This invention provides a rumen-bypass dietary supplement in compacted particulate form. The supplement has the capability to transport fatty acid calcium salt and between about 65-96 percent of rumen-protected undegraded aminoacid content to the post-ruminal digestive system of a ruminant. A feedstock containing the supplement for ruminants benefically improves feed efficiency and body growth. The feedstock also is adapted to improve the lactational performance of dairy cattle.