On the Relationship Between Country Sex Ratios and Teen Pregnancy Rates: A Replication

The ovarian follicular population has been used as a parameter to evaluate fertility and also the potential of donors undergoing assisted reproductive procedures in both human medicine and animal practice. There is a high correlation between follicular population and oocyte recovery by ovum pickup (OPU), but the relationship between oocyte recovery, embryo production and pregnancy rates may not be fully understood. The aim of the present study was to evaluate whether the conversion rate of oocytes to embryos and further pregnancies could be positively related to the number of cumulus–oocyte complexes (COC) recovered after OPU in cattle. For this purpose, records of 626 OPU sections from 251 nonlactating Gyr cows (dairy Zebu breed) were analysed. The animals had a good body condition score, were kept in a good feeding pasture (Brachiaria spp.) and were supplemented with corn silage and a mixture of corn, soybeans and vitamin and minerals, according to their nutritional requirements. For each ovarian aspiration, the ovarian follicular wave was previously synchronized with an auricular implant (Norgestomet-Crestar®), IM injections of 2 mg of oestradiol benzoate (Gonadiol®) and 0.25 mg of D-cloprostenol (Sincrocio®). The OPU procedures were performed using an ultrasound device (Aquila Vet, Esaote, São Paulo, Brazil) equipped with a vaginal sector 7.5-MHz probe, disposable 20 G needles and a vacuum pressure of 80 mmHg. The cows were ranked in quartiles regarding the total number of COC recovered. To reduce bias related to the eventual fluctuation of OPU results, for the present analysis the authors used only the recorded OPU session of each cow with the highest number of COC recovered. Viable COC were fertilized with sex-sorted (X) semen of Gyr bulls previously tested for in vitro embryo production. Conversion rates (%) of the total and viable oocytes to embryos, viable oocytes to pregnancy and embryo to pregnancy were evaluated for each quartile. Differences between the first and fourth quartiles were accessed by Fisher's exact test. In the 251 OPU, 4246 total and 3173 viable COC were recovered, resulting in the production of 1001 embryos (31.5%) and 453 pregnancies (45.3%). The cows ranked in the first, second, third and fourth quartiles produced >30 (41.6 ± 10.6), 21 to 30 (25.2 ± 3.0), 12 to 20 (15.9 ± 2.6) and <12 (6.7 ± 3.1) total oocytes. The average viable oocyte (29.1 ± 11.0, 18.1 ± 5.3, 11.1 ± 3.7 and 4.5 ± 2.7, respectively) and embryo production (8.6 ± 5.7, 5.2 ± 3.6, 3.8 ± 2.8 and 1.8 ± 1.8, respectively) were different (P < 0.0001) among all quartiles. Pregnancy rates, however, did not differ (46.0, 44.9, 43.9 and 45.6%, respectively; P > 0.05). Interestingly, the conversion rates (viable oocytes to embryos and viable oocytes to pregnancies) were higher (P < 0.0001 and 0.002) in cows from the last quartile (51.1 and 31.9%) compared with those from the first quartile (23.7 and 14.7%). In conclusion, the number of COC recovered by OPU (and consequently the ovarian follicular count) can further predict the total number of embryos and pregnancies produced, but it is not directly related to the oocyte development potential. Biotran and Fapemig Project CVZ APQ 01654/09 and BPD 0007/10.

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Theoretical Model of the Relationship between Single Embryo Transfer Rate and Multiple Pregnancy Rate in Japan

Journal of Pregnancy ◽

10.1155/2012/620753 ◽

2012 ◽

Vol 2012 ◽

pp. 1-7 ◽

Cited By ~ 3

Author(s):

Syuichi Ooki

Keyword(s):

Pregnancy Rate ◽

Embryo Transfer ◽

Multiple Pregnancy ◽

Early Period ◽

Reproductive Technology ◽

Single Embryo Transfer ◽

Pregnancy Rates ◽

Sigmoid Curve ◽

The Relationship ◽

Multiple Pregnancy Rate

The purpose of the present study was to examine the effect of single embryo transfer (SET) in assisted reproductive technology (ART) on the reduction of the multiple pregnancy rate. We also estimated the monozygotic (MZ) twinning rates according to the SET diffusion indirectly. A reverse sigmoid curve was assumed and examined using nationwide data of SET from 2007 to 2009 in Japan. The multiple pregnancy rate decreased almost linearly where the SET pregnancy rate was between about 40% and 80% of regression approximation. The linear approximation overestimated multiple pregnancy rates in an early period and underestimated multiple pregnancy rates in the final period. The multiple pregnancy rate seemed to be influenced by the improvement of the total pregnancy rate of ART in the early period and by the MZ twinning after SET in the final period. The estimated MZ twinning rate after SET was around 2%.

