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Browsing by Author "Restrepo Betancur, Luis Fernando"

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    Caracterización de parámetros productivos para líneas genéticas de ponedoras, ubicadas en zona de trópico alto
    (Corporación Universitaria Lasallista, 2015-08-24) Estrada Pareja, Mónica María; Restrepo Betancur, Luis Fernando
    Introduction. Genetic companies that work with the different ovipositor lines have achieved advances in the quantitative parameters and provide management guides that suggest techniques and systems of breeding and management to producers, according to the needs of the animals. Objective. Characterize the production parameters of the different ovipositors lines from Hacienda la Montaña, which belongs to Universidad de Antioquia, comparing them with those from the genetic companies. Methodology. The data were collected from poultry flocks in a period between 2002 and 2008, keeping into account, during the breeding and raising stages, the following variables: weight of the hen, quantity of food accumulated, feasibility percentage and duration of the period. For the production stage, the following variables were considered: quantity of food accumulated, average production percentage, eggs per housed hen, age according to sexual maturity, feasibility percentage and persistence in the production. Unidimensional descriptive exploratory analyses were performed to the data collected and the variables evaluated, plus a correlation analysis and a multivariate analysis of variance –MANOVA-. Results. For the breeding and raising stage, the lines that achieved the weight desired were ISA Brown, Hisex Brown and Lohmann LSL. For the oviposition, the ISA Brown and Hisex Brown lines achieved better results for the main performance parameters. Conclusion. A good ovipositor is the result of a high quality chicken, and this is why the chickens with the right weight and body composition at the end of the raising and the beginning of the oviposition stage will be more able to maximize the genetic potential.
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    Curvas de lactancia de cabras mestizas utilizando modelos matemáticos no lineales
    (Corporación Universitaria Lasallista, 2009) Ángel Marín, Paula Andrea; Agudelo Gómez, Divier Antonio; Restrepo Betancur, Luis Fernando; Cañas Álvarez, Jhon Jacobo; Cerón Muñoz, Mario Fernando
    Introduction. Lactation curves in milk cattle are now an important tool to select female animals with high genetic values, allowing the increase and optimization of milk production in herds. Objective. To identify the best mathematical functions to explain the curves of milk production, time and peak production in goats with different hybridations, kept in an Antioquian sheepfold. Materials and methods. 865 milk weightings from 32 lactations that took place in 2007 were used. The milk came from hybrid goats, from different births. Four nonlinear mathematical models were evaluated and the significant curves percentage (P< 0.05), the Akaike and Bayesino´s criteria and the values of the determination quotient R2 were taken into account to select the best of those models. Results.Papajcsik and Bordero´s model was identified as the one that best adjusted the lactation curves in this population, with lower AIC and BIC values, a high significance of the model (P<0.001) and a convergence of 100% of the goats, regardless of the number of lactations. Besides, peak production was estimated (ymax) for female goats with 1, 2, 3 or more births, and it was 3.06 ± 0.966, 3.10 ± 0.875 and 3.36 ± 0.691 kg, respectively. Conclusion. Papajcsik and Bordero´s model allows the modeling of lactation curves in goats.
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    Efecto de la osmolaridad, sobre el diámetro y la calidad de oocitos bovinos madurados in vitro
    (2009) Lenis Sanín, Yasser Yohan; Restrepo Betancur, Luis Fernando; Olivera Ángel, Martha; Tarazona Morales, Ariel Marcel
    Ooocytes are susceptible to osmolar changes, and show some phenomena that affect the plasma membrane Objective. To evaluate the effect of hypo and hyperosmolarity from the culture’s environment on the diameter and the quality of in vitro matured oocytes. Materials and methods. 75 oocytes of excellent and good quality were use in the study. As a control the M 199 was used, suplemented with 10 % of FCS, 30 μg of FSH and 30 μg of LH (290 mOsm/l T2). The oocytes were evaluated under two osmolar concentrations: Hyperosmotic media, 497mOsm/L (T1), and hyposmotic media 150mOsm/L (T3). The diameter and the quality were measured at 0 hours and after 24 hours. Results. The oocyte diameter at 24 hours was bigger in the T3 (148,7±9.7) and smaller in the T1 (134,6±1.2). Regarding the control (147.9±11.5) (p <0.05.), no difference was found between the percentage of excellent and good quality oocytes after 24 hours of treatment T1 in comparison to the control (56 % and 60 %) (p> 0.05.), but the quality in the T3 was lower (36 %). Conclusions. It was demonstrated that the hyperosmotic media had a bigger detrimental effect on the oocytes than the hyposmotic media. It is possible that the oocytes show more mechanisms to avoid the water flow into the cytoplasm than to avoid the exit of solutes and water flow towards the outside. The necessity to adopt rigorous measurements in the quality control of osmolarity for the culture mediums used in the processes of in vitro maturation for oocytes, is evident.
