干旱区生态环境知识资源中心

This study was conducted at the Agricultural Scientific Research Centre in Syria within the Arab Center for the studies of the Arid Zones and Dry Lands (ACSAD). Milk yield records from 6411 Awassi ewes were collected between 1991-2005. These records were used to evaluate the factors influencing the milk production and to define the differences between the selected meat and milk lines. Results showed that lactation milk yield (LMY) was significantly (P<0.01) affected by ewe line (EL), year of production (YP), parity (P) and birth type (BT). Lactation period (LP) averaged 157.69 +/- 0.63 days and was significantly affected (P<0.01) by the same factors with the exception of birth type (BT). Lactation milk yield for the whole flock averaged 243.3 +/- 3.96 kg with significant differences (P<0.05) between milk and meat lines (272.5 +/- 4.93 vs. 224.0 +/- 4.88 kg respectively). Ewe body weight at lambing was also found to have a positive effect (P<0.01) on LMY. Lactation milk yield increased at a rate of 1.35 kg for each 1kg the ewe was above average body weight at lambing. These results provided evidence that the response to selection program for milk traits in Awassi sheep is significant. Selection for LMY can be improved with a simplified record system.