The net contribution of ruminant production to the protein supply for humans

Total protein conversion efficiency of ruminant production systems is low (between 0.05 for meat and0.25 for milk), but this calculation usually does not differentiate human-edible from human non-ediblefeedstuffs (e.g. grass, by-products of food and biofuels industries). To evaluate the net contribution ofruminant livestock to protein production for human consumption in France we estimated the humanedibleprotein Fraction (hepF) of the diets and the net protein efficiency (human-edible proteinefficiency) from six contrasting feeding systems in dairy, beef cattle and sheep systems. The hepF valuesof diets ranged from 3% (extensive sheep production) up to 26% (intensive dairy cattle production). Thenet protein efficiency ranged from 0.34 (intensive sheep production) up to 2.57 for grass-based dairycattle production with low concentrate consumption. Each type of ruminant production can producemore edible protein than they consume (net protein efficiency > 1). The use of grass and by-products arethe key factors to improve the net contribution of ruminant production to protein supply for humans