The effect of GnRH, eCG and progestin type on estrous synchronization following laparoscopic AI in ewes

Luther, J. S.; Grazul-Bilska, Anna T.; Kirsch, James D; Weigl, R.M.; Kraft, Kim C.; Navanukraw, Chainarong; Pant, Disha; Reynolds, Lawrence P.; Redmer, Dale A.

doi:10.1016/j.smallrumres.2006.10.015

Cited by 36 publications

(28 citation statements)

References 23 publications

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“…The unsatisfactory result obtained in ewes in this treatment might have been caused by IAL average time (52.4 h after device removal), which was shown to be more effective when using frozen semen (Luther et al, 2007). In the present study, the interval from device removal to IAL was very close to ovulation time (55 h).…”

Section: Discussionsupporting

confidence: 42%

“…Conversely, average conception rates obtained after laparoscopic artificial insemination (IAL) with fresh semen was lower (25.4%) when compared to authors using similar protocols. Luther et al (2007) synchronized estrus with norgestomet and obtained a pregnancy rate of 70% with frozen semen. The same authors used fluorogestone acetate and verified a pregnancy rate after IAL of 66.7%.…”

Section: Discussionmentioning

confidence: 99%

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Reproductive parameters of Santa Inês ewes submitted to short-term treatment with re-used progesterone devices

Pinna

Brandão

Cavalcanti

et al. 2012

Arq. Bras. Med. Vet. Zootec.

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The aim of this study was to verify the efficacy of reusing intravaginal progesterone (P4) devices on the reproductive parameters in Santa Inês ewes. Females received intravaginal P4 devices for their first, second or third use for five days plus 300 IU eCG IM and 5mg dinoprost laterovulvar 24h before device removal. Blood was collected at different moments. Transrectal ultrasonography was performed from device removal to ovulation. Part of the ewes were submitted to artificial insemination by laparoscopy (IAL -n=55) with fresh semen, whereas the rest were bred by fertile rams (n=41). On the initial 18 h, ewes that received devices for the first time showed higher P4 concentrations (5.1±1.8 vs 3.5±1.4 vs 2.4±1.1 -P<0.05). However, after the first 48h no difference was observed among all treatments and P4 supraluteal concentrations were detected in all ewes upon device removal. Estrous response, interval from device removal to estrus, rate of ovulating animals, number of ovulations, time from device removal to ovulation and average conception rates after IAL or natural mating were similar among all 3 groups. Intravaginal progesterone devices can be used up to three times without altering reproductive parameters in Santa Inês ewes.Keywords: sheep, artificial insemination, CIDR, intravaginal progesterone insert, ovulation Palavras-chave: ovino, inseminação artificial, CIDR, dispositivo intravaginal de progesterona, ovulação RESUMO Avaliou-se a eficácia da reutilização de dispositivos intravaginais de progesterona (P4) sobre características reprodutivas em ovelhas Santa Inês. As fêmeas receberam dispositivos intravaginais contendo P4 para o seu primeiro, segundo ou terceiro uso por cinco dias, associado a 300 UI eCG IM e 5mg dinoprost laterovulvar 24h antes da remoção dos dispositivos. Ultrassonografia transretal foi realizada da remoção dos dispositivos até a ovulação. Parte das ovelhas foi submetida à inseminação artificial laparoscópica (IAL-n=55) com sêmen a fresco, enquanto outra parte foi acasalada por machos férteis (n=41). Nas 18 h iniciais, as ovelhas que receberam dispositivos pela primeira vez

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Section: Discussionsupporting

confidence: 42%

Section: Discussionmentioning

confidence: 99%

Reproductive parameters of Santa Inês ewes submitted to short-term treatment with re-used progesterone devices

Pinna

Brandão

Cavalcanti

et al. 2012

Arq. Bras. Med. Vet. Zootec.

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“…Previous studies (Boscos et al, 2002;Luther et al, 2007) reported similar interval to estrous using short (6 days) or long (14 days) progestagen protocols, with or without GnRH. The interval to estrus (29.85±6.98 h for T GnRH and 32.9±7.5 h for T Control ) was shorter than those reported previously (Pierson et al, 2003).…”

Section: Resultsmentioning

confidence: 74%

“…Reyna et al (2007) confirmed ovulation in 100% of Merino ewes during the breeding season using sponges impregnated with 30 mg Flugestone Acetate for 12 days plus an intramuscular injection of 400 IU pregnant mare serumgonadotrophin (PMSG) at SW and 40 μg of a synthetic GnRH given at 36 h after SW. From the standpoint of mean follicle size (6.09±1.16 vs 6.09±1.16 mm) and synchronization of ovulation (3.8 vs 4.4 days) these authors did not observe difference between GnRH-treated or non-treated groups. Luther et al (2007) also tested GnRH in Hampshire and Montadale ewes during the breeding season. All ewes were implanted with norgestomet plus 400 IU eCG and 25 μg GnRH 36 h after progestin removal.…”

