Scientific Results: Clippers are superior to scissors in the collection of hair for cortisol analysis in companion dogs – A Dog Aging Project preliminary study

March 20, 2024 - 6 minutes read

Posts in our Scientific Results series introduce recent papers published in the scientific literature by members of the Dog Aging Project research team. Follow this series to learn more about the scientific questions we’re asking, the kinds of results we’re getting, and what it all means for you and your dog.

Who worked on this research?

Bobbie Ditzler
Jeremy B. Evans
Kate Illing
Matt Kaeberlein
Daniel E.L. Promislow
Eleanor Brindle
Jessica M. Hoffman
Kate E. Creevy

Where was it published?

American Journal of Veterinary Research

What is this paper about?

In this study, we set out to determine the best method for collecting hair samples from dogs. We wanted a tool that was easy and efficient to use, provided a clean hair sample free from contaminants of previous dogs, and could be used on different lengths and types of fur. We wanted a method that was fast, safe, and not overly stressful for the hospital staff or the patient. We picked two tools initially: scissors and single-use, disposable razors. To our surprise, the razors vastly underperformed and sometimes wouldn’t cut fur at all! So we added electric clippers which are common in veterinary settings but originally not included because of the ease of contamination. After sorting out that clippers could, in fact, provide significant quality samples, we moved forward.

We used a questionnaire to evaluate each tool, and we used two tools on each dog by cutting the ischiatic region (the upper thigh on the back of the dog). When analyzing the results, we found that clippers outperformed scissors. However, scissors are a good alternative if clippers are not available. Razors scored so low that we don’t recommend their use.

What do these results mean for me and my dog?

If your dog joins or is part of a cohort that collects fur samples, then this is the method we use. This study and the subsequent protocol were established at the dawn of the Dog Aging Project cohorts. Otherwise, hair collection is not common in a veterinary setting. But as the scientific community expands its knowledge and methods for chemical analysis (like testing hormone levels), this may become a useful collection method compared with other procedure methods like blood draws.

Where can I learn more?

Ditzler B, Evans J, Illing K, Kaeberlein M, Promislow DE, Brindle E, Hoffman JM, Creevy KE. 2024. Clippers are superior to scissors in the collection of hair for chemical analysis in companion dogs: a Dog Aging Project preliminary study. American Journal of Veterinary Research Online Early.


OBJECTIVE To identify the safest, most efficient method for hair sample collection from companion dogs among clippers, scissors, and razors and to validate obtained samples with cortisol concentration analysis.
ANIMALS 25 healthy, privately owned dogs.
METHODS 2 hair samples were collected from each dog’s ischiatic region with different implements (scissors, razors, or clippers). The collecting clinician completed a Hair Collection Questionnaire (HCQ) for each sample that compared subjective sample quality, time of collection, restraint needed, and patient experience. Each sample was evaluated by cortisol enzyme immunoassay.
RESULTS Clippers had higher overall HCQ scores than scissors, and scissors had higher HCQ scores than razors. Collection was faster for clippers than scissors, and scissors were faster than razors. There were no differences in sample quality between scissors and clippers, and sample quality was lower with razors. There was no difference in restraint needed or patient experience. Collection of long hair had higher HCQ scores than collection of medium and short hair. Collection of hair from dogs with an undercoat had higher HCQ scores than collection of hair from dogs without an undercoat. Dog size had no effect on HCQ score. Hair cortisol concentration did not vary between scissors or clippers (P = .111). Hair color and age did not affect hair cortisol concentration (P = .966 and P = .676, respectively).
CLINICAL RELEVANCE Clippers are recommended for hair sample collection from companion dogs. Scissors are an adequate alternative.