In vitro gas and methane production of silages from whole-plant corn harvested at 4 different stages of maturity and a comparison with in vivo methane production

• Published in: Journal of dairy science Vol. 100; no. 11; p. 8895
• Main Authors: Macome, F M, Pellikaan, W F, Hendriks, W H, Dijkstra, J, Hatew, B, Schonewille, J T, Cone, J W
• Format: Journal Article
• Language: English
• Published: United States 01-11-2017
• Subjects: Agriculture; Animal Feed; Animals; Cattle - metabolism; Dairying; Diet - veterinary; Female; Methane - biosynthesis; Nitrogen; Rumen; Silage; Zea mays - growth & development; methane; in vivo; corn silage; maturity; in vitro
• ISSN: 1525-3198
• DOI: 10.3168/jds.2017-12953

The current study investigated the relationship between in vitro and in vivo CH
production by cows fed corn silage (CS)-based rations. In vivo CH
production was measured in climate respiration chambers using 8 rumen-cannulated Holstein-Friesian cows. In vitro CH
production was measured using rumen fluid from the 8 cows that were fully adapted to their respective experimental rations. The animals were grouped in 2 blocks, and randomly assigned to 1 of the 4 total mixed rations (TMR) that consisted of 75% experimental CS, 20% concentrate, and 5% wheat straw [dry matter (DM) basis]. The experimental CS were prepared from whole-plant corn that was harvested at either a very early (25% DM), early (28% DM), medium (32% DM), or late (40% DM) stage of maturity. The 4 experimental TMR and the corresponding CS served as substrate in 2 separate in vitro runs (each run representing 1 block of 4 animals) using rumen fluid from cows fed the TMR in question. No relationship was found between in vivo CH
production and in vitro CH
production measured at various time points between 2 and 48 h. None of the in vitro gas production (GP) and CH
production parameters was influenced by an interaction between substrate and origin of rumen fluid. In vitro measured 48-h GP was not affected by the maturity of whole-plant corn, irrespective whether CS alone or as part of TMR was incubated in adapted rumen inoculum. Incubation of the experimental TMR did not affect the kinetics parameters associated with gas or CH
production, but when CS alone was incubated the asymptote of GP of the soluble fraction was slightly decreased with increasing maturity of CS at harvest. In vitro CH
production expressed as a percent of total gas was not affected by the maturity of whole-plant corn at harvest. Several in vitro parameters were significantly affected (GP) or tended to be affected (CH
) by diet fed to donor cows. It was concluded that the current in vitro technique is not suitable to predict in vivo CH
production from CS-based rations.