تقويم بعض الصفات الإنتاجية لنعاج العواس لدى بعض محطات بحوث الثروة الحيوانية في سورية

الملخص EN

This study was carried out to evaluate total milk yield (TMK), lactation length (LL), and litter size at birth weight (LZBW), during the period from 2005 to 2010, at Sheep Research Stations, Marj AlKarim and Wadi Azeeb in Hama and Shola Station in Deir Ezzor (Syria).

The numbers of studied records were estimated 6012, 6255, and 6009 for TMK, LZBW, and LL, respectively.

The data was statistically analyzed by Least Squares methods\ Fixed Linear Model to evaluate studied traits and study the effect of some non-genetic factors using statistical program SAS.

In addition, heritability and breeding values were estimated according to Animal Model for the studied traits using genetic evaluattion\ MTDFreml.

Moreover, genetic correlations among Breeding Values were estimated by Spearman corrrelation coefficient using the program SAS.

The results showed that, Lambing type, Parity, Year of Production, Station, age and weight at lambing, the interaction between age of ewes at lambing and parity were highly significant on TMK, LL.

The results showed that, Lambing type, station, weight at lambing and year of production were highly signnificant on LZBW.

While parity, age at lambing, interaction between ewes age at lambing and parity effects were non-significant on The LZBW.

The Least Squares Means for TMK, LL, and LZBW were 247.2±64.6 kg, 161.5±33.8 day, and 7.30±3.04 kg, respectively.

The regression values of TMK, LL, and LZBW on ewe age; weight at lambing were -1.02±0.78; 1.33±0.12, -0.53 ± 0.14; 0.61±0.34, -0.014±0.002; 0.025±0.002, respectively.

Heritability estimates of TMK, LL, and LZBW were 0.37, 0.10, and 0.17, respectively.

The estimate of genetic correlation was 0.31 between TMK and LL.

While genetic correlations were -0.26, and -0.032 between LZBW and TMK, LL, respectively.

The genetic correlation among TMK and LL, LZBW was highly significant, while it was significant between LL and LZBW.

The studied traits were negatively affected by ewe age at lambing (<7.0 years), while it were positively affected by ewe weight at lambing (<62.5 kg).

The genetic variation has been found many studied traits.

The genetic correlations among LZBW and TMK, LL were negative and statistically significant in Awassi sheep in Syria.

So the study advise to improve environment conditions, exclusion of ewes over 7 years old, give of ewes over ration before lambing, and continue of genetic selection within two production lines, the first line for total milk yield and second line for meat production (lambs production at birth).