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Journal of Agriculture and Animal Sciences

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Browsing Journal of Agriculture and Animal Sciences by Author "Álvarez Arango, Andrea"

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    La vitrificación como alternativa de conservación de embriones producidos in vitro
    (Corporación Universitaria Lasallista, 2012-08-21) Giraldo Giraldo, John Jairo; Ordóñez Ramírez, Sebastián; Álvarez Arango, Andrea
    Cryopreservation of bovine embryos produced in vitro eases the use of embryo transfer programs, establishing germplasm banks with a permanent access to genetic material of a determined individual or race and the biotechnologies related such as cloning and transgenesis (Albarracín, 2005). Therefore, this has brought a necessity to conserve the embryos remaining from the in vitro production. Nevertheless, the cryopreservation of such embryos by the use of conventional freezing methods has not reached satisfactory survival rates (Vajta, 2000), so other methods, such as vitrification, have been being used. This method hast cooling curves above those from the traditional freezing, allows to reduce the embryo´s exposition time in the critical temperature points, reduces thermal and mechanic damage caused during the formation of ice and increases the feasibility of the embryos after the devitrification (Lazar, 2000; Arteaga et al., 2002; Vajta and Kuwayama, 2006, Mucci et al., 2006).
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    Relación del tamaño del folículo dominante y tasa de concepción al momento del servicio en vacas holstein de alta producción
    (Corporación Universitaria Lasallista, 2015-09-03) Álvarez Arango, Andrea; Giraldo Giraldo, John Jairo
    Introducción. According to the research conducted, some correlations between the dominant follicle´s size and the fertility in high producing cows have been reported. However, there are still some knowledge gaps concerning the effect of follicular dynamics on the conception. Objective. To identify the correlation between the dominant follicle size at the artificial insemination time and the conception rates in high producing Holstein cows. Material and methods. 42 high production animals were evaluated, determining their dominant follicle´s size at the artificial insemination time and location (right or left ovaries), body condition score (BCS) and body weight. The data were analyzed by means of the Statgraphics software, version 15; a confidence level of 95% was used to find significant differences. By adjusting regression equations, the relationships between the size of the dominant follicle at the time of service and the conception rate with the size of the dominant follicle were established. Results. A connection between the three average sizes of the follicles related to the body condition and the effective service with each one of the weights was found. As the dominant follicle´s size increased, so did the effective service percentages but, when the weights and the body conditions of the animals increased, the effective service percentages decreased. The larger the dominant follicle size, the higher the effective service percentage. However, if the animal’s weight and body conditions increase, the effective service percentage decreases. Conclusions. At the service time, the follicular diameter is directly related to the rate of conception, regardless of the ovary in which the dominant follicle is. This fact could be considered as a fertility indicator.