Lucerne (Medicago sativa) plant tips as protein feed for lactating sows in an organic farming system

Lucerne is a very interesting feed for sows in organic pig production because it is rich in the essential amino acids lysine and methionine. The amount of protein can be increased through innovative harvesting methods as the so-called lucerne plant tips can be separated from the rest of the plant (crude protein: 274 g/kg dry matter (DM)). The present feeding trial evaluated the use of hot-air dried lucerne plant tips as a protein source for lactating sows in an organic farming system. Twenty-two lactating sows were fed either a control concentrate mixture or a test concentrate mixture containing lucerne plant tips (20%, based on fresh matter) during an average lactation period of 45.8 days. The daily feed intake, the growth rate of the piglets, and the change in backfat were measured. Due to the sows’ high initial backfat thickness (control group: 26.7 mm and lucerne group: 29.3 mm, p = 0.22), the daily feed intake was low in both groups. Additionally, the test group showed significantly lower energy intake (control group: 81.4 MJ ME/d; lucerne group: 65.8 MJ ME/d, p < 0.0001), indicating the need for acclimatization to lucerne plant tips in the gestation period. Nevertheless, a lower growth rate of the piglets was not detected (control group: 268 g and lucerne group 254 g, p = 0.33). On day 42, the piglets’ individual weight for the control and lucerne groups was 13.6 kg and 13.3 kg, respectively (p = 0.623). This underlines the resilience of lactating sows.