This study aimed to survey milk yield, lactation stages and milk quality traits of Damascus goats reared under different feeding systems. Goats were divided according to feeding systems as pasture based and concentrate based. Feeding systems were found to have significant effect on lactation milk yield but not on lactation duration. Although differences between feeding systems were not found significant on pH, milk composition factors (fat, lactose, dry matter), somatic cell count and malondialdehyde (except for early lactation stage) for each lactation stage, significant effects were detected on same parameters among lactation stages. Calcium levels at early lactation stage in milk differed either between feeding systems or among lactation stages. Also, other minerals were found to decrease with lactation. While most of the fatty acids were affected in any of the lactation stages by the feeding system, all of them were significantly altered by lactation stages. Pastured goats had a lower percentage of total saturated fatty acids, atherogenic index, thrombogenic index and odour index ratios. In accordance with milk fatty acid composition, compared to the milk obtained from goats fed with concentrate, the milk obtained from the goats that pastured was healthier and early lactation stage was found to produce healthier milk than late lactation stage.

This study aimed to identify the expression levels of some candidate genes for mastitis resistance (LTF and BRCA1), milk yield (POU1F1 and IGF-1), and milk quality (PPARγ and CSN2) in different feeding systems (pen-and pasture-based) used for Damascus goats. Milk samples were taken from all goats in both pen and pasture groups at 4 times, at the 1st, 3rd, 5th, and 7th months of the study. It was found that, compared to the pen group, the LTF and CSN2 genes in the pasture group had significant levels of upregulation in the 7th month of lactation (3.538-and 5.436-fold, respectively), the PPARγ gene had downregulation at the beginning of lactation (0.399-fold), and the IGF-1 gene had upregulation in the 3rd month of lactation (2.313-fold) but had significant levels of downregulation (2.332-fold) in the 5th month of lactation. It was determined that LTF gene expression levels in goats might be used as a criterion in identifying mastitis resistance, IGF-1 for lactation milk yield, and PPARγ for milk fat yield. This study is the first report that presents LTF, BRCA1, IGF-1, and PPARγ gene expression levels in goat milk and udder epithelial cells and the effect of BRCA1, POU1F1, and PPARγ genes on milk protein yield.