Evaluación genética y fenotípica de tres razas ovinas criolla, mora colombiana y cheviot mediante la técnica de modelos mixtos
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2003
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Universidad de La Salle. Facultad de Ciencias Agropecuarias. Zootecnia
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Se evaluaron 6746 individuos de la raza Criolla y sus respectivos cruces con animales de las razas Romney Marsh, Hampshire y Corriedale, 2530 individuos de la raza Mora Colombiana y 1533 individuos de la raza Cheviót. Se hicieron estimaciones para características de tipo productivo y reproductivo. En relación a las características de tipo productivo se evaluaron el peso al nacimiento P. N, peso al destete ajustado a 120 días PDA120D, peso de lana a edad adulta P. L y peso a edad adulta P. A.. De igual forma en las características de tipo reproductivo se estimó y reportó por primera vez los valores de edad al primer parto e intervalo entre partos en cada una de las razas para nuestro país. Todas estas características fueron medidas y evaluadas con base al efecto que sobre ellas ejercían efectos fijos como son el año de nacimiento de cada individuo, el número de parto, el tipo de parto, la raza y el sexo. Los índices de heredabilidad estimados para cada una de las características fueron de bajo nivel, encontrando que en la mayor parte de las características este no supera valores del orden del 25 %. Finalmente se estimó el índice de consanguinidad encontrando un bajo número de individuos consanguíneos en las razas Mora Colombiana (65) y Cheviót (21) aunque con un valor alto 6.3% y 10% respectivamente que obliga a realizar una fuerte presión de selección a fin de eliminar los individuos consanguíneos al interior del rebaño.
6746 individuals of the Criolla breed and its corresponding crosses with animals of the Romney Marsh, Hampshire and Corriedale breeds, 2530 of the Mora Colombiana breed and 1533 individuals of the Cheviót breed were evaluated in this study. Estimations for reproductive and productive traits were made. For traits of productive type, lambs birth weight, adjusted weaning weight at 120 d ays, grease wool weight at naturity and weature body weight were evaluated .For traits of reproductive type, for the first time , the age at first lambing and the interval between lambings for each breed in our environmental , were estimated and reported. All these traits were measured and evaluated based on the effect of fixed effects such as year of birth, lambing number, type of birth, breed and sex. The estimated heritability ranges for each trait were of low level and it was found that most tracts were not over 25%. Finally, the inbreeding value was estimated; a low number of inbreed individuals in Mora breed (65) and Cheviót (21) was found , although it was of high value, 6.3% and 10% respectively , meaning that a strong selection pressure must be applied in order to eliminate inbreed individuals within the flock.
6746 individuals of the Criolla breed and its corresponding crosses with animals of the Romney Marsh, Hampshire and Corriedale breeds, 2530 of the Mora Colombiana breed and 1533 individuals of the Cheviót breed were evaluated in this study. Estimations for reproductive and productive traits were made. For traits of productive type, lambs birth weight, adjusted weaning weight at 120 d ays, grease wool weight at naturity and weature body weight were evaluated .For traits of reproductive type, for the first time , the age at first lambing and the interval between lambings for each breed in our environmental , were estimated and reported. All these traits were measured and evaluated based on the effect of fixed effects such as year of birth, lambing number, type of birth, breed and sex. The estimated heritability ranges for each trait were of low level and it was found that most tracts were not over 25%. Finally, the inbreeding value was estimated; a low number of inbreed individuals in Mora breed (65) and Cheviót (21) was found , although it was of high value, 6.3% and 10% respectively , meaning that a strong selection pressure must be applied in order to eliminate inbreed individuals within the flock.
Palabras clave
Razas ovinas, Reproducción de ganadería ovina, Ovinocultura