Cloprostenol Research Articles

Enantioseparation of cloprostenol on the polysaccharide chiral stationary phase: Influence of the mobile phase on enantioselective adsorption

Cloprostenol (CLO) is an important chiral drug widely used in veterinary practice. In high-performance liquid chromatography (HPLC), the acetonitrile/water system is more effective in the chiral resolution of CLO. The change in the ratio of acetonitrile and water has a great influence on the chiral selectivity of CLO. The enantioselective adsorption and nonselective adsorption of CLO on the polysaccharide stationary phase with three groups of mobile phases (Acetonitrile / 0.1 TFA; 95 Acetonitrile/5 H2O/0.1 TFA; 45 Acetonitrile/55 H2O/0.1 TFA) were determined and fitted with the subtraction fitting method (SFM). Adding a small amount of water to the mobile phase mainly reduced the enantioselective equilibrium adsorption constants Ks of (-)-CLO and thus changed the selectivity. Among them, the true separation factor (αtrue) of the 95 Acetonitrile/5 H2O mobile phase was as high as 92.86. Chiral preparation was performed on the basis of this mobile phase. The preparation performance in kkd (kilograms per kilogram of stationary phase purified compound per day) was 0.25 kg racemate/kg CSP/day.

Low invasive estrous synchronization protocol for wild animals: an example with melengestrol acetate in brown brocket deer (Mazama gouazoubira)

Deer are sensitive to stressful stimuli by handling and their reproductive physiology could be altered by these procedures, making it necessary to develop less invasive protocols for ART. Melengestrol acetate (MGA), a synthetic progestin administered orally, appears as an alternative for estrous synchronization protocols (ESP), such as reported in cattle. Firstly, we compared two MGA doses (0.5 and 1.0 mg/day/animal), which would have suppression effect in estrous behavior (EB). Eight females were randomly and equally distributed in Group 1 (G1) and Group 2 (G2), which received 0.5 and 1.0 mg/day/animal respectively for 15 days (D1 to D15). Two cloprostenol (CP) applications were performed on D0 and D11. Estrus detection (ED) was performed every day. All females from G1 displayed estrus during treatment period, whereas all females from G2 displayed estrus after treatment, suggesting a suppressive effect of 1.0 mg in the EB. Once the suppressive MGA dose (1.0 mg) was defined, we used this dose for assessing ESP. The same eight females received 1.0 mg/animal for eight days (D-8 to D-1), followed by 0.25 mg of estradiol benzoate on D-8 and 265 μg of CP on D0. Feces for fecal progesterone metabolites (FPM) measurement were collected from D0 until seven days after the last day of estrus. Seven females displayed estrus between 12 and 72 h after CP application, which was followed by a significant increase in FPM levels (except female MG6), suggesting the formation of corpus luteum. After ED, females were placed with a fertile male to assess the fertility of the protocol. Pregnancy was confirmed by ultrasound 30 days after mating in 3/6 individuals. Although the low effectiveness of MGA protocol, it should be considered as a promising alternative in deer ESP since this protocol has less stressful effect on the animal during reproductive management when compared to other ESP.

Evaluation of reproductive performance of dairy heifers subjected to two estrus detection systems and treated with two prostaglandin formulations

Efficient and accurate identification of estrus is critical for the success of estrous detection based reproductive management. We hypothesized that management of dairy heifers with the aid of an automated estrous detection system (AES) would improve service rate and consequently the reproductive performance of dairy heifers. In addition we hypothesized that treatment of heifers with cloprostenol (CLO) would improve pregnancy per service compared with treatment with dinoprost (DIN). The objectives were to evaluate the reproductive performance of dairy heifers managed with the aid of an AES vs a mounting detector device (MD) and synchronized with CLO vs DIN.