Section: Resultsmentioning

confidence: 99%

Effects of GnRH administration on ovulation and fertility in ewes subjected to estrous synchronization

et al. 2012

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-The objective of this study was to verify the effects of GnRH on ovulation and pregnancy of ewes subjected to a short-term synchronization of estrus. Santa Inês and crossbred Santa Inês/Dorper ewes received 60 mg MAP sponges during 6 days plus 300 IU eCG and 30 μg d-cloprostenol 24 h prior to sponge withdrawal (SW). Ewes were assigned to receive 0.9% NaCl solution (T control ; n = 32) or 25 μg GnRH (licerelin, T GnRH ; n = 34) 24 hours after SW. Each group was assigned to intrauterine insemination by laparoscopy (n = 25) or to natural mating (n = 41). Artificial insemination was performed with a single dose of fresh semen. For controlled mating, females were exposed to males 12, 24, 36 and 48 hours after SW. Ten females per treatment were subjected to transrectal ultrasound examination at 12-hour intervals (SW to 60 hours after). Estrous response (100.0% vs 95.2%), interval from SW to estrus (32.9±7.4 vs 29.8±6.9 hours), estrous length (37.4±9.0 vs 31.5±10.4 hours), pregnancy rates (57.0% vs 41.0%), ovulation rate (100.0% vs 90.0%), number of ovulations/ewe (1.1±0.3 vs 1.2±0.4), maximum follicular diameter (6.4±0.7 vs 6.1±0.6 mm), interval from SW to ovulation (59.1±3.5 vs 58.4±3.5 hours) did not differ between T control and T GnRH , respectively. Administration of GnRH 24 hours after SW does not improve ovulation or pregnancy rate in estrous synchronization in ewes.

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“…Another study by Cavalcanti et al (2012) expressed that the injection of 25 μg GnRH 24 h after sponge removal had no significant effect on the time of oestrus. Luther et al (2007) also tested GnRH treatment did not affect the efficiency of oestrus synchronization in ewes during the breeding season (GnRH, 85.1% versus without GnRH, 90.3%). Kaya et al (2013) reported that hCG injections on day 7 following progesteron applications increased pregnancy in Tushin sheep during non-breeding season.…”

Section: Discussionmentioning

confidence: 99%

Effect of double GnRH injections on reproductive parameters in Awassi ewes receiving long-term progesterone

Zonturlu

Kaçar

Kaya

et al. 2018

Journal of Applied Animal Research

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The aim of this study was to investigate the effect of single or double Gonadotropin releasing hormone (GnRH) injections at the time of mating and following on day 9 on pregnancy rates and litter size in ewes. Oestrus was synchronized in 130 adult ewes using intravaginal sponges containing 20 mg of fluorogestone acetate for 14 days. All ewes received 10 IU/kg of pregnant mare serum gonadotropin (PMSG) at the sponge withdrawal. Then animals were divided into three groups. Ewes in group 1 (G1; Control, n = 68) received 1 ml placebo injection. In group 2 (G2; n = 30), ewes in oestrus were treated with 1 ml GnRH (4 μg/ml) at the time of mating. In group 3 (G3; n = 32), ewes were injected 1 ml GnRH not only at the time of mating but also on day 9 post-mating. There was significantly higher in duration of oestrus G1 compared with the G2 and G3. Pregnancy rate was found to be higher in G3 (96.0%) than in G1 (72.7%) and G2 (83.3%). The litter size was significantly higher for G3 (1.26 ± 0.14) in comparison with the G1 (1.18 ± 0.07) and G2 (1.22 ± 0.10). In conclusion, Post-mating GnRH injection enhanced the pregnancy rate and litter size, because of its beneficial effects on embriyo viability by increasing luteal formations. ARTICLE HISTORY

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The effect of GnRH, eCG and progestin type on estrous synchronization following laparoscopic AI in ewes

Cited by 36 publications

References 23 publications

Reproductive parameters of Santa Inês ewes submitted to short-term treatment with re-used progesterone devices

Reproductive parameters of Santa Inês ewes submitted to short-term treatment with re-used progesterone devices

Effects of GnRH administration on ovulation and fertility in ewes subjected to estrous synchronization

Effect of double GnRH injections on reproductive parameters in Awassi ewes receiving long-term progesterone

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