The Relationship Between Placental Efficiency And Reproductive Performances In Landrace×Large White Sows

The relationship between placental efficiency and reproductive performances in LandraceXLarge White Sows was analyzed. The placentas and the piglets of the LandraceXLarge White Sows were weighted immediately after the piglets were born and when their hair was dried. The relationship between placental efficiency and litter size, the number of live births, the number of stillborn , the mummified fetuses, litter weight at birth were compared. The relationship between placental acreage, placental thickness and litter size in Landres X Large white were determined.To study the genetic characteristics of the placental efficiency, high placental efficiency LandraceXLarge White Sows (Ti)and low placental efficiency LandraceX Large White Sows (T2) were artificial insemination with Duroc boars semen respratively, their progenies were analyzed. The results showed that:1. The litter size of high placental efficiency group (H1) and medium placental efficiency group (H2) of LandraceXLarge White Sows was higher than that of low placental efficiency group (H3) significantly (PCO. 01), the litter size of H1 was higher than that of H2 too (P<0.01) ; the number of live births of H1 and H2 were higher than that of H3 (P<0.01) ; The different of the placental efficiency among the three groups were highly significant (P<0.01).2. The different of litter size of Landrace X Large White Sows between parturition land parturition 3, 4, 5 was highly significant (P<0.01); the different of the number of live births of LandraceXLarge White Sows between parturition 1 and parturition 3 and 4 was highly significant (P<0.01); The difference of the number of stillborn between parturition 1 and parturition 2, 3 and 5 was significant (P<0.05); The different of number of mummified fetuses between parturition 3 and...