GENETIC EVALUATION OF SOME REPRODUCTIVE EFFECINIECY INDICATOR IN HOLSTEIN FRIESIAN CATTLE

Abstract

At the Nasr and Al-Ishaki Dairy Cattle Station, 944 , 931 and 977 records of period from cow birth to first service(BFC), cow birth to first days open (BDO) and age at first calving (AFC) belonged to Holstein Friesian cattle were analyzed statistically.The aim of present study is to investigate the estimate of genetic variance after adjustment of fixed effects and to estimate genetic parameters of traits.The Bolls of Holsteins Friesian at the both Station were evaluated genetically due to their daughters BFC , BDO and AFC. The General Linear Model (GLM) in the SAS program was used to study the effects of stable factors (season & year of birth and herd). Components of variance for the random effects in the employed mixed model were estimated by the Restricted Maximum Likelihood procedure. The Harvey program was also used to estimate BLUP values. The overall means for the BFC , BDO and AFC were 19.43, 21.51 and 30.91 month respectively. Season of birth significantly (P<0.05) affected on BFC and BDO, whereas, effects year of birth on physiological traits highly significant, herd affected significantly on BDO (P<0.05) and AFC(P<0.01). The heritability of the BFC , BDO and AFC were 0.38 , 0.29 and 0.35 respectively. BLUP (Best Linear Unbiased Prediction) estimates displayed a wide range among bolls included in the current study. Therefore, they are of utmost importance for selection programs aiming at reducing and curtailing of bolls.