We have previously reported that prostaglandin F2 alpha (PGF2 alpha) activates p44/p42 mitogen-activated protein kinase (MAPK) through protein kinase C (PKC) in osteoblast-like MC3T3-E1 cells. In the present study, we investigated the mechanism of vascular endothelial growth factor (VEGF) synthesis induced by PGF2 alpha and the effect of incadronate on the VEGF synthesis in these cells. PGF2 alpha significantly stimulated the VEGF synthesis in a dose-dependent manner between 1 pm and 10 microm. Cycloheximide reduced the PGF2 alpha effect. PGF2 alpha increased the levels of mRNA for VEGF. Cloprostenol, a PGF2 alpha-sensitive receptor agonist, potently induced the VEGF synthesis. Indomethacin, an inhibitor of cyclooxygenase, significantly reduced the PGF2 alpha-induced VEGF synthesis. Bisindolylmaleimide, an inhibitor of PKC, reduced the PGF2 alpha-induced VEGF synthesis. The VEGF synthesis induced by PGF2 alpha was significantly attenuated in the PKC down-regulated cells. PGF2 alpha elicited the translocation of PKC beta I from cytosol to membrane fraction. PD98059 or U0126, inhibitors of MEK, suppressed the VEGF synthesis induced by PGF2 alpha. Farnesyltransferase inhibitor failed to affect the PGF2 alpha-induced VEGF synthesis. Incadronate enhanced the synthesis of VEGF induced by PGF2 alpha. NaF-induced VEGF synthesis was also amplified by incadronate. PD98059 suppressed the enhancement by incadronate of PGF2 alpha-induced VEGF synthesis. Incadronate markedly enhanced the phosphorylation of Raf-1, MEK1/2, and p44/p42 MAPK induced by PGF2 alpha or 12-O-tetradecanoylphorbol-13-acetate, a PKC activator. Incadronate significantly enhanced the cloprostenol-increased level of VEGF concentration in mouse plasma in vivo. These results strongly suggest that PGF2 alpha stimulates VEGF synthesis through the PKC-dependent activation of p44/p42 MAPK in osteoblasts and that the incadronate enhances the VEGF synthesis at the point between PKC and Raf-1.

Prostaglandins (PG) mediate IL-1beta regulation of several interleukin mRNAs in progenitor Leydig cells. PGE(2) and PGF(2alpha) potently reverse indomethacin (INDO; a cyclooxygenase inhibitor) inhibition of IL-1beta autoinduction. IL-1beta increases PGE(2) and PGF(2alpha) production. To determine the PG receptors involved in this regulation, this study established by RT-PCR and Western analyses which specific receptors for PGE(2) (EP receptors) and PGF(2alpha) (FP receptors) are expressed in progenitors. Pharmacological characterization of receptors involved in PGE(2) and PGF(2alpha) regulation of IL-1beta mRNA levels was ascertained using real-time PCR analyses. FP, EP(1), EP(2), and EP(4) receptor mRNAs and proteins, and an EP(3) receptor subtype were detected. IL-1beta treatment (24-h) significantly decreased EP(1) receptor levels; INDO abrogated this down-regulation. FP, EP(2), and EP(4) receptor levels increased after IL-1beta and IL-1beta + INDO. A selective FP agonist, cloprostenol (0.1 micro M), and PGF(2alpha) (10 micro M) had similar effects on IL-1beta mRNA levels in progenitors treated with IL-1beta + INDO. None of the EP(2)/EP(4) agonists [butaprost, misoprostol, or 11-deoxy PGE(1) (10 micro M)] affected IL-1beta mRNA levels. In contrast, EP(1)/EP(3) agonists (17-phenyl trinor PGE(2) and sulprostone) increased IL-1beta mRNAs in a dose-dependent manner. EP(1) receptor subtype-selective antagonist, SC-51322, blocked IL-1beta-induced and [IL-1beta + INDO + 17-phenyl trinor PGE(2)]-induced increases in IL-1beta mRNAs. Taken together, our data demonstrate that FP and EP(1) receptors mediate PGF(2alpha) and PGE(2) induction of progenitor IL-1beta expression.

Progesterone production by dispersed luteal cells obtained from the marmoset monkey on day 14 after ovulation can be stimulated by both prostaglandin F2 alpha (PGF2 alpha) and its structural analogue, cloprostenol. To establish whether these responses can be attributed to cross-reaction with the prostaglandin E2 (PGE2) receptor, this study compared the involvement of cyclic adenosine-3',5'-monophosphate (cAMP) and protein kinase C (PKC) in the luteotrophic responses to PGE2, PGF2 alpha and cloprostenol. While all three prostaglandins stimulated similar increases in progesterone production (239.5 +/- 7.9% of control; P < 0.01), only PGE2 stimulated a significant increase in cAMP accumulation (373.2 +/- 28.4% of control; P < 0.01). This study is the first to demonstrate PKC activity in the marmoset ovary. Following down-regulation of PKC with a tumour-promoting phorbol ester, 4 beta-phorbol 12-myristate 13-acetate (4 beta-PMA), basal progesterone production was significantly increased (150.9 +/- 8.2% of control; P < 0.05) and the luteotrophic effects of PGF2 alpha and cloprostenol were no longer evident, whereas the response to PGE2 was unaffected. These observations are consistent with the differential involvement of cAMP and PKC in the luteotrophic responses to PGE2 and PGF2 alpha/cloprostenol respectively. Hence, we conclude that the luteotrophic actions of prostaglandins E2 and F2 alpha on dispersed marmoset luteal cells are mediated via different receptors and signal transduction pathways.