Uterine and placental expression of HPGD in cows during pregnancy and release of fetal membranes

15-Hydroxyprostaglandin dehydrogenase (HPGD) plays a key role in prostaglandins (PGs) catabolism. Its expression and activity appear to be regulated by progesterone (P4). We investigated the HPGD mRNA-expression and protein localization in placentomes and interplacental uterine sites throughout gestation (Study I), and after fetal membranes retention (RFM) compared with normally delivered fetal membranes (DFM) (Study II). Furthermore, we analyzed the influence of aglepristone (AP), dexamethasone (GC) or cloprostenol (CP), on HPGD expression in bovine placentomes (Study III). Tissues from late gestation (D272) and at normal term (NT) served as controls. HPGD was highest in all sites at the beginning of pregnancy and at (NT). Following induced parturition HPGD was lower after (AP) and (GC) compared with (NT), and was similar in RFM and DFM. Placentomes stained primarily in fetal compartments; interplacentomal signals were observed in endometrial glandular and luminal epithelium. Results indicate that HPGD may play a role during establishment and termination of gestation.

Progesterone and ultrasonographic changes during aglepristone or cloprosternol treatment in queens at 21 to 22 or 35 to 38 days of pregnancy

Progesterone (P4) is a requirement for pregnancy development. Previous reports observed a maximal value of serum P4 concentration on 21 days after the first mating after which it slowly declines throughout the rest of pregnancy. Ultrasound examination should be performed to ensure that pregnancy interruption is complete. Limited information is available on the ultrasonic appearance of conceptuses during pregnancy termination in cats The objective was to study serum P4 concentration and ultrasonographic changes during aglepristone (ALI) or cloprostenol (CLO) treatment and to evaluate the fertility after treatment. Two experiments (EXP) were carried out to accomplish this aim. Sixty queens, 12- to 36-month-old, were used. On Days 21 to 22 of pregnancy (EXP I) or 35 to 38 of pregnancy (EXP II), queens were divided into three groups (G). Queens in G1 received ALI (10 mg/kg, sc; EXP I, n = 10; EXP II, n = 10) for 2 consecutive days. Queens in G2 received CLO (5 μg/kg, sc; EXP I, n = 10; EXP II = 10) for 3 consecutive days. Queens in G3 received 1 mL of saline solution (PLA, sc; EXP I, n = 10; EXP II = 10). Blood samples were taken before treatment (Day 0) and every day during 10 days after the treatment to measure serum P4 concentrations. Likewise, after treatment, queens were monitored daily by ultrasonography for 10 days and weekly until the end of gestation to obtain gestational sacs measurements (GS), fetal measurements, and fetal biophysical profile. Data were analyzed by ANOVA. Serum P4 concentrations were significantly different on Day 6 (EXP I) and on Day 1 (EXP II) in ALI and CLO groups compared with PLA group (P < 0.05 and P < 0.01; respectively). The ultrasonographic monitoring during treatment allowed assessing changes in the GS and fetal measurements, embryo-fetal viability, and risk of pregnancy loss. In conclusion, the results from this study reported changes in serum P4 concentration and in ultrasonography measurements during pregnancy interruption with ALI or CLO treatment. Also it was observed that ALI and CLO are safe drugs and can preserve posttreatment queen fertility. Therefore, the results obtained in our work will be applied in feline reproduction practice.

Estrus synchronization schemes and application efficacies in anestrus lanzhou fat-tailed ewes

ABSTRACTThis study aims to investigate the estrus efficacy of FIS (fluorogestone intravaginal sponges)/eCG (equine chorionic gonadotropin) and cloprostenol treatments to establish the optimum protocols for estrus synchronization in ewes. Forty-two ewes were assigned into groups A (FIS/eCG group) and B (CLO (cloprostenol) group). Each group was randomly divided into three subgroups (n = 7) according to the dose of eCG (ECG1, ECG2 and ECG3) or cloprostenol (CLO1, CLO2 and CLO3). The estrus rates, lambing rates and average litter sizes were accounted. Serum concentrations of progesterone (P4), follicle-stimulating hormone (FSH) and luteinizing hormone were determined. Selected optimum schemes were employed in 636 ewes in four sheep farms. Estrus rates of groups A and B were 85.72% and 57.14%. Estrus onset times (EOTs) were 53.91 ± 12.26 and 46.41 ± 4.65 h for groups A and B. EOT of ECG1 was longer than that of CLO3 (P < .05). Lamb numbers, lambing rate and litter size of group B were lower than those of group A. The maximum and minimum lambing rates were calculated in ECG3 and CLO1 (157 vs. 57). On day 11, higher P4 values (P < .05) were determined of ECG3 and CLO1 compared to CLO2 and CLO3 subgroups. FSH concentration of ECG1 was significantly higher than that in group B (P < .05). Application results showed that estrus rate, pregnancy rate and lambing rates of ECG3 and CLO3 protocols were 95.97% vs. 70.91%, 91.37% vs. 88.89% and 149.87% vs 132.69% (P < .05), respectively. FIS/eCG and cloprostenol improved estrus synchronization. Injection of 400 IU eCG after FIS withdrawal was an optimum protocol for estrus synchronization of ewes.

