In resent year there has been research on benefits of conjugated linoleic acid (CLA) and docosahexaenoic acid (DHA) for human health. The effect of a fat supplement made from seaweeds meal plus palm olein meal (FS) and replacement of concentrate on milk production, and milk fatty acid (FA) profiles of dairy cows fed grass silage based diets was evaluated. Ten Holstein lactating cows were divided into a two groups. The cows in a group were fed concentrate at 40% on TDN basis (control). The cows in another group (Treatment) were supplemented 0.5㎏/day/cow of FS as a substitute for 2㎏/day/cow of concentrate. The medium chain fatty acids and DHA content of FS were 345 ㎎/g DM and 35 ㎎/g DM, respectively. Total DMI, DM digestibility and milk production as well as milk composition did not differ between the two groups. The intake of ether extract was higher (P＜0.01) in Treatment than control group (1.1 ㎏/day/cow vs. 1.3 ㎏/day/cow). The short and medium chain of FA in the milk did not differ between two groups. The trans11C18:1vaccenic acid, cis9trans11CLA and C18:3 concentrations in the milk were higher (P＜0.01) in Treatment than control group(1.88 g/100gFA vs. 1.03 g/100gFA, 0.93 g/100gFA vs. 0.51 g/100gFA and 0.48 g/100gFA vs. 0.48 g/100gFA). However, the C18:2 concentration in the milk was lower (P＜0.05) in Treatment than Control group (1.38 g/100gFA vs.1.17 g/100gFA). There were detected 0.13 g/100gFA of DHA in the milk in Treatment group. Results indicated that addition of the FS has the potential of increasing CLA and DHA in cow's milk.

Walking distance and eating time of Holstein (HF) and Brown-Swiss (BS) cows on the temperate pasture were measured on two dairy farms (A and B) in June, August and October to compare the foraging activity using Global Positioning System (GPS) device and voice recorder. The cows on A farm were supplemented concentrate and com silage about 43% of daily dry matter intake and the cows on B farm were supplemented concentrate about 23% of daily dry matter intake. The cows in both farms were grazed in daytime and night except for October in the A farm when the cows were kept in the bam during the night. There was no significant difference in walking distance between HF and BS in the A farm, however the walking distance of BS tended to be longer than HF in the B farm. Eating and ruminating time of the cows in the A farm did not differ between HF and BS. However, eating time of the cows in the B farm was higher in BS than in HF. These results suggest that foraging activity of dairy cows on the temperate pasture differ between HF and BS, and is also affected by amount of supplement.