Estimates of genetic parameters and trends of various performances traits of Red Sindhi cattle using single trait animal model

Lactation records (809) of 160 Red Sindhi cows, daughters of 24 sires, from 1st to 11th parity during 1958 to 2005 maintained at State Government Cattle breeding farm, Kalsi, Dehra Dun, (Uttaranchal), India, were used to estimate the genetic parameters of various performance traits by uni trait animal model. The variance components and genetic parameters were estimated by the derivative free maximum likelihood animal model (DFREML) procedure. The mixed model used in the study incorporated fixed effects, direct additive genetic effect (animal), permanent environment effects, error effects and the linear regression of age at first calving. The fixed effects included in the model were sex of calf, parity season and period of calving. The genetic trends were estimated by averaging the predicting breeding values of different traits over the birth period of cows. The average lactation milk yield (kg), lactation length (days), dry period (days), service period (days) and calving interval (days) were 1565 kg, 293 days, 178 days, 184 days and 471 days, respectively. The corresponding estimates of heritability and repeatability were 0.275 +/- 0.051; 0.34, 0.064 +/- 0.036; 0.11, 0.153 +/- 0.046; 0.24, 0.085 +/- 0.044; 0.22 and 0.127 +/- 0.046; 0.31, respectively. The range of predicting breeding values for LMY, LL, DP, SP and ICP were -624 to 604, -34 to 36, -55 to 100, -43 to 57 and -54 to 79, respectively. The genetic and phenotypic trends among various economic trends revealed that in all the traits during all the periods cows contributed significantly while environmental effects could not nullify the negative effects of cows in some of the traits. The correlation of predicted breeding values of LMY with all other traits were nonsignificant. The significant and high correlation among predicted breeding values of DP, SP and ICP indicated that improvement in one trait simultaneously resulted improvement in other trait too.