Herbage yield, leafiness and water-soluble carbohydrate content, and silage composition and utilization in sheep of first- and second-cut Italian and Westerwolds ryegrasses (Lolium multiflorum Lam.)

Abstract

Italian ryegrasses, cultivars Barmultra and Lemtal, and Westerwolds ryegrasses, cultivars Barspectra, Merwester and Promenade, (Lolium multiflorum Lam.) were harvested as first- and second-cut herbages and compared for yield, leafiness and water-soluble carbohydrate content during the 2-yr study. These herbages were conserved as silages and compared for chemical composition and for intake, digestibility, and total-N retention in sheep. First-cut ryegrass yielded more dry matter than second-cut ryegrass (3.3 vs. 2.6 t ha−1). First-cut ryegrass silages contained less dry matter and NDF, and sheep consumed less, but digested better and retained less total-N in comparison with second-cut ryegrass silage. Italian ryegrasses yielded less dry matter, were more leafy, contained less ADF, and were better digested compared with the Westerwolds ryegrasses. The herbage content of water-soluble-N, and the ratio of ammonium-N to total-N in silage were not different between the ryegrasses. Italian Barmultra was more leafy than Lemtal cultivar but no other significant differences were measured between these cultivars. Westerwolds Merwester yielded more dry matter, was less leafy, contained more NDF and ADF, and had lower voluntary intake, digestibility, and its total-N was less retained in sheep as compared with the Barspectra or Promenade Westerwolds ryegrass. Italian ryegrasses were superior in composition, voluntary intake, and digestibility to Westerwolds, but the latter were superior on the basis of yielding ability and efficiency of total-N utilization in sheep.Key words: Silage, ryegrass, intake, digestion, composition, Nitrogen retention