Feed and feed storage factors in relation to aflatoxin M1 contamination in bulk milk of smallholder dairy farms

The aim of the study was to determine feed and feed storage factors associated with aflatoxin M 1 (AFM 1 ) contamination in bulk milk of dairy farms. The study was conducted from May to July 2016, at all smallholder farms in Mae Wang dairy cooperative, Chiang Mai, Thailand. Data on feed and feed storage factors were collected from the farmers using interviews and observations. For feed, we included type of roughage and physical appearance of concentrated feed, and for feed storage factor, we included storage method of roughages. AFM 1 concentration was measured using the Charm ® ROSA ® MRLAFMQ (afla-toxin M 1 ) Test. Fisher’s exact chi-square test was used to determine the association of feed and feed management factors with AFM 1 contamination. From a total of 67 farms, 50 farms were included in the analysis. AFM 1 contamination was observed in 46% of the samples. Farms using factory-corn silage had a significantly higher percentage of AFM 1 contamination (62.5%) than farms that did not use factory-corn silage (30.8%). AFM 1 contamination in farms that used concentrates with cracked pellets was significantly higher (64.3%) than in those that did not (22.7%). For feed storage, roughage stored in piles within the barn was associated with significantly higher AFM 1 contamination than that stored outside (61.5% and 29.2%, respectively). In addition, AFM 1 contamination for roughage piles with mold on the surface was higher (60%) than that for roughage piles without mold (25%). Our results indicate that type of feed and feed storage factors are associated with AFM 1 contamination in bulk milk.