Effects Of Supplementation Of Soybean Oil And Linseed Oil On Fatty Acids Digestibility And Fatty Acids Composition In Milk

Four primiparous Holstein cows with cannulas in the rumen and proximal duodenum wererandomly assigned to four diets with a 4×4 latin square experiment. Cows in four treatment were fedhigh forage (60%DM) diets without oil supplement (CK), 4% soybean oil (LOC1), 4% linseed oil(LOC2) or mix of 2% soybean oil and 2% linseed oil (LOC3) on dry matter basis. The objective was toexamine the effects of supplemental fat on intake, apparent ruminal digestibility, and total tractdigestibility of DM, OM, NDF, ADF, milk production and composition in dairy cows.Experiment 1: The effects of supplementation plant oil on the digestibility of rumen and totaltract:The results also indicated that intake,apparesnt ruminal digestibility, and total tract digestibility ofDM,OM,NDF,ADF were not affected by the oil supplementation(P＞0.05), however the fatsupplement tended to reduce the digestibility of DM,OM,NDF,ADF on rumen and total tract.Experiment 2: The effects of supplementation plant oil on the duodenal flow of long chain fattyacids,the C18 unsaturated fatty acids hydrogenation,the digestibility of fatty acids. Compared withcontrol group,the duodenal flow of trans-C18:1, C18:2, C18:3, CLA of supplementation plant oil wereincreased greatly (P＜0.05).Parficularly the duodenal flow of trans-C 18:1 was more 5 times than controlgroup (94.1 vs 15.9g/d).The hydrogenation rate of cis-C 18:1 ,C 18:2,C 18:3 of supplementation plant oilwas higher than control group (P＜0.05). The total tract digestibility cis-C18:l, C18:2, C18:3 was notaffected by add plant oil (P＞0.05), but supplementation plant oil decreased the total tract digestibilityof trans-C 18:1 (58.8%vs95%).Experiment 3: Cows fed diets supplementation plant oil did not alter milk production, milk Lactoseand milk protein percentage (P＞0.05).Compared with control group,the C18:0, cis-C18:1, trans-C18:l,C 18:2, C18:3, unsaturated fatty acids and CLA concentration in Milk were increased greatly when cowfed diets dupplemented plant oil (P＜0.01). The proportions of cis9, trans11 CLA were increased by236%, 156% and 176% in.LOC1, LOC2 and LOC3 treatments compared with cows fed control diet,Soybean oil rich in linoleic acid are more effective in enhancing cis9, trans11 CLA in milk fat than thanother treats when fed at 4% of dietary DM to dairy cows.