cloprostenol and norgestomet

Fifty-six cows received a norgestomet implant and an injection of norgestomet and estradiol valerate; half (n = 28) received 500 IU equine chorionic gonadotrophin (eCG) at implant removal, 9 d later. A third group (n = 25) received 2 doses of cloprostenol (500 micrograms) 11 d apart. Estrous rate was higher (P < 0.05) for cows given norgestomet and estradiol plus 500 IU eCG (75.0%) than for those receiving cloprostenol (44.0%); for those receiving norgestomet and estradiol alone, it was intermediate (67.8%). Pregnancy rates to artificial insemination (after estrus or timed) were higher (P < 0.05) for cows given norgestomet and estradiol than for those given cloprostenol (23 of 28, 82.1% vs 13 of 25, 52.0%), and intermediate (67.8%) for those given norgestomet and estradiol plus eCG. In a second experiment, for heifers treated with norgestomet and estradiol plus eCG (n = 15) or with 2 doses of cloprostenol (n = 16), estrous rates were 66.7% vs 56.2% (P > 0.5), ovulation rates were 100.0% vs 81.2% (P = 0.08), intervals from implant removal or cloprostenol treatment to estrus were 48.0 +/- 4.4 hours vs 61.3 +/- 7.0 hours (P = 0.12) and to ovulation were 70.4 +/- 4.4 hours vs 93.2 +/- 7.5 hours (P < 0.01), respectively; pregnancy rates were 41.7 and 35.7%, respectively (P > 0.5). Norgestomet and estradiol were as good as (heifers) or superior to (cows) a 2-dose cloprostenol regimen. In cows given norgestomet and estradiol, injecting eCG at implant removal did not significantly improve estrous or pregnancy rates.

Topics: Analysis of Variance; Animals; Cattle; Cloprostenol; Drug Administration Schedule; Drug Implants; Drug Therapy, Combination; Estradiol; Estrus Detection; Estrus Synchronization; Female; Gonadotropins, Equine; Injections, Intramuscular; Pregnancy; Pregnenediones

Maiden heifers and lactating cows of known ovarian status and of several breeds were treated with a synthetic prostaglandin, cloprostenol, or a synthetic progestagen, norgestomet, at the start of an artificial insemination (AI) program. Animals in the cloprostenol treatment received 2 injections 10 days apart. Over the next 26 days those animals that showed oestrous behaviour were inseminated. Synchronisation rates and calving rates to insemination over the first 7 days were calculated. Those in the norgestomet treatment received an implant of norgestomet plus an injection of norgestomet and oestradiol valerate. The implant was removed 10 days later and the animals were given an injection of pregnant mare serum gonadotrophin (PMSG). They were inseminated at 48 h (maiden heifers) or 56 h (lactating cows) after implant removal. Calving rates to fixed-time insemination were recorded. After completion of the AI program the animals in both treatments were joined with bulls. Overall calving rates (AI plus bulls) were calculated. By day 7 of the program, 82% of the maiden heifers and 76% of the lactating cows in the cloprostenol treatment had been detected in oestrus. By day 21 the respective figures were 99% and 81%. Norgestomet treatment had an immediate and a prolonged effect on ovarian activity in those females classified as having inactive ovaries at the start of the AI program. Calving rates of those females to fixed-time AI and overall were similar to those of the females with active ovaries in both treatments. Their calving rates to fixed-time insemination, and overall calving rates for the lactating females, were significantly higher than the corresponding values of their contemporaries treated with cloprostenol and inseminated on observed oestrus over 7 days. For those females classified as having active ovaries at the start of the AI program, calving rates to first insemination and overall were similar for both treatments. Overall calving rates of lactating cows of each breed were, with one exception, higher in the norgestomet treatment than in the cloprostenol treatment. Although norgestomet treatment was more expensive than cloprostenol treatment, the advantage in calf crop resulted in an overall monetary advantage to the norgestomet treatment.

