Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Estrus Synchronization”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 109 records · Page 6Linked to original sources
PubMed1975

[Effect of a gestagen used for the induction of synchronous estrus and fertilization of cattle].

The preparations Synchrosyn, Gestafortin, and Bovisynchron, having chlormadinonacetate as a common active ingredient, were used to induce synchronous estrus and fertilization in heifers. A total of 254 animals were involved belonging to the following breeds: Bulgarian Simmental, Bulgarian Red, Bulgarian Brown, and Black Pied. All three preparations were administered orally: Synchrosyn and Gestafortin were given with the forage at the rate of 10 mg chlormadinonacetate, and Bovisynchron was offered twice daily at an interval of 12 hours, rated 1 cu. cm each time, by means of a syringe (a daily dose of 20 mg clormadinonacetate).

Animals↗
PubMed1998

The fertility of autumn calving suckler beef cows is increased by the addition of prostaglandin to progesterone and eCG estrus synchronization treatment.

The objective of this study was to determine the efficacy of PGF2 alpha treatment on pregnancy and calving rates in autumn-calving suckler beef cows synchronized with progesterone and eCG. The population studied consisted of 124 Charolais and 130 Limousin cows in 13 and 12 beef herds, respectively. In each herd, pairs of cows were formed according to parity, body condition score and calving difficulty. Group 1 received a progesterone releasing intravaginal device (PRID) for 12 d with a capsule containing 10 mg estradiol benzoate at implant insertion and 500 IU eCG at PRID removal (Day 0). Group 2 received the same treatment plus 25 mg i.m. dinoprost at Day -2. Each cow was artificially inseminated 56 h after PRID removal (Day 3). Plasma progesterone concentrations were measured to determine cyclicity prior to treatment in samples take on Days -22 and -12, to confirm the occurrence of ovulation (Day 13) and to determine the early pregnancy rate (Day 26). Serum pregnancy-specific protein B (PSPB) concentrations were determined to assess pregnancy rate at Day 39. The effects of variation factors on pregnancy and calving rates after treatment were studied using logistic mixed models and a Cox model, respectively. There were no significant differences between groups or breeds for the rate of cyclicity before treatment nor for ovulation rate (means, 74.1 and 95.7%, respectively). Cyclicity was, however, influenced by individual factors such as body condition score (OR = 3.36, P = 0.001), parity (OR = 5.4, P = 0.001) and herd factors such as stocking rate (OR = 5.62, P = 0.001). The use of a prostaglandin injection increased pregnancy rate at Day 26 (71.7 vs 56.7%, P = 0.01) and at 39 d (67.7 vs 54.3%, P = 0.02) and the calving rate at induced estrus (64.5 vs 48.5%, P = 0.01). We observed 9 twin calvings (5.6%) which occurred in cyclic cows only before treatment. Cows in Group 2 had a 1.5 greater chance of calving before 300 d following the first AI than cows in Group 1 (P = 0.03). In conclusion, the addition of PGF2 alpha injection, 48 h before PRID removal, increased reproductive efficiency in autumn-calving Charolais and Limousin suckler beef cows compared to a classical estrus synchronization treatment using a PRID + eCG.

Abortifacient Agents, Nonsteroidal↗
PubMed2001

Comparison of different protocols used to induce and synchronize estrus cycle of Saanen goats.

The objective of the present study was to determine the efficiency of different protocols in inducing and synchronizing the estrus cycle of Saanen goats by using new or reused synchro-mate-B (SMB) and controlled internal drug release (CIDR) in combination with either equine chorionic gonadotrophin (eCG) or cloprostenol. Female goats (n=120) were divided at random into six groups of 20 animals each. In the T1-SMB group, the females were injected intramuscularly (i.m.) with 2.5mg estradiol valerate+1.5mg norgestomet and received a subcutaneous ear implant containing 2.0mg of norgestomet for 9 days. On the day of implant removal, the animals received 100IU of eCG and 0.05mg of cloprostenol. In the T2-SMB group, the animals were identically treated, except that the ear implant they received had been previously used in cattle. In the T3-SMB group, the treatment was identical to that for T1-SMB, but eCG was not administered. In the T1-CIDR group, the animals were treated for 9 days with an intravaginal device inpregnated with 0.3g of progesterone and injected i.m. with 100IU of eCG and 0.05mg of cloprostenol on the day of implant removal. The animals of the T2-CIDR group were treated like those of the T1-CIDR group, except that the intravaginal implant they received had been previously used in goats. The animals of the T3-CIDR group were treated like those of the T1-CIDR group, but did not receive eCG. The percentages of estrus and fertility were 100/80% (T1-SMB), 90/80% (T2-SMB), 75/75% (T3-SMB), 100/95% (T1-CIDR), 100/100% (T2-CIDR) and 70/65% (T3-CIDR), respectively, with the results for both parameters being lower (P</=0.05) in the T3-SMB and T3-CIDR groups. It is concluded that auricular implants or intravaginal devices may be reused, at last one more time, because they are efficient for inducing and synchronizing estrus in cyclic dairy goats.