Farrowing induction is a common practice among swine producers to manage timing of farrowing and the labor associated with farrowing. In this experiment, the effect of induction of labor using cloprostenol on Day 114 of gestation ( = 88) was compared to our standard farrowing protocol at USMARC (natural farrowing with induction using cloprostenol on Day 116 if needed, = 82) in gilts and sows up to fourth parity. In a subset of dams ( = 10 each treatment), colostrum was collected within 30 min of birth of the first piglet, and at 4, 8, 12, and 24 h. Colostrum samples were measured for immunoglobulin G (IgG) using the immunoglobulin immunocrit and porcine IgG specific ELISA, and for total protein. Blood samples were collected from each live piglet on d 1 of age and measured using the immunocrit assay, and average immunocrit was calculated for each litter. Total piglets born and born alive, birth and weaning weights, and the stillbirth rate and preweaning mortality rate were also recorded for each litter. Results indicated that induction of farrowing by cloprostenol treatment on d 114 reduced average gestation length by 0.5 to 1 d depending on parity ( < 0.05), and reduced overall colostrum immunocrit, IgG and total protein ( < 0.05). Colostrum immunocrits and IgG concentrations were well correlated ( = 0.89; < 0.01) but IgG was curvilinearly related to total protein. Litter average immunocrits were similar in gilts between treatments, but were reduced in later parity sows induced to farrow using cloprostenol on d 114 of gestation. Total born, born alive, birth and weaning weights, and stillbirth and preweaning mortality rates were unaffected by treatments. In conclusion, induction of farrowing using cloprostenol injection on d 114 reduced colostrum IgG concentrations in dams, but this was reflected in a reduction in litter average immunocrit only in later parity sows. This reduction in litter average immunocrit was not sufficient to influence preweaning mortality, but other effects are possible given the reported influence of colostrum on growth and reproductive traits.

One of the causes of poor fertility in high producing dairy cows is inadequate progesterone. Therefore, we determined the efficacy of an intravaginal insert containing 1.55 g of progesterone (PRID) given before and/or after timed AI (TAI) on ovarian response, plasma progesterone concentrations, pregnancy per AI (P/AI) and pregnancy losses. Lactating dairy cows at three locations were assigned (Day 0) to an Ovsynch protocol with (N = 294) or without (N = 314) a PRID. The Ovsynch protocol consisted of two injections of 100 μg gonadorelin (GnRH) 9 days apart and one injection of 500 μg cloprostenol (PG) 7 days after the first GnRH treatment. Insertion and removal of PRID occurred concurrent with the first GnRH and PG treatments, respectively. Timed AI was carried out 12 to 16 hours after the second GnRH. Ovarian status of a subset of 217 first service cows had been presynchronized with 2 treatments of PG 14 days apart with the last PG given 12 days before the first GnRH of the Ovsynch protocol. Body condition score (scale of one to five) was recorded at TAI. Ultrasonographic examinations were done in all cows at first GnRH, at PG, at TAI, and 24 hours after TAI for response to treatment and at 32 and 60 days after TAI for confirmation of pregnancy. At 4.5 days after TAI (Day 14), cows that responded to PG and ovulated after the second GnRH treatment were reassigned to receive (N = 223) or not receive (N = 229) a PRID for 7 days. Blood samples were taken for progesterone determination at PG treatment, at TAI, and post TAI on Days 14 and 21. The PRID treatment pre-TAI reduced the percentage of cows ovulating before TAI (5.8% vs. 11.1%), and significantly increased P/AI in nonpresynchronized cows (41.3% vs. 25.1%). Cows ovulating in response to the first GnRH treatment, cyclic cows, and cows with body condition score of 2.75 or more had increased P/AI, but the addition of a PRID pre-TAI to these cows did not increase P/AI. The PRID treatment post TAI did not affect P/AI, but reduced pregnancy losses (6.1% vs. 11.4%) between 32 and 60 days of gestation. The reduction in pregnancy losses tended (P = 0.10) to be significant in acyclic cows receiving a PRID than in those not receiving a PRID (5.6% vs. 33.3%). Plasma progesterone concentrations at PG treatment and on Day 21 (11.5 days after TAI) were linearly associated with P/AI. In conclusion, progesterone supplementation pre-TAI increased P/AI in nonpresynchronized cows. Progesterone supplementation post TAI reduced pregnancy losses, particularly in acyclic cows.

