Die bumsfidelen Mädchen vom Birkenhof(1974)

Three sexy sisters take care of their guest house, on a scenic hill in Birkenhof, Switzerland. A young man, vigorous mountain biker, arrives to take a rest, and the girls are all over him. The two older sisters decide to fight, nude, all-in on the hay of the barnyard - and while they are at it, the younger and quicker sister is already in bed with their guest! The cow participates in a quick, undignified end to the female wrestling match...