Journal Article↗
PubMed1985

Effect of PMSG dosage on the reproductive performance of adult ewes and ewe lambs bred at a progestagen-PMSG synchronized estrus.

The effect of dose of pregnant mares' serum gonadotropin (PMSG) on the reproductive performance of adult ewes and ewe lambs and lamb survival at birth after treatment with fluorogestone acetate (FGA)-impregnated intravaginal sponges and PMSG (250 IU or 500 IU) to synchronize estrus was evaluated. Ewes were exposed to rams for breeding at the synchronized and subsequent estrous cycles. The flock, comprised of three synthetic strains and two control breeds, was maintained in a controlled environment and exposed to an artificial light regimen which alternated at 4-mo intervals from 16h of light daily to 9h of light daily. Trials were conducted during January, May and September at the end of a 9-h daylength cycle. Adult ewes were bred in May and 8 mo later in January. Ewe lambs were bred in September at 6.5 to 7.5 mo of age. The overall reproductive performance of the adult ewes was similar at the two breedings: fertility approximately 90%, prolificacy approximately 2.7, fecundity approximately 240% and lambs born alive approximately 2.4. Dosage of PMSG had no effect. Reproductive performance of ewe lambs was lower and there was a strain x treatment interaction, suggesting greater variability in response. The results indicate there is no advantage to using a higher dose of PMSG in ewes with a natural relatively high fecundity. Moreover, the use of the artificial photoperiod appears to overcome the natural seasonal variation in reproductive performance.

Journal Article↗
PubMed1992

Reproductive response of yearling beef heifers to a melengestrol acetate-prostaglandin F2 alpha estrus synchronization system.

A study was designed to evaluate estrus response and fertility after treatment with melengestrol acetate (MGA) and prostaglandin F2 alpha (PGF2 alpha) in yearling beef heifers. Three hundred four heifers at three locations were allotted to one of two treatments: Treatment 1 served as a nonsynchronized control (CON); and heifers in Treatment 2 received .5 mg of MGA.animal-1.d-1 for 14 d and 25 mg of prostaglandin F2 alpha (PGF2 alpha) 17 d after MGA (MGA-PGF). Heifers in CON and MGA-PGF groups were artificially inseminated 12 h after observed estrus for 21 and 6 d after PGF2 alpha, respectively. Blood samples were collected from each heifer 10 d before and on the day MGA feeding began and 10 d before and on the day PGF2 alpha was administered. Heifers with concentrations of serum progesterone greater than 1 ng/mL on either date before administration of MGA or PGF2 alpha were considered pubertal. More (P = .02) prepubertal heifers that received MGA attained puberty by initiation of breeding than did CON heifers (72 vs 45%, respectively). The proportion of heifers that displayed estrus within 6 d after PGF2 alpha was greater (P less than .001) for MGA-PGF than for CON heifers (77 vs 25%, respectively) but was also influenced by location (P = .03). Conception rate at first service for MGA-PGF heifers that attained puberty during MGA feeding and before PGF2 alpha was not different (P = .50) from that of CON that attained puberty during the same period.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Effect of estrus synchronization with Syncro-Mate-B((R)) on serum luteinizing hormone, progesterone and conception rate in Brahman heifers.

