Dogs and cats are very different species, and they have unique nutritional needs throughout their lifetimes that you as their caretaker should be aware of. While both dogs and cats are carnivores, dogs are functional carnivores while cats are obligate carnivores. Obligate carnivores are “true” carnivores because they depend on the nutrients found only in their prey for their survival. While obligate carnivores occasionally may consume small amounts of plant material, they cannot effectively digest it. Dogs are functional carnivores, which means that they are able to digest plant material slightly better than cats, but their digestive systems are optimized for digesting meat.
A dog’s metabolism has peaks and valleys like a human’s. Dogs burn calories more slowly than cats, which means that dogs are better suited to go longer without food.
A cat’s metabolism burns consistently all day, which means that they must eat multiple times throughout the day. They should not go longer than 12 hours without eating unless directed by a veterinarian. Their overall caloric intake will be greater than the average dog.
Essential Vitamins & Amino Acids
Dogs are able to synthesize Vitamin A and to a lesser extent Niacin as well. They therefore do not typically need much supplementation in their food. Unless formulated to meet the nutritional needs of both canine and feline, dogs must eat food formulated for dogs.
Vitamin A and Niacin are two vitamins essential for proper bodily function that cats cannot synthesize and thus must obtained through their diet. Taurine is an essential amino acid that helps protect the liver, kidney, and eyes. Arginine is another essential amino acid that must be included in cats’ diets. Unless formulated to meet the nutritional needs of both canine and feline, cats must eat food formulated for cats.
Dogs in good health will seek out water to compensate for what they are not getting in their diet. That means that if your dog eats solely dry kibble (about 10% moisture), they will drink more water on average than a dog that eats a combination of canned food (70%-80% moisture) and kibble. Dogs eating raw food (60%-70% moisture) drink substantially less water than dogs on kibble.
Regardless of your dog’s diet, fresh water should be provided at all times to maintain optimal hydration and health.
Cats have evolved from desert creatures, and as a result they are designed to get the majority of moisture in their diet from their prey. They lack a sufficient thirst drive to drink enough water on their own. Since dry kibble only provides 10% moisture on average, it can help to use a water fountain, offer fresh water daily, and/or change the style or location of the water bowl for your cat.
For optimal feline hydration, it is highly recommended that cats be fed wet food. Canned food is typically 70%-80% moisture, which is comparable to a cat’s natural prey. Raw food (60%-70% moisture) is also an excellent option to provide sufficient moisture to keep your cat hydrated.
Without proper hydration, your cat will not be able to produce enough urine to flush their system. Consequentially the urine will become highly concentrated, which can lead to bladder and urinary tract issues.
Overall mineral content in pet food is commonly referred to as the ash content. Keeping this ash content at a reasonable level and providing fresh water at all times can greatly help your dog maintain urinary health.
As obligate carnivores, wild cats eat a diet that is almost purely protein. This creates urine that has acidic pH levels, which is ideal for preventing the formation of struvite crystal. Paired with the moisture content of raw meat (60%-70%), wild cats are able to produce sufficient urine to flush the system and keep urine potency down. All this is why it’s important to provide your cat with sufficient amounts of protein and moisture.
Too much protein however, can create overly acidic urine and will require a low protein diet and medication for your cat.
Male cats are more prone to crystal issues due to their smaller urethras. To prevent these issues, it is important to monitor your cat’s intake of magnesium and phosphorus. These minerals are the building blocks of struvite crystals, so while they are essential to your cat’s diet, they should not be consumed in excess.
Reading the Ingredient Label
Ingredients are listed on the label by their weight prior to cooking. The cooking process causes whole meat proteins to lose water content and move down the ingredients list. This is not the case for meals, because they have had the water and fat removed prior to cooking. Starches including grains, legumes, potatoes, fruits, and vegetables do not lose as much water as whole meat proteins. All of this considered, the first ingredients listed on an ideal food for a carnivore will be a combination of whole meat and meal proteins before getting into plant matter.
