Not really a holiday, but one of the most fun festivals I have ever attended in Austria, was the Almabtreib.
The Almabtrieb (drive from the mountain pasture) is an annual event in the alpine regions in Europe, referring to a cattle drive that takes place in late September or early October.
During summer, all over these alpine regions, herds of cattle feed on the alpine (Almen in Austria) pastures high up in the Alps. The heads of cattle number about 500,000 in Austria, 380,000 in Switzerland, and 50,000 in Germany.
While there is often some movement of cattle between the Almen, or Alpen respectively, during the summer, there is usually one concerted cattle drive in the autumn to bring the cattle to their barns down in the valley. If there were no accidents on the Alm during the summer, in many areas the cattle are decorated elaborately, and the cattle drive is celebrated with music and dance events in the towns and villages. Upon arrival in the valley, joint herds from multiple farmers are sorted in the Viehscheid, and each animal is returned to its owner.
In many places this Alpine custom of Almabtrieb has today evolved into a major tourist attraction, with a public festival, and booths set up along the course for selling agricultural, as well as artisans', products along with alcoholic beverages.
In the spring, the reverse cattle drive moves from the valley barns to the Alp (in Switzerland: Alpaufzug, Alpfahrt, Alpauffahrt; in Germany/Austria: Almauftrieb), which is celebrated in Switzerland, but not in Germany nor Austria.
The photos in this post are of the Almabtrieb when we visited Achensee Austria. It was such great fun.
I found a great video on the Almabtrieb: See https://youtu.be/nDRuXWj2QBI