Efficacy of a mycotoxin-deactivating product to reduce the impact of Fusarium mycotoxin-contaminated rations in dairy cows during early lactation

: Livestock feeds can be contaminated by several fungi. Among these, Fusarium spp. are widespread and produce mycotoxins, such as deoxynivalenol (DON), zearalenone (ZEN), and fumonisins B1 and B2 (FB1 and FB2). We investigated whether feeding a TMR contaminated with moderate to high concentrations of ZEN, DON, FB1, and FB2 to dairy cows in early lactation alters (1) their feeding behavior and rumination time; (2) milk yield, composition, and quality; (3) plasma metabolic profile and biochemical traits; and (4) postpartum uterine involution and resumption of cyclicity. We tested whether adding a mycotoxin-deactivating product (MDP; Mycofix Plus 5.Z, Biomin Holding, GmbH, Tulln, Austria) to the TMR prevents or mitigates such effects. From calving to 56 d in milk, 30 lactating Holstein cows were fed with a TMR that was: (1) mildly contaminated with Fusarium mycotoxins (control group [CTR]; n = 10; with 55.42, 226.8, 578.79, and 313.60 µg/kg DM of ZEN, DON, FB1, and FB2, respectively); (2) moderately to highly contaminated with Fusarium mycotoxins (mycotoxin group [MTX]; n = 10; with 366.63, 1141.54, 613.49, and 338.06 µg/kg DM of ZEN, DON, FB1, and FB2, respectively); and (3) moderately to highly contaminated with Fusarium mycotoxins and supplemented with MDP (n = 10; with 319.72, 1,028.42, 559.56, and 282.88 µg/kg DM of ZEN, DON, FB1, and FB2, respectively). Daily DMI, BW, BCS, rumination, and resting time were not influenced by diet, as well as apparent digestibility for NDF, starch, and protein. Milk yield and quality were similar among groups, but milk urea concentration was higher in the MTX compared with CTR and MDP cows; milk from MTX-fed primiparous individuals tended to have the lowest protein concentration. No dietary effect was observed on plasma metabolic profile and on the timing of postpartum uterine clearance. The size of the ovarian reserve was similar among groups, as assessed by serum concentrations of anti-Müllerian hormone and number of ovarian antral follicles. The mean number of corpora lutea detected weekly was lower in MTX compared with CTR, and it was intermediate in MDP cows. Mean milk progesterone weekly concentration was higher in CTR versus MDP and MTX cows from wk 4 to 6 of lactation. The proportion of postpartum anestrus cows per week of lactation was lower in CTR than MTX. The first dominant follicle detected postpartum ovulated in 78%, 50%, and 18% of CTR, MDP, and MTX individuals, respectively. These preliminary results indicate that Fusarium mycotoxin contamination could modify the physiological postcalving resumption of ovarian activity. However, the current trial does not demonstrate the direct effect of the MDP on mycotoxins.