Interrelations between herbage yield, α-tocopherol, β-carotene, lutein, protein, and fiber in non-leguminous forbs, forage legumes, and a grass-clover mixture as affected by harvest date.

Abstract

Pastures with diverse botanical composition may enhance animal-derived product quality. A recent study demonstrated high vitamin concentrations and yields in some forb species. The objectives of the present study were to investigate interrelations between herbage yields, vitamin concentrations, protein and fiber contents and analyze the effect of harvest date. We hypothesized that interrelations would be similar across investigated forage species. Four nonleguminous forbs: salad burnet (Sanguisorba minor), caraway (Carum carvi), chicory (Cichorium intybus), and ribwort plantain (Plantago lanceolata), three legumes: yellow sweet clover (Melilotus officinalis), lucerne (Medicago sativa), and birdsfoot trefoil (Lotus corniculatus) and a perennial ryegrass (Lolium perenne)-white clover (Trifolium repens) mixture were sown in a field trial with two replicated and randomized blocks. Forage in 1.5 m × 9 m plots was grown in two consecutive years and cut four times per year (May-October). Analyses of variance were performed. In most herbages, α-tocopherol and β-carotene were positively correlated as were β-carotene and lutein; all vitamins were negatively correlated with fiber content and herbage yield. β-Carotene was positively correlated with protein content. α-Tocopherol and β-carotene contents were generally highest in October and lowest in July. Our results showed similar interrelationships in most investigated species, and we suggest that these species may be mixed when designing novel biodiverse mixtures for particular product quality characteristics.