The objective of this experiment was to determine the effect of sequential treatment with buserelin (a GnRH agonist) and cloprostenol (a prostaglandin F2 alpha analog) on estrous response and fertility in beef cattle with different ovarian conditions. On d 0 (1st d of treatment), the control group (n = 52, 10 heifers and 42 cows) and the GnRH group (n = 48, 10 heifers and 38 cows) received 2 mL of saline or 2 mL of Receptal (8 micrograms of buserelin), respectively. On d 6, all cows that had not exhibited spontaneous estrus were given i.m. 500 micrograms of cloprostenol (PGF). Ultrasonography on d 0 and assays of progesterone in blood on d -11, 0, and 6 were used to identify follicular and luteal status of animals. Cattle were observed for estrus from d 0 to 10. Cows showing estrus were bred artificially 12 h after onset of estrus. Over the 10-d period, the number of cows detected in estrus and pregnancy and conception rates were identical for the two groups. However, between d 0 and 6, the proportion of cows exhibiting estrus was lower (P less than .01) in the GnRH group than in the control group. Between d 6 and 10, the synchronization rate and precision of estrus were greater (P less than .01) in the buserelin-treated group than in the control group. Conception rate and interval from PGF injection to onset of estrus were not different between the two treatment groups. Presence of a large (greater than 10 mm) follicle on d 0 enhanced synchronization rate and precision of estrus.(ABSTRACT TRUNCATED AT 250 WORDS)

Actinomyces pyogenes can cause embryonic death and abortion during the early stages of pregnancy in cows. Bovine pregnancy-specific protein B (PSPB) is produced in response to a viable embryo and as such it could be a potential marker for embryronic survival. The plasma concentration of PSPB was monitored in cows following an intrauterine infection with A. pyogenes and during the subsequent abortion and recovery from infection. Plasma progesterone concentrations were also monitored, and the results were compared withthose for animals in which abortion had been induced by prostaglandin F2alpha treatment. In abortions induced both by infection and by cloprostenol, the plasma concentration of PSPB fell steadily from the day of treatment, with a half-life of 7 days. In the cloprostenol-induced abortions, progesterone levels fell dramatically to <0.5ng/ml within 24 hours of treatment, while following inoculation with A. pyogenes , progesterone concentration remained elevated for 20 to 40 days and fell to <0.5ng/ml after evacuation of pus from the uterus. Sequential monitoring of PSPB, which identifies embryonic death when a continuing fall in plasma concentration is demonstrated, is a better indicator of embryonic death following bacterial infection with A. pyogenes than plasma progesterone concentration, which falls only when infection is resolved.

The aim of this study was to characterize the regulation of connexins (Cx26 and Cx43) in the bovine ovary (experiment 1-3). Experiment 1: ovaries containing preovulatory follicles or corpora lutea (CL) were collected at 0, 4, 10, 20, 25 (follicles) and 60 h (CL) relative to injection of GnRH. Experiment 2: CL were assigned to the following stages: days 1-2, 3-4, 5-7, 8-12, 13-16, >18 (after regression) of oestrous cycle and of early and late pregnancy (<4 and >4 months). Experiment 3: induced luteolysis, cows on days 8-12 were injected with PGF2alpha analogue (Cloprostenol), and CL were collected by transvaginal ovariectomy before and 0.5, 2, 4, 12, 24, 48 and 64 h after PGF2alpha injection. Real-time RT-PCR was applied to investigate mRNA expression and immunofluorescence was utilized for protein localization. Cx26 mRNA increased rapidly 4 h after GnRH injection (during LH surge) and decreased afterwards during the whole experimental period. Cx43 mRNA expression decreased continuously after GnRH application. Cx26 mRNA in CL increased significantly in the second part of oestrous cycle and after regression. In contrast, the highest mRNA expression for Cx43 in CL was detected during the early luteal phase. After induced luteolysis the mRNA expression of Cx26 increased significantly at 24 h. As shown by immunofluorescence, Cx26 was predominantly localized in the connective tissue and blood vessels of bovine CL, whereas Cx43 was present in the luteal cells and blood vessels. This resulted in a strong increase of Cx26 expression during the late luteal phase and after luteal regression. Subsequently, Cx43 expression was distinctly decreased after luteal regression. These data suggest that Cx26 and Cx43 are involved in the local cellular mechanisms participating in tissue remodelling during the critical time around periovulation as well as during CL formation (angiogenesis), function and regression in the bovine ovary.

The components of the IGF-system were shown to be differentially regulated in bovine antral follicles and corpora lutea (CL) during different stages of the estrous cycle, and to have important functions for specific stages. The aim of this study was to investigate the detailed pattern of mRNA expression of most constituents of the IGF-system and their possible involvement in prostaglandin (PG)F2alpha-induced luteolysis in the bovine CL. Therefore, cows in the mid-luteal phase (days 8-12) were injected with the PGF2alpha-analogue Cloprostenol, and CL were collected by transvaginal ovariectomy at 2, 4, 12, 48 and 64 h after PGF2alpha-injection. Real-time RT-PCR using SYBR Green I detection was employed to determine mRNA expressions of the following factors: ubiquitin (UBQ), insulin-like growth factor I (IGF I), IGF II, IGF-receptor type 1 (IGFR-1), growth hormone receptor (GH-R) and IGF-binding proteins-1-6 (IGFBP-1-6). Total extractable RNA decreased with ongoing luteolysis. IGFBP-1 mRNA was significantly up-regulated at 2h after PGF2alpha and maximal at 4h with a 34-fold increase. IGFBP-5 mRNA was significantly up-regulated after 12h with a maximum of an 11-fold increase at 64 h. For GH-R, IGFR-1, IGF II, IGFBP-3 and -4 mRNA expression, we found a significant down-regulation in certain stages. There was a significant up-regulation for IGFBP-2 and -6 mRNA at 64 h after induced luteolysis. There were no significant changes in IGF I mRNA expression. In conclusion, the IGF-system with all its components seems to play an important role in the very complex process of PGF2alpha-induced luteolysis in bovine CL.

