We performed a clinical trial to study whether cows with palpable corpora lutea treated with cloprostenol by the farmer on the morning following examination (median time 0630 hours) were seen in heat and conceived more frequently than cows treated by the veterinarian immediately following the reproductive examination (median time 1210 hours).There were no significant differences between the two groups in the proportions of cows seen in estrus or fertility at the induced estrus.The proportions of animals that had the time of onset of estrus recorded and were seen in estrus during working hours (0800-1600 hours) were also not significantly different between the veterinary-treated and farmer-treated groups.Under the conditions of this study, there was no reason to prefer prescribing early morning administration of cloprostenol by farmers over immediate administration of the drug by the clinician.

The percentage of dairy cows that were mated and became pregnant during a 42 day breeding period was not significantly different when animals were routinely observed for estrus and mated when detected (71%, n = 56), inseminated at estrus following a single injection of cloprostenol (72%, n = 29), or inseminated at a fixed time after two cloprostenol treatments 11 days apart (69%, n = 28). However, 11 cows in the control group were not detected and mated during the breeding period and inclusion of these animals reduced the actual pregnancy rate to 60%. Results indicated that a controlled breeding program could have practical application in dairy herds but should be used with caution. Practitioners must evaluate management programs and decide, in consultation with the herdsman, if the introduction of controlled breeding technology might be advantageous.

A superovulatory and surgical protocol was developed for recovery of bovine zygotes. Holstein cows and heifers were given follicle-stimulating hormone and cloprostenol to induce superovulation. Surgical cannulation and lavage of the uterine tube was performed 40 to 48 hours after the start of standing estrus. In general, cows had more corpora hemorrhagica than did heifers, but a higher percentage (P less than 0.05) of ova recovered from cows were infertile. Several heifers were subjected to the procedure twice, and embryo recovery rates were equivalent both times.

Estrus was synchronized in 64 dairy goats in July with norgestomet ear implants. Half the does received ear implants that contained 6 mg norgestomet and the remaining does received implants that contained 3 mg. Implants were left in place for 11 days. Each doe received i.m. injections of 400 IU PMSG and 50 mug cloprostenol 24 hours prior to implant removal. Twenty-eight of 32 does (87.5%) that received 6 mg or 3 mg norgestomet exhibited onset of estrus within 24 hours of implant removal. All does had exhibited onset of standing estrus by 43 hours after implant removal. Does were hand-mated to fertile bucks twice daily while in standing estrus. There were no differences between does implanted with 6 mg or 3 mg in fertility to the induced estrus (74.2% vs 75% kidding), mean length of gestation (151.0 +/- 3.2 vs 151.6 +/- 2.0 days), mean number of kids per doe (2.1 +/- 0.8 vs 2.3 +/- 0.7) or in mean kid weights (3.10 +/- 0.80 vs 3.06 +/- 0.86 kg) (6 mg vs 3 mg, respectively). It was concluded that ear implants that contained 3 mg of norgestomet were equally as effective as implants that contained 6 mg for synchronization of estrus in dairy goats.

The difficulty of devising a standard treatment regime for cattle which would predictably terminate pregnancies in the 200 to 250 day range is described. Eight 15-month-old heifers which had been accidentally mated when approximately eight months old were examined by rectal palpation and condition scored. To induce abortion an intramuscular injection of 20 mg dexamethasone phenylpropionate was given followed 11 days later by an intramuscular injection of 500 microgram cloprostenol. A record was made of the time of calving along with calving and post calving details. Two of the heifers aborted before the injection of cloprostenol. The other six aborted within 48 hours of receiving this injection. The practical problems associated with aborting immature cattle are discussed as well as the financial aspects.

During the periods January to April, May to August, and September to December in two consecutive years, sows were assigned at breeding to receive semen doses supplemented with 87 µg cloprostenol (PG; n = 158), 5 IU oxytocin (OT; n = 154), 2 µg buserelin (GN; n = 93), or served as non-supplemented controls (CON; n = 605). Sows were inseminated at the detection of estrus, and again 24 h later, but only the first inseminations were supplemented. Compared to CON, only buserelin increased pregnancy and farrowing rates (p ≤ 0.05); there was no effect of a period or a treatment × period interaction. Litter size was larger (p ≤ 0.001) for all seminal additive groups during the first two periods and tended to increase in GN compared to CON (p ≤ 0.1) during the third period, resulting in a tendency (p < 0.1) for a period × treatment interaction. The addition of cloprostenol, oxytocin or buserelin to semen doses at first insemination increases litter size in multiparous sows.

