Effect of presence of corpora lutea on cumulus expansion of in vitro matured bovine oocytes selected by trypan blue and brilliant cresyl blue tests

Trypan Blue (TB) and Brilliant Cresyl Blue (BCB) are used to select and determine viability and competence of oocytes, however, the effects of corpora lutea on cumulus expansion during in vitro maturation are still undetermined. Cumulus-oocytes complexes (COCs) from ovaries with ipsilateral (ICL), contralateral (CCL) and without corpora lutea in either ovary (OCL) were selected by visual examination, TB and BCB staining, and matured in vitro to evaluate cumulus expansion. The overall percentage of visually selected COCs was similar in ICL, CCL and OCL (P > 0.05). Proportions of live and mature COCs were similar in all groups (P > 0.05). The overall percentage of BCB+ COCs was 70.1%. BCB+ ICL COCs had less cumulus expansion (60.5%) than BCB+ CCL and OCL COCs (75.7 and 71.4%, respectively; P < 0.01). BCB− ICL COCs had less cumulus expansion (20.0%) than BCB− CCL and OCL (39.7 and 46.1%; P < 0.01). BCB+ CCL and OCL COCs showed the highest cumulus expansion index (P < 0.01). Presence of corpus luteum in the ovary affects negatively cumulus cells expansion. TB and BCB staining facilitate the selection of oocytes with higher degrees of cumulus expansion

Factores de riesgo asociados con placenta retenida en ganado lechero en el norte de México

Abstract: The objective was to determine the association between different risk factors for placental retention (PR) in northern Mexico. Records of 2,492 Holstein cows from a commercial stable in Ciudad Juárez, Chihuahua, Mexico were used. Variables were analyzed using the chi-square test (χ2) and odds ratios (OR) were calculated to determine the association of risk factors with PR. The total incidence of PR was 10.15%. Risk factors associated with PR were twin calving and premature calving, followed by stillbirth and dystocia. The presence of PR did not increase the number of inseminations, but decreased days in milk in affected cows (p < 0.05). In conclusion, risk factors of twin calving, premature calving, stillbirth, dystocia and cow age affect the incidence of PR, while calving season does not predispose the animal to the presentation of this alteration.Resumen: El objetivo fue determinar la asociación entre diferentes factores de riesgo para retención placentaria (RP) en el norte de México. Se utilizaron registros de 2 492 vacas Holstein de un establo comercial en Ciudad Juárez, Chihuahua, México. Las variables se analizaron mediante la prueba de ji-cuadrada (χ2) y se calcularon las razones de momios (RM) para determinar la asociación de los factores de riesgo con RP. La incidencia total de RP fue del 10.15%. Los factores de riesgo asociados con la RP fueron nacimiento gemelar y nacimiento prematuro, seguidos por mortinatos y distocia. La presencia de RP no aumentó el número de inseminaciones, pero disminuyó los días en leche en las vacas afectadas (p < 0.05). En conclusión, los factores de riesgo de parto gemelar, parto prematuro, mortinatos, distocia y edad de la vaca afectan la incidencia de RP, mientras que temporada de parto no predispone a la presentación de esta alteración