Abstract

MEJIA-DELGADILLO, Mario A. et al. Digestion of wheat hay as compared to alfalfa and ryegrass in steers. Agrociencia [online]. 2011, vol.45, n.1, pp.13-21. ISSN 2521-9766.

Wheat (Triticum aestivum) is a major crop in the Valley of Mexicali, México. Based on its chemical composition, the entire wheat plant is considered of a quality similar to that of alfalfa (Medicago sativa) or to ryegrass (Lolium multiflorum). Digestion of wheat hay, grown for grain and harvested at two stages of growth (45 and 90 d), was compared with alfalfa hay (at intermediate flowering) and ryegrass hay (120 d after sowing). Four Holstein steers (326 ±20 kg BW) with ruminal and duodenal cannulas were used en a Latin square 4X4 design. The treatments (hays) were the following: 1) alfalfa, 2) ryegrass, 3) wheat harvested 45 d after sowing (T45d), 4) wheat harvested at 90 d (T90d). The steers fed T45d and T90d consumed less (p≤0.5) N (0.10 and 0.11 kg d^-1) than those fed alfalfa and ryegrass (0.16 and 0.19 kg d^-1). NDF duodenal flow (1.49 kgd^-1) was greater (p≤0.05) and that of N (0.15 dg d^-1) was lower (p≤0.05) in steers fed T90d. Also, the lowest (p≤0.5) ruminal (336 g kg^-1) and total (517 g kg^-1) digestion of organic matter (OM) was for T90d. Ruminal and total OM and NDF digestion of T45d was similar (p>0.05) to that of alfalfa and ryegrass and higher than wheat harvested at 90 d. It is concluded that digestion of wheat hay harvested at 45 d was similar to alfalfa and ryegrass hays, but superior to wheat harvested at 90 d.

Keywords : digestion; ruminal fermentation; duodenal flow; wheat.

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