Canine Digestion, Metabolism & Nutrient Requirements (copy)

Dentition

Large canines for seizing prey; carnassial cheek teeth slice flesh/bone rather than grind.

GI tract layout

Simple-stomach animal layout: Stomach → duodenal loop → long small intestine → short large intestine/colon → tiny cecum.

Carnivore to Omnivore

Dogs are evolutionary carnivores but functionally omnivorous, consuming a variety of carcass parts and seasonal fruits.

Nutritional Mind-set

Nutritionists focus on nutrients (proteins, fats, carbs, vitamins, minerals) rather than just ingredients used in pet food.

Surface-area principle

Bigger animals have lower heat loss per kg, affecting energy and nutrient requirements.

Resting Energy Expenditure (REE)

For dogs, REE is approximately 70 times body weight to the power of 0.75.

Ileal digestibility

Range from 50–100%; meat & casein nearly 100% digestible.

Essential amino acid

Arginine is essential for dogs to maintain the urea cycle.

Lipid Digestion

Dogs digest fats 85–100% and metabolize fat approximately twice as fast as humans.

Fatty Acid Pathways

n-6 pathway leads to arachidonic acid; n-3 pathway leads to EPA and DHA.

Carbohydrate Digestion

Dogs lack salivary amylase but have robust pancreatic amylase for efficient starch digestion.

Fiber Categories

Insoluble fiber helps firm stool; soluble fiber aids in bacterial fermentation.

Gluconeogenesis in Dogs

Dogs can gluconeogenically meet glucose needs if adequate protein is provided.

Nutrient Requirement Parallels

Vitamin requirements per 1000 kcal in dogs typically mirrors those of other mammals.

Exercise Metabolism Hierarchy

1. ATP + creatine-P; 2. Anaerobic glycolysis; 3. Aerobic oxidation; 4. β-oxidation of fatty acids.

Starvation Physiology

Dogs maintain euglycaemia with minimal ketosis during prolonged fasting.

Diet Quality Assessment

Assess diet quality by nutrient composition and balance, not just ingredient lists.

Endurance vs. Sprint

Endurance work (>30 min) typical in dogs; sprint relies on quick energy sources.

Key Numerical Reference

REE for dogs is approximately 70 BW^0.75 kcal·day^-1.

Feeding Implications for Performance Dogs

High-fat (>50% kcal) ration needed for endurance performance; ensure hydration.