Twenty-two estrous cyclic, 2-yr-old Brahman heifers were randomly assigned to receive either estrus synchronization with Syncro-Mate-B((R)) (SMB; 11) or no treatment (Control; 11). Blood samples were collected via tail vessel puncture at onset of estrus and daily thereafter until Day 11 after estrus. Blood samples were also collected from five SMB and five Control heifers at 0, 4, 8 and 12 h after the onset of estrus. All samples were processed to yield serum and stored at -20 degrees C until radioimmunoassay. Heifers were inseminated by one technician using semen from a single ejaculate of a Brahman bull 12 h after the onset of estrus. All SMB heifers exhibited estrus within 72 h of implant removal. All heifers had corpora lutea (CL) detected by rectal examination 8 to 12 d following estrus. Serum luteinizing hormone (LH) was not affected by treatment, time (4 - h intervals) or an interaction of treatment by time (P > 0.10). Independent analysis with h indicated that at h 12, SMB (2.2 +/- 0.06 ng/ml) had lower LH than did control heifers (8.9 +/- 2.1 ng/ml). Serum progesterone increased from Day 1 through Day 12 in all heifers, which is indicative of functional CL. Serum progesterone was affected by treatment (P < 0.0001) and time (d intervals; P < 0.10). Progesterone elevation was lower (P < 0.05) and area under the progesterone curve was lower (P < 0.03) in SMB (5.6 +/- 0.5 ng/ml, 32.0 +/- 4.5 units, respectively) when compared with control heifers (7.0 +/- 4 ng/ml, 43.7 +/- 2.4 units, respectively). Conception rate was lower (P < 0.01) in SMB heifers (2 of 11) than in control heifers (8 of 11). The lowered conception rate in SMB treated Brahman heifers may be due to altered timing of LH release following estrus, resulting in an altered time of ovulation.

Journal Article↗
PubMed1986

Estrus synchronization systems involving prostaglandin F(2alpha) and progesterone pretreatment in beef heifers.

Two trials were conducted to evaluate treatments combining progesterone pretreatment and prostaglandin F(2alpha) (PGF(2alpha)) on estrus response, pregnancy and calving rate in heifers. Treatments in Trial 1 were 1) control (T(1); n=59), 2) 25 mg PGF(2alpha) on Day 0 (T(2); n=58), 3) 150 mg progesterone (P(4), i.m.) in corn oil on Day -24 plus PGF(2alpha) (T(3); n=61), and 4) 150 mg P(4) on Day -5 plus PGF(2alpha) (T(4); n=59). Trial 2 had T(2) and T(4) only. Heifers were artificially inseminated 8 to 16 h after detection of estrus for 10 and 5 d in Trials 1 and 2, respectively. In Trial 1 more heifers in T(3) and T(4) showed estrus by 72 h compared to T(1) and T(2). In T(3), percentages were greater at 84 and 96 h than in T(1) and T(2). There were no differences between T(3) and T(4) or T(1) and T(2) over time. Cumulative distributions of responses showed that more heifers in T(3) and T(4) were in estrus by 84 h after PGF(2alpha) than after other treatments, while T(3) showed the greatest total number of heifers in estrus by 84 h; this difference persisted for 180 h. In Trial 2, percentages of heifers observed in estrus for T(1) and T(4) were not different. Average interval from PGF(2alpha) to estrus was shorter in Trial 1 for T(3) heifers compared to other treatments. No difference was observed in interval to estrus for T(2) and T(4) in Trial 2; this interval averaged 58 h. Artificial insemination pregnancy rates were not different among treatments in either trial and averaged 67.4%. In Trial 1, a greater proportion of heifers in T(2), T(3) and T(4) calved by 35 days into the calving season compared to T(1), but in Trial 2 calving rates for T(2) and T(4) were not different. Progesterone pretreatment combined with PGF(2alpha) appeared to enhance estrus synchronization without influencing either pregnancy or calving rates.

Journal Article↗
PubMed1979

Estrus synchronization and superovulation with a subcutaneous gestagen implant (Norgestomet, Intervet) in suckler cows and heifers.

Four trials were conducted to investigate the suitability of a gestagen implant (Norgestomet, Intervet) for estrus synchronization and superovulation in suckler cows and heifers kept under field conditions in Germany. In trial 1 out of 17 heifers treated 12 responded with one ovulation each. In trial 2 57 suckler cows were treated at the University experimental farm. Of 23 cows treated sooner and 34 cows treated later than 50 days post partum one (4 %) and 16 (47 %) respectively calved at the expected time. Trial 3 was a field trial involving 126 suckler cows and 21 heifers. Of 24 cows treated sooner and 102 cows treated later than 50 days post partum 17 % and 52 % respectively calved at the expected time. Of the 21 heifers only 19 % calved at the expected time. In trial 4 superovulation of 13 cows and 17 heifers resulted in 62 % and 94 % responding with 10.0 +/- 2.5 and 11.1 +/- 3.0 (x +/- SD ) ovulations per animal respectively.

Journal Article↗
PubMed2001

Effect of different dietary energy level intakes on efficiency of estrus synchronization and fertility in Mashona goat does.

