This invention provides a control release formulation or rumen-bypass dietary supplement in compacted form. The formulation or supplement has the capability to transport fatty acid calcium salt and between about 1-75 percent of one or more rumen-protected undegraded biologically active agents to the post-ruminal digestive system of a ruminant. A feedstock containing the formulation or supplement for ruminants beneficially improves feed efficiency and body growth. The feedstock also is adapted to improve the lactational performance of dairy cattle.