Abstract #W383

# W383
Milk fatty acid profile of dairy cows fed omega 3 and 6 fatty acid sources during transition period and early lactation.
Caio Seiti Takiya*1, Jefferson Rodrigues Gandra2, Lenita Carmago Verdurico1, Rodolfo Daniel Mingoti1, Rafael Villela Barletta1, Jose Esler de Freitas3, Gustavo Delfino Calomeni1, Elmeson Ferreira de Jesus1, Thiago Henrique Annibale Vendramini1, Francisco Palma Rennó1, 1Departamento de Nutrição e Produção Animal da Universidade de São Paulo, Pirassununga, São Paulo, Brazil, 2Faculdade de Ciências Agrárias da Universidade de Grande Dourados, Itahum, Mato Grosso do Sul, Brazil, 3Departamento de Zootecnia da Universidade Federal da Bahia, Ondina, Bahia, Brazil.

The objective of this study was to evaluate the effects of omega 3(n-3) and 6 (n-6) fatty acids (FA) supplementation on milk FA profile of dairy cows in early lactation. Forty 8 Holstein cows were divided randomly distributed into 4 groups to receive one of the diets: 1) Control (C, n = 12), without FA supplementation; 2) Flaxseed (WF, n = 12), addition of 60 and 80 g/kg diet DM of whole flaxseed (n-3 FA source) during pre and postpartum, respectively; 3) Soybean (WRS, n = 12), addition of 120 and 160 g/kg diet DM of whole raw soybean (n-6 FA source) during pre and postpartum, respectively; 4) Calcium salts of FA (CSFA, n = 12), addition of 24 and 32 g/kg diet DM of Megalac E (n-6 FA source) during pre and postpartum. The diets were offered from 35 d of expected calving date until 84 DIM and were formulated according to NRC (2001). Milk samples were collected weekly, proportionally of each milking (6h00 and 15h00) and proportionally of each cow yield. The extraction of lipids was made according to Feng et al. (2004) and methylated according to Kramer et al. (1997). Fatty acids were quantified by gas chromatography. Data were subjected to PROC MIXED of SAS (2004) using as fixed effect diet and weeks, and using as random effect interaction between week and diet and residual error. Orthogonal contrasts were performed (C vs WRS+CSFA+CSFA; WRS vs CSFA and WF vs WRS+CSFA). Fat supplemented diets increased total saturated FA compared with control (P < 0.01) and tended to increase C18 unsaturated FA (P = 0.08). Fatty acids with less than 16C were decreased with and FA with higher than 16Cwere increased FA supplementation. Whole raw soybeans increased C18:3, C18:2 and decreased C18:1 trans-11 FA compared with CSFA. However, SCFA presented higher unsaturated / saturated ratio than cows fed WRS. Increased cis-9, trans-11 FA was observed in cows fed WRS and CSFA when compared with WF. Whole flaxseed did not increase unsaturated FA in milk and SCFA increased the total unsaturated FA acids in milk. Supplementation of n-3 and n-6 FA altered milk fatty acid profile of early lactating cows.

Key Words: calcium salts of fatty acid, flaxseed, soybean