Methane emission by goats consuming different sources of condensed tannins

TitleMethane emission by goats consuming different sources of condensed tannins
Publication TypeJournal Article
Year of Publication2008
AuthorsAnimut, G, Puchala, R, Goetsch, AL, Patra, AK, Sahlu, T, Varel, VH, Wells, J
JournalAnimal Feed Science and Technology
Pagination228 - 241
Date PublishedJan-07-2008

Twenty-four yearling Boer × Spanish wethers (7/8 Boer; initial body weight (BW) of 37.5 ± 0.91 kg) were used to assess effects of different condensed tannin (CT) sources on methane (CH4) emission. Diets were Kobe lespedeza (Lespedeza striata; K), K plus quebracho providing CT at 50 g/kg dry matter (DM) intake (KQ), Sericea lespedeza (Lespedeza cuneata; S), and a 1:1 mixture of K and S (KS). Forages harvested daily were fed at 1.3 times the maintenance metabolizable energy requirement. The experiment was 51 days divided into two phases. In phase A forage diets were fed alone, and in phase B, 25 g/day of polyethylene glycol (PEG) was given mixed with 50 g/day of ground maize grain. Adaptation periods were 28 and 7 days in phases A and B, respectively. After adaptation there were 8 days for feces and urine collections, with gas exchange measured on the last 2 days. Ruminal fluid was collected at the end of the experiment via stomach tube for microbiology assays. The N concentration was 22.8 and 23.6 g/kg DM, in vitro true DM digestibility was 0.698 and 0.648, and the level of CT was 140 and 151 g/kg DM for S and K, respectively. DM intake was similar among treatments in both phases (phase A: 720, 611, 745, and 719 g/day (SE = 59.0); phase B: 832, 822, 867, and 880 g/day (SE = 55.3) for K, KQ, S, and KS, respectively). N digestibility was affected by treatment in phase A (P < 0.05) but not in phase B (phase A: 0.514, 0.492, 0.280, and 0.413 (SE = 0.0376); phase B: 0.683, 0.650, 0.638, and 0.662 (SE = 0.0203) for K, KQ, S, and KS, respectively). Gross energy digestibility was similar among treatments in phase A (0.475, 0.407, 0.393, and 0.411 (SE = 0.0353)) but differed among treatments in phase B (0.449, 0.373, 0.353, and 0.409 for K, KQ, S, and KS, respectively (SE = 0.0221)) CH4 emission was 9.6, 6.8, 10.6, and 8.9 l/day (SE = 1.44) in phase A and 19.0, 16.6, 21.8, 19.2 l/day (SE = 1.51) in phase B for K, KQ, S, and KS, respectively (SE =1.25). When data of both phases were pooled, supplementation with PEG in phase B markedly increased (P < 0.05) CH4 emission (9.0 versus 19.1 l/day). In accordance, there was a substantial difference (P < 0.05) between phases in in vitro CH4 emission by ruminal fluid incubated for 3 weeks in a methanogenic medium and with other conditions promoting activity by methanogens (11.5 and 22.9 ml in phases A and B, respectively). Counts of total bacteria and protozoa were similar among treatments in both phases, but values were greater (P < 0.05) in phase B versus phase A. In summary, CT from different sources had a disparate influence on N digestion, but similar effects on ruminal microbial CH4 emission by goats, possibly by altering activity of ruminal methanogenic bacteria though change in actions of other bacteria and/or protozoa may also be involved.

Short TitleAnimal Feed Science and Technology