Intake, digestibility, rumen fermentation and performance of beef cattle fed diets based on whole-crop wheat or barley harvested at two cutting heights relative to maize silage or ad libitum concentrates

• Published in: Animal feed science and technology Vol. 144; no. 3; pp. 257 - 278
• Main Authors: Walsh, K., O’Kiely, P., Moloney, A.P., Boland, T.M.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.07.2008; [New York, NY]: Elsevier Science; Elsevier
• Subjects: Ad libitum concentrates; ad libitum feeding; animal performance; beef cattle; Biological and medical sciences; carcass characteristics; cattle feeding; corn silage; Cutting height; diet; digestibility; experimental diets; Feed and pet food industries; feed barley; feed concentrates; feed grains; feed intake; Food industries; Fundamental and applied biological sciences. Psychology; harvesting; Hordeum vulgare; Maize; rumen fermentation; ruminant nutrition; Triticum aestivum; wheat; whole crop silage; Whole-crop barley; Whole-crop wheat; Zea mays; DOMD; PRF; Whole-crop barley; Whole-crop wheat; DM; WCW; Maize; LW; VFA; ADFom; A w; ME; SMEI; DMD; Cutting height; aNDFom; OM; Ad libitum concentrates; KO; HCB; MS; WSC; FCE; CP; WCB; ALC; HCW; TR; ATR; Barley; Digestive system; Harvesting; Corn; Rumen; Fermentation; Cutting; Vertebrata; Mammalia; Diet; Silage; Beef cattle; Cereal; Height; Artiodactyla; Performance; Wheat; Ungulata; Digestibility
• ISSN: 0377-8401; 1873-2216
• DOI: 10.1016/j.anifeedsci.2007.10.018

This experiment aimed to quantify the relative intake, digestibility, rumen fermentation, performance and carcass characteristics of beef cattle fed diets based on good quality whole-crop wheat and barley silages, each harvested at two cutting heights, and to rank these relative to good quality maize silage and an ad libitum concentrates-based diet. Ninety beef steers, initial live-weight 438 ± 31.0 kg, were allocated to one of the following dietary treatments in a randomised complete block design: maize silage (MS), whole-crop wheat harvested at a normal cutting height (WCW) (stubble height 0.12 m) or an elevated cutting height (HCW) (stubble height 0.29 m), whole-crop barley harvested at a normal cutting height (WCB) (stubble height 0.13 m) or an elevated cutting height (HCB) (stubble height 0.30 m), each being supplemented with 3 kg concentrates/head/day, and ad libitum concentrates (ALC) supplemented with 5 kg grass silage/head/day for the duration of the 160-day study. Mean dry matter (DM) of the maize silage, whole-crop wheat, head-cut wheat, whole-crop barley and head-cut barley was 301, 488, 520, 491 and 499 g/kg, respectively. There were no differences in total DM intake among treatments, or in rumen fermentation characteristics (except ammonia), or in DM digestibility among the forage-based treatments. Neutral detergent fibre digestibility was lower (P<0.05) for whole-crop wheat than head-cut barley, and starch digestibility was lower (P<0.05) for whole-crop barley and head-cut barley than maize silage. Steers fed ALC had a higher carcass gain (P<0.001) and carcass weight (P<0.05) than all other treatments, but there were no differences between any of the forage-based treatments. Steers fed MS had a better feed conversion efficiency (FCE) than those on WCW or WCB (P<0.05) but were similar to HCW and HCB. The FCE was better for ALC versus any of the other treatments, particularly compared to WCW or WCB (P<0.001). Subcutaneous fat from steers fed ALC was more yellow (P<0.01) than that from steers fed the other treatments. Neither intake nor performance were altered by raising the cutting height of cereals or by replacing whole-crop wheat by barley. However, head-cut cereals numerically favoured DM intake, carcass gain and feed conversion efficiency values nearer to that of maize than whole-crop cereal silages. Ad libitum concentrates supported superior levels of growth by steers compared to all other treatments.