Shetland Sheepdog (Sheltie) Stud Dog: MDR1, CEA, Health Testing, and What to Look For

The Sheltie is a remarkably capable herding dog in a beautiful, compact package — with genetics that demand careful attention

The Shetland Sheepdog is one of the most intelligent, responsive, and trainable breeds in existence. A miniature herding dog developed on the Shetland Islands, the Sheltie excels in obedience, agility, herding, and as a devoted companion. Their stunning coat — available in sable, tricolor, blue merle, and more — makes them one of the most beautiful breeds in the show ring.

But Shelties carry several significant inherited conditions that make health testing essential for every breeding.

Health Testing Requirements for Sheltie Studs

The American Shetland Sheepdog Association (ASSA) has established comprehensive health testing requirements.

MDR1 (Multi-Drug Resistance Gene) — DNA Test

The MDR1 mutation is one of the most critical genetic tests for Shelties. Dogs with one or two copies of the mutation have a defective P-glycoprotein that normally pumps drugs out of the brain. Without it, commonly used medications accumulate to toxic levels in the brain and cause severe neurological reactions — including seizures, coma, and death.

MDR1-sensitive medications include:

• Ivermectin (at high doses, such as in some parasite treatments)
• Loperamide (Imodium — an over-the-counter anti-diarrheal)
• Acepromazine (a sedative)
• Butorphanol (a pain medication)
• Several chemotherapy drugs

Status and breeding implications:

• Clear (WT/WT) — Normal drug metabolism. No restrictions.
• Carrier (MDR1/WT) — Intermediate sensitivity. Should use caution with MDR1-sensitive drugs.
• Affected (MDR1/MDR1) — Severely sensitive. Must avoid all MDR1-sensitive drugs.

All breeding Shelties should be DNA tested. Buyers of Sheltie puppies must be informed of their puppy's MDR1 status.

Collie Eye Anomaly (CEA) — DNA Test and CAER Exam

CEA is an inherited eye condition affecting the development of the choroid. It ranges from subclinical (mild, no vision impact) to severe (colobomas, retinal detachment, blindness).

DNA testing identifies Clear, Carrier, and Affected dogs. An annual CAER exam by a board-certified ophthalmologist is also recommended, as CEA DNA testing and CAER exams complement each other — the DNA test identifies genetic status regardless of phenotypic expression.

Progressive Retinal Atrophy (PRA) — DNA Test

PRA-prcd DNA testing is recommended. Clear studs should be used whenever possible.

Hip Dysplasia — OFA Evaluation

Hip dysplasia occurs in Shelties. OFA evaluation at 24 months or older, rated Good or Excellent, is the standard.

Dermatomyositis (DM) — DNA Test

Dermatomyositis is a heritable inflammatory condition affecting the skin and muscles of young Shelties. It causes crusty lesions on the face, ears, and paws, and in severe cases can cause muscle wasting. A DNA test is available through the University of Minnesota. Clear, Carrier, and Affected dogs can be identified. Carrier-to-Carrier pairings produce 25% Affected offspring and should be avoided.

von Willebrand's Disease Type III (vWD3) — DNA Test

A severe bleeding disorder in Shelties. Affected dogs cannot clot normally and can bleed to death from minor injuries or surgery. DNA testing identifies all statuses. Clear studs are strongly preferred.

Thyroid Testing

Hypothyroidism occurs in Shelties. Annual OFA thyroid panel is recommended for breeding dogs.

Sheltie Color Genetics

Shelties come in several AKC-recognized colors and patterns:

Sable

Ranges from golden-yellow to dark mahogany. The most common Sheltie color. Sables can be "clear sable" (uniform golden with no dark tipping) or "shaded sable" (dark mahogany with significant black overlay). Sable is produced by the Ay allele at the A locus.

Tricolor

Black body with white markings (collar, chest, feet, blaze) and tan points on the face, legs, and under the tail. Classic and elegant. Tricolor is produced by the at (tan points) allele at the A locus combined with dominant black.

Blue Merle

A mottled silver-blue pattern with black patches, white collar, and tan points. Blue merle is the merle gene (Mm) acting on a tricolor base. One of the most striking color patterns in dogdom.

Critical merle rule: Never breed blue merle to blue merle. Double merle (MM) Shelties are predominantly white and typically have severe visual and hearing defects.

Bi-Color (Black and White, No Tan)

Black with white collar but no tan points. Sometimes called "bi-black."

Sable Merle and Bi-Blue

Less common variants produced by merle acting on sable or bi-black base colors.

Color-Headed White (CHW)

CHW Shelties are predominantly white with a fully-colored head. These dogs often carry two copies of a white-causing gene and have high rates of deafness and vision defects. Most responsible Sheltie breeders do not breed for CHW dogs, and many breed clubs discourage it.

What Does a Sheltie Stud Fee Cost?

Sheltie stud fees in 2026 typically range from $700 to $2,500 depending on:

• AKC Championship or performance titles (obedience, agility)
• Full DNA health panel (MDR1, CEA, DM, vWD3, PRA)
• OFA hips and thyroid clearances
• Color and merle status documentation

Questions to Ask Before Booking

• Has the stud been DNA tested for MDR1, CEA, DM, vWD3, and PRA-prcd?
• Can I see OFA hip certification and current CAER eye exam?
• Has the stud been tested for thyroid disease?
• Is the stud merle — and is there any risk of a double merle pairing with my dam?
• What are his performance or conformation titles?
• Is he AKC registered?
• Has he produced litters, and can I speak with previous dam owners?
• Will you provide a written stud contract?

Summary

A quality Sheltie stud has a complete DNA health panel — MDR1, CEA, dermatomyositis, vWD3, and PRA — as well as OFA hip clearance and thyroid testing. Merle status must be confirmed and documented to prevent double merle pairings. The Sheltie's intelligence, trainability, and beauty are extraordinary — a thoughtfully tested breeding program is what keeps them that way.