Analysis of reproductive seasonality in Entrepelado and Retinto Iberian pig varieties under intensive management

•Farrowing distribution can be properly analyzed by von Mises circular mixed models.•Iberian sows under intensive management practices have low reproductive seasonality.•The parity number delays (adult sows) or advances (gils and old sows) farrowing peak.•Farrowing distribution in Iberian sows have small or null genetic background.