Staffordshire Bull Terrier nutrition: L-2-HGA and itchy skin

Staffordshire Bull Terriers are compact and heavily muscled for their size. The American Kennel Club gives 28 to 38 pounds (13 to 17 kg) for males and 24 to 34 pounds (11 to 15 kg) for females, with a life expectancy of 12 to 15 years. The breed has two inherited conditions with DNA tests, L-2-hydroxyglutaric aciduria (L-2-HGA) and hereditary cataract, and breeders also screen hips, elbows, knees and eyes. Diet does not change the genetics. It does decide how much weight those joints carry, and it is the main tool for working out whether itchy skin has anything to do with food.

L-2-HGA, an inherited metabolic disease

In L-2-HGA a faulty enzyme fails to break down L-2-hydroxyglutaric acid, which builds up in the body and damages the brain. The condition is autosomal recessive: a dog needs two copies of the mutation to be affected, and carriers stay healthy. Among dogs, it has been described most fully in Staffordshire Bull Terriers.

Owners of 27 affected Staffies described their dogs' signs in a study published in the Veterinary Record. Signs began at 12 months on average, but anywhere from 10 weeks to 5 years. Every dog whose owner answered that question had an abnormal gait, and stiffness in all four legs was usually the first thing noticed. Other common signs were:

• Tremors of the body or head, and a hunched back
• Exaggerated, high-stepping movements
• Staring into space, confusion and loss of training
• Episodes resembling seizures

The disease is progressive, but the outlook was better than its reputation. Seventy percent of the dogs were still alive at an average of more than six years after signs began, and the authors concluded that signs can be managed well enough for some affected dogs to reach a normal lifespan.

A young Staffie with stiffness, wobbliness, tremors or behavior changes needs a vet, and often a neurologist. No specific diet has been shown to change the course of L-2-HGA, and supplements marketed for brain health have not been tested in these dogs. Any diet change for an affected dog belongs in the plan the vet sets. The better answer is prevention: with the DNA test, breeders can avoid mating two carriers, so asking for both parents' results is the most useful step before buying a puppy.

Itchy skin and food allergy

Itchy skin, paw licking and repeated ear infections are familiar to many Staffie owners. Food allergy is one possible cause, but not the most common one. A systematic review found cutaneous adverse food reactions in only 1 to 2% of dogs seen by vets for any reason, and in 9 to 40% of dogs with itching. Environmental allergies, fleas and skin infections look much the same, so a vet should rule those out first.

The standard way to diagnose it is an elimination diet followed by a food challenge:

• Choose the trial food with the vet. It is either a prescription hydrolyzed protein diet, in which proteins are broken into pieces too small to trigger most reactions, or a diet built on a protein and carbohydrate the dog has never eaten.
• Feed nothing else. No treats, chews, table scraps or flavored medicines. Many owners use pieces of the trial food as training rewards.
• Keep going for at least eight weeks. A review of elimination diet trials found that eight weeks were needed for more than 90% of food-allergic dogs to go into full remission.
• Challenge with the old food. If the itch comes back after reintroducing it, food allergy is confirmed. Single ingredients can then be tested one at a time.

The most commonly reported food allergens in dogs are beef, dairy, chicken and wheat. Once a dog's triggers are known, a long-term diet that avoids them is enough. The advice to rotate proteins every few months to prevent new allergies has no published evidence behind it. For more on the subject, see the guide to food allergies in pets.

Protein, calories and body shape

A muscular dog does not need an unusual diet to stay muscular. A complete and balanced food for the dog's life stage, with enough exercise, maintains it. Under AAFCO guidelines, adult dog food must contain at least 18% protein on a dry matter basis and growth diets at least 22.5%. Protein beyond what the dog needs is used for energy, and exercise is what keeps the muscle.

For calories, the Merck Veterinary Manual gives resting energy requirement as 70 multiplied by body weight in kilograms to the power 0.75, multiplied by 1.6 for a neutered adult, 1.8 for an intact adult and 1.4 for an adult prone to weight gain.

These figures are starting points, and Merck notes that dogs of the same weight can differ by up to 30%. The AKC also warns that some Staffies are prone to weight gain. The breed's build makes that easy to miss. A heavy Staffie can look powerful rather than fat, yet at the right weight the ribs are easy to feel under a thin layer of fat, the waist is visible from above and the belly tucks up behind the ribs. If the ribs cannot be felt without pressing, the dog is carrying too much.

Hereditary cataract and other eye conditions

Hereditary cataract in Staffordshire Bull Terriers has been linked to a mutation in the HSF4 gene that appears to be inherited recessively, and a DNA test lets breeders avoid producing affected puppies. According to the AKC, responsible breeders also have their dogs' eyes examined for other inherited problems, including persistent hyperplastic primary vitreous and posterior polar subcapsular cataract.

No diet or supplement prevents an inherited cataract or reverses one once it forms. Antioxidant and lutein products are sold for eye health, but they have not been shown to protect dogs with this mutation. Cloudiness in the eye, bumping into things or reluctance on stairs or in dim light all need a vet check. A veterinary ophthalmologist can advise whether surgery is an option.

Hips, elbows and exercise

Breeders screen Staffies for hip and elbow dysplasia and patellar luxation. Genetics set the risk, but body weight affects how much strain the joints take. In a lifelong study of 48 Labrador Retrievers, dogs fed 25% less than their pair-mates stayed leaner, lived longer and developed signs of chronic disease later. The study used Labradors, not Staffies, but the principle of keeping a dog lean from puppyhood applies to any breed with joint risks.

Puppies should grow steadily, not fast. Feed a complete growth diet in measured meals rather than free choice, weigh regularly, and adjust portions to keep the puppy lean. Joint supplements are widely given to adult dogs, but there is no established dose that prevents dysplasia in a healthy young Staffie, and an older dog with stiff joints needs a vet's assessment rather than a guess.

Adult Staffies need regular, vigorous exercise. The AKC recommends waiting until 18 months, when the growth plates have closed, before running a Staffie beside a bike or on long jogs. It also notes that the breed can be heat intolerant and should never be worked hard in warm or humid weather.

Sources

1. Staffordshire Bull Terrier Dog Breed Information. American Kennel Club.
2. Clinical features and disease progression of L-2-hydroxyglutaric aciduria in 27 Staffordshire bull terriers. Veterinary Record, 2016.
3. Critically appraised topic on adverse food reactions of companion animals (3): prevalence of cutaneous adverse food reactions in dogs and cats. BMC Veterinary Research, 2017.
4. Critically appraised topic on adverse food reactions of companion animals (1): duration of elimination diets. BMC Veterinary Research, 2015.
5. Critically appraised topic on adverse food reactions of companion animals (2): common food allergen sources in dogs and cats. BMC Veterinary Research, 2016.
6. Nutritional Requirements of Small Animals. Merck Veterinary Manual.
7. Identification of mutations in HSF4 in dogs of three different breeds with hereditary cataracts. Veterinary Ophthalmology, 2006.
8. Effects of diet restriction on life span and age-related changes in dogs. Journal of the American Veterinary Medical Association, 2002.