Alpine transhumance has a strong impact on the production of cheese in the Alps. It ensures that cows, sheep and goats produce high-quality aromatic milk, the so-called Heumilch (hay milk), based on their special diet of natural meadow grasses. The use of hay milk in cheese production contributes to the distinctive flavour that determines more than 30 Alpine cheeses, including Alpkäse, Bergkäse and Sura Kees. The chief shepherd in charge of the Alp and responsible for the cheese production is known as the Senn.