Factors influencing the success of transcervical insemination in Merino ewes

Windsor, D.P.

doi:10.1016/0093-691x(95)00065-g

Cited by 28 publications

(19 citation statements)

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“…The physiological characteristics of the ewe such as age, breed, individual variation in cervical structure, parity, season, and reproductive history may all contribute to this variability. Windsor et al, [36] and Szabados et al, [13] have shown a positive correlation between ewe parity and the depth of cervical penetration using an AI catheter and presently the method is not recommended for nulliparous ewes. Kaabi et al, [28] found a significant difference in cervical penetrability between the Assuf, Churra, Castellana and Merino breeds; upon a morphometric analysis of the cervices from these breeds, they noticed significant breedrelated differences in cervical length, width, number of folds, and the distance between folds.…”

Section: The Guelph System For Tcaimentioning

confidence: 99%

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A Review of Advances in Artificial Insemination (AI) and Embryo Transfer (ET) in Sheep, with the Special Reference to Hormonal Induction of Cervical Dilation and its Implications for Controlled Animal Reproduction and Surgical Techniques

Candappa¹,

Bartlewski²

2011

TORSJ

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Artificial insemination (AI) and embryo transfer (ET) play an important role in the genetic improvement of sheep herds. This review primarily describes the methods that have recently been researched and/or adapted to circumvent the problematic anatomy of the ovine cervix, which prevents the widespread application of transcervical AI and ET in this species. A mechanism of cervical ripening at parturition and the endocrine influences on cervical tone are described as a backdrop to understanding the action of various pharmacological agents used to induce cervical dilation. Although several catheters have been designed to penetrate the ovine cervix, and a specific protocol has been developed for TCAI in sheep (Guelph Method), penetration rates and resulting pregnancy/lambing rates are still inconsistent and unpredictable. Hormonal dilation of the cervix may significantly improve the ease with which the ovine cervix can be traversed. Treatment with Cervidil ® , a dinoprostone-containing vaginal insert with a slow release mechanism, currently used to induce labor in women, could significantly improve cervical penetration in ewes without adverse effects on uterine contractility. This mode of drug delivery holds promise to result in the development of a safe method to induce cervical dilation for a broad range of transcervical reproductive manipulations in mammalian species including, but not limited to, AI, ET, embryo and oocyte recovery, treatment of ringwomb and transcervical surgical procedures. However, more studies are needed to evaluate the effects of hormonal methods on cervical morphology/pathomorphology, sperm/embryo transport and viability, and fertility in both cyclic and seasonally anovular ewes.

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Section: The Guelph System For Tcaimentioning

confidence: 99%

“…this and similar methods ranged from 44% to 91% [13,18,20,26,29,[34][35][36][37]. Reports on the total time taken to complete the procedure are 0.5 min to 4.8 min.…”

Section: The Guelph System For Tcaimentioning

confidence: 99%

A Review of Advances in Artificial Insemination (AI) and Embryo Transfer (ET) in Sheep, with the Special Reference to Hormonal Induction of Cervical Dilation and its Implications for Controlled Animal Reproduction and Surgical Techniques

Candappa¹,

Bartlewski²

2011

TORSJ

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“…Windsor et al [15] found a significant effect of ewe parity on cervical penetration rates in synchronized ewes during seasonal anestrus but not in normally cycling, non-synchronized ewes in the breeding season. Some studies have reported a correlation between the breed and cervical penetrability [16], which may be due to the morphological differences in cervical structure between various genotypes of ewes; in general, the breeds with higher cervical complexity exhibited a lower degree of cervical penetration.…”

Section: Discussionmentioning

confidence: 99%

Induction of cervical dilation for transcervical embryo transfer in ewes

Candappa

Bartlewski

2014

Reprod Biol Endocrinol

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BackgroundA major limitation in the application of assisted reproductive technologies in sheep arises from the inability to easily traverse the uterine cervix. The cervix of the non-pregnant ewe is a narrow and rigid structure, with 5–7 spiral folds and crypts that block its lumen. The first two folds closest to the vagina appear to be the greatest obstacle for the instrument insertion into the sheep cervix. Therefore, the dilation of the distal part of the cervix could provide the conformational change necessary to perform non-invasive transcervical procedures. The present study set out to assess the efficacy of Cervidil®, a patented dinoprostone (PgE2)-containing vaginal insert with a controlled-release mechanism, to safely induce sufficient cervical dilation for the purpose of transcervical embryo transfer (TCET) in cyclic ewes.MethodsThe transfer of frozen-thawed ovine embryos was attempted in 22 cross-bred Rideau Arcott x Polled Dorset ewes, with or without the pre-treatment with Cervidil® for 12 or 24 h prior to TCET.ResultsCervical penetration rate was significantly improved after Cervidil® pre-treatment, with 55% (6/11) of treated versus 9% (1/11) of control animals successfully penetrated (χ2-test, p < 0.05). Within the treated ewes that were penetrated, 67% (4/6) had been exposed to Cervidil(R) for 24 h and 33% (2/6) had had a 12-h exposure (p > 0.05). Variations in the age, weight, genotype, parity, lifetime lamb production (LLP) and post-partum interval (PPI) between penetrated and non-penetrated ewes were not significant (p > 0.05). The time taken to traverse the uterine cervix was negatively correlated (p < 0.05) with the age, parity, LLP and PPI. Progesterone assays and ultrasonographic examinations performed 25 days after ET confirmed pregnancy in 2 of 7 penetrated ewes, but no fetuses were detected ultrasonographically 55 days post-TCET.ConclusionsThe present results indicate a significant benefit of using Cervidil® for inducing cervical dilation during the mid-luteal phase in ewes but the reason(s) for impaired fertility after the transfer of frozen-thawed ovine embryos remains to be elucidated.