Aglepristone efficiency with and without the canine pyometra cloprostenol

ABSTRACTObjective. Evaluate the effectiveness of aglepristone with and without cloprostenol for treating canine pyometra. Materials and methods. Ten female French Bulldogs between 3-8 years of age diagnosed with pyometra were divided into two groups, one receiving a 10 mg/kg dose of aglepristone subcutaneously on days 1, 2, 8, 14 and 28, and the other an equal dose on days 1, 3, 8 and 15, as well as a 1 μg/kg dose of cloprostenol subcutaneously on days 3 and 8. Both groups received 5 mg/kg of enrofloxacin orally every 12 hours for 28 days. Hematic profiles were generated on days 1 and 28 and counted days until the next heat, expelling purulent material and of clinical recuperation. Results. There was no statistical difference in the variables of the line red blood cells between times and protocols. The line of white blood cells showed a statistical difference between days of treatment but not between the two groups. Both treatments were effective resulting in complete clinical recuperation. The combination of aglepristone with cloprostenol acted more quickly, decreasing the number of days of secretion, abdominal pain, and the recuperation of normal activity and appetite. All 10 females were bred during their first heat. Three females from the aglepristone group and one from the combined aglepristone with cloprostenol group were impregnated. Conclusions. Both protocols, combined with enrofloxacin, produced complete clinical recuperation in bitches with pyometra, but it was achieved more rapidly when given the combination of both aglepristone and cloprostenol.RESUMENObjetivo. Evaluar la efectividad del aglepristone con y sin el cloprostenol en el tratamiento del piómetra canino. Materiales y métodos. Diez hembras Bulldog Francés entre 3–8 años de edad con diagnóstico de piómetra, se dividieron en dos grupos, uno recibió aglepristone a la dosis de 10 mg/kg subcutáneo los días 1, 2, 8, 14 y 28, y otro una dosis igual los días 1, 3, 8 y 15, más cloprostenol a dosis de 1 μg/kg subcutáneo los días 3 y 8. Ambos grupos recibieron enrofloxacina 5 mg/kg oral cada 12 horas por 28 días. Se realizaron perfiles hemáticos los días 1 y 28, y se valoraron días de retorno al celo, expulsión del material purulento y de recuperación clínica. Resultados. No hubo diferencia estadística en las variables de la línea roja sanguínea entre tiempos y protocolos. La línea de glóbulos blancos mostró diferencia estadística entre los días de tratamiento pero no entre los dos grupos. Ambos tratamientos fueron eficaces en la recuperación clínica completa, siendo el aglepristone más cloprostenol más rápido en disminuir los días de secreción, dolor abdominal, recuperación de la actividad normal y apetito. Las 10 hembras fueron servidas en el primer celo y quedaron preñadas tres hembras del grupo del aglepristone y una del grupo aglepristone con cloprostenol respectivamente. Conclusiones. Ambos protocolos combinados con enrofloxacina, produjeron la recuperación clínica completa en perras con piómetra, pero se consiguió más rápidamente en el grupo de aglepristone con cloprostenol.

