The title contains a pun, because the "versaute Hochzeitsnacht" (spoiled wedding night) Alois Brummberger (Muxeneder) is experiencing also involves a piglet (sau=sow) which some pranksters smuggled into his wedding bed. His new wife is busy anyway having sex with one of the wedding guests in the barn.
This episode is merely a distraction from the main plot involving an inefficient railway line, run by Sepp (Steiner) and Willi (Kleiber). When this line is threatened with closure they come up with the ingenious (oh well) plan to purchase it and run it as a brothel on wheels.
The plot idea clearly has not been thought through, on several levels. First, Sepp & Willi had apparently no difficulties whatsoever persuading a group of local beauties who ran a girls-only-farm to turn hooker. Secondly, they keep the fact that the new railway line is a brothel as a secret from the authorities - while everyone else seems to know, since they are not short of customers. And all of this seems even comparatively plausible when we look at the conclusion of the film...
In other words, this is one of those sex films one can only appreciate with the brain shut down to 25% capacity. With that constraint the film's fine: the girls are pretty, the humour is lowly low brow, the acting is competent, and the general production values are good.