When Do Border Collies Stop Growing? Understanding Their Development

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Many pet owners wonder, when do Border Collies stop growing? This question is crucial for properly caring for and training this highly intelligent and energetic breed. Border Collies go through several growth phases before reaching full maturity, and each stage comes with its own set of needs and challenges. This article will explore the growth timeline of adult Border Collies here, examining their physical and behavioral changes from puppyhood to adulthood. Stay tuned to learn more about when Border Collies typically stop growing and how you can support their development every step of the way.

Border Collie Physical Growth: What to Expect in the First Year

The first year of a Border Collie’s life is marked by rapid and significant physical growth. Understanding these developmental stages helps pet owners provide appropriate care and support as their puppies mature into healthy adult dogs.

Birth to Three Months

Newborn Border Collies are tiny and vulnerable, requiring constant care. By three- months old, they typically experience a surge in growth, both in size and energy. Regular feeding with high-quality puppy food is crucial to support their rapid development.

Three to Six Months

During this period, a Border Collie puppy will continue to grow quickly, reaching approximately half their adult weight. This is also when mature border collie puppies should start receiving more structured training and socialization to positively harness their energy and intelligence.

Six to Twelve Months

Growth starts to slow down, but Border Collies will still gain height and mass. By their first birthday, most Border Collies will be near their full adult height, up to about 22 inches tall, at the shoulder for adult male border collies and slightly less for females. They may still appear lanky and will continue to fill out with muscle over the next several months.

Diet and Nutrition

Proper nutrition is vital throughout the first year. A diet formulated for medium-sized, high-energy puppies helps ensure they receive the necessary calories and nutrients for optimal growth and health.

Regular Veterinary Check-ups

Scheduled vet visits are essential during the first year to monitor growth, administer vaccinations, and address health concerns early. These check-ups help ensure the puppy develops correctly and maintains a healthy weight.

Exercise Requirements

While it’s important to keep young Border Collies active, care should be taken to avoid over-exertion, which can stress growing bones and joints. Appropriate exercise during the first year includes short walks, light running, and plenty of playtimes.


Border Collie Behavioral Development Milestones

Border Collies are renowned for their intelligence and energy, shaped significantly during their early behavioral development. Understanding the milestones in this process is crucial for owners to nurture well-adjusted and capable adult dogs. Here’s a look at the key behavioral development stages of Border Collies:

Socialization Period (3 to 16 Weeks)

This is a critical window for puppy socialization. Border Collie puppies are naturally curious and receptive during this time, making it ideal for introducing them to various people, pets, environments, and sounds. Proper socialization can help prevent fearfulness and aggression later in life.

Fear Impact Periods (8-10 Weeks & 6 Months)

Negative experiences during these stages can disproportionately impact the puppy’s temperament. Managing interactions carefully and reinforcing positive behavior is important to help the puppy develop confidence.

Basic Training (From 8 Weeks Onward)

Border Collies are eager learners who can start basic obedience training at eight weeks old. Due to their keen intelligence, commands like sit, stay, come, and leash training are absorbed quickly. Consistency and positive reinforcement techniques are critical at this stage.

Teething and Mouthing (3 to 6 Months)

Like all puppies, Border Collies go through a teething phase where they might nip and chew more frequently. Providing appropriate chew toys and teaching bite inhibition is important to manage this behavior without discouraging the puppy’s natural curiosity and playfulness.

Adolescence and Testing Boundaries (6 Months to 18 Months)

During adolescence, Border Collies may test limits and try to establish dominance. This can be managed through firm yet fair leadership, consistent training, and ongoing socialization to reinforce desired behaviors.

Maturity (18 Months to 2 Years)

By this time, a Border Collie should have a solid training and social skills foundation but may continue to refine their behaviors and fully mature emotionally and mentally. Continuing education, training, and regular physical and mental stimulation are crucial to keep them engaged and well-behaved.

Factors Influencing Growth Rates in Border Collies

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Like all breeds, Border Collies have growth rates influenced by various factors. Understanding these can help owners anticipate how their puppy may develop and provide appropriate care throughout their growth. Here are some key factors that influence growth rates in Border Collies:


The genetic background of a Border Collie plays a crucial role in determining its size, weight, and overall growth rate. Traits inherited from the puppy’s parents, such as height, weight chart, and build, largely dictate how big a Border Collie will get and how quickly it will reach maturity.


Adequate and balanced nutrition is essential for healthy growth. Puppies fed a high-quality diet formulated for active; medium-sized breeds are more likely to achieve their genetic potential. Overfeeding and underfeeding can adversely affect growth rates and lead to health problems.