Cloprostenol and eCG influence oestrus synchronisation and uterine development in mice

The aim of this study was to investigate the efficacy of equine chorionic gonadotropin (eCG) and cloprostenol (CLO) administration on oestrus synchronisation, uterine development as well as serum LH and FSH concentrations in mice. One hundred and five KM mice were assigned into eCG-1, eCG-2, eCG-3, CLO-1, CLO-2, CLO-3 and control groups (CG, n = 15). The eCG-1, eCG-2 and eCG-3 groups were intramuscularly injected with 10, 20 and 40 IU eCG. CLO-1, CLO-2 and CLO-3 were intramuscularly injected with 10, 15 and 20 μg cloprostenol acetate. The results showed that 93.33% and 66.67% of synchronised mice displayed oestrus within 18.68-37.59 h. Oestrus numbers, oestrus onset time (EOT) and oestrus rate in CLO and eCG groups were greater than in CG ( P < 0.05). EOT in CLO and eCG groups were 19.88 ± 2.91 h and 34.84 ± 5.05 h. Uterine weights of treatment groups were larger than CG. Uterine weights of the eCG group were higher than those in the CLO group. Uterine horn longitudial diameters (ULD) in treatment groups were larger than CG during the experiment. ULD in eCG-2 and eCG-3 were significantly greater when compared to CG (P < 0.05 or P < 0.01). On days 14 and 21, uterine horn transverse diameters (UTD) in CLO-1, eCG-1, eCG-2 and eCG-3 subgroups were significantly larger than that of CG ( P < 0.05 or P < 0.01). Serum LH concentrations in eCG and CLO increased. Increments in eCG and CLO groups were greater than that of CG. FSH concentrations in eCG mice were higher than those in CLO and CG mice ( P < 0.05) on day 21. Thus, eCG and cloprostenol treatments in mice can improve uterine development and promote the secretion of LH and FSH.

Cloprostenol and pregnant mare serum gonadotropin promote estrus synchronization, uterine development, and follicle-stimulating hormone receptor expression in mice.

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 effects of aglepristone alone and in combination with cloprostenol on hormonal values during termination of mid-term pregnancy in bitches

This study was designed to assess endocrine changes associated with termination of mid-term pregnancy after use of two different protocols. For this purpose we compared the effects of aglepristone (AGL) alone and in combination with cloprostenol (CLO) on serum concentrations of progesterone (P4), estradiol (E2) and relaxin (RLN) measured at short-term intervals during the abortion period in bitches. Fourteen pregnant bitches between day 25 and 32 of gestation were used in the study. In the AGL group (n=7), aglepristone was administered solely (10mg/kg body weight (BW), subcutaneously, once daily on two consecutive days) whereas in the AGL-CLO group (n=7), aglepristone (dosage as in AGL group) and cloprostenol (1μg/kg BW, subcutaneously, same with aglepristone) were combined. All pregnancies were successfully terminated 5.2±1.6 days after initiation of treatments, which was significant in both groups (P>0.05). At the time of the start of abortion (SA) and the end of abortion (EA), the mean P4 concentrations were 26.6±7.3 and 12.0±6.4ng/ml in AGL group, and 2.7±0.7 and 0.9±0.1ng/ml, in AGL-CLO group, respectively (P<0.01). Serum E2 concentrations were significantly higher (P<0.05) in AGL group at 42, 48, 54h and SA after initiation of treatment. In the AGL-CLO group, serum RLN concentrations did not significantly change from the initiation of treatment to EA (P>0.05). However, markedly higher RLN concentrations (P<0.05) were observed in the AGL group at 48h (1.5±0.7ng/ml) and at SA (1.6±0.5ng/ml). The results of the present study indicate that changes in the hormonal concentrations affect the mechanism of abortion in different ways. Further in depth studies investigating changes in the expression of hormone receptors inside the ovary, endometrium and placenta might be helpful to our understanding of the endocrinological differences observed in this study.

