Carbohydrate and protein fractions of fresh and dried common vetch at three maturity stages

Mixed cereal and sheep (Ovis aries) production systems in the Mediterranean area and the Middle East region rely on annual forage legumes as a source of complementary forage. Fractionation of carbohydrates (CHO) and crude pro tein (CP) into chemical entities of refined biological significance may imp rove the forage utilization of these feed resources. Fresh and dried (field -cured) common vetch (Vicia sativa L.) samples were collected during two gr owing seasons (1996-1997 and 1997-1998) at La Poveda Field Station in centr al Spain with the objective of determining chemical CHO and CP fractions re quired for application of new feed models (Cornell System). Fresh and dried samples were harvested at three maturity stages-flowering (>50% of plants with flowers), seed filling phase 1 (280 g DM kg(-1) seed), and seed fillin g phase 2 (380 g DM kg(-1) seed)-and the treatments were arranged in a comp letely randomized design. Nonfiber carbohydrates (NFC) and neutral-detergen t fiber (NDF), corrected for neutral-detergent insoluble protein (NDIP), we re evenly distributed in fresh and dried samples, and were not affected by maturity. The B-1 and B-2 CHO fractions were the most abundant with mean va lues of 342 and 303 g kg(-1) of total carbohydrates (TC), respectively, acr oss maturities, harvest forms, and years. Fraction CP B2 was the most abund ant CP fraction with mean value of 408 g kg(-1) of total CP. Fraction CP B- 3 was <100 g kg(-1) of total CP and increased with maturity. Harvesting com mon vetch within the seed filling phase would increase ruminal escape prote in in vetch.