Tchessking

Okay so I am kind of new to tekkit and am not sure what is going on. Every time I collect milk from a cow via bucket, it disappears as if I drank it. I tried doing it with an empty inventory ( i thought my void ring or ring of Arcana was the problem) and it still disappeared. Any help would be appreciated as I am tired of black coffee. I am having this problem on my serve. I have not tried it in single player.