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    Efecto meteorológico sobre la producción y calidad de la leche en dos Municipios de Antioquia - Colombia
    (Corporación Universitaria Lasallista, 2009) Echeverri Zuluaga, José Julián; Restrepo Betancur, Luis Fernando
    Introduction. In the tropical countries the meteorological changes exert an effect on the production and composition of milk, The most important effect is due to the temperature, precipitation, relative humidity and solar brightness. Materials and methods. More than 240,000 registers corresponding to the production and sanitary and composicional quality of the milk of dairy herds in 2 municipalities of the Department of Antioquia were collected during 4 years and associated to the changes in temperature, relative humidity, solar brightness and precipitation reported by IDEAM in the same period of time, the statistical analysis was carried out whit SAS. Results. Was not correlation between the milk production, percentage of protein and fat, CSC and bacteriological quality, the analysis had statistical significance (p < 0,01), was significant effect of the temperature, the solar brightness, precipitation on the production parameters and quality of milk. Discussion. The results found in this investigation agree in their majority with the presented by other authors in similar investigations. Conclusions. Perhaps the parameters of production and quality of milk are affected by the change in the meteorological factors the main cause is the effect that these changes generate on the forage production in the dairy herds and the additional problems generated by caloric stress that physiologically undergo the bovines with these changes.
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    Estimación de las curvas de lactancia en ganado Holstein y BON x Holstein en trópico alto colombiano
    (Corporación Universitaria Lasallista, 2008) Cañas Álvarez, Jhon Jacobo; Restrepo Betancur, Luis Fernando; Ochoa S, Jorge; Echeverri, Alex; Cerón Muñoz, Mario Fernando
    Introduction. Changes in milk production in a given time can be graphically represented by using a lactation curve, which allows the characterization of the different production systems. Objective. To estimate lactation curves in Holstein and BON x Holstein cattle by using the Incomplete Gamma model and explain the effects of the genetic group and of some environmental factors on the coefficients of the lactation curve. Materials and methods. 1835 milk production records from the first and second lactations of 23 cows were used. The effects of the race, the birth and the time on the different coefficients estimated from the Incomplete Gamma model and other production and reproduction characteristics of interest were determined. Results. Significant differences among the racial groups were evident for the following characteristics: Initial production, total production, duration of the lactation period, milk production at the peak and in the 33rd week, production per day, post-peak slope, number of weeks with production above 15 litters, calving interval and the milk production per day of calving interval (P<0.05). In the calving interval there was a significant difference in the characteristics: Initial production, deceleration of the curve, peak milk production, production per day, post-peak slope, persistence, persistence percentage and number of weeks with a production above 15 litters (P<0.05). Conclusion: The coefficients estimated by using the Incomplete Gamma model are highly influenced by the genetic group, the number of births and, in a lower measure, by the weather.
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    Evaluación comparativa de dos metodologías de diagnóstico de mastitis en un hato lechero del Departamento de Antioquia
    (Corporación Universitaria Lasallista, 2010) Echeverri Zuluaga, José Julián; Jaramillo, Manuel Guillermo; Restrepo Betancur, Luis Fernando
    Introducción. La mastitis es la enfermedad que mayor impacto tiene sobre la ganadería de leche en el mundo entero. Estrategias de todo tipo se han implementado para lograr disminuir su impacto sanitario y económico. La alta producción de leche, las vacas con muchos partos y la falta de higiene al momento del ordeño se constituyen en algunas de las principales causas para la presentación de esta enfermedad. En su forma subclínica, la mastitis causa únicamente pérdidas en producción y calidad de la leche, pero el bienestar del animal no se ve afectado. cuando la enfermedad empeora, se afecta gravemente la salud del animal y puede causar pérdidas de cuartos o inclusive la necesidad de descarte por falta de producción o perdida completa de la funcionalidad de la glándula mamaria. El recuento de células somáticas ha sido utilizado como un método para determinar el grado de sanidad de la glándula mamaria. La medición del RCS es una técnica sencilla, pero requiere de equipos especializados que normalmente no están a disposición de los productores. Por esto el CMT o California Mastitis Test se ha aceptado como una técnica de campo válida para, a partir de su resultado, tomar correctivos que disminuyan la presencia de la enfermedad en los hatos. Objetivo. comparar la eficiencia de dos métodos diagnósticos de mastitis subclínica en la determinación del grado de infección de la glándula mamaria. Materiales y métodos. El análisis se llevó a cabo mediante la estimación de la correlación de Spearman de los resultados cualitativos de cada uno de los métodos con el análisis cuantitativo del RCS realizado en el laboratorio a 104 muestras de leche, correspondientes a los 4 cuartos de 26 vacas con niveles de células somáticas desconocidos. Resultados. la correlación para ambos tratamientos fue significativa, siendo 42.9% para el tratamiento 1 y 49% para el tratamiento 2. Según estos resultados, se puede concluir que ninguno de los dos tratamientos logra explicar con exactitud el nivel sanitario de la glándula mamaria, pero además no existe diferencia en emplear cualquiera de los dos. Conclusión. el análisis más preciso sigue siendo el conteo de células somáticas directo.
