Protein content — common vetch

The protein concentration in the tissues of common vetch varies significantly depending on the morphological part of the plant. The highest values are characteristic of seeds, where the protein content ranges from 25% to 37%. In green mass during the flowering phase, this figure is in the range of 20–22%, in hay it reaches 18–22%, whereas in straw it decreases to 6–10%.

The high nutritional value of the crop is due to the presence of essential amino acids such as lysine, tryptophan, and threonine. Protein accumulation is closely linked to nitrogen fixation processes, which makes vetch an effective component of mixed agrocenoses. At the same time, the full utilization of its fodder potential is limited by the presence of anti-nutritional factors in the plant, such as cyanogenic glucosides and trypsin inhibitors.

To achieve maximum nutritional value, the crop is harvested at the beginning of the mass flowering phase, as delaying the harvest leads to a decrease in protein concentration. Laboratory assessment of raw material quality is carried out primarily by the Kjeldahl method or by express analysis using NIR spectroscopy.