The aim of this study was to evaluate the effect of inactivated feeder cells (feeder layer system) from two segments of the bovine oviduct (isthmus and ampulla) in the in vitro development of bovine embryos. Cell lines from segments of the isthmus and ampulla were generated and subsequently inactivated with mitomycin C (40 μg/ml) to inhibit their ability to divide and eliminate competition for nutrients with embryos. Bovine oocytes were matured in vitro for 24 h and were fertilized for 18 h in conventional culture with Brangus bovine semen. The expected fertilized oocytes were cultured for seven days in the feeder layer system with isthmus and ampulla cells separately at a concentration of 1.44 x 10 5 cells/ml. The best results in the production of in vitro bovine embryos were obtained with ampullary cells (280/84, 30%) in comparison with the isthmus cells (278/75, 26.9%) and the contro...

The aim of this study was to evaluate the effect of inactivated feeder cells (feeder layer system) from two segments of the bovine oviduct (isthmus and ampulla) in the in vitro development of bovine embryos. Cell lines from segments of the isthmus and ampulla were generated and subsequently inactivated with mitomycin C (40 μg/ml) to inhibit their ability to divide and eliminate competition for nutrients with embryos. Bovine oocytes were matured in vitro for 24 h and were fertilized for 18 h in conventional culture with Brangus bovine semen. The expected fertilized oocytes were cultured for seven days in the feeder layer system with isthmus and ampulla cells separately at a concentration of 1.44 x 10 5 cells/ml. The best results in the production of in vitro bovine embryos were obtained with ampullary cells (280/84, 30%) in comparison with the isthmus cells (278/75, 26.9%) and the contro...

This study demonstrates the use of nuclear somatic cell transfer to produce the first cloned cattle in Peru. Skin fibroblasts and cumulus cells from adult donors were obtained for use as carioplasts; likewise, oocytes obtained from ovaries in the slaughterhouse were matured in vitro for 24 h. The mature oocytes were incubated 2 h in demecolcin (2.5 μg/ml) to promote cone formation with the metaphase plate and to guide manual enucleation. The zona pellucida in pronase (2 mg/ml) was removed for 3 min. The enucleation was manual with a microblade dividing the ova into two halves, where the nucleus-lacking halves were fused by the «sandwich» method (cytoplast–fibroblast– cytoplast). The reconstructed structures were chemically activated by incubation for 5 min in 7% absolute ethanol, followed by 5 h of cytochalacin B (5 μg/ml) and cycloheximide (10 μg/ml). The structures were cultur...

En este estudio se demuestra el uso de la transferencia nuclear de células somáticas para producir los primeros bovinos clonados en el Perú. Se obtuvieron fibroblastos de piel y células de cúmulos de donantes adultos para ser usados como carioplastos; asimismo, ovocitos obtenidos a partir de ovarios de camal fueron madurados in vitro por 24 h. Los ovocitos madurados se incubaron 2 h en demecolcina (2.5 ìg/ml) para promover la formación del cono con el plato metafásico y para orientar la enucleación manual. Se eliminó la zona pelúcida en pronasa (2 mg/ml) por 3 min. La enucleación fue manual con una microcuchilla dividiendo el óvulo en dos mitades, donde las mitades carentes de núcleo fueron fusionadas por el método «sandwich» (citoplasto–fibroblasto–citoplasto) por electrofusión. Las estructuras reconstruidas se activaron químicamente mediante incubación por 5 min...

Background: The implementation of routine fixed-time artificial insemination programs can generate significant waste and costs, which good management practices can help mitigate. The objective of the study was to assess the effects of second- and third-use progesterone devices on estrus characteristics and pregnancy rates in synchronized crossbred Gyr cows. Methods: Ten cows were synchronized with first-use Bovine Intravaginal Progesterone Devices (DIB), nine with second-use DIB and ten with third-use DIB. All cows were ≥90 days postpartum, had an average milk production of 6.9±1.9 L/day and were aged 4-10 years. Estrus signs were recorded at insemination and pregnancies were confirmed at 60 days by ultrasonography. Result: No significant associations were found between DIB use intensity and estrus detection patch response, mucus color, body condition score (CC), calvings, or breed pu...