The Effect of Dose and Type of Cloprostenol on the Luteolytic Response of Dairy Cattle during the Ovsynch Protocol under Different Oestrous Cycle and Physiological Characteristics

The objective of this study was to characterize the effect of dose and type of cloprostenol (CLO) on the luteolytic response of dairy cattle during the Ovsynch protocol under different oestrus cycle and physiological characteristics. Twelve non-lactating dairy cows and 111 lactating dairy cows were used in three experiments. In Experiment I, cows were synchronized so that they had only a 5.5- to 6-day-old corpus luteum (CL) at the time of the prostaglandin F2α (PGF2α ) treatment of Ovsynch. In Experiment II, cows were synchronized so that they had at least a CL of approximately 14days old at the time of PGF2α treatment and an accessory CL if they had responded to the first GnRH of Ovsynch. Furthermore, in each experiment, cows received either a standard or a double dose of d-CLO as the luteolytic treatment. In Experiment III, lactating cows were blocked by parity and assigned to one of three luteolytic treatments during Ovsynch: 500μg d,l-CLO, 150 or 300μg of d-CLO. In Experiment I, the dose of d-CLO had an effect (p=0.08) on the percentage of cows with full luteolysis, but not in Experiment II (p>0.1). More cows in Experiment II had full luteolysis than did cows of Experiment I (87% vs 58%, respectively; p=0.007). In Experiment III, 87.1%, 84.4% and 86.2% lactating dairy cows had full luteolysis and 37.8%, 36.8% and 36.1% of cows became pregnant after treatment with 500μg d,l-CLO, 150 or 300μg of d-CLO, respectively (p>0.05).

Efficacy of Cloprostenol or Aglepristone at 21–22 and 35–38 Days of Gestation for Pregnancy Termination in Queens

The objective of this study was to evaluate the efficacy of cloprostenol (CLO) or aglepristone (ALI) for pregnancy termination in queens at 21-22 and 35-38 days of gestation. Two experiments (EXP) were carried out to accomplish this aim. Thirty-seven 12- to 14-month-old mixed breed queens were used in a randomized design. At oestrus, queens were housed for mating with a tom, and pregnancy was confirmed by transabdominal ultrasonographic examination (US). On days 21-22 of pregnancy (EXP1) or 35-38 of pregnancy (EXP2), queens were divided into three groups (G). Queens in G1 received ALI (10 mg/kg, sc; EXP1, n = 6; EXP2, n = 6) on two consecutive days. Queens in G2 received CLO (5 μg/kg, sc; EXP1, n = 6; EXP2 = 7) on three consecutive days. Queens in G3 received 1 ml of saline solution (PLA, sc; EXP1, n = 6; EXP2 = 6). After treatment, females were monitored daily by US during for 10 days and weekly until the end of gestation. In EXP1, pregnancy was terminated in (6/6, 100%), (0/6, 0%) and (0/6, 0%), for the ALI, CLO and PLA groups, respectively (p < 0.001). In EXP2, pregnancy was terminated in (6/6, 100%), (1/7, 14%) and (0/6, 0%) for the ALI, CLO and PLA groups, respectively (p < 0.001). In both EXP, after CLO administration, animals vomited and were depressed for 30 min; but no side effects were observed in the animals in the ALI group. In conclusion, the results from this study indicate that three injections of CLO are not effective, but two injections of ALI are effective to induce abortion in queens at 21-22 or 35-38 days of pregnancy.

The effect of hormone treatments (hCG and cloprostenol) and season on the incidence of hemorrhagic anovulatory follicles in the mare: A field study

The association between use of hormone treatments to induce estrus and ovulation and the incidence of hemorrhagic anovulatory follicles (HAFs) was studied in a mixed population of mares ( Equus caballus) during two breeding seasons in a commercial breeding clinic. Mares treated with cloprostenol (CLO) were more likely to develop HAFs than were mares with spontaneous cycles (P < 0.001) or those treated with human chorionic gonadotropin alone (P = 0.08). There was no significant effect of season on the incidence of HAFs. The mean (±SEM) interval from CLO treatment to beginning of HAF development was 6.1 ± 0.5 d. Age of mares with HAF cycles was not different (12 ± 1.3 yr; P > 0.05) from that of mares with ovulatory cycles (10.5 ± 1.5 yr).

