Factors associated with stillborn and mummified piglets in high-prolific sows

Stillbirth concerns about 2.5 million piglets each year in France and is expected to worsen in the coming years, due to hyperprolific sows. The present study was performed to determine the risk factors of the presence of stillborn piglets or mummies in the litter using data from three experimental herds. From June 1999 until June 2000, sow, stillborn and mummy characteristics were closely recorded around farrowing. Information was recorded on 455 litters, from 308 sows. After selection, a total of 447 litters, originating from 302 crossbred (Large White $\times$ Landrace) sows were used. Two hundred and fifty-five litters had no stillborn. Neither individual piglet body weight nor variability of piglet body weight within litters were found to influence stillbirth. A reduction in the average litter or sow live weights increased the probability of having a stillbirth. When a full litter was born with a human presence, the proportion of litters without a stillborn was higher than in cases of partial supervision (65.7 vs. 4.5 to 45.6%). At the same time, the number of litters with two or more stillborn piglets was lower (11.2 vs. 23.6 to 30.9%). Only 46% of the litters had no stillborn when no supervision was performed. These results indicate that good supervision (more than 75% of births with a human presence) decreased stillbirth in pigs, while individual piglet weight did not alter it. A reduction in litter live weight decreased the risk of having mummies, whereas an increased litter size had the opposite effect. Facteurs associés à la présence de porcelets momifiés ou mort-nés dans les portées de truies hyperprolifiques. La mortinatalité touche chaque année 2,5 millions de porcelets en France et devrait augmenter encore dans les années à venir, à cause de l'introduction des truies hyperprolifiques dans les troupeaux. L'objectif de cette étude est de déterminer les facteurs de risques liés à la présence de porcelets mort-nés et momifiés dans une portée, à partir d'observations réalisées dans trois stations expérimentales. De juin 1999 à juin 2000, les informations autour de la mise bas concernant les truies, les porcelets mort-nés et momifiées sont enregistrées. Ces informations sont disponibles sur 455 portées, issues de 308 truies. Après sélection, 447 portées provenant de 302 truies croisées (Large White $\times$ Landrace) sont utilisées. Au total, 255 portées n'ont pas de porcelets mort-nés. Le poids individuel du porcelet et la variabilité du poids ind