Milk composition in Damascus, Mamber and F1 Alpine crossbred goats under grazing or confinement management

The interactive effect of breed and feeding management on milk composition was established in local goats (Damascus, Mamber) and their F1 Alpine crossbreeds, half of which grazed daily for 4 h in Mediterranean brushland (Pasture - P) and half were fed clover hay (Hay - H) indoors, in addition to concentrate fed individually. Milk composition and fatty acid profile were measured, and individual nutritional composition was estimated by fecal NIRS; DM intake was calculated from the proportion of dietary concentrate. Milk and feces were collected at 65 (pretreatment), 110, 135 and 170 days of lactation. DM intake was lower in the H vs. P group (P < 0.0001) in Damascus and Damascus crossbreed (P < 0.01), but not in the other breeds. The Alpine crossbreeds yielded 0.6 kg more milk (P < 0.001) than their local counterparts. P group yielded milk that was richer in protein (P < 0.01) and fat (P < 0.0001), especially in the Damascus breed. Urea concentration in milk was 66% higher in H-group of all breeds throughout the experiment (P < 0.001). H goats produced milk richer in medium-chain fatty acids (P < 0.001) and monounsaturated fatty acids (P < 0.01) than P goats. Omega 6 was higher for P goats with a strong breed × diet interaction effect (P < 0.01) in Mamber goats. The P group produced milk that was 20% richer in omega 3 than the H group (P < 0.0001). In the P group of Damascus goats, low omega 6/3 ratio was found compared with H group. This study shows that breed and management interact to affect milk composition and fatty acid profile. Therefore both factors and their interaction should be considered when industry pursues means to enrich milk with bioactive, essential lipid components which can turn milk into health promoting commodity.