Canine Nutrition & Feeding – Comprehensive Study Notes

Moisture-Based Categories of Commercial Pet Food

• Canned / Wet Food (≈75 % water)
  • More palatable; lower caloric density because buyer is paying for water weight.
  • \text{Fewer kcal}\;\Rightarrow\;\text{more volume needed to meet energy}.
  • Cost per calorie is higher.
• Soft-Moist / Semi-Moist (20–65 % water, AFCO definition)
  • Still on the market mainly as treats (≈30 % water).
  • Would mold quickly if not chemically preserved; water is “tied up” with high levels of sugars or sugar alcohols (same concept as jam).
  • Unsuitable for diabetic dogs/cats due to high simple-sugar load.
  • Typically expensive and extremely palatable.
• Dry Food (≈10 % water) — Mentioned indirectly: higher caloric density (≈4 kcal g⁻¹) and typically lower in fat than canned.

Treats & Oral Health

• Chew treats can mechanically remove plaque/tartar IF they do not shatter and last long enough to abrade tooth surface.
  • Some feature surface calcium chelators to inhibit tartar mineralisation.
• Tooth-brushing remains the “gold standard.”
  • Training and owner compliance are limiting factors.
• Calorie awareness
  • Small Milk-Bone ≈ 40 kcal; large ≈ 240 kcal.
  • Six large treats could meet the entire daily energy (~1 500 kcal) of a big dog; easily displace balanced ration.
  • Treats are expensive per kcal and usually not nutritionally balanced.
• Rule: keep treats ≤ 10 % of daily calories unless they are “complete & balanced.”

Home-Prepared Diets: “Complete” vs “Balanced”

• Complete = contains every essential nutrient.
• Balanced = when fed in the quantity that maintains ideal body weight/condition, all essential nutrients are supplied.
  • Example: Owner designed a diet that was complete on paper but required ~1 000 kcal day⁻¹ for a tiny Yorkie that only needed ~100 kcal → practical deficiency.
• Typical shortcomings of home diets
  • Mineral and essential-fat deficiencies common.
  • Owners must consult a veterinary nutritionist; University of Florida offers diet-balancing.
  • Recipes from the internet/books seldom analysed or animal-tested.
• Compliance issues: pets selectively eat tastier items (e.g., chicken vs rice), destroying intended balance.
• Time, cost, lack of feeding-trial data, and need for periodic veterinary monitoring (bloodwork) make home diets challenging.

Cooking: Nutritional & Microbial Effects

• Pros
  • Destroys pathogens; primary rationale for advocate.
  • Mild cooking ↑ digestibility:
  • Proteins: unfolding quaternary structure → enzymes access.
  • Starch: gelatinisation (observable when cornstarch thickens as water boils).
• Over-cooking
  • Excess heat/time → Maillard/browning reactions (protein–carbohydrate cross-linking).
  • Lysine often involved; trypsin can’t cleave → ↓ protein digestibility.
  • Commercial manufacturers tightly regulate cook time/temperature; over-cooked batches discarded.
• Nutrient losses & industry compensation
  • Heat-labile: taurine, methionine, thiamine, other B-vits, creatine.
  • Companies add extras pre-cook so post-cook levels remain adequate.
  • Dogs endogenously make creatine; supplementation not currently required.

Raw-Food Debate

• Popular because “wolves eat raw.”
• Major concern: widespread bacterial contamination (e.g., Salmonella, E. coli).
  • Young, old, pregnant, immunocompromised animals should never receive raw.
  • Pets can become intermittent shedders, posing human public-health risks (cats lick fur, dogs contaminate environment).
• Still often nutritionally incomplete; professional formulation essential.
• Perceived benefits often due to ↑ fat content of meat relative to kibble:
  • Better coat, smaller stool, higher palatability — identical effects achieved with balanced high-fat canned diets without pathogen risk.

Processed Pet Food vs Human Processed Food

• Pet foods: formulated to be complete & balanced; moderate salt; fat desirable for dogs.
• Human processed foods: not balanced, high salt/fat → unsuitable as staples.
• Keep packaging lot number even if food is decanted; essential for recall tracing.

Meat By-Products: Definition & Role

• AFCO “meat” = striated muscle (skeletal, heart, diaphragm, esophagus).
• “Meat by-products” = spleen, liver, kidney, bone, blood, fat, cleaned intestines — NOT hair, horn, hoof, teeth.
• Wild carnivores consume entire carcass; by-products supply essential nutrients absent in muscle meat alone.
• Balanced pet foods purposefully blend meat + by-products to reconstitute a whole-prey nutrient profile.

