| Budget Amount *help |
¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 2005: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 2004: ¥1,100,000 (Direct Cost: ¥1,100,000)
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| Research Abstract |
Four trials were conducted to investigate the factors affecting fatty acids composition, especially focused on CLA (conjugated linoleic acid), in milk of grazing cows.
In experiment 1,fatty acids composition in milk collected from whole day grazing dairy farms (WG), time restricted grazing farms (TG) and non grazing farms (NG) were measured from April to December. The cows in WG and TG were grazed on temperate pasture from May to October. The cows in NG were offered total mixed ration throughout the season. Across the grazing season, proportions of CLA to total fatty acids in milk of WG,TG and NG were 1.4,0.9 and 0.4 mol%, respectively.
In experiment 2,six milking cows were kept under grazing and non-grazing condition to investigate the effect of linoleic and linolenic acids intake on the CLA content in the milk. These results suggested that the increase of CLA in milk under grazing condition was due to the increase of vaccenic acid supply, which was synthesized form linolenic and linoleic acids in the rumen, to mammary gland
In experiment 3,three steers were offered fresh herbage to investigate the fatty acid composition in duodenum digesta. The amount of vaccenic acid flow to the duodenum of steers fed fresh herbage was about ten times more than that of CLA flow, suggesting that the CLA in the milk of grazing cows are mainly synthesized from vaccenic.
In experiment 4,cheeses were made from the milk of the grazing cows to test whether the CLA in milk could remain in the cheese. The proportion of CLA to total fatty acids in cheese increased linearly with increase of the proportion of CLA in milk, suggesting that it could be possible to make a cheese containing high level of CLA using the milk produced from grazing cows.
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