Effects of soybean oil or rumen protected conjugated linoleic acid supplementation on accumulation of conjugated linoleic acid in dairy cows' milk

The effects of feeding soybean oil (SBO) or rumen protected conjugated linoleic acid (RP-CLA) on CLA accumulation in milk, and performance of lactating dairy cows were studied. Twenty four Holstein Friesian crossbred lactating dairy cows, averaging 126 +/- 45 days in milk, 15.6 +/- 2.43 kg of milk and 452 +/- 51 kg body weight were stratified randomly and assigned in a randomized complete block design (RCBD) to three treatments of 8 cows each. The treatments were control, 150 g of SBO and 150 g of RP-CLA supplementation. Performance parameters showed that DM intake, NELP intake and body weight change were similar across treatments, while CP intake was decreased by SBO and RP-CLA supplementation. Milk yield and milk composition were not significantly different among treatments, except for milk fat percentage and fat yield which were significantly decreased by 27% (p < 0.05) and by 28% (p < 0.01), respectively, by RP-CLA supplements compared with control treatment. Feeding RP-CLA reduced 3.5% FCM compared with the other treatments (p < 0.003). Both SBO and PR-CLA supplementation reduced < C16:0 fatty acids but increased 08:0 and CLA concentration in milk fat.