Cyclic Spanish Merino ewes were treated on Day 13 of the estrous cycle with 12 mg, i.m., FSH-P in saline (n = 9) or propylene glycol (n = 24), currently with 100 micrograms, i.m., Cloprostenol (Day 0). From Day-6 to Day 0, the ewes were observed daily by transrectal ultrasonography, after Day 0, ultrasonography was performed every 12 h for 72 h. Sizes and locations of>> or = 2 mm follicles were recorded at each observation. The ovulation rate was determined by laparoscopy on Day 7 after estrus. The number of ovulations ranged from 0 to 6 in ewes treated with FSH-P in saline and from 0 to 16 in ewes receiving FSH-P in propylene glycol (P < 0.05). In the latter group, the response was bimodally distributed; about half of the females had 1 ovulation, whereas the remainder had>> 4 with a mean of 7 ovulations. The ovulation rate was associated with 2 characteristics of the largest follicle present at treatment (Day 0). First, if the largest follicle on Day 0 had not changed in diameter from Day-1 to Day 0, then 7 of 9 ewes had>> 3 ovulations; if the largest follicle had either increased or decreased, only 8 of 24 ewes had>> 3 ovulations (P < 0.05). Second, there was a linear trend (P < 0.07) for ovulation rate to decrease as the persistence of the largest follicle at treatment increased; no ewe in which the largest follicle on Day 0 remained present for more than 36 h ovulated more than 6 follicles. As with the ovulation rate, the numbers of large follicles on Days 1.5, 2 and 2.5 varied with the interaction of change in diameter of the largest follicle on Day 0 from Day-1 to Day 0 and with vehicle. In summary, the superovulatory response was affected by the change in diameter from Day-1 to Day 0 of the largest follicle on Day 0 and the period required for that follicle to regress after treatment with FSH-P and cloprostenol.

Ovarian follicular dynamics and embryo yield were studied during 2 different FSH regimens for superovulation of cattle. Twenty heifers were given intramuscular injections of FSH (total of 35 mg NIH) either once daily for 3 days (Group 3x1) or twice daily for 4 days (Group 4x2). At 72 h after the first FSH injection, each animal was injected with 0.75 mg cloprostenol. Inseminations were performed at 12 h and 24 h after the onset of heat. Transrectal ultrasonography was performed on the day of the first FSH injection, the day of cloprostenol injection, the day of insemination and finally on the day of embryo recovery (day 6 or 7 after heat). The numbers of small (2-4 mm), medium (5-9 mm) and large >> 10 mm) size follicles were recorded. The total number of corpora lutea, eggs and transferable embryos were recorded on the day of embryo recovery. No differences were found between the 2 groups in either of the parameters studied (p>> 0.05). It can be concluded that treatment with this FSH preparation once daily for 3 days gives a folliculogenic and superovulatory response similar to a treatment regimen where it is given twice daily for 4 days.

Experiments were done to compare the in vivo and in vitro maturational characteristics of cumulus-oocyte complexes (COC) collected from live wood bison. In Experiment 1 (anovulatory season), follicular ablation was done to synchronize follicle wave emergence among bison on Day -1, and FSH was given on Days 0 and 2. Bison were then assigned to 5 groups (n=5/group) in which COC were collected by transvaginal follicle aspiration on Day 4 and either fixed immediately with no maturation (control), matured in vitro for 24 or 30h, or collected on Day 5 after in vivo maturation for 24 or 30h (i.e., after hCG treatment). In Experiment 2 (ovulatory season), bison were treated as described for Experiment 1, but PGF2α (cloprostenol) was given to control the luteal phase on Days -9 and 3. In both experiments, cumulus cell expansion was more extensive following in vivo than in vitro maturation, and the percentage of fully expanded COC was highest in the in vivo 30h groups. Nuclear maturation occurred more rapidly in vitro; 60-70% of oocytes were at the MII stage 24h after in vitro maturation while only 25-27% of oocytes had reached the MII stage after 24h of in vivo maturation. In conclusion, nuclear maturation occurred more rapidly during in vitro vs. in vivo maturation, but was associated with less cumulus expansion than in vivo maturation. In vivo oocyte maturation was more complete at 30 vs. 24h after hCG treatment. Season had no effect on the maturational capacity of wood bison oocytes.

This study was conducted to determine whether or not exogenous gonadotropin releasing hormone (GnRH) alters the timing or improves the synchrony of estrus, the LH surge, and ovulation following estrous synchronization in dwarf goats, and to assess the effects of season on these parameters. In January and June, estrus was synchronized in 12 Pygmy and Nigerian Dwarf goats with a 10-day progestagen sponge, 125 microg cloprostenol i.m. 48 h before sponge removal, and 300 IU equine chorionic gonadotrophin (eCG) i.m. at sponge removal. Six of the 12 goats were given 50 microg GnRH i.m. 24h after sponge removal. Onset of estrus was monitored using two males. Samples for plasma LH were collected at 2 h intervals beginning 22 h after sponge removal and ending at 48 h in January and at 58 h in June. Time of ovulation time was confirmed by laparoscopy at 36, 50, 60, and 74 h in January and at 50, 60, and 74 h in June. Administration of GnRH had no significant effect on the onset of estrus; however, it reduced the interval from sponge removal to the LH surge and improved the synchrony of the LH surge (P<0.05). Treatment with GnRH also reduced the interval from sponge removal to ovulation and improved the synchrony of ovulation (P<0.05). Season had a significant effect on the timing and the synchrony of estrus with and without GnRH treatment (P<0.05). A seasonal shift was also observed in the timing of the LH surge in the absence of GnRH treatment (P<0.05). Further research is required to determine the optimum time for GnRH administration and the minimum effective dose in dwarf goats.

