Abstract:

This study compared the interaction between breed and management on milk lipid composition in Damascus, Mamber, Damascus X Alpine and Mamber X Alpine goats (n=10). Goats were randomly assigned to two different dietary managements of pasture vs. confinement (n=5) for each breed and n=20 for each treatment). At 60, 110, 135 and 170 days in lactation we determined plasma NEFA, milk yield and solid concentrations, milk lipid composition, and milk fat globule (MFG) size. No differences in milk yield were found between treatment groups throughout the experiment whereas protein and fat content increased in the grazing compared with confinement group. Accordingly, MFG size increased in the pasture group by 1 μm (P <0.0001). Breed affected MFG size and composition. In the Mambers treatment did not affect yield, fat content and MFG size. In contrast, fat and protein content and MFG size were higher in the pasture compared with confinement group for the Damascus. Differences in MFG size were associated with phospholipid concentration per mg of fat, which was 40% higher in the Damascus confinement compared with pasture group (P<0.05).

Finally, in the Damascus breed, grazing group produced milk with higher omega 3 fatty acid content and higher ratio between omega 3 and omega 6 fatty acids compared with the confinement group.