Livestock rearing

Patent Granted PROBLEM TO BE SOLVED: To establish a means for efficiently increasing a conjugated linoleic acid in a ruminant such as cattle. ; SOLUTION: The content of a conjugated linoleic acid in the muscle, etc., of a ruminant such as cattle can be efficiently increased by a rearing method for a ruminant such as cattle by feeding the ruminant with one or more substances selected from perilla seed, perilla oil, bitter gourd seed, bitter gourd seed oil, flax seed and flax seed oil, or using a feedstuff composition based on the rearing method, etc.