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Closer Clipping Does Not Automatically Mean Cleaner Skin

What a controlled #10 versus #40 blade study found, and how to separate cutting length, skin response and hygiene in professional grooming.

4 min read Updated 14 September 2026

“Take it shorter so it stays cleaner” sounds like a practical request. It can also hide two quite different decisions: how much coat to leave, and how to manage hygiene. A very close finish is not evidence that either the skin or the equipment is cleaner.

A controlled veterinary study gives us a useful reason to question the assumption—and to be precise about what its results mean for salon work.

What the blade comparison actually found

Researchers studied 67 dogs receiving an epidural. Each preparation site was divided: one half was clipped with a #10 blade, the other with a #40. At 24 hours, the #40 side had more redness and more Micrococcaceae bacteria. Total colony counts did not differ significantly between blade sizes. Read the original study.

This was a surgical preparation study, including antiseptic scrubbing, not a salon trial. It did not test VUNRO blades, establish the best pet haircut or prove that a #10 cannot irritate skin. Its useful finding is narrower: cutting closer did not deliver a simple overall bacterial-count advantage, and the skin response differed.

Ask what “cleaner” needs to achieve

A client may mean less material catching in a particular area, easier washing at home, fewer tangles or simply a neater outline. Those are separate problems. Before selecting a blade, identify the area and the maintenance difficulty.

“Where are you finding the problem between appointments?” is more useful than agreeing to a shorter all-over cut. A local concern may need a local solution. A recurring problem associated with soreness, discharge or a change in skin condition belongs in a veterinary conversation, rather than being treated as a styling defect.

For your working record, separate three things:

Purpose: the specific maintenance problem the trim is meant to solve.
Method: the blade or guard system, direction, preparation and areas actually worked.
Observation: what you saw before and after, without assigning a diagnosis.

This is especially helpful when another groomer takes the next appointment. “Short hygiene trim” leaves too much room for interpretation; a clearly marked area and a recorded tool setting are reproducible.

Preserve options while you assess the coat

On suitable prepared coat, a conservative test area lets you judge the finish before committing to a larger region. Once length has been removed, you cannot use a different guard to put it back. Where the skin is already sore or the coat cannot be prepared comfortably, stop and reconsider the service rather than experimenting with closer cuts.

Do not use the study as a shortcut around ordinary blade checks. Correct fit, intact teeth, a smooth-running assembly and a comfortable working temperature remain separate requirements. A particular blade number does not guarantee that every blade bearing it is in good condition.

Build a useful range of lengths

The VUNRO #10 A5 blade has a nominal cutting length of 1.5 mm. That describes the tool; it does not make it the right choice for every body area or every dog.

Keep longer options available when your services call for them. The #5F A5 blade offers a nominal 6.4 mm setting. For a range of longer clipped finishes, the VUNRO Universal Guard Comb Set fits the specified standard-width A5 and D-Series base blades. Match the base blade to the instructions; these are not wide-blade or trimmer guards.

A useful kit gives you a choice of appropriate finishes and a maintained spare for the work you repeat. It should not push you towards the shortest blade simply because that is the only clean, ready tool left in the drawer.

Use clear language at collection

Explain what you changed and why: “I kept the body length and tidied the area that was catching debris. Please let me know how manageable that is at home.” If you noticed a concern, describe its location and appearance, and recommend veterinary advice where appropriate.

The goal is a comfortable, maintainable result with a defensible process behind it. For preparation before any clipping decision, read our complete coat-preparation guide.

Source and scope

Messiaen Y., MacLellan J.D., Pelsue D.H. Evaluation of the number of colony forming units on the skin of dogs after clipping the hair with two sizes of clipper blades. American Journal of Veterinary Research, 2019;80(9):862–867. Study abstract. DOI: 10.2460/ajvr.80.9.862. The salon decision record above is a practical application, not a protocol validated in that study.

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