Effects of maturity stage at harvesting of intercropping whole plant faba bean (Vicia faba) with whole plant oat (Avena sativa) silage on the nutritional values for dairy cows

Studies have shown positive results from faba bean forage and legume–cereal intercropping in cow performance. This study aimed to evaluate the effects of maturity stages (MS) on intercropped faba bean ( Vicia faba, CDC Snowbird)–oats ( Avena sativa, CDC Haymaker) silage. Oats and faba beans were seeded together in Outlook, SK, CA. The faba–oat crop was manually harvested from three plots on days 62 (MS1), 72 (MS2), and 82 (MS3). Wilted samples were chopped (1 in. length) and packed into mini silos ( n = 9). The dry matter (DM) content after wilting was 261, 355, and 421 g/kg for MS1, MS2, and MS3, respectively ( P < 0.01). The crude protein (CP) and carbohydrates (CHO) contents (g/kg DM) in the silage were higher for MS2 and MS3 than for MS1 ( P < 0.05). The net energy for lactation (NE Lp3x ) for MS2 and MS3 was 1.17 and 1.23 Mcal/kg, respectively ( P < 0.01). The silage pH was 6.96 for MS1 and averaged 4.66 for MS2 and MS3 ( P < 0.01). The rumen degradable neutral detergent fibre for MS2 and MS3 averaged 157 g/kg DM ( P = 0.02). Harvesting faba bean–oat forage between 72 and 82 days seems promising to produce good quality silage for lactating dairy cows.