Morphological Examination of the Corpora Lutea from Pregnant Bitches Treated with Different Abortifacient Regimes

Different abortifacient regimes in dogs were analysed for their effect on the pregnancy corpora lutea (CL), namely, prostaglandin F2a analogue cloprostenol (CLO) combined with dopamine agonist cabergoline (CAB), or progesterone (P4) receptor antagonist aglepristone (AGL). Ovaries were collected after 6-10 days of treatment during first trimester. The CL of the control-group showed strong expression of relaxin (RLX), its receptor RXFP1 and enzymes of steroid biosynthesis (HSD) with high peripheral P4-levels. Whereas RXL, RXFP1 and HSD were lowest expressed in the CLO/CAB-group with a massive degeneration of CL and their blood vessels combined with low peripheral P4-level. The AGL-group showed less extensive CL degeneration and more intensive staining of the examined factors than CLO/CAB. In summary, all examined factors are associated with normal luteal function and are useful tools to stage luteolysis. Although both treatments have the same abortive action, their sequence of events on the CL is different.

BIBLIOGRAPHIC STUDY: PROTOCOLS FOR THE INDUCTION OF OVULATION IN THE MARE

Although various regimes are available, some are sp ecific to cycling mares during the ovulatory season and noncycling mares during anovulatory or transitional season and early postpartum . In this regard this paper discusses and summarizes the basi s for the use of some regimens for controlling ovul ation in the mare. For controlling the estrous cycle of the cycling ma re there are some conventional regimens and novel methods. Before beginning any regimen with the help of ultrasonography or transrectal palpation the reproductive tract sho uld be assessed and then a decision about when to use one regimen over another can be taken. The most common hormonal treatments used in the regimens are presented below. The natural form of PgF2 α and some of its analogues have been used in mares to induce luteal regression and hasten estrous and ovu lation. Treatment with native PgF2 α (dinoprost, 5-10 mg/dose 36 ) may induce some undesirable side effects , that's why analogues (cloprostenol ,100-250 �g/dose 36 ; luprostiol 7,5 mg/dose 3 ) that produce less side effects but with a potent luteolytic action are sometimes prefe rred .Treatment with PgF2 α can be done by any parentheral routes , but the most common used i s the intramuscular injection. A recent study involved administration of PgF2 α at one-tenth the conventional dose (dinoprost ,0.5 mg) into the sacral-lumbar space at mid-diestrus 1 .Results indicated a significant and sustained decrease in systemic levels of progesterone 24 hour s after the sacral-lumbar injection, witch was similar to the changes obtained in mares that r eceived the conventional dose intramuscular. A regimen for the induction of ovulation consists i n a PgF2 α injection (day1) followed by an hCG treatment (day 7-8) and another PgF2 α administration (day 15) followed by hCG treatment (day 21-22).The interval between the end of the treatment and the ovulation time is of 2-4 days 17

Use of oxytocin and cloprostenol to facilitate semen collection by electroejaculation or transrectal massage in bulls

Two experiments were conducted with 24 bulls in which semen collection was attempted by transrectal massage (RM) and electroejaculation (EE). In experiment 1, bulls received the following treatments on successive semen collection days: saline 10 min prior to electroejaculation (control); saline 10 min prior to 2 min of transrectal massage followed by electroejaculation; cloprostenol (CLO) 10 min prior to 2 min of transrectal massage followed by electroejaculation; oxytocin (OXY) 10 min prior to 2 min of transrectal massage followed by electroejaculation. Transrectal massage consisted of general, back and forth motion over the ampullae, prostate and urethra with a flattened hand. In experiment 2, bulls received saline (control), oxytocin, or cloprostenol 10 min before attempting semen collection by transrectal massage. Massage was applied specifically to the ampullae for a maximum of 5 min or until a semen sample was obtained. Electroejaculation was attempted in all bulls following transrectal massage. In experiment 1, semen was obtained in <1% of bulls by transrectal massage. However, by using an improved massage technique in experiment 2, semen was obtained in 97.2% of attempts. Semen was obtained in 96.9 and 98.9% of attempts by electroejaculation in experiments 1 and 2, respectively. Oxytocin treatment increased the time to penile protrusion during electroejaculation in experiment 1 and during massage in experiment 2. In experiment 1, oxytocin decreased the time to semen emission and tended to decrease the number of electroejaculation stimuli to semen emission. Cloprostenol treatment, in experiment 1, resulted in an increased number of electroejaculation stimuli to penile protrusion, but did not affect the number of stimuli required for semen emission. Massage of the ampullae prior to electroejaculation reduced both the time to semen emission and the number of electroejaculation stimuli required for semen emission. Transrectal massage of the ampullae was very effective in this experiment for producing semen emission, but quantity of semen samples was less than for electroejaculation. The usefulness of transrectal massage for semen collection in breeding soundness evaluations needs to be investigated further under field conditions.

