Location: Meats Safety & Quality ResearchTitle: Effects of different fresh-cut forages and their hays on feed intake, digestibility, heat production, and ruminal methane emission by Boer x Spanish goats) Author
|Wells, James - Jim|
Submitted to: Journal of Animal Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 2/19/2012
Publication Date: 8/1/2012
Citation: Puchala, R., Animut, G., Patra, A.K., Detweiler, G.D., Wells, J., Varel, V.H., Sahlu, T., Goetsch, A.L. 2012. Effects of different fresh-cut forages and their hays on feed intake, digestibility, heat production, and ruminal methane emission by Boer x Spanish goats. Journal of Animal Science. 90(8):2754-2762. Interpretive Summary: This study was conducted to determine if fresh or hay forages with low and high levels of tannins would affect rumen activities differently. Three sources of fresh or hay forages were fed; a grass which has low condensed tannins, alfalfa which has an intermediate level of tannins, and a legume which has a high level of tannins. The latter treatment was fed with and without a supplement of polyethylene glycol (PEG). The PEG is known to bind tannin compounds, and tannins are thought to reduce methane production. Results indicate that feeding the legume containing the high level of tannins reduced methane production and nitrogen digestibility the most. If PEG was supplemented to this diet, PEG increased nitrogen digestibility but little effect on methane production, indicating that tannin mode of action may differ. It is concluded that feeding hays containing high levels of tannins can reduce methane emission (greenhouse gas) and reduce nitrogen loss from ruminant animals.
Technical Abstract: Twenty-four yearling Boer (87.5%) × Spanish wethers (32.5 ± 0.36 kg body weight) were used in a 32-day experiment to assess effects of frequency of feeding condensed tannin (CT)-containing Sericea lespedeza (SL; Lespedeza cuneata) on ruminal methane emission. Fresh SL (15.3% CT) was fed at 1.3 times the maintenance energy requirement every day (1SL), other day (2SL), fourth day (4SL), and eighth day (8SL), with alfalfa (Medicago sativa) offered at the same level on other days. Ruminal fluid for microbial assays was collected 1 day after SL feeding and at the end of the feeding interval (short and long interval samples, respectively). Average daily dry matter intake (881, 904, 957, and 906 g for 1SL, 2SL, 4SL, and 8SL, respectively; SE = 51) was similar among treatments. Average daily methane emission varied among all treatments (P < 0.05; 9.7, 11.6, 15.5, and 18.3 g/day, respectively), but emission on days when SL was fed did not differ (9.7, 10.2, 10.7, and 10.7 g/d for 1SL, 2SL, 4SL, and 8SL, respectively; SE = 0.64). There were carryover effects of feeding SL on methane emission. For example, with 8SL methane emission did not reach a maximum until day 5-6, or 4-5 days after SL was fed. Average daily methane energy relative to digestible energy was 5.6, 5.2, 7.0, and 8.6% for 1SL, 2SL, 4SL, and 8SL, respectively (SE = 0.981). The number of protozoa in the short interval sample was similar among treatments (5.2, 5.3, 5.7, and 6.5 × 10 to the 5th/ml; SE = 0.98), whereas the number in the long interval sample was 6.5, 10.4, 18.4, and 20.5 × 10 to the 5th/ml for 1SL, 2SL, 4SL, and 8SL, respectively; SE = 1.84). In vitro methane emission (3-wk incubation for methanogens) was similar among treatments for the short interval sample (18.2, 18.2, 19.7, and 20.0 ml; SE = 1.45) but less (P < 0.05) for 1SL and 2SL vs. 4SL and 8SL in the long interval sample (20.5, 20.3, 26.3, and 29.5 ml, respectively). In conclusion, greatest effects of CT occurred with 1SL and 2SL, although there were carryover effects with 4SL and 8SL. The influence of CT-containing SL on methane emission was immediate with no or minimal time for adaptation, and the effect appeared attributable to activity of methanogenic bacteria and possibly ciliate protozoa.