Fresh grass clover intake and energy metabolism in organic sows fed a control or a low protein compound feed in winter and summer

Summary

A control and a low dietary protein strategy was tested in 47 organic 1st and 2nd parity sows in winter and summer under Danish weather conditions. Sows on the low protein strategy ingested more fresh grass clover than the control group in summer (2.60 kg/d vs. 2.29 kg/d; P = 0.007). The mean SID lysine intake from grass clover amounted to 21 g/d in gestation, which is well above the daily SID lysine requirement throughout pregnancy. There were no differences between the two dietary regimens on sow productivity, body composition, locomotive activity or blood- and urine metabolites (data not shown; P>0.05) in both seasons. The daily intake of protein- and amino acid exceeded the requirements during pregnancy, also when sows were fed the low protein compound feed, but the low protein diet supplied insufficient SID lysine during lactation, which compromised the milk production. Sows lost 794 g/d of body fat in the period from d5 to d40 in lactation and the energy requirement amounted to 120 MJ ME/d at peak lactation. In conclusion, sows with access to pasture can be fed lower protein during gestation and also in lactation during summer.