Effect of Particle Length and Sodium Hydroxide Treatment of Wheat Straw on Site and Extent of Digestion by Lambs

Abstract

Summary Two lamb trials were conducted to determine the effects of particle length (PL; 2.5 vs 10 cm) and sodium hydroxide (NaOH) treatment (0 vs 4%) of wheat straw on dry matter (DM) intake and site and extent of DM and neutral detergent fiber (NDF) digestion. Lambs in the first trial were fed ad libitum once daily. Lambs in the second trail were fed four times/d at 6-h intervals and were sacrificed after 7 d of fecal collection to determine site of digestion. For both trials, NaOH increased (P .10), lambs fed 2.5-cm, NaOH-treated straw appeared to have a greater percentage of total NDF digestion occurring postruminally than lambs fed untreated straw, suggesting an increased flow of potentially digestible fiber to the hindgut. This is supported by a shorter ruminal retention time of digesta in lambs fed the 2.5-cm, NaOHtreated straw. Ruminal volatile fatty acid concentrations were greater for NaOH-treated straw diets, which reflect the site of digestion results. Results of the present study suggest