Milk and meat withdrawal times

Definition

A withdrawal period (also withdrawal time or withholding period) is the minimum time between the last dose of a drug and the point at which milk from the animal may enter the food supply, or the animal may be slaughtered for food, so that drug residues have fallen below the legal tolerance.

Dairy cattle have two separate withdrawals for most drugs:

Milk withdrawal: usually stated in hours (e.g. 72 or 96 hours) or in milkings. Milk from a cow in milk withdrawal must be discarded, not shipped.
Meat (slaughter) withdrawal: usually stated in days. The cow may not be sold for slaughter, or leave the farm as a cull, before it ends.

Who sets the period:

Labeled use: the FDA-approved label gives the withdrawal for the approved species, class, dose, route and indication. Some labels say the drug is not for use in lactating dairy cattle, or carry the standard FDA wording “do not use in female dairy cattle 20 months of age or older” (FDA GFI #45; some labels add “including dry dairy cows”). Those labels give no milk withdrawal because no use in milking cows is approved. 21 CFR 530.41 also bans some extra-label uses outright, e.g. phenylbutazone in female dairy cattle 20 months of age or older.
Extra-label drug use (ELDU): any use that differs from the label (dose, frequency, duration, route, indication, or class of animal). ELDU is legal only under the conditions of AMDUCA and 21 CFR Part 530, on a veterinarian’s order within a valid VCPR. The veterinarian must set an extended withdrawal long enough to avoid violative residues, typically using FARAD guidance. The label withdrawal no longer applies.

A cow is in withhold from the first treatment through the withdrawal end date, inclusive. Milk and meat withhold are tracked separately and usually end on different dates.

Formula

Plain text:

milk withhold end = time of last treatment + milk withdrawal (label, or vet-set for ELDU)
meat withhold end = date of last treatment + meat withdrawal (label, or vet-set for ELDU)

cow is in withhold on day D  if  first treatment <= D <= withhold end   (inclusive)

LaTeX:

t_{\text{end}} = t_{\text{last dose}} + W
\qquad
\text{in withhold on } D \iff t_{\text{first dose}} \le D \le t_{\text{end}}

W is the labeled withdrawal for labeled use, or the extended withdrawal set by the veterinarian for extra-label use. W is never shortened.

Working rules:

Count from the last dose, not the first. A 3-day course with a 96-hour milk withdrawal ends 96 hours after the third dose.
Hours vs days: a milk withdrawal in hours ends at a clock time. Milk can return at the first milking after that time. When converting to a calendar date, always round later, never earlier.
Multiple drugs: the cow’s withhold end is the latest end date across all drugs given.
Dry-cow and intramammary products can carry conditions tied to the dry period or calving (e.g. a minimum days dry, or milk discard for a set time after calving). Follow the label exactly.

How to pull it in DC305

Withdrawal is tracked through treatment events plus withhold-date items:

Treatment events (mastitis, metritis, lameness, pneumonia, etc.) record the treatment date. Drug, dose and protocol usually live in the remark or in a protocol code. See DC305 events.
Withdrawal-date items: the standard DC305 items are MKDAT (Milk Withdrawal Date) and BFDAT (Beef Withdrawal Date), both stored date items. Herds can add their own items as well.
Treatment protocols: DC305 can store protocols with milk and meat withholding days, so entering the event sets MKDAT and BFDAT on the cow.
List cows still in withhold by filtering on the withdrawal-date item being today or later:
```
LIST ID PEN MKDAT BFDAT FOR MKDAT>-1
```

DC305 is not always the legal record. Many herds keep the official treatment record on paper, on a treatment board or in a separate app, and DC305 may lag it. Check which system the herd treats as authoritative before reporting.

Typical range

Herd context: US lactating dairy cows (mostly Holstein), freestall or dry-lot; FDA rules and FARM Animal Care v5 expectations as of 2026.

Milk withdrawal for common lactating-cow products runs from 0 hours (a few products) to several days; many intramammary mastitis tubes fall in the 36–96 hour range.
Meat withdrawal runs from 0 days to a month or more; some injectable antibiotics and long-acting products are 28 days or longer.
ELDU withdrawals set by the veterinarian are usually longer than the label, often substantially.
Hospital-pen discipline: treated cows are milked last or into a separate system, and are physically marked (leg bands, tail paint, a dedicated pen).

Requirements change; confirm the current version with the program or regulator. This page is not legal or veterinary advice.

Common mistakes

Counting from the first dose instead of the last.
Using the label withdrawal for an extra-label use. Any change in dose, frequency, route or duration voids the label withdrawal; the vet must set one.
Rounding the end date down, e.g. returning a cow to the tank on the calendar day the withdrawal ends, before the end time.
Forgetting the meat withdrawal when culling. A cow done with milk withdrawal may still be in meat withdrawal.
One end date for several drugs. The drug that ends latest governs.
Unmarked treated cows, or a treated cow moved back to a milking pen before withdrawal ends.
Fresh cows after dry-cow therapy shipped before label conditions are met (short dry period, early calving).
Treatments entered late in the record system, so the “in withhold” list is wrong on the very days it matters.
Compounded or unapproved products with no label withdrawal and no vet-set withdrawal on file.