Topics: Animals; Cattle; Cloprostenol; Estrus Synchronization; Female; Fertility; Gonadotropins, Equine; Insemination, Artificial; Lactation; Ovary; Pregnancy; Pregnancy Rate; Pregnenediones; Prostaglandins F, Synthetic

The aim of the present study was to compare a synchronization of time of ovulation protocol for fixed-timed embryo transfer (FTET) with the usual administration of a single dose of prostaglandin associated with detection of estrus. Also, the effect of the presence of CL at the beginning of FTET protocol was evaluated. Lactating Holstein cows (n=651) with three previous artificial inseminations were classified according to presence or absence of a corpus luteum (CL). Cows with a CL were randomly assigned to two additional treatments and submitted to embryo transfer after detection of estrus (PGF-Estrus) or FTET (FTET-CL). Cows without CL were allocated to the FTET-NoCL treatment. On a random day of the estrous cycle (Day 0), cows in the PGF-Estrus treatment (n=229) were treated with 150 microg d-cloprostenol (PGF) i.m. followed by detection of estrus from Day 1 through Day 5 after PGF. Embryos were transferred 6-8 days after estrus detection. Cows in the FTET-CL (n=208; presence of CL) and FTET-NoCL (n=214; absence of CL) treatments received a norgestomet ear implant plus 2mg estradiol benzoate (EB) and 50mg progesterone i.m. on Day 0. On Day 8, the implant was removed and 400 IUeCG, 150 microg d-cloprostenol and 1mg estradiol cypionate i.m. were administered. No detection of estrus was performed and Day 10 was arbitrarily considered as the estrus day. Ultrasonographic exams were performed in all recipients and only cows with a single CL> or =15 mm or multiple CL received a fresh or frozen-thawed embryo on Day 17. Pregnancy was diagnosed by ultrasonography at 30 and 60 days of pregnancy. When FTET and PGF-Estrus were compared, the proportion of cows receiving an embryo (recipients transferred-to-treated rate) was greater in the FTET-CL (75.0% (156/208) than in PGF-Estrus (34.5%, 79/229; P<0.0001) treatment. Pregnancy rate (60 days) was also greater in FTET-CL (29.3%, 61/208) when compared to PGF-Estrus (16.2%, 37/229; P=0.001). However, no differences were found in pregnancy loss [PGF-Estrus=11.9% (5/42), FTET-CL=9.0% (6/67); P=0.62] and circulating progesterone concentration at embryo transfer [PGF-Estrus=4.02+/-0.52 ng/mL (n=25), FTET-CL=3.33+/-0.32 ng/mL (n=27); P=0.25] among these treatments. The presence of CL at the beginning of FTET protocol resulted greater transferred-to-treated rate [FTET-CL=75.0% (156/208) vs. FTET-NoCL=61.2% (131/214); P=0.003], but showed no effect on pregnancy rate at 60 days [FTET-CL=29.3% (61/208) vs. FTET-NoCL=22.9% (49/21

Topics: Animals; Breeding; Cattle; Chorionic Gonadotropin; Cloprostenol; Corpus Luteum; Drug Implants; Embryo Transfer; Estradiol; Estrus Detection; Female; Pregnancy; Pregnenediones; Progesterone; Prostaglandins F; Reproduction; Time Factors; Ultrasonography

A total of 177 Nelore heifers were examined by ultrasonography to determine the presence or absence of a corpus luteum (CL) and received a 3mg norgestomet ear implant plus 2mg of estradiol benzoate i.m. On Day 8, implants were removed and 150 microg of d-cloprostenol i.m. was administered. At the time of norgestomet implant removal, heifers with or without CL at the time of initiating treatment were assigned equally and by replicate to be treated with 0IU (n=87) or 400IU (n=90) eCG i.m. All heifers received 1mg of EB i.m. on Day 9 and were submitted to fixed-time artificial insemination (FTAI) 30-34h later. The addition of eCG increased the diameter of the largest follicle (LF) at FTAI (10.6+/-0.2mm vs. 9.5+/-0.2mm; P=0.003; mean+/-SEM), the final growth rate of the LF (1.14+/-0.1mm/day vs. 0.64+/-0.1mm/day; P=0.0009), ovulation rate [94.4% (85/90) vs. 73.6% (64/87); P=0.0006], the diameter of the CL at Day 15 (15.5+/-0.3mm vs. 13.8+/-0.3mm; P=0.0002), serum concentrations of progesterone 5 days after FTAI (6.6+/-1.0 ng/ml vs. 3.6+/-0.7ng/ml; P=0.0009), and pregnancy per AI [P/AI; 50.0% (45/90) vs. 36.8% (32/87); P=0.04]. The absence of a CL at the beginning of the treatment negatively influenced the P/AI [30.2% (16/53) vs. 49.2% (61/124); P=0.01]. Therefore, the presence of a CL (and/or onset of puberty) must be considered in setting up FTAI programs in heifers. In addition, eCG may be an important tool for the enhancement of follicular growth, ovulation, size and function of the subsequent CL, and pregnancy rates in progestin-based FTAI protocols in Bos indicus heifers.