The objective of the study was to determine the effects of three dietary energy levels: 0.27 (low level: LL); 0.53 (medium level: ML), and 1.06 (high level: HL) MJMEkg(-1)W(0.75) on estrus synchronization and fertility in Mashona goat does. Forty-five multiparous Mashona goat does of average bodyweight 19.9+/-2.5kg were randomly allocated in equal numbers to the three dietary energy levels. The diets were made from a complete feed ration providing 9.83MJMEkg(-1)DM and 15.5% CPkg(-1)DM. Does were fed initially during a 60-day pre-synchronization period, and blood samples were collected twice a week for the determination of plasma progesterone concentrations to ascertain ovarian activity. Intramuscular injections of cloprostenol (100µg each) were administered 11 days apart. Immediately after the second injection of cloprostenol, three fertile bucks were introduced to the does and were left with the does for 21 days. The does were maintained on their dietary treatments throughout gestation except for those does in the LL treatment. Pregnancy was diagnosed 90 days post-mating using an ultrasound scanner. After pregnancy diagnosis, does on the LL treatment were randomly allocated to ML (n=7) and HL (n=8) treatments. During the pre-synchronization period, does on the LL treatment lost 12.3% whereas those on ML and HL treatments gained 2.1 and 28.8% of their initial bodymasses, respectively. The proportion of does exhibiting overt estrus within 96h after the last cloprostenol injection was significantly lower (P<0.05) for does on the LL treatment (60%) than for those on ML (93%) or HL (100%) treatments, respectively. However, based on plasma progesterone concentrations, the percentage of does on the LL treatment that exhibited ovarian cycles was numerically lower than that of does that were bred (40 versus 73%). Conception, fecundity and twinning rates were significantly lower (P<0.05) on the LL treatment than on the ML and HL treatments. These results indicate that feeding Mashona goat does 0.27MJMEkg(-1)W(0.75) compared to 0.53 and 1.06MJMEkg(-1)W(0.75) reduces the expression of estrus, conception, fecundity and twinning rates, and that feeding 0.53MJMEkg(-1)W(0.75) suffices for optimum reproduction. In addition, the results suggest that cloprostenol administration may induce ovarian cycles in reproductively quiescent does on dietary energy restriction.

Journal Article↗
PubMed1991

Evaluation of three estrus synchronization regimens for use in extensively managed Bos indicus and Bos indicus/taurus heifers in Northern Australia.

Two herds of extensively managed yearling Bos indicus and Bos indicus x Bos taurus heifers (n=169) were assigned to one of three estrus synchronization treatment groups. The treatments consisted of 1) two injections of the prostaglandin (F2alpha) analogue, luprostiol (7.5 mg), given 12-d apart; 2) insertion of an intravaginal progesterone-releasing device (CIDR-B), followed by 400 IU i.m. pregnant mare serum gonadotrophin (PMSG) and 7.5 mg luprostinol at CIDR-B removal or 3) subcutaneous progestagen implant (SMB) for 10-d, followed by 400 IU i.m. and 7.5 mg i.m. luprostiol at implant removal. A dual tail paint-raddle system was used to evaluate response to treatment. Each treatment group was inseminated according to the manufacturer's recommendations for fixed-time artificial insemination (A.I.; luprostiol, 72 h after the second injection, SMB and CIDR-B 48h after implant/device removal). The overall 51-d pregnancy rates for the three treatments were 18.6% (luprostiol), 48.8% (CIDR-B), and 53.3% (SMB). There were significant differences in the pregnancy rate between CIDR-B and luprostiol (P=0.004) and between SMB and luprostiol (P=or<0.0001), but there was no difference in pregnancy rate between CIDR-B and SMB treatment.

Journal Article↗
PubMed2000

Estrus synchronization in ewes treated with sponges impregnated with different doses of medroxyprogesterone acetate.

The objectives of this study were to determine residual and absorbed levels of medroxyprogesterone acetate (MAP) after treatment with intravaginal sponges impregnated with different doses of MAP in an ewe herd and to determine the effects of such treatments upon estrus incidence, interval to estrus onset and pregnancy rate. Polyurethane sponges impregnated with 40, 50 and 60mg of MAP were prepared. Real amounts of progestagen on sponges were checked prior to sponge treatment insertion. During autumn 1999, 608 cyclic Merino ewes were treated with intravaginal sponges impregnated with different doses of MAP (groups I, 40; II, 50 and III, 60mg). After 14 days, sponges were removed and residual levels of MAP (RMAP) on removed sponges were measured by spectrophotometry. Real amounts for unused sponges were 39.60+/-1.10, 44.10+/-1.06 and 59.10+/-1.26mg for the intended doses of 40, 50 and 60mg MAP respectively. RMAPs were different (p<0.05) among groups (I: 17.98+/-1.97mg; II: 24.32+/-2.03mg; III: 34.25+/-3.23mg). Absorbed levels of MAP were not different among groups (I: 21.62+/-1.97mg; II: 19.78+/-2.03mg; III: 24.85+/-3.23mg). Artificial insemination was performed in 16 ewes from Group I, 17 ewes from Group II and 11 ewes from Group III, 12h after estrus onset. There were no differences among groups, neither for estrus incidence (I: 79.27%; II: 77.42%; III: 80.87%) nor interval to estrus onset (I: 55.94+/-1.87h; II: 56.74+/-1.13h; III: 57.70+/-1.02h). There were also no differences among groups for pregnancy rate (I: 43.75%; II: 52.94%; III: 45.45%). It was concluded that under similar conditions, a dose as low as 40mg MAP could be effectively used for estrus synchronization in cyclic Merino ewes.