Cloprostenol was administered IV or IM to diestrous dairy cows to study luteolysis and synchrony of estrus and ovulation. In Study 1, 28 Holstein cows were assigned to receive injections of cloprostenol, IV or IM, on day 8 or 10 of the estrous cycle. Differences in cloprostenol-induced luteolysis or interval to estrus, were not detected. Ultrasonography revealed that 2 cows treated IV on day 8, 1 cow treated IM on day 8, and 2 cows treated IV on day 10 did not ovulate despite evidence of an apparently normal estrus. In Study 2, 20 Holstein cows were assigned to receive cloprostenol injections, IV or IM, on day 10 of the estrous cycle. Interval to estrus was not affected by route of administration. Analysis of these data indicated that cloprostenol given IV did not alter luteolysis or improve synchrony of estrus and ovulation when compared with cloprostenol given IM.

We tested the influence of 30 mg/kg/per os BN 52021, 300 micrograms/kg Cloprostenol (CIPG) and of 5 mg/kg per os LY 171883B in stress restrain and indomethacin induced ulcers in rats. The data obtained show that CIPG and LY 171883 have a significant gastroprotective action in both ulcer models. BN 52021 has a significant protective activity in stress ulcer and less in indomethacin-induced ulcers.

Partus induction is an important integrative component of reproduction management in the swine industry. In this context, the question is to what extent the application of uterotonic substances may influence the vitality of piglets. The blood pH value is used as a laboratory objective diagnostic parameter of neonatal acidosis. This parameter of the acid-base balance was examined in piglets born spontaneously at the 115th to 116th day of gestation (group 1, n = 57) and after two different partus induction protocols starting at the 114th day of gestation (group 2: combination of 175 microg of cloprostenol and 20 IU of oxytocin, n = 55; group 3: 175 microg of cloprostenol and 35 microg of carbetocin, n = 56). Initial blood samples were taken from each piglet at birth and 2 h later. The results show that the different protocols have no negative influence on the initial pH value and the compensation of neonatal acidosis until the second hour post-natum.

The relationship between the corpus luteum and the uterus in terms of the secretion of oxytocin and PGF2 alpha was investigated in free-living and captive roe deer Capreolus capreolus. During the breeding season the corpus luteum contained oxytocin and oxytocin-neurophysin mRNA, and secreted oxytocin in response to administration of the PGF2 alpha analogue cloprostenol. The oxytocin receptor was present in the uterus during the bleeding season and during delayed implantation; however, in contrast to the situation observed in other ruminants in which it has been studied, administered oxytocin did not stimulate uterine secretion of PGF2 alpha. Trophoblast interferon was undetectable at any stage of conceptus development. The absence of the mechanism underlying episodic uterine secretion of PGF2 alpha during luteolysis, which may account for the monoestry of roe deer, is consistent with the previously observed luteolytic effect of the PGF2 alpha analogue.

Lactating dairy cows were superovulated with a pregnant mare serum gonadotrophin (PMSG)/cloprostenol (PG) regimen in their mid-luteal phase (day 10). The average interval from the PMSG injection to heat was 4.1 +/- 0.05 days. First insemination occurred 18--24 hrs after standing heat and the second insemination 12--18 hrs later. Six to eight days later (the day of recovery) the superovulatory response was assessed. The variation in number of ovulation points (corpora lutea, C.L.) was sizable, and right ovary (4.1 C.L./donor) appeared more active than left ovary (3.3 C.L./donor). The non-surgical embryo collection equipment was developed for practical use on the farms and it was possible to recover 6.0 +/- 0.6 eggs per donor (54 +/- 5% recovery rate). Approximately half of these (54.2%) were considered viable, and suitable for either direct transfer or freezing, Other eggs were retarded (5.8%), degenerated (25.7%) or unfertilized (16.3%). Several influential factors were examined and there was only little conclusive evidence for any specific effect on the superovulatory response and/or egg number and quality. The non-surgical transfer experiments with a common insemination gun was encouraging and gave rise to a pregnancy rate of 56%.

In two experiments, we examined the effect of administration of cloprostenol at artificial insemination on fertility of multiparous sows. Lactation length was 21 days and only sows exhibiting estrus by 7 days after weaning were included. Cloprostenol was administered by IM injection (175 microg; n=126) or supplemented in the semen dose (525 microg; n=129). Control sows (n=130) received no hormone. In either experiment, there was no effect of any treatment on subsequent litter sizes. In experiment 1, there was no effect of treatment on farrowing rate, but in experiment 2, farrowing rate was higher (p < 0.05) in sows receiving cloprostenol by injection. Taken together, these results indicate no consistent effect of cloprostenol administration by intramuscular injection or by inclusion in the semen dose on sow fertility and so its routine use is not warranted.