What are Sweet-Cream and Cultured Butters?

American butters are made with sweet cream. Indian butters are cultured

In United States, the cream is harvested from the top of the raw whole milk. It is called sweet cream. The butter is made from 'sweet cream' and sold as 'salted' or 'un-salted'.
In India, the milk is fermented with culture same as making Dahi yogurt. The butter is extracted from cultured milk and it is called Makhan or Cultured Butter. The cultured butter may be sold 'salted' or 'un-salted'. Cultured butter is also available in most of the Europe.
Lately, some stores in United States have started to sell 'cultured butter', however, it is done by adding lactic acid to the sweet cream butter. It has no live culture.
Butter has about 81% fat.