What historic factor, rather than wartime losses, caused the gradual decline in the Picard population?

Answer

Gradual decline in the necessity for their traditional farm work

The population decline was gradual, stemming from the reduced need for their traditional duties on farms, combined with breeders prioritizing purity over rapid growth.

What historic factor, rather than wartime losses, caused the gradual decline in the Picard population?
DogbreedBerger Picard