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THE RELATIONSHIP BETWEEN NUMBER OF FOLLICLES 14mm OR GREATER AT TIME OF TRIGGER OF PREGNANCY RATES IN IUI CYCLES IN WOMEN 38 YEARS AND OLDER

Fertility and Sterility ◽

10.1016/j.fertnstert.2020.08.459 ◽

2020 ◽

Vol 114 (3) ◽

pp. e160

Author(s):

Maryam Al Shatti ◽

Namaa Steiner ◽

Russell Frank ◽

Jacob Ruiter-Ligeti ◽

Michael H. Dahan

Keyword(s):

Pregnancy Rates ◽

The Relationship

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Sex ratios in offspring of sex-reversed sea bass and the relationship between growth and phenotypic sex differentiation

Journal of Fish Biology ◽

10.1111/j.1095-8649.1999.tb00730.x ◽

1999 ◽

Vol 55 (5) ◽

pp. 916-930 ◽

Cited By ~ 50

Author(s):

M. Blazquez ◽

M. Carrillo ◽

S. Zanuy ◽

F. Piferrer

Keyword(s):

Sex Differentiation ◽

Sex Ratios ◽

Sea Bass ◽

The Relationship

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The relationship between sex ratios and marriage rates in South Africa

Applied Economics ◽

10.1080/00036846.2011.610749 ◽

2013 ◽

Vol 45 (5) ◽

pp. 663-676 ◽

Cited By ~ 12

Author(s):

Dorrit Posel ◽

Daniela Casale

Keyword(s):

South Africa ◽

Sex Ratios ◽

Marriage Rates ◽

The Relationship

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Marion Island elephant seals: the paucity-of-males hypothesis tested

Canadian Journal of Zoology ◽

10.1139/z99-127 ◽

1999 ◽

Vol 77 (10) ◽

pp. 1547-1554 ◽

Cited By ~ 10

Author(s):

I S Wilkinson ◽

R J van Aarde

Keyword(s):

Sexual Activity ◽

Sex Ratios ◽

Elephant Seal ◽

Southern Elephant Seal ◽

Marion Island ◽

Mirounga Leonina ◽

Breeding Sites ◽

Research Activities ◽

Mating Opportunities ◽

The Relationship

The southern elephant seal, Mirounga leonina, population at Marion Island has declined since the start of research activities there in 1973, as have populations at other Indian Ocean breeding sites. One suggested mechanism for the decline at Marion Island is a shortage of males, resulting in low insemination rates. We tested this "paucity-of-males" hypothesis by looking at (i) adult sex ratios, (ii) male sexual activity, and (iii) the relationship between levels of sexual activity and the probability of a cow pupping in the following season. Sex ratios were similar to those at other sites where populations are either stable (South Georgia) or increasing (Peninsula Valdes). Dominant bulls monopolised mating opportunities, achieving 98.1% of 629 observed copulations over three seasons. Of the 138 cows coming ashore, only 4 (2.9%) were not seen mating and 89% copulated with only one bull; dominant bulls copulated with all but 1 of the 134 (99.3%) cows that did mate. Cows were mated more frequently than at sites with stable and increasing populations. There was no difference in the observed level of sexual activity between cows seen pupping in the following season and those who failed to pup. This indicates that bulls monopolising harems are capable of inseminating all the cows. Such findings refute the paucity-of-males hypothesis.

