Heritability and genetic trends for growth characteristics in Romosinuano creole cattle
The heritability and genetic trends were estimated for birth weight, weaning and 16 months of age of Colombian Creole roe cattle Romosinuano, in order to identify the genetic variability of the three characters. 4032 records from 5616 animals, including parents and descendants, obtained in the period from 1943 to 2018 at the Turipaná Research Center, were used. Six mixed animal models were adjusted for each character, using univariate analysis. The models included the contemporary group and the number of births as fixed effects, and as random effects the effect of the animal, the maternal effect and the effect of the permanent maternal environment, obtaining from the heritability estimates of the characteristics analyzed. Genetic trends were estimated by simple linear regression of the average genetic values over the year of birth of cattle. The heritability estimates for direct effects were higher than maternal heritability values, while total heritability for birth weight, weaning and 16 months, they were equal to 0.17 x 0.03, 0.09 x 0.02 and 0.06 x 0.03 respectively, indicating that much of the variation in weights in all three ages is due to environmental factors more than genetic differences between the individuals analyzed. Genetic trends had both positive and negative and near-zero regression coefficients, indicating the preservation of genetic variability in the Romosinuano race and making it clear that to improve growth characteristics, factors associated with the year and time that are beyond the scope of this study must be modified and are of great importance when making a genetic improvement program using this Creole breed
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