• Journal of Animal Science and Technology
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• v.54 no.1
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• pp.15-22
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• 2012

This study was conducted to investigate the effects of grain sources on the ruminal methane production in Hanwoo steers. Six Hanwoo steers (BW = 614.4 ${\pm}$ 8.3 kg) were fed, on a DM basis (TDN 6.91 kg), 10% rice straw and 90% barley or corn based concentrate, respectively, according to Korean Feeding Standards (Hanwoo). Each period lasted 18 days including a 14-day adaptation and a 4-day measuring period. The steers were in the ventilated hood-type respiration chamber system (one cattle per chamber) during each measuring period to measure heat and methane production for 1 day. Nutrient intake and digestibility were not affected by steer fed grain sources. Methane concentration was not affected by steer fed either barley or corn-based concentrate, respectively (0.022% vs. 0.025%). Methane production was greater by steers fed corn than those fed barley (119.3 g/day vs. 139.4 g/day). This result indicated that methane emission factor by maintenance energy requirement for the late fattening Hanwoo fed corn was higher than the steers fed barley (43.6 kg/head/year) vs. corn (50.9 kg/head/year). Methane conversion rate (Ym) was 0.04 Ym and 0.05 Ym for barley and corn, respectively.

• Journal of The Korean Society of Grassland and Forage Science
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• v.32 no.1
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• pp.59-74
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• 2012

Buffer solubility and protein fractionation were evaluated from the hays (timothy, alfalfa and klein) and straws (tall fescue and rice), and $In$ $vitro$ trial was conducted to examine the effect of buffer extraction on fermentation characteristics, degradability and gas ($CO_2$ and $CH_4$) production. Buffer soluble protein (SP) content and A fraction in total protein were highest in alfalfa hay as 61% and 41.77%, respectively while lowest in rice straw (42.8% and 19.78%, respectively). No difference was observed in B1 fraction among forages but B2 fraction was slightly increased in klein hay (12.34%) and tall fescue straw (10.05%) compared with other forages (6.34~8.85%). B3 fraction of tall fescue was highest as 38.49% without difference among other forages while C fraction was highest in rice straw. pH in incubation solution was higher in all forages after extraction than before extraction at 3h (P<0.01) and 6h (P<0.05), and pH from hays of timothy and alfalfa was higher than the other forages at 6h (P<0.05) and 12h (P<0.001). Regardless of extraction, ammonia-N concentration from alfalfa hay was increased at all incubation times and extraction effect was appeared only at 3h incubation time (P<0.01). Total VFA concentration from alfalfa hay was highest up to 24h incubation while those from tall fescue straw and rice straw were lowest. Buffer extraction decreased (P<0.01~P<0.001) the total VFA concentration. Acetic acid proportion was increased (P<0.001) before extraction of forages but no difference was found between forages. Propionic acid($C_3$) proportion was also increased(P<0.001) before extraction in all forages than in straws at 3h, 24h and 48h incubations, and $C_3$ from hays were mostly higher (P<0.05) than from straws. Butyric acid proportion, however, was not affected by extraction at most incubation times. Parameter 'a' regarding to the dry matter (DM) degradation was increase (P<0.001) in all forages before extraction, and was decreased (P<0.05) in tall fescue straw and rice straw compared with hays. Parameter 'b' was also increased (P<0.001) before extraction but no difference was found between forages. Effective degradability of DM (EDDM) was higher (P<0.001) before extraction in most forages except for rice straw. Buffer extraction decreased (P<0.05) all parameters (a, b, and c) regrading to the crude protein (CP) degradation but no difference was found between forages. Effective degradation of CP (EDCP) was lower (P<0.05) in straws than in hays. Parameters 'a' and 'b' regarding to the NDF degradation (P<0.01) and effective degradability of NDF (EDNDF, P<0.001) were also higher in forages before extraction than after extraction but no difference was found between forages. Buffer extraction reduced (P<0.05~P<0.001) $CO_2$ production from all the forages uo to 24h incubation and its production was greater (P<0.05~P<0.01) from hays than straws. Methane ($CH_4$) production was also greater (P<0.01~P<0.001) in all forages at all incubation times, and its production was greater (P<0.05) from hays than from straws at most incubation times. Based on the results of the current study, it can be concluded that buffer solubility and CP fractionation might be closely related with $In$ $vitro$ VFA concentration, degradability and gas ($CO_2$ and $CH_4$) production. Thus, measurement of buffer solubility and protein fractionation of forages might be useful to improve TMR availability in the ruminants.