GENETIC EVALUATION FOR FRIESIAN CATTLE IN EGYPT USING SINGLE-TRAIT ANIMAL MODEL

Abstract

A total number of 1011 first lactation records of Friesian cows daughters of 705 dams and 103 sires for a period of 19 years raised at Agricultural Research Station, Sakha, Kafr El-Sheikh Province, belonging to Animal Production Research Institute, Ministry of Agriculture, Egypt were used to evaluate the genetic parameters of total milk yield (TMY), 305-day milk yield (305-dMY), lactation period (LP), age at first calving (AFC), number of service per conception (NOS), calf birth weight (BW) and calf weaning weight (WW) as well as estimating breeding values (BV) of animals using single-trait animal model. Data were analyzed using Multi-trait Derivative Free Restricted Maximum Likelihood (MTDFREML) Program to calculate the genetic parameters and BV. Statistical Analysis System (SAS) was utilizing to investigate the effect of fixed effects on these traits using mixed model procedure. Means (± SD) of TMY, 305-dMY, LP, AFC, NOS, BW and WW were 2653±1191, 2338±864 kg, 332±107 days, 31.8±5.8 months, 2.25±1.80, 29±4.26 and 95±10.5 kg, respectively. Heritability estimates (h2) for the same traits were 0.07, 0.27, 0.12, 0.04, 0.25, 0.19 and 0.06, respectively. The range of BV for all animals was -2.64 to 2.95, -3.43 to 5.62 kg, -3.41 to 6.44 days, -4.01 to 7.94 months, -2.77 to 3.34, and -2.12 to 1.62 kg, respectively. Spearman rank correlations and Pearson correlations between estimated breeding values of all animals in pedigree (cows, dams and sires) provided by the genetic analysis ranged between 0.19–0.99. Rank correlations of animals between traits were the lowest for reproduction traits. It could be concluded that improving the environment conditions will improve these traits. Also, with the moderate h2 and the wide range in BV between animals regarding to 305-dMY and AFC will help in improving these traits genetically.