Supplementing lactation diets with herbal extract mixture during summer improves the performance of sows and nursing piglets

A total of 45 Landrace × Yorkshire multiparous sows were used to evaluate the effect of dietary herbal extract mixture (Scutellaria baicalensis and Lonicera japonica, HEM) supplementation in lactating sows under heat stress. Sows were randomly allotted to 1 of 3 dietary treatments: 1) CON, basal diet; 2) TRT 1, basal diet with 5 g/d HEM; 3) TRT 2, basal diet with 10 g/d HEM. During lactation, dietary HEM supplementation linearly increased (P<0.05) the average daily feed intake (ADFI) and linearly decreased (P<0.05) backfat loss. The digestibility of dry matter (DM) was increased after farrowing (linear, P<0.05; quadratic, P<0.05) and weaning (linear, P<0.05) by HEM supplementation. Furthermore, HEM treatment led to a lower (linear, P<0.01) serum cortisol level. In addition, administration of HEM improved (linear, P<0.05) the piglets weaning weight and overall average daily gain (ADG) during suckling period. Meanwhile, on day 7 and 14 after birth, the fecal score of piglets was decreased (linear, P<0.01) by HEM supplementation. Taken together, under high ambient temperatures, inclusion of HEM to lactation diets could improve the feed intake, digestibility of DM, piglets weaning weight and ADG, while decreasing backfat loss, serum cortisol level, as well as the diarrhea of piglets.