Effect of some non-genetic factors on milk yield and composition of Draa indigenous goats under an intensive system of three kiddings in 2 years

摘要

With 5 millions heads, goats occupy the second place after sheep in Morocco. The indigenous populations are generally raised for meat, except Draa goat that is raised as a dual purpose doe. The objective of this study was to assess milk yield and composition of Draa indigenous goat breed under an intensive system of three kiddings in 2 years and to evaluate the effects of non-genetic factors. Data were collected on 381 lactations between 2006 and 2012 and on 174 samples for milk composition between 2008 and 2010. The highest milk yield was recorded in does of 36-48 months old (84.3 +/- 4.78), those suckling more than one kid (80.0 +/- 3.39) and those kidding in spring (80.4 +/- 3.60) and summer (79.9 +/- 3.67). Except protein content, milk composition was not affected by age of does. Dry matter and fat content increased significantly with the lactation stage, protein content decreased from early to middle/late lactation, and lactose content was high in middle lactation. The highest dry matter and fat and lactose contents were obtained for summer kiddings, while the highest percent of protein was recorded for autumnal kiddings. It was concluded that under the three kiddings in 2-year system, Draa does produce enough milk with an interesting milk composition, indicating that this system may be used with success to improve farmers' income.