This manual describes the use of the transfer model to estimate aflatoxin B1 and/or aflatoxin M1 concentrations in products of the dairy cow based on oral exposure to feed contaminated with aflatoxin B1. Aflatoxin M1 is the hydroxylated metabolite of aflatoxin B1. This model has several input fields (left side) and output fields (right side). The input and results can be saved using the button “Report (*.docx)”. Source information and a citation suggestion are provided (top).
Step1: Contamination level of feed
The user can provide the contamination level (expressed in µg aflatoxin B1/kg feed) in the contamination field.
Step 2: Feed intake
The user has to select the type of feed that is contaminated with aflatoxin B1. For this, the user first chooses between a summer or winter feed regimen, and then the relevant type of feed.
a) This can either be:
- Total feed intake
- Grass silage
- Maize silage
- Total compound feed (blend of various raw materials and additives)
- Compound feed ingredients
When compound feed ingredients are selected, the user has to select the contaminated compound feed ingredient from a drop down menu.
b) After selecting the contaminated feed (ingredient), a default feed intake value is provided (in kg dry matter per day)1. The user can adjust this default value to the value corresponding to the actual feeding regime. The user should be aware that whether the feed of the dairy cow is protein rich or protein poor can influence the default feed ingredient intake. The default values for compound feed ingredients used here are based on a protein-rich diet.
Step 3: Exposure period of dairy cow to contaminated feed
To estimate the concentration of aflatoxin B1 and/or aflatoxin M1 in dairy cow products, the user has to enter the duration of exposure of the animals to the contaminated feed (ingredient) and the time period after the exposure stopped (both expressed in days).
Step 4: Regulatory limit (optional)
A regulatory limit (for instance maximum level) (expressed in µg aflatoxin M1/L milk) can be inserted. This limit will be displayed in the output graph on the screen, but not yet in the report.
Step 5: Results
A graph with only the aflatoxin M1 concentration in milk (expressed in µg/L milk) versus time will be generated. In addition, graphs with aflatoxin B1 and M1 concentrations in muscle, liver and kidney (expressed in µg/kg tissue) versus time will be generated. These concentrations are valid for the average Holstein-Friesian dairy cow. The user can switch between the graphs for milk and organs using the button below the graph(s).
Step 6: Saving input and output
Using the “Report (*.docx)” button, present in the left corner, input data and the results of the model run can be stored locally as a report file in word. The optional regulatory limit is not yet visible in the report. Input data and results are not stored at the website.
Step 7: Citation suggestion
At the top of the model page the references that describe the model are listed, as well as a citation suggestion. Please use the suggested citation at the bottom of the webpage, when referring to the model.
1 Van Raamsdonk LWD, Kan CA, Meijer GAL, Kemme PA (2007) Key figures for some farm animals and their consumption patterns [in Dutch]; https://research.wur.nl/en/publications/kengetallen-van-enkele-landbouwhuisdieren-en-hun-consumptiepatron.