The region’s efforts have been especially focused on protecting its “superstuds” — bulls that have been carefully selected to produce calves with the optimal fattiness.

The studs, picked by local agricultural officials in a multiyear selection process, are monitored for the quality of meat from their offspring. Only one or two bulls out of the nearly 39,000 bulls born in the prefecture each year eventually attain superstud status. Tadafuji, the best superstud in recent memory, sired 220,000 calves, local officials say.