Newfoundland nutrition: growth, cystinuria and bloat

Newfoundlands are among the heaviest dog breeds. The American Kennel Club gives 130 to 150 pounds (59 to 68 kg) for males and 100 to 120 pounds (45 to 54 kg) for females, with a life expectancy of 9 to 10 years. Breeders screen for hip and elbow dysplasia, heart disease and cystinuria, and the breed is at risk of bloat. Several of these connect directly to feeding: how fast a puppy grows, how the daily ration is split, how much protein a stone-forming dog eats, and whether a Newfoundland makes enough taurine.

Calories and growth

Big dogs need fewer calories per kilogram than small ones, but the totals are still large. The Merck Veterinary Manual gives resting energy requirement as 70 multiplied by body weight in kilograms to the power 0.75, then multiplied by 1.6 for a neutered adult, 1.8 for an intact adult and 1.4 for an adult prone to weight gain.

Merck notes that dogs of the same weight can vary by up to 30%, so treat these as starting points and adjust to body condition. The AKC suggests at least half an hour of moderate exercise a day and warns that some Newfoundlands are prone to weight gain. A heavy coat hides fat, so feel for the ribs rather than judging by eye.

Puppies need the most care. Merck explains that puppies from weaning to about 6 months old may not be able to regulate how much calcium they absorb when the diet contains too much, and that rapidly growing large-breed puppies fed diets supplemented above 3% calcium on a dry matter basis developed more severe osteochondrosis than puppies on 1% to 3%. For a Newfoundland puppy that means a complete growth food made for large or giant breeds, no added calcium or bone meal, and measured meals that keep the puppy lean. A plump puppy is growing faster than its skeleton needs. The vet can track weight at each visit and advise when to change to adult food.

Cystinuria and bladder stones

Cystinuria is an inherited defect in the kidney tubules. Cystine, an amino acid that is normally reabsorbed, is lost into the urine, where it dissolves poorly and forms stones. The condition has been found in more than 60 breeds, but Newfoundlands have a severe form caused by a mutation in the SLC3A1 gene, and a DNA test identifies affected dogs and carriers. Breeding from tested parents is how the breed avoids it.

Stones can irritate the bladder or lodge in the urethra and block urine flow, which is an emergency. Straining to urinate, passing only drops, blood in the urine or repeated trips outside all need a vet the same day.

For a dog that has formed cystine stones, the ACVIM consensus recommendations on uroliths set out the approach:

• Dilute the urine. High-moisture canned food, or dry food with plenty of water added.
• Limit animal protein and methionine, the sulfur amino acid the body turns into cystine. High-protein diets should be avoided.
• Limit sodium and raise urine pH, since cystine dissolves better in alkaline urine. The vet may prescribe potassium citrate.
• Neuter, which lowers urine cystine in some forms of the disease and prevents passing the gene on.
• Add tiopronin for dogs whose stones keep coming back despite these steps.

The same guidelines carry a warning that matters for this breed. How far to restrict protein is controversial, and carnitine deficiency with dilated cardiomyopathy has been reported in cystinuric dogs fed low-protein diets. A low-protein diet for a Newfoundland should be chosen and monitored by the vet, not improvised at home. Owners should also avoid urinary acidifier supplements, which push pH in the wrong direction.

Bloat (gastric dilatation-volvulus)

In bloat the stomach fills with gas and food and can twist, cutting off its blood supply. It progresses quickly and needs emergency surgery. Newfoundlands were one of the breeds followed in a five-year study of GDV in large and giant dogs recruited at dog shows, so its findings are relevant to the breed:

• Do not raise the food bowl. A raised feeding bowl was linked to higher risk, and about 52% of GDV cases in the giant-breed dogs were attributed to it. Faster eating, older age and a first-degree relative with GDV also raised risk.
• Split the ration. Dogs fed a larger volume per meal had higher risk, which was highest for dogs fed a large volume once a day. Two or three meals keep each one smaller.
• Slow down fast eaters with a slow-feeder bowl.
• Keep hard exercise away from meals. The AKC notes that experts agree several small meals and no vigorous exercise around mealtimes may help, though the causes are not fully understood.

Signs of bloat include restlessness, drooling, a swelling belly and retching without bringing anything up, followed by weakness and collapse. Go straight to an emergency clinic. Ask the vet about a preventive gastropexy, which fastens the stomach so it cannot twist, especially if the dog is being spayed or neutered anyway.

Heart disease and taurine

Two heart conditions matter in Newfoundlands. The first is subvalvular aortic stenosis (SAS), a congenital narrowing just below the aortic valve that makes the heart work harder. In ten years of records at the UC Davis veterinary hospital, Newfoundlands had the second-highest prevalence of SAS of any breed, 4.46%, with odds about 35 times those of the comparison population. SAS is structural and diet cannot change it. It is often picked up as a murmur in a puppy or young dog, and a cardiologist's examination confirms it. Breeding dogs should be screened.

The second is dilated cardiomyopathy linked to taurine. Dogs can normally make taurine from the sulfur amino acids methionine and cysteine, but Newfoundlands appear to make less. In a study of 216 privately owned Newfoundlands, 8% had low plasma taurine. When fed the same diet, Newfoundlands made less taurine than Beagles. Of nine taurine-deficient dogs examined in detail, three had dilated cardiomyopathy that reversed with taurine supplementation.

For owners, this means a heart check that includes a taurine blood test is reasonable for a Newfoundland with a murmur, an irregular heartbeat, tiring easily, coughing or fainting. It also means low-protein or unusual diets, including those used for cystinuria, deserve extra monitoring. Supplementing taurine or carnitine without testing is not a substitute for that check.

Joints and daily feeding

Breeders screen Newfoundlands for hip and elbow dysplasia. Dysplasia is partly inherited, and body weight changes how much load those joints carry for life, which is one more reason to keep puppies lean and adults trim. Joint supplements are widely sold, but evidence that they prevent dysplasia is lacking. A limping or stiff Newfoundland needs a vet assessment first.

A few practical points for a dog this size:

• Weigh the food. A cup or scoop is imprecise, and a small error repeated twice a day adds up in a dog eating over 2,000 kcal.
• Keep water available at all times, in more than one place. For a stone-forming dog, drinking is part of treatment.
• Brush the coat thoroughly at least once a week, as the AKC recommends, and daily during shedding season.
• Feed where drool is easy to clean. Newfoundlands drool heavily around food.

Sources

1. Newfoundland Dog Breed Information. American Kennel Club.
2. Nutritional Requirements of Small Animals. Merck Veterinary Manual.
3. Canine cystinuria: polymorphism in the canine SLC3A1 gene and identification of a nonsense mutation in cystinuric Newfoundland dogs. Human Genetics, 2000.
4. ACVIM Small Animal Consensus Recommendations on the Treatment and Prevention of Uroliths in Dogs and Cats. Journal of Veterinary Internal Medicine, 2016.
5. Non-dietary risk factors for gastric dilatation-volvulus in large and giant breed dogs. Journal of the American Veterinary Medical Association, 2000.
6. Diet-related risk factors for gastric dilatation-volvulus in dogs of high-risk breeds. Journal of the American Animal Hospital Association, 2004.
7. Congenital Cardiac Outflow Tract Abnormalities in Dogs: Prevalence and Pattern of Inheritance From 2008 to 2017. Frontiers in Veterinary Science, 2019.
8. Low plasma taurine concentration in Newfoundland dogs is associated with low plasma methionine and cyst(e)ine concentrations and low taurine synthesis. Journal of Nutrition, 2006.