Chihuahua Health Testing Requirements for Stud Dogs

Chihuahuas are the world's smallest recognized breed and carry health risks that reflect their extreme small size, including structural vulnerabilities and inherited cardiac disease.

The Chihuahua Club of America (CCA) participates in the OFA CHIC program with requirements targeting the breed's primary health concerns.

CHIC Requirements for Chihuahuas

• OFA Cardiac Evaluation
• OFA Eye Examination (CAER)
• OFA Patella Evaluation
• OFA Neurological Evaluation

Cardiac Evaluation

Patent Ductus Arteriosus (PDA) and pulmonic stenosis occur in Chihuahuas. Cardiac evaluation by auscultation (and echocardiogram if abnormalities are found) is essential. Any Chihuahua stud dog with a heart murmur should be fully evaluated before breeding.

Patellar Luxation

Patellar luxation (slipping kneecap) is extremely common in Chihuahuas. OFA Patella evaluation grades luxation severity 0-4. Stud dogs should ideally be Grade 0 (Normal). Grade I may be acceptable with disclosure; Grade II or higher should not be used for breeding.

Neurological — Hydrocephalus and Molera

Molera (open fontanelle/soft spot on skull) occurs naturally in many Chihuahuas. Severe molera can be associated with hydrocephalus. OFA Neurological evaluation can document status.

Hydrocephalus causes skull enlargement, behavioral changes, and seizures. Apple-headed Chihuahuas are more commonly affected than deer-headed. Selecting for dogs without hydrocephalus history is important.

IVDD Risk — CDDY Mutation

Chihuahuas carry the CDDY chondrodystrophy mutation associated with IVDD. DNA testing can identify whether a dog is N/CDDY (one copy) or CDDY/CDDY (two copies). Two-copy dogs have the highest disc disease risk. Radiographic disc screening is a practical tool.

Hypoglycemia

Toy breed hypoglycemia is common in Chihuahua puppies and can be fatal without management. Selecting for appropriately sized dogs and proper puppy management minimizes risk.

Summary

A responsible Chihuahua stud dog should have: OFA Cardiac evaluation, OFA Patella evaluation (Grade 0-I only), OFA CAER eye exam, OFA Neurological evaluation, and CDDY DNA testing with results disclosed. Patellar luxation is the most common cause of suffering in the breed and should be prioritized in selection decisions.