Animal breeding

Study of different structures of additive genetic groups to increase the efficiency of genetic selection in beef cattle

G. A. Oliveira Junior, Study of different structures of additive genetic groups to increase the efficiency of genetic selection in beef cattle, vol. 13. pp. 115-116, 2014.

The structure of genetic groups is a technique that allows animals with unknown pa­ternity to be included in genetic evaluation programs. The ways these groups are formed are still arbitrary, making it important to study different formation strategies for genetic groups, aiming for a suitable framework for the genetic evaluation of seedstock in animal breeding programs.

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.

Estimates of genetic trend for carcass traits in a commercial broiler line

J. L. B. M. Grosso, Balieiro, J. C. C., Eler, J. P., Ferraz, J. B. S., Mattos, E. C., T. Filho, M., Felício, A. M., and Rezende, F. M., Estimates of genetic trend for carcass traits in a commercial broiler line, vol. 8, pp. 97-104, 2009.

Data from the slaughter of 24,001 chickens that were part of a selection program for the production of commercial broilers were used to estimate genetic trend for absolute carcass (CW), breast meat (BRW), and leg (LW) weights, and relative carcass (CY), breast meat (BRY), and leg (LY) weights. The components of (co)variance and breeding values of individuals were obtained by the restricted maximum likelihood method applied to animal models. The relationship matrix was composed of 132,442 birds.

Myostatin (GDF8) single nucleotide polymorphisms in Nellore cattle

A. B. Grisolia, D’Angelo, G. T., Neto, L. R. Porto, Siqueira, F., and Garcia, J. F., Myostatin (GDF8) single nucleotide polymorphisms in Nellore cattle, vol. 8, pp. 822-830, 2009.

The myostatin gene, also known as GDF8 (growth dif­ferentiation factor 8), is located on bovine chromosome 2 (BTA2); it has three exons and two introns. Myostatin is specifically expressed during embryonic development and in adult skeletal muscle, func­tioning as a negative regulatory protein. Several cattle breeds (Pied­montese, Belgian Blue and Blond’Aquitaine, and others) show poly­morphisms in this gene; these polymorphisms are directly related to the double muscling phenotype.

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.

Genetic trends of absolute and relative heartweight in a male broiler line

L. G. Gaya, Costa, A. M. M. A., Ferraz, J. B. S., Rezende, F. M., Mattos, E. C., Eler, J. P., T. Filho, M., Mourão, G. B., and Figueiredo, L. G. G., Genetic trends of absolute and relative heartweight in a male broiler line, vol. 6, pp. 1091-1096, 2007.

Data of chickens from a broiler-breeding program have been collected and used for determination of genetic trends of absolute and relative heart weight. The genetic trends have been estimated by regression of the genetic values of the traits over hatch-year. Genetic values of 42,912 individuals, obtained by restricted maximum likelihood, were used for regression analysis. The estimates of the genetic trends for absolute and relative heart weight were found to be -0.08 g and -0.004% per hatch-year, respectively.

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