Selective Dry Cow Therapy: A Practical Guide

Selective dry cow therapy means deciding cow by cow how to protect the udder at dry-off, rather than handling every cow the same way. It rests on good records and a close working relationship with your vet.

Key points

Selective therapy matches the dry-off plan to each cow's udder history.
It depends on accurate, easy-to-find records.
Your vet should write the criteria and decide on products.
Clean technique and clean housing carry more weight when fewer cows get treatment.
Track fresh cow mastitis to learn whether the plan works.

What selective means

For many years, blanket dry cow therapy meant every cow received the same plan at dry-off. Selective dry cow therapy changes that. Your vet looks at each cow's udder health history and sorts cows into groups that get different approaches.

The reason is stewardship. Using antibiotics only where there is a reason supports animal health and helps keep medicines working. This guide does not cover products or doses. Those decisions belong to your veterinarian, and certification programs and milk buyers may set their own rules.

Selective plans work best on farms that already run a clean milking routine and have steady record keeping. If your records are patchy, start by fixing that, and let your vet guide when to begin selecting cows.

What records the decision depends on

A selective plan is only as good as the data behind it. Most herds use a mix of herd test somatic cell counts, clinical mastitis history in the lactation just finished, and sometimes milk cultures or rapid on-farm tests. Your vet decides which of these fit your herd.

Records must be clear and easy to find. If a milker cannot tell whether a cow had mastitis in the last lactation, the plan will not work.

Cow ID and dry-off date
Cell count history through the lactation
Clinical mastitis cases, quarter and date
Culture results if available
Notes on chronic or repeat cases

Sorting cows with your vet

Ask your vet to help you set written criteria for who falls into each group. A cow with a clean history is handled differently from a cow with repeated infections. The criteria should be specific enough that any trained milker can follow them.

Review the criteria after the first season. If fresh cow mastitis rises, the criteria may need to change. This is a plan that grows with your herd's data.

Give the crew a one-page sorting sheet. Seeing each cow's history at dry-off, rather than relying on memory at the moment of the procedure, prevents mix-ups.

Teat sealants and hygiene

Selective plans often include internal teat sealants in some cows. Whether to use them, and in which cows, is another vet decision. What matters for you is that sealant must be placed with very clean technique, since touching or contaminating the teat end can cause infection.

Whichever route is chosen, thorough teat-end cleaning, clean gloves and a clean work area are non-negotiable. The plan is only as safe as the person carrying it out.

Housing and the close-up period

New infections in the dry period often come from the environment. Clean, dry bedding, enough space per cow and good ventilation matter more under a selective plan because there is less protection from treatment for low-risk cows.

Check udders at regular intervals through the dry period and in the close-up pen, and record anything unusual. Early detection of swollen quarters or leaking teats lets your vet respond fast.

Heat, mud and wet weather raise the environmental load on teats, so pay more attention to bedding and pen cleanliness in those periods.

Common errors and what to ask

A typical error is adopting a selective approach without enough records, or applying criteria loosely. Another is skipping environmental management, then blaming the plan when fresh cow mastitis rises.

Bring these questions to your vet: Which cows in my herd are low risk and why? What results will tell us the plan is working? What happens if clinical cases rise? How often should we revisit criteria?

Relying on memory rather than written records
Copying another farm's criteria
Weak teat-end cleaning at dry-off
Not tracking fresh cow mastitis afterwards
Ignoring udder checks in the dry pen

Measuring success

Track clinical mastitis in the first weeks after calving, early lactation cell counts and cows leaving the herd for udder reasons. Compare these year to year with your vet, not month to month, since small changes can be noise.

Any treated cow's milk and meat must be held for the full withdrawal time on the label or set by the vet, under any plan.

When to get help: Work with your vet to write the selection criteria and review them yearly, and check your milk buyer's or program's rules on antibiotic use. Follow label or vet-set milk and meat withdrawal times exactly.

Sources and further reading

Organization homepages are linked so you can search them for current guidance on this topic.

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