Resumen:
Ruminants are one of the major generators of methane, a greenhouse gas (GHG) with a global warming
potential, 25-fold that of carbon dioxide. Methane production by ruminants also reduces the gross feed
energy intake utilization by about 2e12%. The present study aimed to test the effects of different levels of
a ruminal fermentation modulator (RFM) on in vitro ruminal fermentation and GHG production of five
total mixed rations (TMR) with different silage (S) to-concentrate (C) ratios (0S:100C, 25S:75C, 50S:50C,
75S:25C, and 100S:0C). The RFM contained mainly calcium propionate and malate, and monopropylene
glycol. The rumen inoculum was collected from a Brown Swiss cow fed a TMR of concentrate and alfalfa
hay (1:1 dry matter (DM)) ad libitum. Gas production (GP) measurements were recorded up to 72 h of
incubation. There were interactions (P < 0.05) between ration type and RFM dose for GP until 18 h and
for partitioning factor and gas yield at 24 h of incubation. The 100S:0C TMR had the highest asymptotic
GP (linear and quadratic effects; P < 0.05) compared with other TMR. The 0S:100C TMR had the lowest
GP rate (linear effect; P ¼ 0.003). Ration type and RFM inclusion had no effect (P > 0.05) on methane
production. The DM digestibility increased (linear effect; P ¼ 0.003) as silage level increased. Overall,
increasing silage in the TMR lowered the asymptotic GP and DM digestibility. The asymptotic GP was
higher with the addition of the RFM without any effect on fermentation kinetics. These results suggest
that the RFM can be used as an environmental cleaner product in animal farming due to its ability to
improve ruminal fermentation of feedstuffs and to reduce methane emissions
Descripción:
Methane is a major greenhouse gas (GHG) produced during the
normal digestive process in ruminant animals (Blaxter and
Clapperton, 1965) with a global warming potential, 25-fold that
of carbon dioxide (IPCC, 2007). In addition to environmental
implications, ruminant methanogenesis represents a loss of 2e12%
of the gross energy intake (Johnson and Johnson, 1995; Soltanali
et al., 2015) with a greater environmental impact from the
confinement system compared with pasture-based system (O'Brien
et al., 2012). A cow can produce 250 to 500 L of methane (CH4) per
day depending on the quantity and quality of the feed which affects
rate of digestion and rate of passage in the fermentation process
(Johnson and Johnson, 1995). Furthermore, cattle consuming high
fibre diets typically lose about 6% of gross dietary energy as
methane (CH4), whereas those on high concentrate rations generally
lose about 3% of dietary gross energy as CH4 (Mc Geough et al.,
2012). According to the Food and Agriculture Organization of the
United Nations, the livestock sector is responsible for about 18% of
total global anthropogenic GHG emissions