The cow as an induced ovulator: Timed AI after synchronization of ovulation

Wiltbank, Milo C.; Pursley, J.R.

doi:10.1016/j.theriogenology.2013.09.017

Cited by 202 publications

(175 citation statements)

References 171 publications

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“…In fact, this doubt is understandable because studies that properly compared insemination to estrus vs. insemination to a FTAI protocol have described lower (Strickland et al, 2010;Carvalho and Fricke, 2016; University of Wisconsin-Madison; unpublished), similar (Rabiee et al, 2005;Nascimento et al, 2013b), or greater (Nascimento et al, 2013a) pregnancies per AI (P/AI) when cows are bred to estrus. However, suboptimal estrus detection rates in cycling cows (Lopez et al, 2004;Fricke et al, 2014) and a substantial percentage (~24%) of cows that are not cycling (Wiltbank et al, 2002;Santos et al, 2009), produces the problem of low service rates (SR) and, in general, lower 21-days pregnancy rates (21-day PR = P/AI x SR, every 21 days after the voluntary waiting period; VWP) for cows bred to estrus than cows bred to FTAI (Nascimento et al, 2013a;Wiltbank and Pursley, 2014).…”

Section: Use Of Ftai In Dairy Cattlementioning

confidence: 99%

Update and overview on assisted reproductive technologies (ARTs) in Brazil

et al. 2016

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The impressive increase in the use of assisted reproductive technologies (ARTs), especially in cattle, during the last few years in Brazil is well known worldwide. In 2015, there were over 13.7 million artificial inseminations (AI), of which, about 77% were carried out using fixed-time AI (FTAI). This technology has helped to substantially improve reproductive efficiency in beef and dairy cattle. In relation to embryo transfer, production of in vivo derived (IVD) embryos remained relatively stable, with average production of 30-40,000 embryos per year, whereas in vitro production (IVP) of embryos had a substantial increase, from about 12,500 IVP embryos in 2000 to more than 300,000 IVP embryos after 2010. The increasing availability and use of sex-sorted sperm was one of the factors responsible for a recent shift from the predominance of IVP embryos from beef breeds to dairy breeds in Brazil. Moreover, there was also an increase from 13% in 2014 to 29% in 2015 in the percentage of vitrified/frozen embryos. Moreover, the successful use of protocols for fixed-time ET (FTET) due to their high efficiency and ease of implementation, has facilitated the dissemination of ET programs all over Brazil. However, there is room for improvement, since there are several reports of high pregnancy loss and high peripartum loss, when IVP embryos are used. The production of healthy cattle by somatic cell nuclear transfer has also increased in the last few years in Brazil, but despite substantial progress in reducing postnatal losses, no drastic increase in cloning efficiency up to parturition has occurred.

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Section: Use Of Ftai In Dairy Cattlementioning

confidence: 99%

Update and overview on assisted reproductive technologies (ARTs) in Brazil

et al. 2016

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“…Since the introduction of ovulation synchronisation into mainstream reproductive management of cattle (Pursley et al 1995), a plethora of studies have examined in detail the benefits of follicle synchrony in reproductive management programs (Bisinotto et al 2014, Wiltbank & Pursley, 2014. However, it has been shown that ovulation of follicles that have not undergone normal physiological maturation can lead to suboptimal luteal function compared with spontaneous ovulation.…”

Section: Introductionmentioning

confidence: 99%

Molecular determinants of a competent bovine corpus luteum: first- vs final-wave dominant follicles

et al. 2016

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Reproductive management in cattle requires the synchrony of follicle development and oestrus before insemination. However, ovulation of follicles that have not undergone normal physiological maturation can lead to suboptimal luteal function. Here, we investigated the expression of a targeted set of 47 genes in (a) a first-wave vs final-wave dominant follicle (DF; the latter destined to ovulate spontaneously) and (b) 6-day-old corpora lutea (CLs) following either spontaneous ovulation or induced ovulation of a first-wave DF to ascertain their functional significance for competent CL development. Both the mass and progesterone-synthesising capacity of a CL formed following induced ovulation of a first-wave DF were impaired. These impaired CLs had reduced expression of steroidogenic enzymes (e.g. STAR and HSD3B1), luteotrophic receptors (LHCGR) and angiogenic regulators (e.g. VEGFA) and increased expression of BMP2 (linked to luteolysis). Relative to final-wave DFs, characteristic features of first-wave

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“…In heifers and beef cattle, the success of artificial insemination depends on gestation rates, which are themselves significantly influenced by the size of the follicle which has ovulated (Perry et al 2005(Perry et al , 2007Meneghetti et al 2009). Maximising the size of the preovulatory follicle and the integrity of the ovocyte is therefore an important objective of reproductive hormonal management programmes which use systematic insemination (Wiltbank and Pursley 2014). In Senepol cattle (Bos taurus) living in tropical regions, which are closely related to the N'Dama (Williams et al 1988), the diameter of the preovulatory follicle is 13.6±0.4 mm (Alvarez et al 2000).…”

Section: Introductionmentioning

confidence: 99%

Preovulatory follicle diameter, growth rate and time of ovulation during induced oestrus using a CIDR® in trypanotolerant female Bos taurus N’Dama cattle

Okouyi

Drion

Hanzen

2015

Trop Anim Health Prod

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The aim of this study was to assess the dose (300 to 600 IU) effects of equine chorionic gonadotropin (eCG) on the preovulatory follicle diameter, growth rate and time of ovulation characterized by echography. The eCG was injected at the end (D 0 ) of the 7-day treatment with a controlled internal device release (CIDR®) and a PGF 2α being injected 2 days before the removal of the CIDR® (d −2 ). The 120 N'Dama female were distributed into five experimental groups. The control group (n=26) was treated with physiological saline at the removal of the CIDR®, while the animals in the four treated groups received, respectively, 300 IU (n=25), 400 IU (n=24), 500 IU (n=22) and 600 IU (n=23) of eCG. The diameter of the preovulatory follicle was significantly higher (P<0.05) in the animals treated with 300 IU (10.1±1.4 mm) than in untreated animals (9.3±1.2 mm). Follicle growth rate was significantly (P<0.05) higher in treated animals (1.0± 0.4 mm/day) than in the control group (0.9±0.4 mm/day). The average interval between the time of eCG injection and ovulation was similar in the non-treated (83.7±14.4 h) and treated animals (79.7±11.9). Treated animals showed a significant increase in the percentage of ovulation (94.7 % compared to 73.1 %) (P<0.01). Use of eCG contributed towards synchronising the time of ovulation between 72 to 96 h, which would facilitate the use of systematic insemination.

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The cow as an induced ovulator: Timed AI after synchronization of ovulation

Cited by 202 publications

References 171 publications

Update and overview on assisted reproductive technologies (ARTs) in Brazil

Update and overview on assisted reproductive technologies (ARTs) in Brazil

Molecular determinants of a competent bovine corpus luteum: first- vs final-wave dominant follicles

Preovulatory follicle diameter, growth rate and time of ovulation during induced oestrus using a CIDR® in trypanotolerant female Bos taurus N’Dama cattle

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