RUMINAL FERMENTATION, DIGESTIBILTY AND METHANE PRODUCTION IN SHEEP FED WITH FOUR LEVELS OF CORN STOVER

Abstract

The objective was to evaluate four inclusion levels of corn stover (CS): T15, T30, T45 and T60 %, on ruminal fermentation, digestibility (D) and methane production in sheep. A 4 x 4 latin square experimental design was used, with four wethers with ruminal and duodenal cannula, and four periods of 14 days. Feed was offered at 2.2 % of live weight, in two portions day-1. Total concentration of VFA were similar (P>0.05) in T15, T30 and T45, but higher (P<0.01) in T15 (103.7) than in T60 (67.6 mmol L-1). VFA molar proportions were similar (P>0.05) between treatments, with a mean of 66.4, 20.9 and 12.8 % for acetate, propionate and butyrate, respectively. DMD was higher (P<0.01) in T15 (75.3 %) than in others (67.2 %), but OMD differed only between T15 and T60: 61.9 % vs 47.5 %. CPD averaged 62.0 %. NDFD was higher (P<0.01) in T15 (55.0 %) than in others (37.5 %). Estimated methane production did not differ (P>0.05) between treatments, with a mean of 0.61 mol mol-1 of fermented glucose equivalent, but if expressed in mol kg-1 of fermented OM, there were differences (P<0.01) only between T15 and T60:1.30 vs 1.65. Mayor differences were between T15 and T60: it is possible to include until 45 % CS without affecting efficiency and without increasing methane production.