Topics: Animals; Cattle; Chorionic Gonadotropin; Cloprostenol; Corpus Luteum; Drug Implants; Estradiol; Estrus Synchronization; Female; Horses; Insemination, Artificial; Luteolytic Agents; Ovarian Follicle; Ovulation; Pregnancy; Pregnenediones; Progesterone; Time Factors; Ultrasonography

Efficacy of estrus synchronization and fertility after synchronization of 60 multiparous Mashona goat does using intravaginal progesterone (P4) sponges (Group 1), norgestomet ear implants (Group 2), cloprostenol (Group 3), or a combination of P4 sponges and cloprostenol (Group 4) was compared with untreated does (Group 5). At the end of treatments, all does were mated to intact fertile bucks for 21 d. The number of does bred within 11 to 96 h was significantly higher (P < 0.05) in the treated groups than the untreated control, with rates of 80, 80, 64, 67 and 30% for Groups 1 to 5, respectively. There were no differences (P > 0.05) among treated does. Kidding rates ranged from 64 to 83% but were not different (P > 0.05) between groups. Prolificacy and overall fecundity were similar (P > 0.05) among the groups. The results indicate that all 4 treatment methods were effective in synchronizing estrus and that none of the methods affected overall fertility of the does.

Topics: Administration, Intravaginal; Animals; Cloprostenol; Drug Implants; Estrus Detection; Estrus Synchronization; Female; Fertility; Fertility Agents, Female; Goats; Injections, Intramuscular; Male; Pregnancy; Pregnancy Outcome; Pregnenediones; Progesterone; Progesterone Congeners; Radioimmunoassay; Random Allocation; Zimbabwe

The influence of ovarian follicle status and follicle dominance on the response to superstimulatory treatment with FSH was examined in cows. In Experiment 1, oestrus was synchronised using Crestar and on Days 4-6 of the ensuing oestrous cycle cows were assigned to: Group NO (n = 9), control, endogenous CL and no treatment; Group N1 (n = 15), injected with a luteolytic dose of cloprostenol (500 micrograms) and implanted with one implant (3 mg) of the synthetic progestogen, norgestomet; Group N8 (n = 18), injected with 500 micrograms cloprostenol and implanted with eight (24 mg) implants of norgestomet. On Days 9-11, seven implants were removed from six cows in Group N8 and these cows, plus eight Group N1 and all Group N0 cows, were superstimulated with porcine FSH (Folltropin-V) over 4 days (360 mg total dose). The remaining implants were removed from cows in Groups N1 and N8 on Days 11-13, and all cows received 500 micrograms cloprostenol. Numbers and sizes of ovarian follicles, and CL, were recorded by trans-rectal ultrasonography; the largest follicle > 10 mm in diameter was considered morphologically dominant (DF). On Days 9-11, the proportions of cows with a DF were: Group N0, 3/9; Group N1, 14/15; Group N8, 0/18. Total follicles on the 4th day of FSH treatment were greater (P < 0.05) for cows in Group N1 (21.6 +/- 4.2) compared with Group N0 (10.9 +/- 2.4), with cows in Group N8 (13.2 +/- 0.9) not different from the other two groups. Subsequent numbers of CL were lower (P < 0.05) for cows in Group N1 (5.0 +/- 1.3) compared with Group N0 (9.4 +/- 2.0), with cows in Group N8 (8.5 +/- 1.0) not different from the other two groups. In Experiment 2, oestrus was synchronised in cows and on Days 4-6, cows were assigned to: Group C0 (n = 7), control, endogenous CL and no treatment; Group C3 (n = 6), received three CIDR-B intra-vaginal devices that delivered progesterone. On Days 9-11, two CIDR-B were removed from cows in Group C3 and all cows treated with FSH as in Experiment 1. The remaining CIDR-B was removed from cows in Group C3 on Days 11-13 and all cows injected with 500 micrograms cloprostenol. Proportions of cows with a DF on Days 9-11 and diameter of largest follicle were: Group C0, 6/7 and 12.6 +/- 0.9 mm; Group C3, 2/6 and 9.6 +/- 0.8 mm. Numbers of CL on Day 8 after oestrus were: Group C0, 20.0 +/- 7.1; Group C3, 14.8 +/- 4.8 (P > 0.05). Exposure to low dose norgestomet allowed development of a persistent dominant follicle, resulting in a reduced

