Cattle, digestive process

Schbnwiese (1995) calculates the CH share in the greenhouse effect of about 2.5% and agriculture is believed to account for roughly two-thirds of the total human-generated CH (Watson ef al. 1996). While paddy rice fields, cattle feedlots and the burning of biomass contribute to methane emissions, about 75% of methane on farms is emitted directly from ruminant animals, from digestive processes and excretion (Stolze ef al. 2000, Alfbldi ef al. 2002, Shepherd ef al. 2003). 

Acetamide has been used experimentally as a source of nonprotein nitrogen for sheep and dairy cattle (13). It does not appear to be toxic in amounts of about 2—3% of ration. Buffering the diet with dibasic acids serves to allow higher levels of intake because the ammonia liberated in the digestive process is then scavenged. 

A series of feeding trials using sheep and cattle were conducted using oak sawdust. In addition, a measurement was made on the influence of the digestive process upon wood fiber. The feeding trials will be described and results reported in the order in which the tests were run. 

All quantitative variables of intake, net nutrient fluxes and energy balance were expressed on a body weight basis. Digestive processes are better expressed per kg body weight (Sauvant et al., 2006). This unit was also the only one that allowed normal distributions of the explanatory variables and a full overlap across cattle and sheep data, as already noted by Vemet et al (2005). Loncke et al (2010b) confirmed the relevance of this unit for the energy expenditure of portal drained-viscera. 

Values in Table 56.1 are expressed in teragrams per year. A teragram is equivalent to 1012 grams. Table 56.1 indicates that approximately two-thirds of methane comes from human sources, principally related to agriculture. Animal digestion (flatulence) is chiefly from livestock such as cattle. An adult cow emits 600 liters of methane each day. Fossil fuel sources include both combustion and processing of oil, natural gas, and coal. Landfills are the primary anthropogenic source of methane in the United States. 

Humans and most other animals cannot digest cellulose. Ruminant animals (cattle, sheep, goats, moose) have bacteria in their stomachs that break down cellulose into products that can be used by the animal. Chemical processes are available to convert cellulose to simple sugars by the reaction... 

Animals lack the enzymes necessary to catalyze the hydrolysis of cellulose and so can t digest it. Cattle and other ruminants use cellulose as a food source in an indirect way. Colonies of microorganisms that live in their digestive tract consume cellulose and in the process convert it to other substances that the animal can digest. 

Exhaust steam is partially recycled after mixing with fresh superheated steam. Grains treated in this way are suitable for direct use as cattle feed with high digestibility. Table 21.13 presents the operating characteristics of such ISD installations used for thermal processing of grains. 

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