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    Evaluación comparativa de los parámetros productivos y agronómicos del pasto kikuyo Pennisetum clandestinum bajo dos metodologías de fertilización
    (Corporación Universitaria Lasallista, 2010) Echeverri Zuluaga, José Julián; Restrepo Betancur, Luis Fernando; Parra Suescún, Jaime Eduardo
    Introduction. Green forage production and its quality are some of the factors that determine the efficiency in the production and composition levels of milk in Antioquian intensive systems. Most common grass species is Kikuyo pennisetum Clandestinum, which can be found in 85% of specialized systems. This grass requires high chemical fertilization levels to achieve biomass productions enough to maintain the high loads they are submitted to by producers. Nitrogen fertilization, recommended for this kind of exploitations, moves between 50 and 70 Kg of nitrogen per hectare/grazing, and this means at least 400 Kg of nitrogen per year. The cost of fertilizers has obligated producers to look for strategies to reduce costs, using, among other options, organic matter as their compost source. Organic matter is important because of its impact on the soil’s structure and on some physical-chemical characteristics that help to a better use of the chemical fertilizer and finally increase the quality and the production of green forage. Objective. To determine the effect of the partial substitution of chemical fertilizers on the production of green forage and the leaf-stem relation in a farm located at the North of Antioquia. Materials and Methods. An experimental design in blocks randomized with three treatments was used, using as blocks 17 land plots in which the research was made. A minimum of three repetitions was made in every plot. The treatments were: 1) 50Kg of N/ha; 2) 25 Kg of N/ha plus 200Kg of organic fertilizar and 3) 25 Kg of N/ha plus 300Kg of organic fertilizer. Results. The statistic analysis was made by the use of the SAS GLM 9.0 version procedure. Conclusion. According to the analysis, there was no significant difference (p<0.05) between treatments for any of the evaluated characteristics, forage production per hectare and leaf:stem relation. This means that, under production and agronomic quality terms of the forage, the organic fertilizer replaced the chemical one, becoming a feasible alternative for fertilization in this kind of exploitations.
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    Parámetros genéticos para el control del peso al nacimiento en bovinos de carne: cruzados en el trópico bajo colombiano
    (Corporación Universitaria Lasallista, 2009) Bolívar Vergara, Diana María; Ramírez Toro, Edison Julián; Vergara Garay, Oscar David; Restrepo Betancur, Luis Fernando; Arboleda Zapata, Elkin Mauricio; Cerón Muñoz, Mario Fernando
    Introduction. The weight, in the moment of birth, is linked to the strength and the survival of beef and is one of the most important factors in death rates during the cattle’s first 24 hours of life. The genetic evaluation for this characteristic must be included as a part of the election criteria in genetic improvement programs. Objective. To estimate the variance components and the genetic parameters for the weight at the moment of birth in a population of crossed beef in the low tropical Colombian zone. Materials and methods. The estimations of the variance components were obtained by the use of the Derivative-free restricted maximum likelihood method. The model included, as fixed effects, herd, individual and maternal genetic group, contemporary group (sex, time and year of birth) and the age of the cow at the birth moment as a covariate. The random effects were the genetic direct and maternal additives, permanent environment of the cow and residual. Results. Direct and maternal heritabilities were 0.24 ± 0.027 and 0.01 ± 0.009, respectively. Differences were found among genetic groups for the characteristic analyzed. The ½A ¼S ¼C, ½A ¼R ¼C, ¾C ¼B y ¾C ¼A groups had, at the moment of birth, a weight superior to that of the Zebu, while the groups ½B ¼A ¼C, ¾A ¼C, ½B ½C, ½R ¼A ¼C, ½R ½C and 9/16 A 7/16 C had a lower weight. Conclusions. The direct heritability found suggests that the selection by the use of this characteristic is feasible for this population. The differences found among genetic groups must be kept in mind, in order to achieve intermediate weights in the moment of the birth.