| Popis: |
The aim of the present study was to evaluate the effects of various non-genetic factors on milk production traits and to estimates its' heritability and variance component in milk production trait among Saudi Aradi and Damascus goats. A total number of 213 (98 Aradi and 115 Damascus goats) was classified according to breed, season, year, and type of birth. Data were analyzed statistically. The variation in milk yield (MY) were moderate (32.80 %), while variations in fat (F %) and protein (P %) were low (fat 17.67 % and protein 19.75 %). The genetic groups had a significant (P≤0.05) effect on milk yield and highly significant on (F % and P %, (P≤0.01)). Damascus goats had higher than Aradi in milk yield, fat and protein. Milk yield and fat% during seasons were not significant differ. Milk protein% during Summer/Spring season (S2) had a significant higher (P≤0.01) than at during Winter/Autumn (S1). The highest fat% (P≤0.05) found in year 2009. Triplets had higher (P≤0.01) effect on milk yield than twins or single. However, there were no significant differences between type of births for protein% and fat%. Damascus had higher heritability estimates (0.45) than Aradi goats (0.29) for milk yield. Also, for protein%, the heritability estimates of Damascus had higher heritability estimates (0.69) than Aradi goats (0.37). But the heritability for fat % in Aradi (0.23) was similar to that in Damascus goats (0.22). In conclusions, the percentage of genetic variance component in Aradi goats is low so that the best programs for the genetic improvement in the Aradi goats could be upgraded through crossing with Damascus goats. |
