How the body condition photo analysis works
The CanAI BDI (Body Dog Index) gives you wellbeing guidance on your dog's weight and body condition from a single photo. Here we explain exactly what it does, what it is based on, and what it cannot do.
WSAVA BCS 1–9
What is the BDI?
The Body Dog Index (BDI) is CanAI's name for the body condition score of your dog, based on the WSAVA BCS 1-9 clinical scale. It is a wellbeing guidance tool — not a medical or veterinary diagnosis. It observes whether a dog appears to be below, at, or above an ideal weight from a photo.
How the analysis works
The analysis runs in two automated steps using a vision model (Claude Haiku 4.5 by Anthropic):
Before analysing, the system checks that the image actually shows a dog. If no dog is visible (or the image is too blurry or badly framed), the analysis stops and the user is informed.
Once the image is validated, the model visually analyses the dog's body: it looks at the ribs (whether visible or not), waist profile, abdomen shape and fat deposits. From these observations it assigns a BDI score from 1 to 9, and returns a descriptive label, specific observations and a confidence level.
We use Claude Haiku 4.5, a multimodal vision model by Anthropic. The model can analyse images, but has no access to clinical records, does not know your dog's breed or age (unless you provide them), and does not make diagnoses. Its output is a guidance estimate based on what it sees in the image.
What it is based on: the WSAVA BCS 1-9 scale
The reference scale is the WSAVA Body Condition Score (BCS) 1-9, an international veterinary standard developed by the World Small Animal Veterinary Association. It is the same scale used by vets worldwide to assess whether a dog is at a healthy weight. It primarily evaluates:
- Visibility and palpability of the ribs
- Waist profile seen from above and from the side
- Fat accumulation in the lumbar area and base of the tail
- General shape of the abdomen
Source: WSAVA Global Nutrition Guidelines and the BCS scale published by the World Small Animal Veterinary Association.
Confidence level of the estimate
Each analysis returns a confidence level (high, medium or low). This reflects how much useful information the model could extract from the photo: a sharp image of a standing dog in profile, with good lighting, produces more reliable estimates. A blurry photo with the dog crouching, lying down or partially hidden produces low confidence. We have not conducted a clinical accuracy study, so we publish no accuracy percentage.
Visual guide to BCS 1-9
What the BDI is NOT
- Not a medical or veterinary diagnosis.
- Does not detect diseases, injuries or internal conditions.
- Does not replace an in-person assessment by a licensed vet.
- Has no validated clinical accuracy — we publish no accuracy percentages because we have not conducted a clinical study.
- Does not consider medical history, blood tests or physical examination.
CanAI's BDI offers wellbeing guidance based on the standard WSAVA BCS 1-9 veterinary scale. It is not a medical diagnosis and we have not conducted a clinical accuracy study. For any concern about your dog's weight, health or wellbeing, always consult your vet.
Want to analyse your dog?
The photo analysis is available in the native CanAI app. Create your free profile and get started.