Resumen

VERDE, Omar; MEDINA, Juan C  y  BORGES, Marta. Beef Cattle Production System at La Cumaca Experimental Station I.- Birth Weight. Rev. Fac. Cienc. Vet. [online]. 2007, vol.48, n.2, pp.97-104. ISSN 0258-6576.

In this first article a brief description of the animal production system used and the results of the  evaluation of the birth weight character in a registered Brahman herd, located at La Cumaca, Alí Benavides Zapata Experimental Station, in the State of Yaracuy, Venezuela is presented. Birth weights, sex, year and month of birth, age of dam, sire and dam effects, were analized using mixed models techniques (including an Animal Model). A total of 5198 animals from 1965 to 2004 was used. The results of the present investigation show an overall average birth weight of 29.4±0.20 kg. All effects were significant (p<0.01), with an estimated annual phenotypic trend of 210 g, a direct genetic trend of 70 g, and a maternal trend of 17 g. Heritability values were 0.48 ± 0.02 and 0.11±0.02 for direct and maternal effects, respectively. Cows produced heavier calves from first to fifth parturition, declining from there

Palabras clave : Beef cattle; Brahman; animal husbandry methods; birth weight; sex; animal models; Yaracuy.

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