Grass intake of sows quantified by plasma metabolites

Summary

Outdoor sows ingest grass during the summer, but the digestibility and intake of grass is unknown. Currently, feed for outdoor sows is therefore formulated based on nutrient recommendations for indoor sows even though the energy- and protein requirements differ substantially between these production systems. Ignoring the energy and nutrients supplied from grazing may lead to poor feed efficiency and nitrogen leaching. Digestibility of dry matter, organic matter, nitrogen and energy in grass was high (64 to 72%). Grass intake in sows was found to be highly correlated with plasma Pipecolic acid (Y = 0.93X+0.29; r=0.91) and with plasma Bisnorbiotin (Y = 5921X-232; r=0.90).