Genetic trend

Genetic analysis of average annual productivity of Nellore breeding cows (COWPROD)

J. P. Eler, Ferraz, J. B. S., Balieiro, J. C. C., and Mattos, E. C., “Genetic analysis of average annual productivity of Nellore breeding cows (COWPROD)”, vol. 7, pp. 234-242, 2008.

With the aim of estimating the coefficient of heritability of average annual productivity of Nellore cows (COWPROD), a data set from 24,855 animals with known pedigree was analyzed. COWPROD is defined as the amount (in kilograms) of weaned calves produced yearly by one cow during her remaining time in herd ignoring a fixed period of 365 days.

Genetic trend estimates of meat quality traits in a male broiler line

G. B. Mourão, Gaya, L. G., Ferraz, J. B. S., Mattos, E. C., Costa, A. M. M. A., T. Filho, M., Neto, O. C. Cunha, Felício, A. M., and Eler, J. P., “Genetic trend estimates of meat quality traits in a male broiler line”, vol. 7, pp. 749-761, 2008.

The present research was conducted to estimate the genetic trends for meat quality traits in a male broiler line. The traits analyzed were initial pH, pH at 6 h after slaughter, final pH, initial range of falling pH, final range of falling pH, lightness, redness, yellowness, weep loss, drip loss, shrink loss, and shear force. The number of observations varied between 618 and 2125 for each trait. Genetic values were obtained by restricted maximum likelihood, and the numerator relationship matrix had 107,154 animals.

Genetic trends of abdominal fat content in a male broiler chicken line

Lde Genova Gaya, Mourão, G. Barreto, de Rezende, F. Marcondes, de Mattos, E. Chicaroni, Filho, T. Michelan, Figueiredo, L. Gustavo Gi, Ferraz, J. Bento Ster, and Eler, J. Pereira, “Genetic trends of abdominal fat content in a male broiler chicken line”, vol. 4, pp. 760-764, 2005.

Data of chickens from a broiler-breeding program were collected and used to determine the genetic trends of absolute and relative abdominal fat content. The genetic trends were estimated by the regression of trait genetic value averages on hatch-years. Genetic values from 32,485 individuals were used for regression analysis. The genetic trend estimate for absolute abdominal fat content was +0.39 g per year, indicating that abdominal fat deposition in the analyzed line, in absolute terms, tended to increase, making the existing excess fat deposition in the broilers even worse.

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