This study aimed to establish a protocol for synchronization of estrus in brown brocket deer (Mazama gouazoubira). Two groups of hinds (n=3) were submitted to two different protocols: Treatment 1 received an intravaginal progesterone (CIDR) device for 8 days, followed by 265microg injection of cloprostenol at the time of removal; and Treatment 2 received two injections of 265microg of cloprostenol 11 days apart. After 30 days, each group of three hinds received the other treatment. Treatment efficacy was evaluated by reproductive behavior, fecal progestin and estrogen concentration and the observation of CL by laparoscopy 6 days after the end of estrus. All the hinds (100%) had estrous behavior upon the completion of treatment, but a significant difference occurred between the time of onset, 70.5+/-5.0h for Treatment 1 and 52.3+/-5.6h for Treatment 2. The mean estrus duration time (34.7+/-4.50 and 37.0+/-8.11h), ovulation rates (5/6 and 4/6), mean CL size (4.85+/-0.74 and 3.21+/-0.19mm) and mean fecal progestin concentration at 6 days after the end of estrus (865.53+/-76.59 and 1073.35+/-106.82ng/g feces) were not significantly different between treatments. There was no difference in fecal estrogen concentrations throughout the treatment and the greatest values of the estrogen:progestin ratio coincided with estrous behavior. Although fertility was not evaluated directly, both treatments were effective in synchronizing estrus in the species M. gouazoubira, with the formation of functional corpora lutea.

This study aims to evaluate the ovulation rate and the presence of functional corpora lutea after treatment by three different protocols designed to cause superovulation in brown brocket deer. Six female received an intravaginal device containing 0.33 g of progesterone (CIDR®) for 8 days, followed by 0.5 mg injection of estradiol benzoate at the time of insertion and 265 µg of cloprostenol at the time of removal. Afterwards, the hinds were divided into three groups (n = 2): Treatment A received injection of 600 IU eCG on Day 4 after CIDR® insertion; Treatment B received injection of 300 IU eCG at the same time; and Treatment C received injection of 250 IU FSH dissolved in PVP, also on Day 4 post-insertion. The treatments were crossed over with 44-48 day intervals after CIDR® removal, such that all the deer were submitted to all three treatments. The mean ovulation rate (Treatment A = 3.40 ± 0.68, Treatment B = 1.40 ± 0.24, Treatment C = 0.80 ± 0.49), total ovarian stimulation (Treatment A = 4.80 ± 1.02, Treatment B = 1.80 ± 0.37, Treatment C = 1.40 ± 0.60), and mean CL diameter (Treatment A = 7.33 ± 0.76 mm, Treatment B = 3.94 ± 0.19 mm, Treatment C = 2.18 ± 0.49 mm) in Treatment A were significantly higher than the mean ovulation rates, total ovarian stimulation, and mean CL diameter in Treatments B and C. The mean fecal progesterone metabolites at the luteal phase in Treatment A (6,277.94±2,232.47 ng/g feces) was significantly different from Treatment C (1,374.82±401.77 ng/g feces). Thus, although fertility was not evaluated directly, Treatment A proved capable of induce superovulation in the species Mazama gouazoubira, presenting the greatest mean ovulation rates, with the formation of functional corpora lutea.

Pregnancy loss during the normal lifespan of endometrial cups (∼37-120-150 days of gestation) may affect a mare's ability to conceive again in the same breeding season, as equine chorionic gonadotropin (eCG) secretion by retained endometrial cups can lead to abnormal ovulations and follicular growth. While intrauterine kerosene infusion has anecdotally been proposed as a treatment for endometrial cup retention, there are no controlled studies evaluating kerosene's ability to enhance endometrial cup regression following abortion. The objectives of this study were to assess uterine response, systemic side effects, and efficacy of intrauterine kerosene infusions after abortion. We hypothesized that kerosene infusions would hasten regression of endometrial cups without detrimental effects on the endometrium and the mare's general health. Twelve light-breed mares were enrolled in the study after an experimentally induced abortion with cloprostenol (n = 12) by 60 ± 2 days of gestation. Mares were randomly allocated to receive an intrauterine infusion with 500 mL of kerosene (n = 6) or 500 mL saline (n = 6) on days 21 and 35 after pregnancy termination. Uterine biopsies were collected at days 7, 21, 35, and 49 post-abortion to evaluate the degree of endometrial fibrosis with Picrosirius Red Stain and to be graded according to the Kenney & Doig 1986 classification. Furthermore, histomorphometry analysis of the endometrium lining, glandular epithelium and glandular density was performed. Endometrial lymphocyte B CD20⁺, lymphocyte T CD3⁺, and macrophage IBA-1⁺ cell populations were characterized by immunohistochemistry. Physical examinations, blood cell counts, and serum biochemistry were performed before, and for 2 days after each uterine infusion. Serum samples were collected for assessment of eCG concentrations. Continuous data were analyzed with MIXED procedure with repeated measures in SAS, categorical data with LOGISTIC procedure of SAS. Significance was set at p < 0.05. Kerosene infusion did not affect complete blood cell counts, serum chemistry parameters, or physical examinations. Concentrations of eCG decreased over time (p < 0.001), but there were no differences between groups or time by group interactions (p = 0.72). Histological evaluation of the uterus showed no signs of increased fibrosis or degeneration in the treatment group. In conclusion, while kerosene infusions did not appear to have detrimental effects on mare health, our findings suggest that the use of kerosene in the uterus does not enhance the regression of endometrial cups by 49 days post-abortion.