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Fertility in female reindeer: the effects of nutrition and growth

Rangifer ◽

10.7557/2.7.2.714 ◽

1987 ◽

Vol 7 (2) ◽

pp. 37 ◽

Cited By ~ 7

Author(s):

N. J.C. Tyler

Keyword(s):

Body Weight ◽

Rangifer Tarandus ◽

Pregnancy Rates ◽

Important Influence ◽

Reindeer Husbandry ◽

Density Dependent ◽

Economic Significance ◽

The Relationship

Pregnancy rates in juvenile reindeer (Rangifer tarandus) vary considerably both within and between flocks. This potentially has considerable economic significance for reindeer husbandry. This paper discusses the influence of nutrition and growth on fertility in female reindeer using examples taken from the literature. Fertility in reindeer is related to body weight, like in many other mammals, but the relationship is not invariant. Weight-specific pregnancy rates appear to be density dependent in juvenile reindeer although not in adults. This strongly suggests that nutrition has an important influence on fertility in juveniles.Fruktbarhet hos simler: effekter av ernæring og vekst.Abstract in Norwegian / Sammendrag: Drektighetsprosenten i ungrein varierer sterkt fra individ til individ og fra flokk til flokk. En høy fruktbarhet i reinflokken er selve grunnlaget for en vellykket reindrift. Overraskende er det derfor at man vet lite om hvilke faktorer som bestemmer om rein skal bli drektig eller ikke. I denne artikkelen blir effekten av ernæring på reinsimlenes fruktbarhet diskutert. Undersøkelser indikerer at rein er som andre pattedyr, der fruktbarheten er relatert til kroppsvekten. Forholdet mellom reinens kroppsvekt og fruktbarhet varierer likevel sterkt. Mye tyder på at drektighetsprosenten i ungrein er avhengig av reintettheten. Dette indikerer at ernæringen er en viktig faktor når det gjelder fruktbarhet i ungrein. Vekt-spesifikk fruktbarhet kan derfor være en brukbar indikator for reinflokkens fortilgang. I prinsippet vil slike fruktbarhetsundersøkelser gi et en brukbar indikator for reinflokkens fortilgang. I prinsippet vil slike fruktbarhetsundersøkelser gi et tidlig varsel om reintallet er for høyt i forhold til beitegrunnlaget før en markert nedgang i slaktevekten observeres.Ravitsemustilan ja kasvun vaikutus vaatimien hedelmållisyyteen.Abstract in Finnish / Yhteenveto: Nuorten porojen hedelmåliisyys vaihtelee suuresti yksilostå yksiloon ja porotokasta toiseen. To-kan korkea hedelmåliisyys on menestyksellisen poronhoidon perusedellytys. Poron kantavaksi tulemiseen vaikuttavista tekijoistå tiedetåån kuitenkin yllåttåvån våhån. Kirjoituksessa kåsitellåån ravitsemustilan vaik-utusta porovaatimen hedelmållisyyteen. Tutkimukset osoittavat ettå poron kuten muidenkin imettåvåisten hedelmållisyydellå on yhteys ruumiinpainoon. Poron hedelmållisyyden ja ruumiinpainon suhteessa esiintyy kuitenkin suurta vaihtelevuutta. Paljon viittaa siihen ettå nuorten porojen tiineysprosentti riippuu porotihey-destå. Tåmå puolestaan viittaa sihen, ettå ravinto on tårkeå tekijå nuoren poron hedelmållisyyttå ajatellen. Tåstå johtuen painoon suhteutettu hedelmåliisyys voisi toimia porotokan rehutaseen osoittajana. Sellaiset he-delmållisyystutkimukset antaisivat periaatteessa varhaisen varoituksen jos poroluku on ylittåmåsså laidunka-pasiteetin, ennen kuin teuraspainojen selvå aleneminen huomataan.

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Effects of semen sexing kits (HeiferplusTM and BullplusTM) supplemented to frozen-thawed bull semen on pregnancy rates, foetal sex ratios and selected reproductive parameters in cows

Veterinární Medicína ◽

10.17221/8245-vetmed ◽

2016 ◽

Vol 60 (No. 6) ◽

pp. 309-313 ◽

Cited By ~ 2

Author(s):

G. Turk ◽

M. Yuksel ◽

M. Sonmez ◽

S. Gur ◽

S. Ozer Kaya ◽

...

