (17.0 +/- 2.9) and Group D12 (23.9 +/- 7.3) being intermediate. Similarly, mean (+/- SEM) numbers of fertilized embryos were highest (P < 0.05) in Group D9 (13.3 +/- 2.2). There was also a nonsignificant trend for the number of transferable embryos to be greatest in Group D9. Neither serum progesterone concentrations 3 d after the LH peak nor peak serum estradiol 17beta concentrations differed among groups, but both were significantly correlated with numbers of observed CL and total ova and embryos.

Although estrus synchronization considered valuable management tools for improving reproductive performance of ewes, their high expenses and complicated usage prevent sheep farmers to apply these techniques. Therefore, the present study was designed to compare three protocols of estrus synchronization on reproductive performance of Ghezel ewes. For this reason, 27 Ghezel ewes were assigned to three estrus synchronization treatment groups based on a completely randomized design included: progestogen sponge for 12 days + 500 IU eCG at the time of sponge withdrawal (P4eCG group, expensive synchronization), two doses of 75 μg cloprostenol with 12 days interval (CLO group, economical synchronization), and CLO +500 IU eCG at day 12 (CLOeCG group, moderately priced synchronization). Four consecutive blood samples were also collected during the experiment to evaluate progesterone concentrations. The results of the present experiment showed that pregnancy and lambing rates of the first estrus as well as blood progesterone concentration were not affected by the treatments (P>> 0.05), though total pregnancy and lambing rates were higher in both P4eCG and CLOeCG groups (P < 0.01). Accordingly, both P4eCG and CLOeCG protocols successfully improved reproductive traits of ewes, though CLOeCG protocol is an advisable technique for sheep farmers through its moderate price, simple application, and high reproductive performance.

Intact cyclic ewes have been used in experiments designed to examine the mechanism by which uterine oxytocin receptor synthesis is controlled during the oestrous cyclic. Previous experiments have shown that the prostaglandin F2 alpha analogue cloprostenol is luteolytic in ewes receiving oxytocin by continuous intra-venous infusion. When ewes receiving oxytocin are given cloprostenol uterine oxytocin receptor concentrations are raised, whereas in animals receiving oxytocin alone, they remain low. To investigate whether inhibition of oxytocin receptor binding activity by oxytocin is either dependent on elevated plasma progesterone concentrations or over-ridden by oestrogens secreted by ovarian follicles maturing as a result of cloprostenol treatment, ewes were given oxytocin by continuous intravenous infusion (3 nmol h-1) between Days 12 and 17 after oestrus and one of the following: no further treatment; cloprostenol [125 micrograms intramuscularly (i.m.)] on Day 15; progesterone, by subcutaneous implant, from Day 14 with cloprostenol on Day 15; medroxyprogesterone acetate (MPA; 6 mg depot i.m.) on Day 14 followed by cloprostenol on Day 15; or oestradiol-17 beta (2.75 mumol i.m.) on Days 14 and 15. Concentrations of oxytocin receptor were measured at autopsy on Day 17 in caruncular endometrium, intercaruncular endometrium and myometrium. Ovarian follicles and corpora lutea were examined to determine the effect of treatment on these tissues. Treatment with oxytocin alone resulted in the maintenance of corpora lutea, reduced follicular development and a low concentration of uterine oxytocin receptor. Cloprostenol initiated luteolysis in oxytocin-treated ewes. This was associated with a high level of oxytocin receptor binding activity in all ewes except those receiving exogenous progesterone.(ABSTRACT TRUNCATED AT 250 WORDS)

To address the potential luteolytic role for prostaglandin F(2 alpha) (PGF(2 alpha)) in the corpus luteum of the common marmoset monkey (Callithrix jacchus), the ability of marmoset luteal cells, maintained in monolayer culture, to produce PGF(2 alpha) was determined in vitro in the presence and absence of human chorionic gonadotrophin (hCG) and other established pharmacological modulators of PGF(2 alpha) synthesis. We also assessed the effects of the PGF(2 alpha) analogue, cloprostenol, on progesterone output from luteal cells isolated in the early luteal phase versus the mid-luteal phase (days 3 and 14 post ovulation, respectively). Cloprostenol had no effect on progesterone output from luteal cells isolated on day 3 of the luteal phase, whereas it significantly inhibited both basal and hCG-stimulated progesterone synthesis by day 14 luteal cells during the culture period 48-72 h (P<0.001). Intra-luteal PGF(2 alpha) concentrations were 5-fold higher in luteal cells isolated in the early luteal phase than in mid-luteal phase cells (16.5+/-3.5 versus 3.5+/-0.6 pmol/10(5) cells). While PGF(2 alpha) production was unaffected by hCG in vitro, it was decreased by indomethacin (1000 ng/ml) (P<0.05) and stimulated by the calcium ionophore A23187 (10 micromol/l) (P<0.05) in luteal cells from both stages of the luteal phase. Phospholipase A(2) did not influence PGF(2 alpha) production by day 3 luteal cells whereas at 10 IU/ml, it significantly stimulated PGF(2 alpha) production by day 14 luteal cells (P<0.05). Hence, the timing of luteolysis in the common marmoset monkey appears to involve changes in both the luteal cell response to and production of PGF(2 alpha).

