Histamine Levels in Forages and Dry Matter Intake of Heifers

Summary Silages and hay fed to dairy heifers and the fecal and urinary samples collected from these animals were analyzed for free histamine. In the silages analyzed, the correlation between the logarithm of the histamine concentrations and the dry matter intakes was low ( r = -.20), although the correlation between the logarithm of the histamine concentrations and the dry matters of the silages was high ( r = to -.98). Hay and urine of hay-fed heifers were relatively low in histamine. In haylage- or silage-fed heifers, high urinary and fecal histamine levels were not necessarily associated with high histamine intakes. The addition of 5g histamine-dihydrochloride to an animal consuming 2.1lb of chopped alfalfa hay per 100lb body weight did not decrease dry matter intake. The data suggest that there is no relation between silage dry matter intake and histamine concentration of the silage.