What external factor led to the Swedish Vallhund facing near extinction by the 1940s?

Answer

The modernization of farming practices

The breed's numbers declined significantly because farming became modernized in the 20th century, reducing the need for traditional, all-around farm dogs.

What external factor led to the Swedish Vallhund facing near extinction by the 1940s?
DogancestrybreedCanineSwedish Vallhund