The present study was conducted to characterize the major proteome of ovarian follicular fluid from locally-adapted, "Canindé" goats in the northeast of Brazil. Eight estrous cycling goats received a hormonal treatment consisting of medroxyprogesterone acetate, D-cloprostenol and FSH. Fluid was collected by laparoscopy from small (<3mm), medium (3-4mm) and large (>4mm) follicles and then, proteins were analyzed by 2-D SDS-PAGE and tandem mass spectrometry. Thirty-six proteins were identified in the goat follicular fluid, including albumin, immunoglobulins, ceruloplasmin, complement factor B, alpha-1B-glycoprotein precursor, serotransferrin, complement C3 and serpins, among others. Albumin and immunoglobulins were the most abundant proteins. Protein concentrations were similar in the fluid from small (45.3±3.1mg/mL), medium (44.2±3.3mg/mL) and large follicles (45.1±2.3mg/mL). The intensities of spots identified in 2-D gels as serotransferrin, zinc-alpha-2-glycoprotein-like, complement factor B and complement protein C3 differed (P<0.05) among follicle categories. The amount of serotransferrin was greater in the medium than small follicles (P<0.05). Content of zinc-alpha-2-glycoprotein-like, complement factor B and complement C3 was greater (P<0.05) in the fluid of large follicles than in medium follicles. Based on gene ontology, the major molecular functions associated with goat follicular fluid proteins were binding and catalytic activity, while the main biological processes were related to regulation, cellular processing, location and the immune system. In conclusion, the major proteome of the follicular fluid from goats subjected to hormonal stimulation was elucidated in the present study. Also, molecules associated with follicle development are potential biomarkers of oocyte competence were prevalent.

The aim of the study was to evaluate the efficacy of aglepristone (10 mg/kg on days 1, 2 and 8) for the treatment of metritis or pyometra in bitches (n = 67) either alone for cases of metritis (n = 15), or in cases of pyometra (n = 52) with (n = 32) or without (n = 20) the addition of low doses (1 microg/kg) of cloprostenol for 5 days (days 3-7). Examinations performed on day 90, in addition to days 8, 14 and 28, determined that treatments had been curative in the long term in 54/67 bitches (80.6%). Bitches in whom pyometra did not resolve, were given additional aglepristone on day 14 (n = 38) and day 28 (n = 20). Aglepristone alone was curative in 15/15 bitches with metritis. In 17/17 bitches with closed pyometra, cervical opening occurred within 48 h of aglepristone administration. Amongst the 52 bitches with open (n = 35) or closed (n = 17) pyometra, the additional treatment with cloprostenol from days 3 to 7, significantly improved the overall success rate at day 90, which was 27/32 (84.4%), compared to 12/20 (60.0%) in bitches without cloprostenol (P < 0.05). The leucocyte count and plasma progesterone concentrations significantly decreased over the course of treatment. Thirteen of 15 bitches in whom plasma progesterone concentrations were initially low (< 3.18 nmol/L) were cured. The recurrence rate after 12 and 24 months was 13.0% (3/23) and 19.0% (4/21), respectively.

Two experiments were designed to test the hypothesis that induction of parturition in the cow would be more predictable with the simultaneous use of a combination of cloprostenol and dexamethasone than with either hormone used alone.In experiment I all 19 beef cows treated with 500 mug cloprostenol and 25 mg dexamethasone in combination calved within 72 hours whereas dexamethasone (n = 19) or cloprostenol (n = 16) treatments alone each resulted in two induction failures. In those cows successfully induced, the mean interval from treatment to birth was 34.6 +/- 1.4 hours for the cloprostenol plus dexamethasone group, 43.3 +/- 2.4 hours for the dexamethasone group and 44.9 +/- 2.1 hours for the cloprostenol group. Control cows (n = 15) did not calve during the first 72 hours after treatment with saline. The incidence of retained placenta ranged from 19 to 53% in induced groups whereas placentae were not retained by cows in the control group.In experiment II all 30 beef cows in the cloprostenol plus dexamethasone group calved within the 72 hour limit, with a mean interval of 39.1 +/- 1.0 hours. Twenty-six of 31 cows calved within 72 hours with a mean interval of 51.9 +/- 3.4 hours after a single injection of cloprostenol and 29 of 33 cows calved within 72 hours with a mean interval of 52.6 +/- 3.3 hours after two injections of cloprostenol, 12 hours apart. Five of 34 control cows calved within 72 hours of time of treatment. The incidence of retained placenta was again high in induced cows. Results indicate that the simultaneous administration of cloprostenol and dexamethasone does constitute a safe, reliable and effective method of inducing parturition in the cow.

