Feed protein value of acidic precipitates obtained from press juices of three types of green forage leaves

The present study investigated the potential of three types of green forage leaves for the extraction of a protein rich precipitate. Samples were taken during calendar weeks 19, 21 and 23 of 2012 from three grass rich pastures (GRP), two legume rich pastures (LRP) and one Trifolium pratense (TP) monoculture around the City of Freising (Germany) (n = 9, n = 6 and n = 3 samples of GRP, LRP and TP). Trifolium pratense and LRP yielded the highest average amounts of precipitate per kg fresh leaf material. The highest amounts of crude protein (CP) within the precipitate were obtained from TP and GRP. Contents of essential and non-essential amino acids (AA) were highest within the precipitates of TP. The extraction efficiency as expressed by total precipitate yield, precipitate CP as well as the amounts of essential and non-essential AA declined in the course of plant development. The amounts of essential AA relative to total AA within the obtained precipitates were in most cases comparable or even higher than average amounts in soybean meal (480 g CP/kg fresh matter). Taken together, we were able to extract a CP rich precipitate from green forage leafs. Products of that kind represent a valuable protein source and may replace soybean meal to some extent in practical livestock diets.