Physical properties

Dry matter (%)

10 - 18

Osmolality

250 - 350 mOsmol/Kg⁻¹

pH

5.5 - 6.9 (Mean 6.4)

Redox potential

−350 to −400 mV

Temperature

38˚C - 41˚C

Chemical properties

Amino acids and oligopeptides

<1 mmol∙L⁻¹ present 2 - 3 h post feeding

Ammonia

2 - 12 mmol∙L⁻¹

Dietary (cellulose, hemicelluloses, pectin) component

Always present

Endogenous (mucopolysaccharides)

Always present

Gas phase (%)

CO₂ 65; CH₄ 27, N₂ 7; O₂ 0.6, H₂ 0.2

Growth factors

Good supply; branched chain fatty acids, long chain fatty acids, purines, pyrimidines, other unknown

Lignin

Always present

Minerals

High Na; generally good supply

Nonvolatile acids (mmol∙L⁻¹)

Lactate < 10

Soluble carbohydrates

<1 mmol∙L⁻¹ present 2 - 3 h post feeding

Trace elements/vitamins

Always present; good supply of B vitamins

Volatile fatty acids (mmol∙L⁻¹)

Acetate 60 - 90, propionate 15 - 30, butyrate 10 - 25, branched chain and higher 2 - 5

Microbiological properties

Anaerobic fungi

10^3-5 g⁻¹ (6 genera)

Bacteria

10^10-11 g⁻¹ (>200 species)

Bacteriophage

10^7-9 g⁻¹ particles ml⁻¹

Ciliate protozoa

10^4-6 g⁻¹ (25 genera)