Reproductive performance of dairy cows with ovarian cysts after different GnRH and cloprostenol treatments

Cystic ovarian disease is an important cause of reproductive failure and economic loss for the dairy industry. This report describes two consecutive studies. The objective of the first was to evaluate the response of cows with ovarian cysts to two therapeutic treatments. In the second study, we compared the effectiveness of the best treatment established in Study 1 with that of the Ovsynch protocol. For Study 1, cows were considered to have an ovarian cyst if it was possible to observe a single follicular structure with a follicular antrum diameter ≥25 mm in the absence of a corpus luteum in three ultrasonographic examinations performed at 7 days intervals. At diagnosis (Day 0), cows were assigned to one of two treatment groups. Cows in Group GnRH/CLP ( n=31) were treated with 100 μg GnRH i.m. and 500 μg cloprostenol (CLP) i.m. on Day 14. Cows in Group GnRH–CLP/CLP ( n=32) were treated with 100 μg GnRH i.m. plus 500 μg CLP i.m. on Day 0, and 500 μg CLP i.m. on Day 14. The animals were inseminated at observed estrus and monitored weekly by ultrasonography for 4 weeks or until AI. Cows in the GnRH–CLP/CLP group showed a lower cystic persistence rate (15.6%<45.2%; P=0.01); a higher estrus detection rate (84.4%>41.9%; P<0.0001); a higher ovulation rate (75% versus 32.3%; P<0.0001) and a higher early response rate (31%>3%; P=0.02) than those in the GnRH/CLP group. For the second study, 128 cows with ovarian cysts were randomly assigned to one of two treatment groups: cows in Group Ovsynch ( n=64) were treated with 100 μg GnRH i.m. on Day 0, 500 μg CLP on Day 7, and 100 μm GnRH i.m. 36 h later. Cows in this group were inseminated 24 h after the second GnRH dose (Ovsynch protocol). Cows in Group GnRH–CLP/CLP/GnRH ( n=64) were treated as those in the GnRH–CLP/CLP group of Study 1 but received GnRH 32 h after the second CLP treatment and were inseminated 24 h after this. A further group of cows without ovarian cysts inseminated at natural estrus served as the Group Control ( n=64). Cows in the GnRH–CLP/CLP/GnRH group showed a lower cystic persistence rate (10.9%<46.9%; P<0.0001); higher ovulation rate (79.7%>17.2%; P<0.0001); higher return to estrus rate (34.3%>12.5%; P<0.01) and higher pregnancy rate (28.1%>3.1%; P<0.01) than those in Ovsynch; and a similar pregnancy rate (28.1% versus 35.9%) to Control cows. These findings indicate that lactating cows with ovarian cysts can be successfully synchronized and time inseminated using a protocol that combines GnRH and CLP, starting treatment by simultaneously administering both products. This protocol also allows the insemination of cows showing estrus within the first week of treatment. Ovarian cysts were less responsive when treatment was started with GnRH alone.

