Quantitative oxidation of nutrients in growing calves.

The present paper deals with the possibility of using measurements of CH4 production in growing calves to estimate the amount of CO2 produced by fermentative processes and to calculate the oxidation of nutrients. Twenty bull calves were fed diets with varying proportions of corn grain and forage. The protein and energy metabolism was measured in 118 individual balance trials in the live weight range of 120-350 kg by means of indirect calorimetry and carbon-nitrogen balances. The values of oxidized carbohydrate (OXCHO) and fat (OXF) were directly dependent on the fermentation level. With increasing fermentation, less glucose was absorbed and oxidized as OXCHO, while more carbohydrate was converted to short chain fatty acids and oxidized as OXF.