A conjugated linoleic acid (CLA) supplement containing trans-10, cis-12 CLA reduces milk fat synthesis in lactating goats

The efficacy of a lipid-encapsulated trans-10, cis-12 conjugated linoleic acid supplement (LE-CLA) on milk production and milk fatty acid (FA) profile was investigated. Thirty multiparous Alpine lactating goats (50 +/- 7.4 kg) in late lactation were used in a 3 x 3 Latin square design. Does were fed a diet of bermudagrass hay, dehydrated alfalfa pellets, and concentrate. Does were randomly allocated to three treatments; A) unsupplemented (Control), B) supplemented with 30 g/d LE-CLA (low-dose; LLE), and C) supplemented with 60 g/d LE-CLA (high-dose; HLE). Milk yield, DMI, and milk protein content and yield were unaffected by treatment (P > 0.05). Compared with Control, milk fat yield was reduced 8.1% by the LLE treatment and 21.2% by the HLE treatment (P < 0.001), with milk fat content reduced 4.8 and 17.6% by the LLE and HLE treatments, respectively (P < 0.001). Milk fat content of trans-10, cis-12 CLA was 0.03, 0.09 and 0.19 g/100 g of fatty acids for the Control, LLE and HLE treatments, respectively. The transfer efficiency of trans-10, cis-12 CLA from the two levels of CLA supplement into milk fat was not different between treatments and averaged 1.85%. In conclusion, trans-10, cis-12 CIA reduced milk fat synthesis in lactating goats in a manner similar to that observed for lactating dairy cows and sheep. However, dose-response comparisons suggest that the degree of reduction in milk fat synthesis is less in goats compared with sheep and dairy cows.