Perinatal piglet mortality is a significant economic and animal welfare concern in pig production. This study expands a recursive binomial model in two ways: (1) allowing recursive phenotypic dependence among traits to vary across crosses, and (2) replacing the binomial distribution with the multiplicative binomial distribution to account for overdispersion. Five models were applied to a diallel cross among three Iberian pig varieties. Results showed overdispersion, with the best-fitting model indicating that piglet mortality increases with litter size. Maternal effects and heterosis were analyzed, revealing that dams with EE mothers had higher stillbirth rates, while RR mothers reduced this probability. Heterosis reduced stillbirths in crossbred sows. The multiplicative binomial distribution proved a useful alternative when data overdispersion is present.

Luis Varona, José Luis Noguera, Joaquim Casellas, Melani Martín de Hijas, Juan Pablo Rosas, Noelia Ibáñez-Escriche