Canine Obesity: Epidemiology & Health Impact

• Prevalence \approx 20\text{–}40\% (may be higher).
• Adipose tissue is metabolically active: secretes TNF-α, VEGF, NGF, hormones → systemic inflammation.
• Landmark Purina life-span study (paired Labrador littermates):
  • Restricted-fed group (median BCS 4.5⁄9) lived ≈2 yr longer than control (BCS 6.9⁄9).
  • Osteoarthritis meds needed 3 yr later in lean dogs.
• Ideal body condition cues
  • “Hourglass” waist from above & side.
  • Ribs palpable with flat fingers (back of hand feel) but not visible.
  • Fist knuckles feel = too thin; palm = too fat.

Estimating & Adjusting Energy Intake

• Practical method: feed, monitor BCS, adjust.
• Worked example
  • Dog eats 120\,\text{g day}^{-1} of kibble \times 4\,\text{kcal g}^{-1} = 480\,\text{kcal day}^{-1} — new diets must supply same kcal, then fine-tune.
• Predictive equations/charts use metabolic body weight BW^{0.75}.
  • Basal: 76\,\text{kcal} \times BW^{0.75}.
  • Maintenance, inactive pet: \approx 95\,\text{kcal} \times BW^{0.75}.
  • True needs vary widely (breed, temperament, climate, neuter status): some corgis maintain on \approx 400\,\text{kcal day}^{-1}.

Activity, Work & Sport

• Energy cost rises with distance, not just speed.
  • Greyhounds: brief sprints → modest extra kcal.
  • Herding/hunting dogs: prolonged running → substantial kcal increase.
  • Racing sled dogs & Tour-de-France cyclists among the highest requirements (several × maintenance), yet individual sled-dog variation remains large.

Life-Stage Nutrition

Pregnancy (≈9 wk gestation)

• Wk 0–5 ≈ no extra kcal.
• Last 3–4 wk: +10–15 % kcal per week.
  • Uterine space limits gastric volume → feed energy-dense, highly digestible diet.

Lactation

• Energy need peaks at 3–4 × maintenance, proportional to litter size — most demanding life stage.
• Feed a diet labelled for “all life stages” or “growth & reproduction.”

Neonatal Puppies

• Bitch’s milk vs cow’s: higher kcal, protein, fat, calcium; lower lactose.
• Use commercial milk replacer if orphaned; aim ≥ 1.2\,\text{kcal ml}^{-1}.
  • Target intake: 25\,\text{kcal} / (100\,\text{g BW·day}).
  • Initial reality: may only reach 15\% BW in fluid first week; warm (≈30 °C) humid environment conserves energy.
• Colostrum within first 24 h vital for passive immunity; veterinary serum therapy possible if missed.
• Feeding frequency: mimic natural 40 mini-feeds→ gradually down-shift to q2–4 h, then 4× day.
• Manual stimulation (cotton ball) needed for urination/defecation.

Weaning & Early Growth

• Introduce canned food “gruel” at ~3 wk but do not separate from dam before 6 wk (preferably 8 wk+).
• Post-weaning schedule: 4× day → 2× day by 6 mo → possibly 1× in adulthood.
• Growth management
  • Keep pups lean to reduce orthopedic disease; large breeds especially sensitive.
  • Growth rate ↓, final stature unaffected.
• Calcium window critical (large breeds): too little → nutritional secondary hyperparathyroidism; too much → osteochondrosis.
  • Do not add calcium to balanced puppy diets; do not feed all-meat.

Calcium Pathologies (Radiographic Examples)

• Deficiency: thin, poorly mineralised bone → fractures (radiolucent femur image).
• Excess: osteochondrosis dissecans (cartilage flap in shoulder radiograph).
• Balanced commercial growth diets carefully match \text{Ca} : \text{P} and absolute Ca (≈ 1.2\text{–}1.8\,\%\,\text{DM} depending on size).

Supplements & “Extras”

• If diet carries AFCO statement “complete & balanced,” NO additional vitamins, minerals, meat scraps, calcium, or people food are needed.
• Supplements may unbalance diet or raise nutrients to toxic levels; many nutraceutical “pep pills” unnecessary.

Key Take-Home Messages

• Dogs have species-specific nutrient needs best met by commercial diets that are complete, balanced, and proven in feeding trials.
• Treats ≤ 10 % daily kcal; favour dental chews with proven efficacy.
• Keep body condition lean throughout life, especially growth, pregnancy, lactation, and senior years.
• Raw meat poses pathogen risk; equivalent benefits achieved with high-fat canned diets without the danger.
• Avoid dietary supplements unless prescribed for a diagnosed medical condition.
• Retain bag/can lot numbers for potential recalls or adverse-event investigations.

Feeding Sick Dogs (Brief)

• Always obtain veterinary diagnosis first; diet rarely primary cause of diarrhoea/vomiting.
• Some diseases benefit from therapeutic diets, but transitions must be slow (≈1 mo for colonic carb adaptation).
• Never institute major dietary changes while dog is acutely ill unless directed by veterinarian.