Genetic parameters and genetic trends of conformation and management traits in Dairy Gir cattle

ABSTRACT The objective of this study was to estimate genetic parameters and trends different conformation management traits regularly measured within the context National Dairy Gir Breeding Program (PNMGL). estimation residual variances for each trait performed using average information restricted maximum likelihood (AI-REML) procedure in AIREMLF90 program software. population divided into three subpopulations constituted by females (with phenotype records), all females, males. Linear regressions were applied trait, considering two periods birth (1st period: 1938-1996; 2nd 1997-2012). estimated heritability varied from 0.01 0.53, denoting a perspective improvement through selection corrective matings purebred populations. changes were, general, variable inexpressive, showing that may have had been directed essentially increase milk yield. analysis indicated some linear present progress (although inexpressive) period (more recent period).