The Canindé breed of goats (Capra hircus) is currently endangered. The aims of this study were to characterize the estrus behavior, ovulatory responses and progesterone profiles, and to evaluate the in vitro embryo production (IVP) in this breed. In Experiment 1, ten nulliparous and seven pluriparous females received medroxyprogesterone acetate (MAP)-containing sponges (60mg) plus 75μg d-cloprostenol for estrus synchronization and their reproductive parameters were evaluated. In Experiment 2, oocytes obtained by laparascopy from hormonally stimulated females (n=15) were used for IVP. There was no difference (p>0.05) between nulliparous and pluriparous goats in terms of estrus response (40.0% vs. 85.7%), time from progestagen sponge removal to the onset of estrus (62.0±15.5 vs. 50.7±19.2h; mean±SEM), duration of estrus (25.0±16.1 vs. 30.0±15.1h), percentage of ovulating animals (60.0% vs. 85.7%), number of ovulations (1.2±0.4 vs. 1.3±0.8), and diameter of the preovulatory follicle (5.8±0.5 vs. 6.1±0.3mm). Progesterone concentrations were also similar (p>0.05) in both groups. During laparoscopic recovery, there were average 12.2 aspirated follicles and 9.1 oocytes per goat, resulting in a high recovery rate (74.3%, 182/245). A total of 78 embryos were produced (51.0%). The mean number of cells in the blastocysts at day 7 of in vitro culture was 170.3±12.5. In conclusion, nulliparous and pluriparous Canindé goats exhibited similar reproductive profiles. It was possible to produce embryos in vitro, allowing the instigation of an embryo bank for preservation of this breed.

The aim of the present study was to confirm earlier findings, obtained with a small number of animals, that gonadotropin-releasing hormone (GnRH) can shorten corpus luteum functional life when it is administered 24 h after cloprostenol (PG) treatments given 7-9 days after estrus. In addition, the effects of two treatments, PG alone or PG + GnRH given before mid-diestrus, on signs of estrus were studied. Sixty cows in farm conditions were used in the experiment. Eight days after natural estrus, they were given an intramuscularly (i.m.) treatment of cloprostenol (0.5 mg). The animals were then divided into two groups. One group (n = 25) received an i.m. treatment of gonadorelin (0.1 mg) 24 h after the PG treatment (PG + GnRH group), while another group (n = 35) served as controls without any further treatment (PG group). Estrous signs were recorded. Progesterone concentrations were measured from samples of whole milk. No short cycles were observed in the PG group, whereas 33% of the cows in the PG + GnRH group exhibited premature luteal regression (P < 0.05). Cloprostenol treatment on Day 8 had no effect on the intensity of the estrous signs. Instead, GnRH treatment 24 h after PG treatment weakened the estrous signs significantly (P < 0.01). It is concluded that GnRH administration 24 h after a PG treatment given 8 days after estrus can cause short estrous cycles in some cows on an individual basis.

Changes in ovarian structures and hormonal profiles in estradiol dipropionate (EDP)-induced pseudopregnant sows following PGF2α-analogue (PGF2α-A) administration and practicality of the estrus synchronization protocol using EDP and PGF2α-A on estrus expression and reproductive performance in commercial conditions were investigated. Pseudopregnancy was defined as absence of estrus maintained for at least 20 days after EDP treatment in this study. When 4 pseudopregnant sows induced by 20 mg EDP were treated with PGF2α-A as 0.175 mg cloprostenol twice at a 24-hr interval between 20 and 28 days after EDP treatment, plasma progesterone concentrations rapidly decreased after treatment. The luteinizing hormone surge and ovulation were detected in all sows. The number of ovulated follicles was 17.3 ± 1.1 (SEM). On commercial farms, 94.2% of 52 gilts and 95.2% of 21 sows received EDP became pseudopregnant. When these pseudopregnant females (48 gilts and 20 sows) were treated with PGF2α-A as described above, estrus was detected in all females at 6.1 ± 0.3 days for gilts and 5.5 ± 0.2 days for sows after the first PGF2α-A treatment. There were no significant differences in farrowing rate (85.0 - 100%), average total litter size (10.0 - 11.4), average born alive litter size (9.4 - 10.3) and average piglet birth weight (1.56 - 1.71 kg) between PGF2α-A treated pseudopregnant female pigs that were inseminated during synchronized estrus and females inseminated during spontaneous estrus. This study indicates that estrus synchronization programs using EDP and PGF2α-A are available as practical and convenient procedures for commercial pig farms.