Topics: Animals; Cattle; Cloprostenol; Estrus; Estrus Synchronization; Female; Follicle Stimulating Hormone; Ovarian Follicle; Pregnenediones; Progesterone; Progesterone Congeners; Progestins

The ultimate aim of any estrus synchronization method is to allow artificial insemination at a predetermined time after the end of treatment. This requires a very tight synchronization of estrus which is not observed in goats after administration of the usual fluorogestone acetate (FGA)/prostaglandin (PG) F2 alpha/equine chorionic gonadotrophin (eCG) treatment. The possibility to improve the synchronization of estrus and luteinizing hormone (LH) peak with different progestagens (FGA versus norgestomet) and routes of administration (vaginal sponge versus subcutaneous ear implant) was evaluated in two experiments where goats received one of three progestagen treatments: (1) a vaginal sponge impregnated with 45 mg of FGA, (2) a half-implant of norgestomet, or (3) a whole implant containing 3 mg of norgestomet. The progestagens were left in place for 11 days and intramuscular injections of 400 or 500 IU of eCG (according to milk yield) and 50 micrograms of an analogue of PGF2 alpha (cloprostenol) were given 48 h prior to progestagen removal. In Experiment 1, 117 cycling goats were checked for the time of onset of estrus, preovulatory LH peak and ovulation rate following estrus synchronization treatment. Goats treated with half-implants came into estrus earlier than those receiving vaginal sponges (27.8 +/- 5.0 h vs. 33.0 +/- 6.6 h, respectively; P < 0.05). No effect of progestagen priming was observed on the variability of the onset of estrus. However, the interval between the time of onset of estrus and LH peak was more variable (P < 0.05) in goats treated with half-implants. In Experiment 2, 170 non-cycling goats were monitored for the time of onset of estrus, percentage of females ovulating, fertility and prolificacy after estrus induction treatment and artificial insemination with frozen-thawed semen performed 24 h after the onset of estrus. No effect of progestagen treatment was observed either on the time or the variability of onset of estrus. The percentage of goats ovulating and overall fertility rate were higher (P < 0.05) in goats receiving vaginal sponges (98.2% and 75.0%, respectively) than those treated with half-implants (81.8% and 45.5%, respectively). However, no significant difference was observed, for the same parameters, in animals receiving implants (86.3% and 58.8%, respectively). In conclusion, estrus synchronization with a norgestomet implant or half-implant did not reduce the variability in the onset of estrus and LH peak. The fertilit

Topics: Animals; Chorionic Gonadotropin; Cloprostenol; Dinoprost; Drug Implants; Estrus Synchronization; Female; Fertility; Flurogestone Acetate; Goats; Horses; Injections, Intramuscular; Luteinizing Hormone; Pessaries; Pregnenediones; Progesterone Congeners; Time Factors

Twelve Hereford cross Friesian cows received subcutaneous implants containing 6 mg norgestomet and intramuscular injections of 5 mg oestradiol valerate and 3 mg norgestomet. Six of the cows also received 0.5 mg cloprostenol eight days later and all implants were removed on day 9. When treatment was commenced between days 3 and 5 of the ovarian cycle, luteal function was not prevented although the luteal phase was shortened in some cases. When treatment was commenced between days 8 and 14 of the cycle progesterone concentrations remained above basal levels for five to seven days. Cows with corpora lutea that were given cloprostenol underwent rapid luteolysis. It is concluded that oestradiol valerate does not control luteal function adequately, particularly if administered early in the cycle, and this may explain failure of oestrus synchronisation in some cases. Administration of prostaglandin 24 hours before norgestomet implant removal may improve the degree of oestrus synchronisation in groups of cyclic cows.

Topics: Animals; Cattle; Cloprostenol; Drug Implants; Drug Therapy, Combination; Estradiol; Estrus Synchronization; Female; Follicle Stimulating Hormone; Gonadotropins, Pituitary; Luteinizing Hormone; Pregnancy; Pregnenediones; Progesterone; Prostaglandins F, Synthetic