Animal feeding studies for seed dressings (residues)

Seed dressings for use on cereal seeds are subject to special requirements. Evidence of their fate when fed to livestock must be presented. Details of the information that should be provided are outlined in this guideline.

When the decision was made to discontinue the use of organo-mercury compounds and hexachlorobenzene as seed treatment chemicals on cereal and coarse grain seeds, the Australian Agricultural Council in August 1971 recommended that ‘fungicides which, when applied to human foodstuffs or feed for animals, are known to give rise to residues of public health significance, should not be permitted registration as dressings on cereal and coarse grain seeds’.

To ensure that this recommendation is met, you may need to conduct feeding studies with poultry, cattle, goats, sheep and pigs to determine whether residues of chemicals used to treat cereals and other coarse grain seeds are likely to occur in the edible products derived from livestock receiving small quantities of those chemicals in their rations.

Livestock feeding studies should, when required, be conducted to provide the following residue data on the understanding that the protocol may require modification in accordance with the results obtained from previously conducted livestock metabolic studies:

  • Poultry – residues in meat, fat, eggs and edible offal
  • Cattle, goats and sheep – residues in meat, fat, edible offal, milk and fat of milk
  • Pigs – residues in meat, fat and edible offal

When required, the test species should be fed a diet containing the chemical in amounts that would normally be expected on cereal and coarse grain seeds treated in accordance with the directions for use, or at an elevated level. It is best if feeding is carried out with treated seed.

This diet, comprising the treated grain in the same proportion as would normally be used for the particular species of livestock, should be fed for a period of 7 days, at which time half the test group should be sacrificed and residue determinations carried out on the appropriate tissues. The remaining portion of the test group should be maintained for a further 7 days on a non-adulterated diet and sacrificed for residue determinations at the end of this second 7-day period. A test group (control) that has had no access to the adulterated feed over the whole 14-day period should be included for comparative purposes.

The test groups do not need to be large. The following figures are the minimum that would be accepted for each of the species concerned:

  • Poultry – 6 birds
  • Cattle – 2 animals
  • Sheep – 2 animals
  • Pigs – 2 animals

Control animals would be in addition to these figures.

Milk and eggs should be collected throughout the period of the test and retained under suitable conditions for analysis at a convenient time along with the other test tissues. The analytical techniques used must be appropriate for both the chemical residue and the particular tissues being examined and should be capable of detecting residues at a level of 0.1 mg/kg or lower.

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