opposite direction for seasonal variation of aflatoxin m1 in bulk milk and aflatoxin b1 in rations: results from a prospective study in selected dairy farms of qazvin province, iran

In the present study, aflatoxin m1 (afm1) in bulk milk (n=72) and aflatoxin b1 (afb1) in concurrent rations (tmrs; n=48) and feed ingredients (n=230) were assessed in 12 dairy farms in winter and summer. bulk milk was sampled on days 1, 15 and 30 of the study. feeds were sampled at days 1 and 30. aflatoxin was measured using elisa kits (detection ranges: 1-81 ngkg−1 for milk, 1.25-101.25 ngkg−1 for feeds). afm1 was identified in all milk samples (range: 2.03 to >81 ngkg−1; median: 70 ngkg−1). overall, 76% of milk samples (n=55/72) had afm1 levels <81 ngkg−1 (iranian limit:100 ngkg-1). contaminations >81 ngkg−1 (n=17/72; 24%) were more frequent in winter (n=15/36 vs. 2/36). sixty-nine percent of winter (n=25/36) and 31% of summer samples (n=11/36) had contaminations above the median. the chance of contaminations above the median was higher in winter (or=5.33, p=0.007). all tmrs and ingredients had higher contaminations in summer. seventy percent of summer and 30% of winter tmrs had contaminations above median (716 ngkg-1). the chance of tmr contamination above median was higher in summer (or=5.57, p=0.002). the lower afm1 levels in summer could be due to reduced hepatic afb1 metabolism and lower dry matter intake induced by heat stress. grain mix (rs=0.90; p=0.001), corn silage (rs=0.66; p=0.001) and wet beet pulp (rs=0.68; p=0.005) were the most prominent contaminants of tmrs. due to the limitations of the diagnostic kit and different year-round nutritional conditions, higher or lower afm1 contaminations are probable. with the current nutritional practices, higher summer contamination may happen if heat stress is efficiently controlled.

opposite direction for seasonal variation of aflatoxin m1 in bulk milk and aflatoxin b1 in rations: results from a prospective study in selected dairy farms of qazvin province, iran

in the present study, aflatoxin m1 (afm1) in bulk milk (n=72) and aflatoxin b1 (afb1) in concurrent rations (tmrs; n=48) and feed ingredients (n=230) were assessed in 12 dairy farms in winter and summer. bulk milk was sampled on days 1, 15 and 30 of the study. feeds were sampled at days 1 and 30. aflatoxin was measured using elisa kits (detection ranges: 1-81 ngkg−1 for milk, 1.25-101.25 ngkg−1 for feeds). afm1 was identified in all milk samples (range: 2.03 to >81 ngkg−1; median: 70 ngkg−1). overall, 76% of milk samples (n=55/72) had afm1 levels <81 ngkg−1 (iranian limit:100 ngkg-1). contaminations >81 ngkg−1 (n=17/72; 24%) were more frequent in winter (n=15/36 vs. 2/36). sixty-nine percent of winter (n=25/36) and 31% of summer samples (n=11/36) had contaminations above the median. the chance of contaminations above the median was higher in winter (or=5.33, p=0.007). all tmrs and ingredients had higher contaminations in summer. seventy percent of summer and 30% of winter tmrs had contaminations above median (716 ngkg-1). the chance of tmr contamination above median was higher in summer (or=5.57, p=0.002). the lower afm1 levels in summer could be due to reduced hepatic afb1 metabolism and lower dry matter intake induced by heat stress. grain mix (rs=0.90; p=0.001), corn silage (rs=0.66; p=0.001) and wet beet pulp (rs=0.68; p=0.005) were the most prominent contaminants of tmrs. due to the limitations of the diagnostic kit and different year-round nutritional conditions, higher or lower afm1 contaminations are probable. with the current nutritional practices, higher summer contamination may happen if heat stress is efficiently controlled.