🐕 Canine Companions: Dogs

📚 Introduction to Canine Science

Dogs (Canis familiaris) have been humanity's companions for over 15,000 years, evolving from wolves through selective breeding to become one of the most diverse species on Earth. With over 340 recognized breeds worldwide, dogs exhibit remarkable variation in size, appearance, behavior, and function. From the tiny Chihuahua weighing just 2 pounds to the massive English Mastiff that can exceed 230 pounds, dogs demonstrate extraordinary genetic plasticity while maintaining their fundamental canine characteristics.

As veterinary professionals, understanding canine biology, behavior, nutrition, and health is essential for providing optimal care. This comprehensive module covers all aspects of canine veterinary science, from breed characteristics and developmental stages to complex medical conditions and preventive care protocols.

🐾 Breed Groups and Characteristics

The AKC recognizes seven distinct breed groups, each developed for specific purposes. Understanding these classifications helps predict behavior patterns, exercise requirements, and potential health concerns.

Originally bred to assist hunters in finding and retrieving game, particularly waterfowl. These breeds possess high energy, gentle mouths, and water-resistant coats.

• Popular Breeds: Labrador Retriever, Golden Retriever, Cocker Spaniel, English Setter, Pointer
• Characteristics: High stamina, trainable, friendly disposition, strong swimming ability
• Exercise Needs: 60-120 minutes daily, enjoy swimming and fetching
• Common Health Issues: Hip dysplasia, elbow dysplasia, progressive retinal atrophy, ear infections

Bred for hunting using either scent or sight. These independent thinkers often exhibit strong prey drive and distinctive vocalizations.

• Scent Hounds: Bloodhound, Beagle, Basset Hound - track prey by smell
• Sight Hounds: Greyhound, Whippet, Afghan Hound - hunt by visual pursuit
• Special Note: Dachshunds, though bred to hunt badgers underground, are classified as hounds due to scent-tracking abilities
• Common Health Issues: Intervertebral disc disease (especially Dachshunds), bloat, ear infections

Developed for specific jobs including guarding property, pulling sleds, and water rescue. These powerful breeds require experienced handlers.

• Popular Breeds: Siberian Husky, Rottweiler, Doberman Pinscher, Great Dane, Mastiff
• Characteristics: Large size, strong protective instincts, high intelligence
• Training Requirements: Early socialization crucial, consistent leadership needed
• Common Health Issues: Hip dysplasia, dilated cardiomyopathy, bloat (GDV)

Originally bred to hunt vermin and go to ground after prey. Known for feisty personalities and tenacious attitudes.

• Popular Breeds: Jack Russell Terrier, Bull Terrier, Scottish Terrier, Airedale Terrier
• Characteristics: High energy, independent, brave, can be dog-aggressive
• Exercise Needs: Moderate to high, need mental stimulation
• Common Health Issues: Luxating patella, skin allergies, dental disease

Bred primarily for companionship. Despite small size, many have big personalities and can be quite protective.

• Popular Breeds: Chihuahua, Pomeranian, Yorkshire Terrier, Maltese, Pug
• Characteristics: Small size (under 20 pounds), portable, often long-lived
• Special Considerations: Prone to hypoglycemia, dental crowding, fragile bones
• Common Health Issues: Luxating patella, dental disease, collapsing trachea

Diverse group with varied backgrounds and purposes. Each breed has unique characteristics and care requirements.

• Popular Breeds: Bulldog, Poodle, Dalmatian, Boston Terrier, Shiba Inu
• Characteristics: Wide variety in size, coat type, and temperament
• Special Notes: Many brachycephalic breeds with breathing concerns

Developed to control the movement of livestock. Highly intelligent with strong working drive.

• Popular Breeds: German Shepherd, Border Collie, Australian Shepherd, Pembroke Welsh Corgi
• Characteristics: High intelligence, trainability, may "herd" children or other pets
• Exercise Needs: High mental and physical stimulation requirements
• Common Health Issues: Hip dysplasia, MDR1 gene mutation (Collies), epilepsy

📈 Canine Life Cycle and Development

Stage	Age Range	Key Developments	Care Requirements
Neonatal	0-2 weeks	Eyes/ears closed, limited mobility, cannot thermoregulate	Constant warmth, maternal care, feeding every 2-3 hours
Transitional	2-4 weeks	Eyes open (10-14 days), ears open (14-17 days), first steps	Introduction to soft foods, gentle handling
Socialization	3-14 weeks	Critical period for social development, fear periods	Exposure to various stimuli, people, animals
Juvenile	3-6 months	Rapid growth, teething, sexual maturity approaching	Training, proper nutrition, vaccination series
Adolescent	6-18 months	Sexual maturity, testing boundaries, growth plates closing	Consistent training, spay/neuter consideration
Adult	1-7 years	Physical and mental maturity	Maintenance diet, regular exercise, preventive care
Senior	7+ years	Slowing metabolism, potential health issues emerging	Bi-annual exams, adjusted diet, joint support

❤️ Vital Signs and Physical Parameters

Parameter	Normal Range	Notes
Temperature	99.5-102.5°F (37.5-39.2°C)	Puppies may run slightly higher; stress can elevate
Heart Rate	Small dogs: 100-140 bpm Medium: 80-120 bpm Large: 60-100 bpm	Athletic dogs may have lower resting rates
Respiratory Rate	10-30 breaths/minute	Panting doesn't count; measure at rest
Capillary Refill Time	< 2 seconds	Press gum, release, measure color return
Mucous Membranes	Pink and moist	Pale = anemia/shock; Blue = hypoxia; Yellow = jaundice
Hydration Status	Skin tents < 2 seconds	Check skin elasticity on neck or back

