and negative for other prevalent toxins
indicate that up to 15 or 10 mg DON/kg diet DM were tolerated by sheep and cattle, respectively,
without any adverse effects on animal health or performance. A recent study conducted at the
University of Minnesota at Morris confirmed these findings. One hundred eighty 415-kg crossbred
steers were fed diets containing 75% barley (0 or 22 mg DON/kg DM) of similar test weights to
provide 0, 6, 12 or 18 mg DON/kg diet DM (Table 3; DiCostanzo et al., unpublished data). Data
were analyzed separately for the initial 28 d, or for the remainder of the 138-d finishing period.
Feeding diets containing as much as 18 mg DON/kg did not affect intake, average daily gain, feed
efficiency or carcass characteristics. Serum biochemistry or hematologic variables were not
affected. Analyses are under way to determine DON residue in rib, liver and kidney samples
obtained from a subset of 24 steers slaughtered immediately, or 21 d after withdrawal from their
DON-contaminated diets. Therefore, taking into consideration results from the previous and this
study, it is apparent that feedlot cattle may consume up to 18 mg DON/kg diet DM without any
apparent effects on animal health or performance, when no other prevalent toxins are present in
significant concentrations.