Grass-based feeding strategies for organic growing-finishing pigs

Summary in the original language of the document

Freshly cut grass-clover (GC) as roughage and biorefined GC protein has been proposed to mitigate the negative climate impact of European pig production. This study aimed to document the effect on productivity of GC-based feeding strategies for organic growing-finishing pigs from 30-110 kg during temperate summer and winter conditions. 135 piglets were randomly assigned to diets with combinations of concentrate (soy press cake or biorefined GC protein) and roughage (freshly cut GC, GC silage or GC pulp silage). Substituting soy with biorefined GC did not impact feed intake, daily gain, or feed conversion ratio (FCR). A higher meat percentage was obtained during the summer trial compared to winter (62.8% vs 61.9%, P = 0.02). Lysine content in the GC concentrate could be reduced by 10% without negative effects on animal performance. The FCR was similar across all diets, but higher during the winter trial (2.87 vs 2.48 kg feed kg gain-1, P = 0.01). Freshly cut GC provided more crude protein (CP) to the pigs than GC silage and pulp (2.45, 1.88, 1.23 g day-1, respectively P < 0.01).
The GC-based concentrate can maintain the productivity of organic growing-finishing pigs during summer and winter conditions and may thus be a sustainable alternative to soy.