Effects of time of PMSG and fixed-time GnRH injections on estrus incidence and fertility in physiologically different ewes pre-treated with progestogen-impregnated vaginal sponge during the nonbreeding season

Fukui, Yutaka; Kobayashi, Momoko; Kojima, Masayasu; Ono, Hitoshi

doi:10.1016/0093-691x(85)90161-x

Cited by 13 publications

(6 citation statements)

References 22 publications

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“…Similarly, deNicolo et al (2008) reported higher pregnancy rate in the breeding season as compared to non-breeding season following estrus synchronization and natural mating. Although the lambing percentage is less in non-breeding season, it is comparable with previous studies (Fukui et al 1985;Wheaton et al 1992;Ungerfeld & Rubianes 2002). In the present study, the breeding season had not influenced the ovulation rate, since the estrus percentage were not significantly different between the breeding and non-breeding season.…”

Section: Discussionsupporting

confidence: 91%

Effect of breeding season on fertility of sheep following estrus synchronization and fixed-time artificial insemination under field conditions in semi-arid tropical region

Kumar

Balaganur

et al. 2016

Biological Rhythm Research

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Accelerated lambing system is heavily reliant on reproductive technologies meant to enable off the season breeding in sheep. Therefore, the present study was programmed to assess the effect of breeding season (BS) on fertility of sheep following estrus synchronization (ES) and fixed time artificial insemination (FTAI). A total of 248 and 365 ewes were synchronized and inseminated during the BS (Febuary-March and July-September) and non-breeding season (NBS) respectively, during 2012-14. Synchronization of estrus was done by AVIKESIL-S, intra-vaginal progesterone sponges kept in situ in vagina for 12 days. 200 IU eCG was administered intramuscularly on 12th day after sponge withdrawal. FTAI was performed twice in ewes exhibiting signs of estrus at 48 and 56h after sponge removal, using liquid chilled semen of Patanwadi/Malpura rams containing 100 million sperm. Breeding season had no significant (p < 0.05) effect on estrus synchronization. The estrous responses during the BS and NBS were 84.68% and 83.29% respectively. The lambing percentage during BS was 66.67%, which is significantly (p < 0.05) higher than the lambing percentage of NBS (57.57%). Although, the lambing percentage in NBS maneuvered ewes were lower than the BS ewes but still the technology can be used to offset the effect of anestrus and to augment production in sheep.

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Section: Discussionsupporting

confidence: 91%

Effect of breeding season on fertility of sheep following estrus synchronization and fixed-time artificial insemination under field conditions in semi-arid tropical region

Kumar

Balaganur

et al. 2016

Biological Rhythm Research

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“…Although the fertility of inseminated ewes on the 3 farms were not directly c o m p a r a b l e d u e t o t h e d i f f e r e n c e i n t h e insemination doses between Farm T (0.2 or 0.4 ml) and the other two (S and M) farms (0.1-0.2 ml), the lambing rates on the 3 farms (48 to 64%) were not significantly different. The fertility of inseminated or naturally mated ewes may be influenced by the body condition and physiological status of each ewe, and the different management feeding systems at each farm [8,9]. The mean body condition score in ewes at Farm S (3.5 units) was higher than that at Farm M (2.4 units) probably due to the short period from the previous lambing, but the score difference was not significantly different and did not affect the lambing rates of the ewes between Farms S and M.…”

Section: Discussionmentioning

confidence: 99%

Fertility of Estrus-Induced Ewes during the Non-Breeding Season and Artificially Inseminated with Frozen Semen Imported from New Zealand.

Fukui

Iida

Okada

et al. 2002

Journal of Reproduction and Development

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Abstract. The present study was conducted to investigate fertility of estrus-induced ewes during the non-breeding season, artificially inseminated with frozen semen imported from New Zealand. A total of 122 Suffolk and Suffolk-crossed ewes in three different sheep farms (T, S, M) were treated with an intravaginal progesterone release device (CIDR-G) for 12 days, and an intramuscular injection of 500 IU equine chorionic gonadotropin one day before CIDR removal. Effects of intrauterine insemination doses (0.2 and 0.4 ml per head) and two rams on fertility were compared at Farm T using 75 ewes. At the other two farms (S and M), 0.1 to 0.2 ml doses were inseminated into the uteri on the fixed-time basis. The lambing rates of ewes inseminated with 0.2 and 0.4 ml doses were 68.4 and 59.5%, and the lambing rates of ewes inseminated with the two rams were 61.3 and 65.9%. No significant differences were found between any of the factors. The lambing rates on Farms S and M were 54.2% and 47.8%, respectively. Overall, there was no significant difference in the lambing rates (58.3% and 59.5%) and prolificacy (2.03 and 1.61) between the two rams. These results indicate that the fertility of ewes inseminated during the non-breeding season with frozen-thawed semen imported from New Zealand is acceptable and that new blood lines of Suffolk sires and dams can be produced on Japanese sheep farms.

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“…The first reports of the use of GnRH in artificially inseminated ewes did not demonstrate an increase in the number of pregnant ewes over control ewes (Fukui et al 1985;, but nevertheless did considerably improve the synchrony of ovulation (Smith et al 1986). Further refinement of the technique may produce positive results and, despite the added cost and effort, it may eventually prove to be worthwhile to use GnRH analogues in conjunction with intrauterine insemination of frozen-thawed semen.…”

Section: Time Oj Inseminationmentioning

confidence: 99%

Current Topics in Artificial Insemination of Sheep

Evans

1988

Aust. Jnl. Of Bio. Sci.

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There have been developments in several aspects of artificial insemination (AI) in recent years, some of which have been directly responsible for proliferation of AI in the sheep-breeding industries of several countries. The most notable advances have probably been associated with the development of intrauterine insemination by laparoscopy. There is potential for refinement of some of the related techniques, particularly in the area of control of ovulation and definition of appropriate times and optimum doses of spermatozoa for insemination. It is unlikely that laparoscopic AI will be developed sufficiently that it will become readily affordable, and therefore widely practised, by commercial producers.

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Effects of time of PMSG and fixed-time GnRH injections on estrus incidence and fertility in physiologically different ewes pre-treated with progestogen-impregnated vaginal sponge during the nonbreeding season

Cited by 13 publications

References 22 publications

Effect of breeding season on fertility of sheep following estrus synchronization and fixed-time artificial insemination under field conditions in semi-arid tropical region

Effect of breeding season on fertility of sheep following estrus synchronization and fixed-time artificial insemination under field conditions in semi-arid tropical region

Fertility of Estrus-Induced Ewes during the Non-Breeding Season and Artificially Inseminated with Frozen Semen Imported from New Zealand.

Current Topics in Artificial Insemination of Sheep

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