Fat and whey supplementation influence milk composition, backfat loss, and reproductive performance in lactating sows.

This study investigates the effects of microencapsulated fat (FAT) and whey protein (WHEY) supplementation on the milk composition, backfat loss, and reproductive performance in lactating sows. A total of 144 sows were divided according to their backfat thickness at farrowing into three groups, i.e., low (12.0-16.5 mm, n = 33), moderate (17.0-21.5 mm, n = 78), and high (22.0-24.5 mm, n = 33). The lactation diet was divided into three types, i.e., a control diet (CONTROL, n = 50), a diet supplemented with FAT (n = 48), and a diet supplemented with WHEY (n = 50). Pooled milk samples were collected at the second and third week of lactation. On average, the sows lost backfat 23.5 % during lactation. The backfat loss during lactation was 24.5, 22.7, and 22.8 % in sows fed with CONTROL, FAT, and WHEY diets, respectively (P > 0.05). Supplementation of FAT increased the percentage of fat in the sow's milk compared to the CONTROL (9.1 and 8.4 %, P = 0.022). For sows with low backfat, FAT and WHEY supplementation increased the average daily gain of piglets compared to the CONTROL (244, 236, and 205 g/days, respectively, P < 0.05). For sows with high backfat, the sows receiving the CONTROL diet had a higher total piglet mortality than those that received FAT or WHEY (28.1, 14.1, and 13.0 %, respectively, P < 0.05). It could be concluded that supplementation of FAT in the diet of sow during lactation significantly enhanced the fat content in the sow's milk, improved the piglet's daily weight gain, and reduced piglet mortality.