Luiz Gustavo Bruno Siqueira

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The objective was to investigate the influence of corpora lutea physical and functional characteristics on pregnancy rates in bovine recipients synchronized for fixed-time embryo transfer (FTET). Crossbred (Bos taurus taurus x Bos taurus indicus) nonlactating cows and heifers (n=259) were treated with the following protocol: 2mg estradiol benzoate (EB) plus(More)
The developmental program of the embryo displays a plasticity that can result in long-acting effects that extend into postnatal life. In mammals, adult phenotype can be altered by changes in the maternal environment during the preimplantation period. One characteristic of developmental programming during this time is that the change in adult phenotype is(More)
A single missense mutation at position 159 of coenzyme Q9 (COQ9) (G→A; rs109301586) has been associated with genetic variation in fertility in Holstein cattle, with the A allele associated with higher fertility. COQ9 is involved in the synthesis of coenzyme COQ10, a component of the electron transport system of the mitochondria. Here we tested whether(More)
The objective of this study was to evaluate ovarian follicular dynamics during intervals between successive ovum pick-up (OPU) and determine its effects on the number and quality of recovered cumulus-oocyte complexes (COCs) in Zebu cows (Bos indicus). Pluriparous nonlactating Gyr cows (Bos indicus; n=10) underwent four consecutive OPU sessions at 96-h(More)
Ultrasound-guided transvaginal follicle aspiration is used to recover cumulus-oocyte complexes (for IVF) and to synchronize follicular wave emergence (ablation of dominant follicle). Although aspirated follicles are generally supposed to undergo immediate atresia, there are indications that they may remain active. The objective was to evaluate the(More)
The objectives of this study were to: (1) evaluate the feasibility of ultrasonic biomicroscopy (UBM) for imaging ovarian follicles in vivo in cows and heifers, (2) compare the transvaginal to the transrectal approach, (3) compare the number of follicles detected by UBM to conventional ultrasonography (US), and (4) identify cumulus-oocyte-complexes (COC)(More)
The objective was to determine the accuracy of a pregnancy test for predicting nonpregnant cattle based on the evaluation of corpus luteum (CL) blood flow at 20 d (CLBF-d20) after timed artificial insemination (TAI). Crossbred Holstein-Gir dairy heifers (n=209) and lactating cows (n=317) were synchronized for TAI using the following protocol: intravaginal(More)
It has been suggested that ultrasound image attributes are a potential indicator of physiological and functional status of the corpus luteum (CL) in several species, including cattle. The aims of this study were to evaluate CL morphological, functional and echotextural characteristics, and also to investigate the hypothesis that those attributes are(More)
The objective of this study was to determine the effects of progesterone and cloprostenol (a PGF(2alpha) analogue) on ovarian follicular development and ovulation in prepubertal heifers. In Experiment 1, crossbred Hereford heifers (Bos taurus; 10 to 12 mo old, 255 to 320 kg) were assigned randomly to three groups and given (1) an intravaginal(More)
Abnormal fetuses, neonates, and adult offspring derived by assisted reproductive technologies have been reported in humans and mice and have been associated with increased likelihood of certain adult diseases. To test the hypothesis that bovine females derived by assisted reproductive technologies have altered postnatal growth and adult function, a(More)