Journal Article↗
PubMed1990

Estrus synchronization and fertility behavior in Black Bengal goats following either progesterone or prostaglandin treatment.

Thirty-six Black Bengal female goats were in the study. They were divided into three groups of 12 goats each. Group I served as the control, Group II was treated with progesterone, Group III was administered prostaglandin F2alpha. There was 100% estrus synchronization in the PGF2alpha treated group and 90% in the progesterone treated group. The total number of kids produced in the PGF2 alpha treated group was 15 followed by 12 in the progesterone - treated group and 6 in the control group. The gestation length was found to be similar in all three groups.

Journal Article↗
PubMed1998

Development of a progestin-based estrus synchronization program: I. Reproductive response of cows fed melengestrol acetate for 20 days with an injection of progesterone.

We designed two experiments to determine the efficacy of an estrus control system in cows that combined long-term progestin exposure (20 d) with an acute increase in progesterone concentration. In Exp. 1, cows (n = 30) were fed either melengestrol acetate (MGA; .5 mg x cow(-1) x d(-1)) or ground ear corn (MGA carrier) for 20 d. On d -15 (last day of MGA feeding = d 0), cows were administered 25 mg of PGF2alpha to regress the corpus luteum (CL) and establish an environment conducive to the development of persistent follicles. To synchronously regress persistent follicles, cows fed MGA (n = 15) were injected with 200 mg of progesterone on d -2 (MGA-P), and the cows fed the MGA carrier were not treated (CONT; n = 15). Cows in the CONT group were artificially inseminated 12 h after detection of spontaneous estrus from d -20 to d 8. Estrus was observed, and all cows in the MGA-P group were artificially inseminated during the period of estrus synchronization (SYNC; d 1 to 8). No difference in conception rate was observed between treatments. In Exp. 2, postpartum cows (n = 113) received either the MGA-P (n = 56) or CONT (n = 57) treatment. More (P < .05) cows were observed in estrus during SYNC in the MGA-P (50%) than in the CONT (28%) group. Of the cows in the MGA-P group that were not observed in estrus during SYNC, 50% were in estrus for the first time 23 to 29 d after MGA withdrawal (SYNC2), suggesting that these cows ovulated without observable estrus during SYNC. Estrus was observed for the first time during SYNC2 in more (P < .05) cows in the MGA-P (25%) than in the CONT (7%) group. Conception rate at the synchronized estrus, pregnancy rate, and interval to first service and pregnancy were similar between treatments. We conclude that administration of MGA-P results in the synchronization and(or) induction of a fertile estrus in cows.

Administration, Oral↗
PubMed1991

Use of Chronogest implants and Folltropin for estrus synchronization and superovulation in goats.

Six Barbari goats each were assigned randomly to treatments 1,2 or 3, comprising im injections of FSH (folltropin) at 12, 14 or 16 mg dose level respectively. Estrus was synchronized with intravaginal sponge impregnated with flugestone acetate (30 mg; chronogest) inserted for 12 days and cloprostenol (125 micrograms) im at the insertion as well as at removal of sponge. FSH treatment started 48 hr before the sponge removal as 4-day declining dose scheme. Estrus could be effectively synchronized in all goats under the study, with significant difference (P less than 0.05) in the onset of estrus between the treatment groups. All goats were administered with 750 IU hCG i.v. at estrus. Recording of ovarian response and embryo recovery was done 45 hr after the onset of estrus. The prime aim of superovulation was effectively achieved in Barbari goats with the use of chronogest implants and folltropin. There was no difference (P greater than 0.05) between the treatment groups in recovery of transferable embryos, however, 14 mg folltropin appeared to be near optimal dose. There was no adverse effect on the quality of recovered embryos with high doses of folltropin.

Animals↗