LAUSR

Abstract Sow milk is important for the survival and growth of suckling piglets. The reserved backfat of sows during late gestation may influence foetal development and milk synthesis. We investigated the effect of backfat thickness of sows at 109 days of gestation on farrowing duration, piglet birth weight, colostrum yield, milk yield and reproductive performance, using 73 sows and 1,291 piglets. Backfat thickness was measured when the sows entered the farrowing house at 109 days of gestation, using A-mode ultrasonography, and sows were classified into three groups: LOW (≤12.5 mm, n = 24), MODERATE (13 to 15 mm, n = 30) and HIGH (≥15.5 mm, n = 19). Sow parameters included backfat thickness at 10, 17 and 21 days postpartum, backfat loss during lactation, farrowing duration, total number of piglets born per litter (TB) and number of piglets born alive per litter (BA), proportion of stillborn piglets (SB) and mummified foetuses per litter (MM). Piglet parameters consisted of the birth interval and body weight of the piglets at 0,1,3,10 and 17 days postpartum. Colostrum intake of the piglets, colostrum yield and milk yield from days 3–10 and 10–17 of lactation were calculated and compared among groups of sows with different backfat thickness at 109 days of gestation. Farrowing duration and birth interval were 275.0 ± 187.5 and 14.8 ± 27.1 min, respectively. Both the duration of farrowing and the birth interval did not differ among sows with LOW, MODERATE and HIGH backfat thickness (P>0.05). Piglet weight at birth, TB, BA and MM did not differ among groups (P>0.05). However, SB in sow with LOW backfat thickness at 109 days of gestation was higher than sows with MODERATE (P = 0.024) backfat thickness. The proportion of stillborn piglets per litter in sow parities 3 to 6 was higher than in parities 1 and 2 (P