Milk production and fatty acid profile of dairy cows supplemented with flaxseed oil, soybean oil, or extruded soybeans

Abstract

The objective of the study was to investigate the effects of oil sources in the diet on milk yield, milk composition, and fatty acid (FA) profiles in mid-lactating dairy cows. Forty-eight Chinese Holstein dairy cows averaging 150 days in milk (DIM) at the start of the experiment (body weight 0596919 kg; milk yield 029.793.00 kg/d) were used in a completely randomized block design. The animals were assigned into four dietary treatments according to DIM and milk yield, and supplemented with no oil (control), 2% flaxseed oil (FSO), 2% soybean oil (SBO), and 2% oil from extruded soybeans (ESB). The experiment lasted nine weeks including the first week for adaptation. Milk yields, milk compositions (fat, protein, and lactose), and milk FA profiles were measured. Daily milk yield from cows fed with FSO, SBO, and ESB were higher than milk yield of the control cows (27.0, 27.0, and 26.5 vs. 25.4 kg/d). Milk fat percentage of the control cows was greater than those cows fed with oil-supplemented diets. However, increasing dietary fat content resulted with no change in fat-corrected milk yield. The FA profile of milk was changed by fat supplementation. Feeding oil reduced the proportion of both short-chain (C 8:0 to C 12:0 ) and medium-chain (C 14:0 to C 16:1 ) FAs, and increased the proportion of long-chain (]C 18:0 ) FAs in milk fat. Cis-9, trans-11 conjugated linoleic acid (CLA) in milk fat was increased from 0.38% for the control to 0.79, 1.51, and 1.56% of fat for the cows supplemented with FSO, SBO, and ESB, respectively. Feeding oils rich in linoleic acid (SBO and ESB) was more effective in enhancing cis-9, trans-11 CLA in milk fat than oils containing linolenic acid (FSO). There was a linear relationship between transvaccenic acid and cis-9, trans-11 CLA content in milk. Overall, feeding the FSO, SBO, and ESB diets increased monounsaturated and polyunsaturated fatty acids and decreased the saturated fatty acid in milk fat.

Milk performance of dairy cows supplemented with rape seed oil, peanut oil, and sunflower seed oil

“…The DM intake was not different among treatments (P > 0.1, average 21.3 kg per day), consistently with previous studies (Loor et al, 2005;Zheng et al, 2005;Ye et al, 2009). …”

“…In previous research (Zheng et al, 2005;Ye et al, 2009), supplementing vegetable oil led to significant increases in the concentration of CLA in milk fat of dairy cows and feeding oils rich in linoleic acid was more effective in enhancing cis-9, trans-11 CLA in milk fat than oils containing linolenic acid. However, few studies were focused on how oleic affected the milk fat composition.…”

“…The examination of previously published literature indicates that the effect of supplemental oils on DMI varied among experiments (Eugčne et al, 2008;Hess et al, 2008;Ye et al, 2009). Previous researches (AbuGhazaleh et al, 2002;Bell et al, 2006) reported that DMI was decreased by fat supplements when replacing the concentrate with fish oil or 6% of DM plant oil.…”

“…Some researchers (Bell et al, 2006) reported that fat supplementation resulted in a decrease in milk fat content while others reported no effect (Ward et al, 2002;Bu et al, 2007). The reduction of milk fat content may be due to the fact that too much unsaturated FA destroy the membrane of bacteria and further decrease the fibre digestion, which may cause decreased acetate production (Onetti et al, 2001;Ye et al, 2009). However, in this study the higher milk yield of cows supplemented with 2% fat indicated no negative effect on rumen fermentation and DMI.…”

“…Milk containing functional factors is more and more favourable and conjugated linoleic acid (CLA) is a hot topic. Previous studies have shown that it is possible to alter the fatty acid composition of milk fat and the CLA content (Zheng et al, 2005;Ye et al, 2009). Interest in CLA is increasing because it may be beneficial to health, including the potent anticarcinogenic activity.…”