evaluation of aflatoxin b1 levels in feedstuffs of dairy herds in khorasan razavi province

the aims of the present study was to evaluate the level of aflatoxin b1 (afb1) in feedstuffs (corn silage, corn, dried alfalfa, cottonseed meal, cottonseed, soybean meal, canola meal, barley, wheat bran, concentrate, sugar beet pulp and wheat straw) that collected from dairy herds in khorasan razavi province that classified according to milk yield in very high (>10000 kg/day), high (5000-10000 kg/day), intermediate (2000-5000 kg/day) and low (<2000 kg/day) milk production. sampling was performed during cold (early december to late january) and warm (early june to late july) seasons. feed samples were placed in sterile packages and were maintained until test at -18 °c. aflatoxin b1 levels were measured using elisa. results showed significant differences between the amount of aflatoxin b1 in cottonseed meal, canola meal, wheat bran, sugar beet pulp and wheat straw among all dairy herd classes (p<0.05). the contents of aflatoxin b1 in all feedstuffs during the cold seasons were higher than those of warm seasons. results also showed that aflatoxin b1 level in %21.87 of the total diet samples were higher than the maximum tolerance limit (50 ng/g).