🥘 Canine Nutrition

Life Stage	Protein %	Fat %	Calories/kg/day	Feeding Frequency
Puppy (0-4 months)	28-32%	15-20%	200-250	4 times daily
Puppy (4-12 months)	22-28%	8-15%	150-200	3 times daily
Adult (1-7 years)	18-25%	5-15%	60-80	2 times daily
Senior (7+ years)	18-23%	5-10%	50-60	2-3 small meals
Pregnant/Lactating	28-32%	15-20%	200-300+	Free feeding or 3-4 times

The 9-point body condition scoring system helps assess whether a dog is at ideal weight:

• 1-3 (Underweight): Ribs, spine, and pelvic bones visible; no palpable fat; obvious waist
• 4-5 (Ideal): Ribs easily felt but not visible; visible waist from above; abdominal tuck present
• 6-7 (Overweight): Ribs palpable with difficulty; waist barely visible; minimal abdominal tuck
• 8-9 (Obese): Ribs not palpable; no waist; pendulous abdomen; fat deposits on neck and limbs

🏥 Common Veterinary Issues

Affects flat-faced breeds (Bulldogs, Pugs, Boston Terriers, French Bulldogs)

• Anatomical Issues: Stenotic nares, elongated soft palate, hypoplastic trachea, everted laryngeal saccules
• Clinical Signs: Noisy breathing, exercise intolerance, cyanosis, collapse
• Management: Weight control, avoid heat/stress, surgical correction if severe
• Emergency Considerations: High risk for heat stroke, anesthetic complications

Life-threatening emergency most common in large, deep-chested breeds

• High-Risk Breeds: Great Dane, German Shepherd, Standard Poodle, Doberman
• Pathophysiology: Stomach fills with gas and rotates, cutting off blood supply
• Clinical Signs: Distended abdomen, non-productive retching, restlessness, drooling
• Treatment: Immediate decompression and emergency surgery
• Prevention: Multiple small meals, no exercise after eating, prophylactic gastropexy
• Mortality Rate: 10-33% even with treatment

Hereditary condition causing abnormal hip joint formation

• Affected Breeds: German Shepherds, Labrador Retrievers, Golden Retrievers, Rottweilers
• Diagnosis: X-rays (OFA or PennHIP evaluation)
• Clinical Signs: Bunny hopping gait, difficulty rising, exercise intolerance
• Treatment: Weight management, NSAIDs, physical therapy, surgery (FHO, THR)

• Transmission: Fecal-oral route, highly contagious, survives in environment for months
• Clinical Signs: Severe bloody diarrhea, vomiting, lethargy, fever, dehydration
• Diagnosis: SNAP test, PCR, CBC showing leukopenia
• Treatment: Aggressive fluid therapy, antiemetics, antibiotics, nutritional support
• Mortality: 91% without treatment, 5-20% with treatment
• Prevention: Vaccination series starting at 6-8 weeks

• Systems Affected: Respiratory, GI, nervous system
• Clinical Signs: Biphasic fever, nasal/ocular discharge, coughing, diarrhea, seizures
• Characteristic Signs: Hardpad, enamel hypoplasia, neurologic tics
• Prognosis: Often fatal; survivors may have permanent neurological damage

• Causative Agents: Bordetella bronchiseptica, Parainfluenza virus, Adenovirus
• Clinical Signs: Harsh, honking cough; gagging; retching
• Treatment: Usually self-limiting; antibiotics if secondary infection
• Prevention: Vaccination (intranasal or injectable)

• Transmission: Mosquito vector required
• Life Cycle: 6-7 months from infection to adult worms
• Clinical Signs: Cough, exercise intolerance, weight loss, ascites
• Diagnosis: Antigen test, microfilaria test, chest radiographs
• Treatment: Stabilization, adulticide therapy (melarsomine), exercise restriction
• Prevention: Monthly preventatives (ivermectin, milbemycin, moxidectin)

• Roundworms (Toxocara canis): Zoonotic, transplacental/transmammary transmission
• Hookworms (Ancylostoma): Blood loss anemia, cutaneous larva migrans in humans
• Whipworms (Trichuris vulpis): Large bowel diarrhea, difficult to treat
• Tapeworms (Dipylidium): Flea intermediate host, rice-grain segments in feces
• Giardia: Protozoan, causes intermittent diarrhea
• Coccidia: Protozoan, common in puppies, bloody diarrhea

🛡️ Preventive Care Protocols

Age	Core Vaccines	Non-Core Vaccines
6-8 weeks	DHPP (Distemper, Hepatitis, Parvovirus, Parainfluenza)	Bordetella (if high risk)
10-12 weeks	DHPP booster	Bordetella, Lyme (endemic areas), Canine Influenza
14-16 weeks	DHPP booster, Rabies	Lyme booster, Leptospirosis
12 months	DHPP booster, Rabies booster	Annual non-core boosters as needed
Adult	DHPP every 3 years, Rabies per local law	Annual assessment based on lifestyle

• Statistics: 80% of dogs show signs of dental disease by age 3
• Daily Care: Brushing with enzymatic toothpaste
• Professional Cleaning: Annual under anesthesia
• Dental Diets: VOHC-approved foods and treats
• Warning Signs: Bad breath, drooling, difficulty eating, facial swelling

• Short Coat: Weekly brushing, monthly baths
• Double Coat: Daily brushing during shedding season, avoid shaving
• Long Coat: Daily brushing to prevent matting
• Wire Coat: Hand stripping or professional grooming every 6-8 weeks
• Curly/Wool Coat: Professional grooming every 4-6 weeks
• Nail Care: Trim every 2-4 weeks, quick recedes with regular trimming
• Ear Care: Weekly cleaning for pendulous ears, check for infection signs

🚨 Emergency Situations