التقييم الوراثي والمظهري لإنتاج الحليب الجزئي في ماشية الهولشتاين بوسط العراق

Abstract

Statistical analysis was taken for 3660 , 3020 , 2735 and 2086 records which belong to partial milk yields in the production period of 60 , 120 , 180 and 270 days respectively, between 1997 to 2000 in AL-Nasar Dairy Cattle Station. This station contain a herd of Holstein cattle. General Linear Model within the SAS program was used to estimate fixed effects and to estimate variance component for random factors by using Restricted Maximum Likelihood (REML) for genetic parameters evaluation.Harvey program was also used to evaluate Best Linear Unbised Prediction (BLUP) for studied traits. Least – squares mean  SE for partial milk yields in 60 , 120 , 180 and 270 days were 1185.9  29.4 , 2311.0  26.0 , 3328.8  23.7 and 4559.3  21.6 kg respectively. Season and year of calving have a highly significant effect for all studied traits. And there are significant effect (p0.01) for parity in all triats studied.The highest milk yield in 60 , 120 , 180 and 270 days were 1151.8 , 2259.9 , 3247.5 and 4517.1 kg respectively in the 3 rd production season. The heritability estimates for the characters that mentioned before were 0.10 , 0.20 , 0.12 and 0.06 respectively. The highest value of the best linear unbiased prediction for sires for partial milk yield in 60 , 120, 180 and 270 days were 17.13 , 65.52 , 39.52 and 8.73 kg while the lowest were -16.52 , -42.90 , -58.44 and -10.29 kg respectively.