This experiment was conducted to study the effects of supplemental fatty acids with different carbon chain lengths on yield and fatty acid composition of milk in lactating dairy cows. Thirty-six Holstein dairy cows, which had the adjacent birth order, lactation stage and milk yield, were selected in a completely randomized design and divided into 3 groups with 12 replicates per group and 1 dairy cow per replicate. Group Ⅰ was the control group, and the cows in this group were fed the basal diet; group Ⅱ was the short- and medium-chain fatty acids (SMCFA) group, and the cows in this group were fed the basal diet supplemented with 400 g/d SMCFA; group Ⅲ was the long chain fatty acids (LCFA) group, and the cows in this group were fed the basal diet supplemented with 400 g/d LCFA. Total duration of the experiment was 63 days (7 days for adaptation and 56 days for trial period). The results showed as follows: 1) the milk fat percentage in SMCFA group was significantly higher than that in LCFA group (P>0.05), while no differences in milk production and other milk components were observed for all groups (P>0.05); 2) LCFA supplementation decreased the contents of C12∶0 and C14∶0 in milk fat (P<0.05); 3) the contents of C12∶0 and C14∶0 in milk fat were significantly increased, whereas the contents of C18∶0 and c-9-C18∶1 in milk fat were significantly decreased by adding SMCFA (P<0.05); 4) the stearoyl-Co A desaturase (Δ-9 desaturase) activity in mammary gland was not significantly different among the 3 groups (P>0.05). These results indicate that supplementation of SMCFA has more contribution to the milk fat percentage compared with LCFA, which has something to do with the increasing contents of C12∶0 and C14∶0 in milk fat.［Chinese Journal of Animal Nutrition, 2011, 23（7）：1116 -1122］
CUI Hai, WANG Jiaqi,LI Fadi,BU Dengpan,ZHAO Xiaowei,XU Xiaoyan,SUN Yan,ZHOU Lingyun
. Effects of Supplemental Fatty Acids with Different Carbon Chain Lengths on Yield and Fatty Acid Composition of Milk in Lactating Dairy Cows[J]. Chinese Journal of Animal Nutrition, 2011
, 23(07)
: 1116
-1122
.
DOI: 10.3969/j.issn.1006-267x.2011.07.008
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