Potential of n-alkanes as biomarkers in grass-feeding steers

Abstract

The objective of this study was to

evaluate the effect of diet (grazing vs. pasture silage with concentrate) and changes in diet

on n-alkane concentrations in cattle feces. The experiment lasted 35 d (15 d of adaptation

and 20 d of sampling). Thirty Holstein-Friesian steers were divided into three groups of ten,

and each group was randomly allocated to one of the following three treatments: GZ, diet

consisting of 100% pasture; SC, diet consisting of pasture silage: concentrate in a 60:40 ratio;

and MX, diet consisting of a gradual decrease in pasture and a gradual increase in SC. Fecal

samples were taken daily from every animal, and their n-alkane content was analyzed using

gas chromatography. The data obtained in this study showed detectable changes in n-alkane

concentrations in steer feces. The changes were noticeable within two to three d after a change

in diet, whereas concentrations of n-alkanes remained stable in the feces of animals that did not

experience any change in diet. These results can be used as the basis for developing a tool that

can determine the type of feed bovines received prior to slaughter.