A comparison of phenol and indole flavour compounds in fat, and of phenols in urine of cattle fed pasture or grain

The concentrations of phenol and indole flavour compounds in the fat of beef cattle finished for nine weeks on either ryegrass/clover pasture or a maize-based grain diet were determined, and compared with urinary concentrations of phenols (both free and total) and with dietary parameters including phenolic acids. The concentration of skatole in the fat was significantly higher for the pasture-fed steers. Treatment effects on phenol concentrations in the fat were not significant for most phenols, although phenolic intake and, in most cases, urinary excretion was higher on the pasture diet. 4-Ethylphenol was a distinctive marker of the maize-based finishing diet in both urine and fat.