Pro Plan Medium Puppy with Optistart is a complete and balanced dry puppy food made for medium-sized puppies. It is also suitable for gestating or lactating mothers. Optistart contains colostrum proven to help strengthen a puppy's natural defences to combat daily challenges. The first year of your dog's life is crucial to their long-term health, which is why feeding them a complete dry puppy food can be so beneficial. To help support puppies' natural defences for an optimal start in life, Purina vets and nutritionists have developed Pro Plan Medium Puppy with Optistart, which contains colostrum found in mothers first milk. Colostrum is proven to support their immune system and proven to protect them from common intestinal upsets.