Experiments were designed to test the hypotheses that ovarian follicular response to superstimulatory treatment initiated during Wave 1 is equivalent to that of Wave 2, and recovery rate and quality of ova embryos derived from follicles of Wave 1 are equivalent to those derived from follicles of Wave 2. In a preliminary experiment (Experiment 1), heifers were given Folltropin-V (20 mg NIH-FSH-P1, im, bid for 5 d) beginning the day after emergence of the first (n=10) or second (n=10) follicular wave of the estrous cycle, equivalent to approximately Day 1 and Day 10, respectively (Day 0=ovulation). Luteolysis was induced with cloprostenol (500 mug im, bid) on the fourth day of treatment. Fewer (P<0.05) ovulations per heifer were induced in the Wave 1 group than in the Wave 2 group (4.6+/-1.0 vs 9.1+/-1.3). However, the interval from wave emergence to initiation of treatment was found, in retrospect, to have been longer (P<0.05) in the Wave 1 group, i.e., treatment was initiated relatively later with respect to wave emergence. Experiment 2 was designed to correct this disparity and to initiate the same treatment protocol on the day of wave emergence rather than the day after (n=21 per Wave group). There was no difference between Wave 1 and Wave 2 groups in the interval from wave emergence to initiation of treatment (0.4+/-0.1 d), the number of ovulations detected by ultrasonography (6.6+/-1.0 vs 8.2+/-1.7), the number of CL detected at slaughter (6.5+/-0.9 vs 8.1+/-1.8), the total number of ova embryos recovered (5.2+/-0.7 vs 5.1+/-0.8), or the number of fertilized embryos collected (2.8+/-0.6 vs 3.0+/-0.6). In addition, there was no difference between groups in the proportion of heifers that ovulated in either experiment; collectively, luteolysis and ovulation was induced in 58 of 60 heifers. The results supported the general hypothesis that follicles and oocytes of the first and second follicular waves are equivalent in the response to superstimulatory treatment. Regardless of which follicular wave, initiation of treatment near the time of wave emergence appears critical for maximal superovulatory response. Because of the consistency in the time of emergence of Wave 1 (day of ovulation) and equivalence in superovulatory response, use of Wave 1 rather than subsequent follicular waves may be more convenient and time-sparing in superovulation programs; the day of estrus (day before ovulation) may be used as a consistent point of reference for the start of treatment.

We determined the effect of GnRH or hCG treatment on day 4 post-time artificial insemination (FTAI) on the formation of accessory corpora lutea (acc-CL) and on the concentration of serum progesterone (P4) in sheep. Multiparous adult Merino ewes (n = 36) were synchronized for estrus using double injection of PGF2α agonist (125 μg Cloprostenol) with an interval of 14 days. At 53-56 h after the second PG application, FTAI was performed. On day 4 post FTAI, ewes were either treated with analogue of GnRH (4 μg buserelin; n = 12) or hCG (300 IU, hCG; n = 12) or saline solution (1 ml; Control; n = 12). Two laparoscopic ovarian examinations were performed on days 4 and 10 post FTAI. In the first observation, we determined the number of post ovulation corpora lutea (po-CL) and the site, number and diameter of follicles present in both ovaries. In the second laparoscopy, we observed the number of po-CL and acc-CL. The sizes of the follicles that generated the acc-CL were determined according to the position of the follicles observed in the first laparoscopy. Serum P4 concentration was determined on days 4, 7, 10, 13, 17 and 21 post FTAI by chemiluminescence. A similar follicular population in size and number was observed in the three experimental groups prior to the beginning of treatments (Follicles 2 mm: 6.4 ± 3.7, 3 mm: 3.0 ± 2.3, 4 mm: 1.1 ± 0.5, 5 mm: 1.4 ± 0.8; P ˃ 0.05). The formation of 1.0 ± 0.4 and 1.1 ± 0.3 acc-CL was observed in the GnRH and hCG groups, respectively (P ˃ 0.05), but was not observed in the Control group (P < 0.05). Follicle sizes from which acc-CL generated were 3, 4 and 5 mm and did not differ between hormonal treatments (P ˃ 0.05). The hCG group had higher mean concentrations of P4 on days 7, 10, 13 and 17 post FTAI compared with the GnRH group and the Control group (P < 0.05), while no differences were observed between these two latter groups (P>> 0.05). Mean P4 concentrations in ewes treated with hCG showed no differences according to the size of the follicle from which acc-CL were generated (P ˃ 0.05). In conclusion, administration of hCG or GnRH on day 4 post FTAI induced the formation of one acc-CL from follicles of 3, 4 or 5 mm, indistinctly. However, serum P4 concentration increased significantly only in the hCG group. The serum P4 concentrations of acc-CL that originated from different follicle sizes did not differ.

