Influence of bitter lupin on consumption and digestibility in organic dairy cattle soya bean free diets.

One of the main principles of organic husbandry is that animal feed must be GMO free, and soya bean is well-known as a high risk GMO alimentary source. About 25 dry dairy cattle of the Italian Holstein breed, from the Cooperativa Emilio Sereni of Borgo S. Lorenzo (FI), were fed in two successive diets: the first with extruded soya bean (A), and the second in which bitter lupin, faba bean and proteinic pea substituted the soya bean (B). We evaluated both the consumption and the apparent digestibility (using acid insoluble ash as internal marker) of the two diets, repeating the trial twice. The presence of bitter lupin did not influence either the consumption of other feed, or the faecal water content. The apparent digestibility of the organic matter resulted satisfactory in both the diets, but was significantly higher in diet (A) than in diet (B) (71,6% vs 67,3%). In conclusion, even though we wish the cultivation of sweet lupin would be increase in Italy, we retain that also bitter lupin (mixed with other feed to increase the palatability) could be used as alternative protein source in dairy cattle diets.