Genetic aspects of beef quality in Piemontese cattle and relations with breeding goal traits

The Piemontese breed is highly specialized for beef production due to double muscling (DM) inherited condition induced by a specific mutation of Myostatin gene (mh) located on Chromosome 2. This phenotype is characterized by greater muscle mass with less fat deposition, reduced weight of the skeleton reduced feed intake, and improved feed conversion. The current breeding goal of the Piemontese population includes traits related to quantitative beef production and maternal calving performance of animals. This thesis is aimed to study the possibility to introduce, indirectly, meat quality traits among the selected traits. This implies that genetic parameters and heritabilities for all meat quality traits need to be estimated. Chapter 3 deals with the development and applications of a calibration curve for Near-Infrared spectroscopy (NIRS) aimed to predict chemical and physical compositions of Piemontese beef cattle. Chapter 4 deals with the estimation of genetic parameters and heritabilities for physical meat quality traits, measured in laboratory, on a dataset of 1,080 Piemontese young bulls using a mixed linear Animal model. Chapter 5 aimed to Predict the fatty acid profiles on a dataset of 733 fresh samples of Longissimus thoracis muscle of Piemontese young bulls using the same regression developed by the calibration curve obtained with near infrared reflectance Spectroscopy (NIRS) technique, and to estimate heritabilities and additive genetic variations for NIRS-predicted traits. Chapter 6 aimed to estimate variance and covariance components and corresponding genetic parameter estimates, and to estimate genetic and phenotypic correlations among meat quality traits in Piemontese beef cattle. (Co)variance components were estimated using a bivariate mixed animal model and was accomplished using Bayesian methodology and the Gibbs sampling integrations. Chapter 7 deals with the estimation of genetic correlations among beef quality traits and performance traits for Piemontese beef cattle, and to evaluate the possibility to include, indirectly, meat quality traits in the selection objective.