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“…Esta técnica visa à deposição do sêmen no interior da cérvice em diferentes graus de profundidade: superficial, média ou profunda, de acordo com a quantidade de anéis cervicais transpassados, portanto, é diretamente influenciada por fatores como momento do estro, idade, ordem de parição (Windsor, 1995). É uma técnica bem difundida por ser rápida e relativamente fácil, de pouca manipulação; preconiza-se a posição bipedal anterior para esta técnica, com a possibilidade de uso de cavalete, ou mesmo o uso da posição quadrupedal (Oliveira & Fonseca, 2013).…”

Section: Cervicalunclassified

Técnicas de inseminação artificial e implicações fisiopatológicas em ovinos

Alvares¹,

Cruz²,

Ferreira³

2015

Pubvet

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RESUMO.A Inseminação Artificial (IA) em ovinos é uma biotécnica reprodutiva que, combinada a outras biotécnicas, como indução / sincronização de estro e ovulação e tecnologia do sêmen, pode agregar valor à criação, por permitir o uso de reprodutores de elevado padrão genético, utilizar fêmeas fora da estação reprodutiva e padronizar os lotes dos produtos gerados. Este trabalho tem como objetivo apresentar os diversos tipos de IA, baseados no nível tecnológico da técnica e consequente forma de deposição do sêmen: vaginal, cervical ou intrauterina, quer seja via transcervical ou por laparoscopia. São abordados resultados comparativos de concepção, gestação, fertilidade e prolificidade, peculiaridades e influências, como status anatômico cervical de ovelhas, tipos de sêmen e concentrações espermáticas. Destaca-se também algumas implicações fisiopatológicas oriundas de técnicas transcervicais, como reações inflamatórias / infecciosas no trato reprodutivo, ou de técnicas laparoscópicas, a exemplo de regurgitação de conteúdo ruminal e acidose respiratória por pneumoperitônio. Assim, busca-se a compreensão de que, apesar da demanda por avanços científicos nas técnicas de IA, não se pode desconsiderar a necessidade de preservação do bem estar destes animais. Palavras chave: Biotecnologia, ruminantes Artificial insemination techniques and physiopathological implications in sheepABSTRACT. Artificial Insemination (AI) in sheep is a reproductive biotech that, combined with other biotechnologies such as induction / synchronization of estrus and ovulation and semen technology, can add value to the livestock by allowing the use of sires of high genetic pattern, using females outside the breeding season and standardize lots of products generated. This work aims to present the various types of AI, based on technical and technological level of the consequent form of semen deposition: vaginal, cervical or intrauterine, whether laparoscopic or transcervical route. Comparative results of conception, pregnancy, fertility and prolificacy, traits and influences, such as cervical anatomic status of ewes, types of semen and sperm concentrations are discussed. We also include some physiopathological implications arising from transcervical techniques such as inflammatory / infectious reactions in the reproductive tract, or laparoscopic techniques, like regurgitation of rumen contents and respiratory acidosis by pneumoperitoneum. Thus, we seek the understanding that, despite the demand for scientific advances in AI techniques, one cannot ignore the need to preserve the welfare of these animals.

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Factors influencing the success of transcervical insemination in Merino ewes

Cited by 28 publications

References 18 publications

A Review of Advances in Artificial Insemination (AI) and Embryo Transfer (ET) in Sheep, with the Special Reference to Hormonal Induction of Cervical Dilation and its Implications for Controlled Animal Reproduction and Surgical Techniques

A Review of Advances in Artificial Insemination (AI) and Embryo Transfer (ET) in Sheep, with the Special Reference to Hormonal Induction of Cervical Dilation and its Implications for Controlled Animal Reproduction and Surgical Techniques

Induction of cervical dilation for transcervical embryo transfer in ewes

Técnicas de inseminação artificial e implicações fisiopatológicas em ovinos

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