Abstract: [Objective] This study aimed to assess the effects of parity, body condition score and backfat thickness on reproductive performance of sows in late pregnancy. [Method] A total of 654 Dannish sows in late pregnancy （109 d of gestation） were selected from the same production batch, and were grouped according to the parity （1-3 parity groups）, body condition score （1-5 score groups）, and backfat thickness （≤ 10 mm group, 11-15 mm group, 16-20 mm group, 21-25 mm group, and > 25 mm group）. The first parity group, body condition score 3 group, and backfat thickness 16-20 mm group were used as the control groups, and the other groups within the same indexes were used as the experimental groups. The data of body condition score, backfat thickness and parity as well as total number of piglets born, live litter weight, number of live piglets, number of healthy piglets, number of weak piglets, number of mummified fetus, and number of stillborn piglets were all entered and processed by the linear mixed model of IBM SPSS Statistics 26.0 statistical software. [Result] With the increased parities of the pregnant sows, the total number of piglets born, live litter weight, number of live piglets, and number of healthy piglets exhibited a significantly （P<0.05） increasing trend. When the backfat thickness of the sows in late pregnancy was in the range of 16-20 mm, the total number of piglets born, number of live piglets, and number of healthy piglets reached the maximum values, while the number of weak piglets and number of stillborn piglets reached the minimum values. When the backfat thickness of the sows in late pregnancy was in the range of 21-25 mm, the number of weak piglets, number of mummified fetus, and number of stillborn piglets were all elevated. When the body condition score of the sows in late pregnancy was 4, the total number of piglets born, number of live piglets, and number of healthy piglets were the highest. [Conclusion] Parity, body condition score and backfat thickness of sows in late pregnancy all have impacts on litter performance and can serve as important references for predicting sow reproductive performance.

Key words: body condition score, backfat thickness, parity, reproductive performance, late pregnancy, sow