Antibiotic Dry Cow Withhold Periods Explained

Antibiotic Dry Cow Withhold Periods Explained

With spring calving rapidly approaching, it is a good time to review the withholding periods associated with antibiotic dry cow therapies. While each product differs, there are some general principles that apply. Labels typically outline several withholding periods that should be straightforward but are often misunderstood.

Key Withholding Periods and What They Mean

“DO NOT USE in lactating cattle”
Some manufacturers may specify a milk withholding period if a lactating cow is accidentally treated, but many do not. If no withholding period is listed, it is safest to test the cow’s milk for antibiotic residues before returning it to the vat. Your milk processor can assist with this, as they are equally concerned about preventing antibiotic residues as you are.

“DO NOT USE less than XX days before slaughter for human consumption”
This one is fairly clear. However, remember that this withholding period also applies to the calf, not just the cow. If a cow calves within the withholding period, she and her calf cannot be sold for slaughter until after the withholding period expires.

“DO NOT USE less than XX days before calving”
The number of days before calving varies significantly between products. Some specify a milk withholding period if the cow calves within the withhold period post treatment, but many do not. If a cow calves within the stated withholding period and no milk withholding is listed, the safest approach is to test her milk until it is confirmed negative for antibiotic residues. Again, work with your processor on this.

“Milk from treated cows MUST NOT BE USED for human consumption for 96 hours 8 milkings after calving”
This is often the most confusing withholding period. Both the 96 hour and 8 milking conditions must be satisfied before milk can go into the vat. This creates a few common points of confusion:

Milking frequency matters:

• If milking three times a day, the 96 hour withhold period is the controlling factor, even though 12 milkings may have occurred in that time
• If milking once a day, the 8 milkings take precedence, extending the withholding period to 192 hours

Timing of calving:
For example, if a cow calves early Monday morning but is not milked until Monday evening, both the 96 hours and 8 milkings apply from the time of calving. So the earliest her milk can be included in the vat is Friday evening, not Friday morning.

Delayed calf separation:
If calves are left on the cows for a day or two post calving, the 8 milkings become the key withholding period, rather than 96 hours.

Other Considerations

Export Slaughter Interval ESI: 

Most manufacturers do not list an ESI. If needed, contact the manufacturer directly for guidance.

Ambiguous label statements:

Some products refer to “colostrum and milk” while others specify only “milk.” Terms like “should not” versus “must not” also cause confusion. It is best to clarify these with the manufacturer if you are unsure.

Use in heifers:

Only one antibiotic dry cow product is registered for use in heifers prior to their first calving.

Other off label use

Off label use of any AgVet Chemical is illegal unless prescribed by a veterinarian. Using two tubes of a dry cow product in one quarter or deliberately using dry cow in a lactating cow are good examples of an off label use. Just do not do it.

Final Advice

Always read product labels carefully. Withholding periods can vary significantly between products even if they have the same active ingredients. If you are unsure, consult your veterinarian, milk processor, the product manufacturer, and probably all three.