The guaranteed analysis lists the minimum or maximum content of protein, fat, fiber, and moisture. Some manufacturers may choose to list additional items beyond these, which are the ones required by the American Association of Feed Control Officials (AAFCO). By listing additional items, they must prove that these levels are present in the food at any given time.
Your pet’s age also influences their nutritional needs. The standard stages as defined by the AAFCO include growth (puppy/kitten), gestation or lactation (pregnant or nursing females), and adult maintenance (animals over one year of age). Pet food for all life stages must meet the nutritional needs of the most demanding life stage, which is growth.
- Small/toy puppy breeds (1-10lbs) from weaning to 10 months or 1 year of age require higher protein and fat for growth and to support their metabolism. Docosahexaenoic acid (DHA) is an omega-3 fatty acid that aids in brain development.
- Medium puppy breeds (1-60lbs) from weaning to 1 year of age require higher protein and fat than adults, but lower levels than for small/toy breeds. DHA aids in brain development.
- Large puppy breeds (60lbs+) from weaning to up to 1.5 years of age require lower fat, calcium, and phosphorus than regular or small breed puppies in order to help control their growth rate. They need a closer calcium to phosphorus ratio to control growth and aid in absorption. DHA aids in brain development.
- Small/toy dog breeds (1-10lbs) from 10 months or 1 year to 8 years of age require higher protein and fat than other adult dogs. Higher omega-3 and -6 levels, as well as antioxidants and probiotics can help with longevity.
- Medium dog breeds (1-60lbs) from 1 to 7 years of age benefit from omega-3 and -6 fatty acids, probiotics, and antioxidants.
- Large dog breeds (60lbs+) from 1 to 6 years of age need slightly lower levels of fat, increased glucosamine and chondroitin, omega-3 and -6 fatty acids, and probiotics.
- Keeping in mind the information above regarding differences in breeds/size, dogs over 1 year of age that need to shed a few pounds will benefit from a formula that is lower in fat and in most cases lower in protein. It should have increased fiber, as well as L-Carnitine to aid in metabolizing fat.
- Keeping in mind the information above regarding differences in breeds/size, dogs over a certain age benefit from slightly lowered levels of protein* and fat to reflect their decreased energy expenditure and slower metabolism. For small/toy breeds that age is 8 years, for medium breeds it’s 7 years, and for large breeds it’s 6 years. Senior dogs can benefit from glucosamine and chondroitin in their diet to provide joint support.
*New research has suggested that aging dogs actually benefit from increased levels of protein (not lower). Some manufacturers are starting to modify their senior formulas to reflect this new research.
- Kittens from weaning to 1 year of age need higher levels of protein and fat to support their growth. DHA aids in brain development.
- Adult cats from 1 to 8 years of age require slightly lower levels of protein and fat than kittens, as well as the addition of omega-3 and -6 fatty acids.
- Indoor cats from 1 to 8 years of age benefit from slightly lower levels of protein and fat to support their lower activity levels. Increased fiber and L-Carnitine to aid in metabolizing fat. Increased omega fatty acids can help reduce shedding, which is often made worse by heat and air conditioning.
- Cats with hairball issues from 1 year of age and over need increased fiber in order to help pull hairballs through the digestive tract. Increased omega fatty acids can help reduce shedding, which is often made worse by heat and air conditioning.
- Light formulas contain lower levels of protein, significantly lower levels of fat, increased fiber, and L-Carnitine to aid in metabolizing fat. These formulas are meant for cats 1 year of age and older.
- Senior cats 8 years of age and older benefit from slightly lower levels of fat and increased fiber in order to support their slowing metabolism. Glucosamine and chondroitin support aging joints, and L-Carnitine aids in metabolizing fat.
The information above was published with the help of Pet Food Experts. Internet sources include nzdl.org, princetonvet.net, thecattlemanmagazine.com, and mayoclinic.com. Other sources include Canine and Feline Nutrition by Case, Daristotle, Hayek, Raasch Third Edition 2011 and Small Animal Clinical Nutrition by Sandy Agar 2001.