Influence of level of deoxynivalenol in the diet of dairy cows on feed intake, milk production, and its composition.

Eighteen primiparous Holstein cows were used in a 10-wk lactation study, preceded by a 2-wk covariate period, to determine the effect of concentration of deoxynivalenol in the diet on cow performance and transfer of deoxynivalenol and its metabolite, deepoxydeoxynivalenol, to milk. Diets were formulated to contain deoxynivalenol at 0, 6, and 12 mg/kg of concentrate DM, and daily intake of deoxynivalenol was .59, 42, and 104 mg, respectively. Increasing deoxynivalenol in the diet did not affect intake of concentrate or forage. Total milk output was not affected; however, milk fat responded quadratically; cows given deoxynivalenol at 6 mg/kg of concentrate DM had the lowest milk fat content and fat output. Overall energetic efficiency was not influenced because reduced energy output in milk was compensated by increased BW gains. No transfer of deoxynivalenol or deepoxydeoxynivalenol to milk was observed; concentrations were below detectable limits (1 microgram/ml) using HPLC-mass spectroscopy. We concluded that diets containing deoxynivalenol up to 6 mg/kg of dietary DM did not reduce feed intake of cows in this study and that deoxynivalenol or deepoxydeoxynivalenol was not transferred to milk. Further studies are required to confirm the apparent lack of effect of deoxynivalenol on milk production.