The objective was to evaluate the effects of temporary calf removal (TCR), eCG administration, or both, in a progesterone-based protocol. Suckled Nellore cows (40-80 d postpartum, n=443) with body condition scores from 2.0 to 3.5 (5-point scale) on three farms were all given a synchronizing protocol (PEPE). At the start (designated Day 0), cows were given an intravaginal device (1.0 g of progesterone) and 2.5mg of estradiol benzoate (EB) im. On Day 8, the device was removed and cows were given PGF(2 alpha) (150 microg of D-cloprostenol im), followed in 24h by 1.0mg EB im, and 30-36 h thereafter, fixed-time AI. The design was a 2 x 2 factorial; main effects were TCR (54-60 h; from device removal to FTAI) and eCG treatment (300 IU im, concurrent with PGF(2 alpha)). Transrectal ultrasonography was done on Days -10 and 0 to detect anestrus (absence of a CL at both examinations) and approximately 30 d after FTAI (pregnancy diagnosis). Data were analyzed by logistic regression. The following variables did not significantly affect pregnancy rates: farm, postpartum interval, cyclicity, inseminators, and semen (sire). Overall, 77% of the cows were deemed anestrus. Pregnancy rates were similar (P>0.05) among treatment groups: Control (54/108=50.0%), TCR (44/106=41.5%), eCG (63/116=54.3%), and TCR+eCG (49/113=43.4%). Pregnancy rate was higher in multiparous than primiparous cows (186/360, 51.7% vs. 24/83, 28.9%, P<0.01), but was not significantly affected by cyclicity status or body condition score. In conclusion, temporary calf removal, eCG, or both, did not significantly increase pregnancy rate to timed-insemination in a progesterone-based synchronization protocol in postpartum Nellore cows with acceptable body condition.

It was the aim of this field study to evaluate two different protocols of ovulation synchronization for the treatment of ovarian cysts and their effect on reproductive performance in dairy cows. In addition, factors with a possible influence on treatment success and pregnancy outcome as well as costs per pregnancy were analysed. The study was performed with 130 German Holsteins with ovarian cysts diagnosed on days 55 to 60 postpartum. Cows belonging to group 1 (n = 65) received a modified ovsynch protocol [day 0: 0.15 mg cloprostenol (PGF) + 0.02 mg buserelin acetate (GnRH); day 14: PGF; day 16: GnRH]. Group 2 (n = 65) was treated with the conventional ovsynch protocol (day 0: GnRH; day 7: PGF; day 9: GnRH). Timed artificial insemination was performed 20 to 24 h later. Cows without ovarian cysts served as controls. Treatment success (disappearance of the ovarian cyst) after the first ovsynch cycle was higher in group 1 (66.2%) than in group 2 (23.1%, p < 0.05). Reproductive measures in group 1 were comparable with those of the control group and, compared with group 2, were conspicuously better (66.2%, 76.9%, 83.1%, 59.5% vs. 40.0%, 50.7%, 60.0%, 27.5% for cumulative pregnancy rate after treatment cycle 1 to 3 and second service conception rate, respectively, p < 0.05). Overconditioned cows and cows with larger ovarian cysts showed a diminished treatment and pregnancy success. In group 1, costs per pregnancy were only slightly higher than in the control group (group 1: €352.44, group 2: €484.59, control group: €333.77). In conclusion, our results suggest that ovsynch protocols can be used in the treatment of ovarian cysts. The modified ovsynch protocol led to a better cure rate as well as a better reproductive performance, and was economically beneficial compared with a conventional ovsynch protocol.

Ram effect, defined as shortening of seasonal anestrus in ewes by exposure to the ram, is now well recognized but the underlying mechanisms are still unclear. Little information also exists whether the ram is able to influence the estrus cycle and ovulation. Three experiments were conducted to investigate endocrine response, time of ovulation and pregnancy rate of ewes in proestrus, exposed to the ram (treated) or an adult ewe (control). In the first experiment, ewes (n = 20) were treated with fluorgestone acetate pessaries for 12 days and were given eCG and cloprostenol one day before withdrawal of pessaries. On the day after removal of the pessaries ewes in the treated group (n = 10) were exposed to the ram and those in the control group (n = 10) were exposed to an adult ewe. Blood samples were taken for LH assay every 20 min from 2 h before to 24 h after ram exposure. In the second experiment, ewes (n = 120) were induced into proestrus and on the day after removal of the pessaries were exposed to either a ram (n = 60) or a ewe (n = 60) as described above and were laparoscoped 50, 60 or 70 h after pessary withdrawal (n = 20 at each time interval). In the third experiment ewes (n = 90) were induced and exposed to the ram (n = 45) or an adult ewe (n = 45) and inseminated via a laparoscope whit frozen-thawed semen at 50 or 60 h after pessary removal, respectively. Exposure to the ram was followed in 2 h by a marked rise in LH, equivalent to a preovulatory surge in duration and amplitude. It was also followed by concentrated ovulation within 25 to 30 h and by an increased pregnancy rate in exposed ewes (73.3 vs. 53.3%).

