One fifth of Finnish beef is from beef-breed animals. The most common breeds are the Aberdeen Angus, Charolais, Hereford, Limousin and Simmental breeds of livestock, as well as crosses between these breeds. Cross-breeds are used to ensure optimal characteristics for the animals and, ultimately, for the meat. Production of beef is based upon suckler cows. They calve once per year and look after their young until they reach an age of 4–6 months. The milk of suckler cows is the most important nourishment that calves receive. In addition to this, the calves are fed coarse animal feed, minerals and mixed concentrated feed. Suckler cows and calves spend their summers on the pasture. By the end of the summer, the calves weigh half as much as the cows. When they reach an age of approximately six months, beef-breed calves are weaned and either transferred for finishing on their own farm or to a farm that specialises in finishing via Atria's calf intermediaries.