Composition and fatty acids profile of bovine milk after supplementation with barley and cottonseed

Resumen

The objective of this study was to investigate the effect of supplementation with oilseeds (C,cottonseed) compared to concentrate with cereal grains (B, barley) on milk composition andfatty acids (FA) profile of Holstein-Friesian dairy cows in an indoor feeding regime. Threegroups of twelve cows at the end of lactation (mean calving date 19 February) were studiedover ten weeks during autumn. Two groups were supplemented with cottonseed at two levels:(C5), 5 and (C7), 7 kg cow-1 d-1 DM and one group was supplemented with barley (B7) at 7 kgcow-1 d-1 DM. Milk yield was significantly higher at the high level of supplementation (C7,16.9 and B7, 17.4 kg cow-1 day-1) compared to the low level (C5, 14.6 kg cow-1 d-1). Milkprotein was significantly lower in cotton treatments (C5, 32.9 and C7, 31.9 g kg-1) than inbarley (B7, 34.4 g kg-1). There were no differences between treatments for milk fat. Mediumchain FA showed a tendency to be higher with barley supplementation, whereas long chainFA were higher with cottonseed supplementation. The lowest ratio of saturated to unsaturatedFA was observed in C7. Polyunsaturated FA and linoleic acid were significantly higher in C7.There were no differences between treatments for conjugated linoleic acid (CLA)