Residues

The objective of feed selection during drought is to choose the lowest cost option or a combination of feeds that meet the livestock's requirement for energy, protein, roughage and minerals while meeting the enterprise production requirements.

This can mean that in a period of drought or a dry time by-products not usually fed to livestock and failed crops that were intended to be harvested can end up being used as feed. In this situation, it is critical that producers understand the history of the feed and whether it may have been exposed to chemicals.

Purchased feed

When buying in feed during a drought, producers need to ensure that the feed they are providing to their livestock is free of chemical residues. The best way to ensure that the feed contains no unpleasant surprises is to insist upon a fully completed fodder vendor declaration or commodity vendor declaration (CVD). This should be provided upon request by the supplier of the feed.

Withholding periods and export slaughter intervals

A withholding period (WHP) is the time that must pass between chemical application, including through the feeding of treated feed, and the slaughter, collection, harvesting or use of the animal commodity for human consumption. These are mandatory for the domestic market and are on the label of all registered products. WHPs can apply to veterinary chemicals such as parasite treatments as well as agricultural chemicals such as herbicides.

An export slaughter interval (ESI) is the period that must lapse between chemical application to livestock and their slaughter for export. An export grazing interval (EGI) is the minimum time interval between application of a chemical to a crop or pasture that is continually grazed and slaughter.

In a drought situation, a crop may have been treated with herbicides or pesticides and subsequently failed due to a lack of rain. Livestock may then be turned onto the crop or the crop may be conserved as hay or silage, however, producers must be aware of the WHP and EGI of all chemicals that have been used on the crop and either defer grazing, feeding or defer sale of livestock until the WHP or EGI has expired. If feed supplies are depleted and the stock must be sold to maintain animal health and welfare, the chemicals and grazing situations must be declared on the Livestock Production Assurance National Vendor Declaration and Waybill (LPA NVD/Waybill).