Carry-over rate of aflatoxin M1 into cow milk during early lactation period

Abstract

To study carry-over rate (AFM1 excreted in milk/AFB1 ingested) of AFM1 excreted into cow milk during the 12-week of lactation period in ten Holstein Friesian cows from ten dairy farms. All dairy cows were fed with concentrate and roughage feed naturally given by the farm owners. All samples were collected individually. Feeds were collected one day earlier before the collection of milk samples. Milk samples were collected from both morning and afternoon milking. The feed samples were analyzed for AFB1 by using column chromatography, thin layer chromatography, and densitometer at the wavelength 366 nm. It was found that 83% (50/60) of concentrate samples contain AFB1 in the range of 0.16-42.54 ppb (Mean = 16.23 ppb, SD = 13.16 ppb). All rice straw samples were not found to be contaminated with AFB1; however, approximately 85 % (51/60) of roughage feed samples were contaminated with AFB1 in range of 0.20-58.73 ppb (Mean = 4 ppb, SD = 16.77 ppb). The daily dairy feeds contaminated with AFB1 in the range of 3.30-1530 ppb (Mean 213.45 ppb, SD = 428.35 ppb, n=60/60). Milk samples were analyzed for AFM1 by using chromatography, and high performance liquid chromatography. We found that 70 % (n= 42/60) of milk samples contaminated with AFM1 in the range of 0.014 and 2.463 ppb (Mean =0.692 ppb, Median = 0.445 ppb). The carry-over rate of AFM1 into cow milk during lactation period was found to be 2.57±0.47% (n=4) (Median = 2.69%).