Effect of two doses of cloprostenol in two schemes for estrous synchronization in Nubian goats

In experiment 1, 12 nulliparous does were randomly assigned to 3 groups. Animals in each group received either: (a) 125 μg cloprostenol (CLO), (b) 62.5 μg CLO or (c) 0.5 ml saline solution injected between the 8th and 15th day of estrous cycle (estrus=day 0). Interval from CLO injection to estrus was (mean±SE) 60.5±11.9 and 60.5±8.3 h for does receiving 125 and 62.5 μg CLO, respectively ( P>0.05). None of the does receiving saline solution exhibited estrus. Estrus duration was (mean±SE) 22.8±1.8 and 24.5±3.5 h for groups a and b respectively ( P>0.05). Fertility rate from natural breeding following either 125 and 62.5 μg CLO was 3 out of 4. In the second experiment, 16 multiparous does were randomly assigned to 2 groups. The first group received as a first injection 125 μg CLO and as a second injection 12 days apart 62.5 μg CLO while the second group received the inverse treatment (first injection 62.5 μg and second injection 125 μg). Estrus response, the interval from treatment to estrus, and estrus duration after the first injection in both groups and after the second injection in both groups were compared. The results were: 50 and 87.5% ( P<0.02), 72.0±4.5 and 52.3±1.9 h ( P<0.01), 40.5±2.2 and 40.3±3.5 h ( P>0.05), respectively. Fertility rates from artificial insemination for 125 and 62.5 μg CLO were 4 in 8 and 5 in 8, respectively. It is concluded that 62.5 μg CLO by the intramuscular route is luteolytic in Nubian goats, and that a scheme of two doses 12 days apart should be an effective method for estrous synchronization.

Reduced incidence of retained placenta with induction of parturition in the cow

Two experiments were designed to determine whether pretreatment with Opticortenol (OPT), a long-acting corticosteroid, prior to induction of parturition with 25 mg of dexamethasone (DEX) alone or in combination with 500 μg cloprostenol (CLO) would result in a reduced incidence of retained placenta. In Experiment 1, 70% of the cows pretreated with 25 mg OPT on Day 270 of gestation calved before or within 24 hours of the scheduled induction treatment on Day 277. Cows induced to calve with DEX plus CLO without OPT pretreatment had an increased rate of placental retention (P<0.05), whereas, cows that received OPT were not different from the controls. In Experiment 2, cows received either 1 mg/25 kg OPT (high dosage) or 1 mg/50 kg OPT (low dosage) on Day 270 of gestation and were induced with DEX plus CLO on either Day 274 (4 days) or Day 276 (6 days). Cows claved 29.0 to 31.8 hours after induction treatment with 95% beginning to calve between 0700 and 1900 hours. The interval from calving to placental release and the incidence of retained placenta was not different between the high dosage 6-day group (29.4±8.2 hours, 29%) and the non-induced control cows (16.1±10.7 hours, 5%). When three cows in the high dosage 6-day group that retained their placentas for 30 to 36 hours were considered as not retained, the incidence of placental retention for that group was reduced still further to 17%. First service conception rates and pregnancy rates were lower in cows with retained placentas. Differences were significant (P<0.01) in Experiment 1 but not in Experiment 2. It was concluded that pretreatment with 1 mg/25 kg OPT 6 days prior to induction of parturition with DEX plus CLO in combination results in a predictable calving time, high calf viability, and a low incidence of placental retention.

Comparison of Prostaglandin F2α and Two Potent Analogues for Synchronizing Estrus in Dairy Heifers

Cyclic dairy heifers (n = 84) were used to compare three different prostaglandin preparations for synchronizing estrus. Animals were first synchronized with norgestomet treatment. When animals reached days 10 to 12 of the treatment cycle (day 0 = estrus), animals were randomly allotted across prostaglandin treatment groups for each day of their estrous cycle. Heifers in Group I received 25mg of prostaglandin F2α (Lm.), Group II received .5mg of cloprostenol (i.m.), and Group III received 1mg fenprostalene (s.q.). Heifers were then continually monitored for estrual behavior for 7 d. Following norgestomet removal, 88% of the animals exhibited estrus with a mean interval from implant removal to estrus of 45h. A total of 89, 92 and 78% of the heifers exhibited estrus following prostaglandin F2α (PGF2α), cloprostenol (CLO), and fenprostalene (FEN) treatments, respectively. The time from injection to estrus for PGF2α, CLO, and FEN was 74, 70, and 70 h, respectively. There was a significant decrease in the number of animals that exhibited estrus (P<.05) in FEN compared with PGF2α and CLO treatments.