Study summary · Dogs · Joint health · Roush et al., 2010
An objective movement measure, with limits to interpretation.
A fish-oil-enriched food showed a promising movement result in dogs with arthritis, but owner assessments did not show a treatment difference. The analysis excluded six dogs who did not finish.
Why this study matters
An owner’s impression and an instrumented movement measurement answer related but different questions. The key is whether a reported change represents a fair comparison between treatments, and whether it translates into an improvement that matters in daily life.
How the study worked
Participants
44 client-owned dogs with osteoarthritis were randomised; 38 completed and were analysed (22 test, 16 control).
What happened?
Fish-oil-enriched test food.
The comparison
Control food.
What was measured?
Weight bearing measured by force plate and clinical assessment.
What the researchers found
| Outcome | Reported result | How to read it |
|---|---|---|
| Peak vertical force | Change: 5.6% test food; 0.4% control. | These are reported changes, not a universal response. |
| Statistical finding | Change was significant within the test group, but not within control. | This alone is not a test of the difference between groups. |
| Dogs showing improvement | 82% with test food; 38% with control (between-group P=.01). | Improvement does not necessarily mean complete pain relief. |
Source access: full article checked, including participant flow, statistical methods and funding.
What strengthens the evidence?
Random allocation, double blinding and an instrumented force-platform outcome strengthen the comparison. The full report allows the participant flow and different statistical comparisons to be checked.
What limits the conclusions?
Six randomised dogs were excluded from the completed-case analysis. The small sample and 90-day follow-up limit precision and long-term conclusions. Body-weight changes differed between groups, complicating interpretation of weight bearing. Owner assessments did not show a treatment difference. The result concerns the tested foods, not every fish-oil supplement.
What the researchers concluded
The authors concluded that the supplemented food improved weight bearing.
Evidence.pet interpretation
The proportion improving differed between groups (82% versus 38%; P=.01). That is more informative than simply noting a significant before-and-after change in one group. However, absolute force values did not differ significantly between groups at the measured visits, and owners did not report a treatment difference. These outcomes answer different questions. This is a reason to consider the dietary approach with a veterinarian and monitor function, not a guarantee of pain relief or a basis for choosing a supplement dose.
Funding and author interests
Hill’s Pet Nutrition funded the trial; several authors were affiliated with the company. Commercial involvement warrants scrutiny but does not, by itself, invalidate the findings.
Read the original research
Roush JK, Cross AR, Renberg WC, et al. Evaluation of the effects of dietary supplementation with fish oil omega-3 fatty acids on weight bearing in dogs with osteoarthritis. JAVMA. 2010;236(1):67–73. doi:10.2460/javma.236.1.67.
Evidence.pet editorial summary · Study ID STU-010 · Source checked 23 September 2026. Strengths, limitations and interpretation are our editorial assessment, not a formal evidence grade.
Full-text editorial appraisal completed. This is a critical reading of one trial, not a systematic review or formal certainty grade.