Rovimix Hy.D Premix: Hy.D is a metabolite of vitamin D3, 25-hydroxycholecalciferol [25-OH-D3]. Hy.D provides a more bioactive form of vitamin D3 to the animal, which has proven advantages over vitamin D3: improvements in weight gain, feed efficiency, bone development, bone mineral density, sow fertility, boar semen quality, shell quality, laying persistence and reductions in bone disorders.