A STUDY OF SOME GENETIC AND NON-GENETIC FACTORS AFFECTING MILK YIELD, COMPOSITIONS AND GROWTH OF LAMBS IN AWASSI AND HAMDANI EWES .

This study was conducted on Awassi and Hamdani sheep belongs to flock of Agriculture and Forestry College, Mosul University during the productive season 2009. The study included 57 Awassi ewes and 17 Hamdani ewes, and 67 , 22 lambs of two breeds, respectively . The overall means of daily milk yield (DMY), fat, protein, lactose and solids not-fat percentages were 563.43 gm , 6.93 , 5.47, 4.46 , and 10.78%, respectively . The mean body weight at birth (BW) , weaning (WW) and six months (6W) of age were 3.53 , 25.47 and 28.00 kg, respectively . Total gain of weight from birth to weaning (GBW) and from weaning to six months (GW6) were 21.94 and 2.05 kg, respectively . The effect of breed was significant only on DMY and fat percentage . The breed affect (BW), (6W) and (GW6) were significant . The sex and type of birth have significant influence (p<0.01) on DMY , while its effect was non-significant on milk constituents . Sex of lamb affect on (BW), (WW) and (GBW) were significant . Type of birth had a significant influence on (BW) and (GW6) whereas its effect was non-significant on other traits . Age of ewe significantly affected on (DMY) whereas no significant effect on milk composition was appeared. The age of ewe also had no significant effect on growth of lambs. There were a negative and a significant correlation between MY and fat, protein, solids not-fat and between lactose and fat percentage . Also the correlation coefficients were positive and highly significant between milk composition with each other. Positive and significant correlations (p<0.01) had been observed between lambs weight at different ages and (GBW) . The BLUP values for daily milk yield were between 419.491 to -551.921gm . Rank-Correlation between MY and its compositions were negative and significant while the values between traits of milk composition were positive and significantly and ranged between 0.522 0.936 .