Feed additives for ruminants

A rumen-bypass preparation for ruminants comprising:

• a core preparation,
• said core preparation containing from 50% to 90% by weight of said core preparation a biologically-active substance,
• said biologically active substance being dispersed in from 10% to 50% by weight of a protective substance,
• said protective substance containing a first substance and a second substance in a ratio of said first substance to said second substance of from 30:70 to 10:90,
• said first substance containing at least one selected from the group consisting of a linear or branched, saturated or unsaturated aliphatic C8-24 monocarboxylic acid, a linear or branched, saturated or unsaturated aliphatic C8-24 alcohol, and a linear or branched, saturated or unsaturated aliphatic C2-8 di- or tri-carboxylic acid,
• said second substance containing at least one of a linear or branched, saturated or unsaturated aliphatic C12-24 monocarboxylate;
• and
• a coating layer applied onto said core preparation,
• said coating layer containing at least one selected from the group consisting of a linear or branched, saturated or unsaturated aliphatic C12-24 monocarboxylate, polymers being insoluble in a neutral pH but soluble in an acidic pH, and zein.