Two experiments were designed to evaluate the responsiveness of beef heifers to superstimulatory treatments administered during the first follicular wave. Heifers were examined daily (Experiment 1) or twice daily (Experiment 2) by ultrasonography to determine the status of follicular wave development and the day of initiation of superstimulatory treatment. Heifers in both experiments were superstimulated with a total dose of 10 ml Folltropin (equivalent to 200 mg of NIH-FSH-P1), divided into 10 equal intramuscular injections over 5 days. On the last day of treatment, heifers received 500 mug of cloprostenol after each injection of Folltropin to induce luteolysis. In the respective groups, superstimulatory treatments were initiated on Day -1, Day 0 (day of ovulation) or Day +1 for Experiment 1, and on Day -1, Day 0, Day +1 or Day +2 for Experiment 2. In Experiment 1, the number of ovulations in each ovary was assessed by ultrasonography and by counting the number of corpora lutea (CL) in each ovary at slaughter. The correlation between both techniques for assessing ovulatory response was high (r= 0.98; P< 0.0001), and there was no significant difference in the mean number of ovulations detected by ultrasound (5.7+/-1.1) versus the mean number of CL counted at slaughter (6.2+/-1.2). In Experiment 1, the mean (+/- SEM) number of CL counted at slaughter in heifers treated on Day -1 (9.4+/-3.8) and Day 0 (7.3+/-1.6) was higher (P< 0.05) than that of heifers treated on Day +1 (0.7+/-0.3). The mean number of follicles>>/=7 mm in diameter on the last day of treatment was also higher (P<0.05) in the Day -1 group compared with the Day +1 group; the Day 0 group was intermediate. In Experiment 2, the mean number of ovulations was higher (P< 0.05) in the Day 0 group (18.4+/-3.4) than the Day -1 (9.5+/-2.3), Day +1 (6.7+/-2.2) or Day +2 (6.5+/-2.3) groups. Heifers in the Day -1, and Day 0 groups had more (P< 0.05) follicles>>/=7 mm at the end of treatment compared with heifers in the Day +1 or the Day +2 group. The stated hypothesis was supported: exogenous FSH treatment initiated at the time of wave emergence, near the expected time of the endogenous wave-eliciting FSH surge, has a positive effect on the superstimulatory response. A higher superstimulatory response was elicited when treatments were initiated on the day of, or the day before, wave emergence compared with that of later treatments.

The purpose of the present investigation was to test the hypothesis that drug-induced changes in rumen contractions influence feed intake in dwarf goats. Intravenous (i.v.) administration of clonidine (1 microgram kg-1 min-1 for 10 min), xylazine (1 microgram kg-1 min-1 for 10 min), and PGF-2 alpha (10 micrograms kg-1 min-1 for 15 min) caused bradycardia and inhibition of rumen contractions. However, no appetite-stimulating effect of these drugs was observed. Other clinical changes induced by the alpha-adrenergic agonists included slight sedation and a decrease in body temperature; all clinical effects of clonidine and xylazine were partly antagonized by tolazoline pretreatment (10 micrograms kg-1 min-1 for 30 min). These results suggest that the CNS control of feeding differs in ruminants and monogastric species. In dwarf goats fasted for 2 h, i.v. administration of oxytocin (0.01 IU kg-1 min-1 for 15 min), vasopressin (0.01 IU kg-1 min-1 for 15 min), octapressin (0.003 IU kg-1 min-1 for 15 min) or PGE1 (0.8 microgram kg-1 min-1 for 15 min) did not change feeding behaviour during the two observation periods (0-30 min and 180-210 min after drug infusion, respectively). In previous studies, similar doses of these drugs induced changes in heart rate and inhibition of rumen contraction in goats. These findings demonstrate that drug-induced changes in forestomach contractions do not simply cause changes in feeding behaviour. The i.v. infusion of the PGF 2 alpha analogues etiproston (10 micrograms kg-1 min-1 for 15 min), luprostiol (30 micrograms kg-1 min-1 for 15 min), cloprostenol (1 microgram kg-1 min-1 for 15 min) and tiaprost (1 microgram kg-1 min-1 for 15 min) induced hypophagic effects and stimulated intestinal propulsion.

Luteolysis, which occurs in a cyclical way to remove luteal tissue, may be an example of physiological apoptosis which counterbalances rapid tissue growth after ovulation. Clusterin is a multifunctional glycoprotein expressed in different tissues undergoing apoptosis. In this study we investigated clusterin and LH receptor gene expression during luteolysis as potential regulators of tissue growth and regression. Luteolysis was induced in pregnant sows (45 days) by Cloprostenol (PGF2 alpha analogue) treatment. Clusterin expression increased in the corpora lutea of pregnant sows ovariectomized 0, 6, 12, 24, 48 or 72 (n = 3) h after the luteolytic stimulus; maximum values were observed 24-48 h after the treatment (P < 0.01). An opposite trend between clusterin mRNA expression and markers of luteal function, such as progesterone levels in the corpora lutea and plasma, and LHr mRNA expression levels, was observed; moreover, clusterin expression was positively correlated with the degree of genomic DNA fragmentation, a marker of occurring apoptosis (P < 0.01). This pattern may be important in regulating luteolysis by a switch between luteotrophic and apoptotic stimulus. Our data indicate that P4 levels decrease prior to the increase in clusterin mRNA and the drop in LHr mRNA expression; we may therefore hypothesize a split between functional and structural luteolysis as reported in other species.