Keyword(s):

Sex Ratios ◽

Pregnancy Rates ◽

Reproductive Parameters ◽

Bull Semen

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216 THE RELATIONSHIP BETWEEN OXYGEN CONSUMPTION RATE AND PREGNANCY RATE OF BOVINE EMBRYOS

Reproduction Fertility and Development ◽

10.1071/rdv19n1ab216 ◽

2007 ◽

Vol 19 (1) ◽

pp. 225 ◽

Cited By ~ 5

Author(s):

N. Sakagami ◽

K. Akiyama ◽

Y. Nakazawa

Keyword(s):

Oxygen Consumption ◽

Pregnancy Rate ◽

Embryo Transfer ◽

Embryo Quality ◽

Calf Serum ◽

Pregnancy Rates ◽

Bovine Embryos ◽

Significant Difference ◽

Consumption Rates ◽

The Relationship

A precise evaluation of embryo quality is important to estimate the suitability of embryo transfer to recipient animal. Recently, an objective evaluation method was reported for bovine embryos, in which the oxygen consumption of embryos can be noninvasively determined by scanning electrochemical microscopy (SECM) (Shiku et al. 2001 Anal. Chem. 73, 3751–3758). Trimarchi et al. (2000 Biol. Reprod. 62, 1866–1874) suggested that the oxygen consumption reflects the cell number and mitochondrial activity of embryos. The objectives of this study were (1) to examine the oxygen consumption of in vivo-derived embryos by SECM, (2) to investigate the relationship between oxygen consumption and morphological estimation of embryos, and (3) to assess the correlation among the oxygen consumption, embryo viability, and pregnancy rates. Fifty-six embryos were collected from Japanese Black cattle, which were superovulated with a total dose of 20 mg porcine FSH (FSH-R; Kawasaki Pharmaceutical Co., Ltd., Tokyo, Japan) followed by AI. The qualities of collected embryos at the stage of compacted morulae (CM), early blastocysts (EB), and blastocysts (BL) on Day 7 after AI were categorized as grade 1 and grade 2, according to the IETS manual (2002). The oxygen consumption rates of embryos were evaluated by SECM, as previously described by Abe et al. (2004 J. Mamm. Ova Res. 21). Embryos were frozen by programmable freezer in Dulbecco's PBS containing 1.5 M ethylene glycol, 0.1 M trehalose, and 20&percnt; calf serum. They were thawed by holding the straws in air for 8 s and then immersing them in a 30°C water bath for 15 s. After thawing, the embryos were examined for oxygen consumption. Twenty-eight embryos were then cultured in TCM-199 supplemented with 20&percnt; fetal bovine serum and 0.1 mM β-mercaptoethanol for 24 h to assess the viability of embryos by re-expansion of blastocole. The remaining 28 embryos were transferred to recipients. The pregnancy rates were determined by rectal palpation on Day 70. Data were analyzed by ANOVA. The consumption rates of BL embryos on Day 7 were significantly higher (P < 0.05) than those of CM collected on the same day (0.84 vs. 1.29 × 10−14 mol s−1, respectively). A significant difference was also observed in consumption rates between grade 1 and 2 embryos at the BL stage (P < 0.05). After freezing–thawing, the average oxygen consumption rates of embryos were 0.52 × 10−14 mol s−1 for CM (n = 9), 0.67 × 10−14 mol s−1 for EB (n = 8), and 0.96 × 10−14 mol s−1 for BL (n = 11). The CM embryos with rates of < 0.5 × 10−14 mol s−1 and the EB and BL embryos with those < 0.6 × 10−14 mol s−1 did not show good morphological appearance after 24 h in culture. Pregnant animals were not obtained from embryos with rates <0.5 × 10−14 mol s−1 for CM (n = 5) and <0.7 × 10−14 mol s−1 for EB (n = 9). A high pregnancy rate (67&percnt;) was obtained from embryos with rates >1.0 × 10−14 mol s−1 for BL (n = 14). These results suggest that the measurement of oxygen consumption of embryos after embryo freezing and prior to embryo transfer may be useful for estimating embryo quality and suitability of embryo transfer.

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