While Border Collies are energetic and require regular exercise, balancing activity levels, especially during growth, is important. Excessive exercise can stress growing bones and joints, whereas insufficient exercise can lead to weight gain and reduced muscle development.

Health Status

Various health issues can impact growth. For example, parasitic infections, gastrointestinal problems, or other illnesses during puppyhood can impede proper development. Regular vet check-ups are important to catch and treat any health issues early.

Spaying and Neutering

The timing of spaying or neutering a dog can affect its growth. Early neutering can sometimes result in a slightly taller dog, as the closure of bone growth plates may be delayed. However, discussing the best timing with your vet, considering all health aspects, is essential.

Environmental Factors

Stressful environments can inhibit growth and development. Puppies that are raised in a nurturing environment with appropriate socialization and minimal stress are more likely to grow at an optimal rate.

Border Collie Nutritional Needs for Optimal Growth

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Proper nutrition is pivotal for the optimal growth and health of Border Collies, a breed known for its high energy and intelligence. As medium-sized dogs with specific dietary needs, Border Collies require a well-balanced diet supporting their rapid growth and overall health into adulthood. Here’s a breakdown of their nutritional needs:

1. Protein: High-quality protein is crucial for muscle development and repair, especially for active breeds like Border Collies. Puppy formulas should contain more protein to support their rapid growth, while adult formulas should be adjusted to maintain muscle mass and energy levels without leading to weight gain.

2. Fats: Fats are a concentrated energy source for dogs and are particularly important for active breeds. Essential fatty acids, such as omega-3 and omega-6, help maintain a healthy coat and skin, support brain development, and regulate bodily functions.

3. Carbohydrates: While dogs don’t necessarily need carbohydrates in large quantities, good quality sources like whole grains and vegetables can provide vital energy, fiber, and nutrients. They also aid digestion and help maintain stable blood sugar levels, which is particularly important for energetic breeds.

4. Vitamins and Minerals: A balanced array of vitamins and minerals supports overall health and is crucial during the growth periods of Border Collies. Calcium and phosphorus must be balanced appropriately for bone growth and health, especially in puppies. Vitamins A, E, and C support immune health and vitality.

5. Water: Adequate hydration is essential, particularly for a breed as active as the Border Collie. Fresh water should always be available, and fluid intake should be monitored to ensure they are sufficiently hydrated, especially after exercise or in hot weather.

Special Considerations: Additional considerations may come into play depending on the individual dog’s health. For instance, if a Border Collie is prone to joint issues like hip dysplasia, a diet supplemented with glucosamine and chondroitin can be beneficial. Likewise, if a puppy grows too quickly, the vet might recommend a diet that slows growth slightly to avoid joint problems later.

Feeding Practices: Feeding schedules and amounts are equally important. Puppies generally require three to four small meals daily to support their high metabolism and growth needs. As border collies mature, this can be adjusted to two meals daily. Avoid free-feeding to prevent overeating and weight gain.

Consultation with a Veterinarian: Given the variability in activity levels and health needs among individual dogs, consulting with a veterinarian to tailor a diet plan is advisable. This ensures that dietary choices support the specific growth and energy requirements of your Border Collie.

Health Considerations During Development of Border Collie Puppy

Raising a Border Collie puppy involves keen attention to their health during their developmental stages to ensure they grow into robust and active adults. Border Collies are generally a healthy breed, but like all dogs, they are prone to certain health issues that can affect their growth and overall well-being. Here are some critical health considerations to keep in mind during the development of a Border Collie puppy:

1. Vaccinations and Parasite Control: Essential from an early age, vaccinations protect against common canine diseases such as parvovirus, distemper, and rabies. Regular deworming and parasite control are also vital to prevent harmful infections from fleas, ticks, and intestinal worms, which can compromise a puppy’s health and development.

2. Hip and Elbow Dysplasia: This genetic condition, where the hip or elbow joint fails to develop properly, is relatively common in Border Collies. Monitoring your puppy’s exercise and avoiding strenuous activities that strain the joints excessively can help manage this risk. Regular veterinary check-ups should include evaluations of joint health, especially if the puppy shows signs of discomfort or lameness.

3. Collie Eye Anomaly (CEA): This inherited condition can affect Border Collies, leading to changes and abnormalities in the eye, which can sometimes result in blindness. Genetic testing of parent dogs and regular eye exams for puppies are recommended to identify and address this issue early.

4. Progressive Retinal Atrophy (PRA): This degenerative eye disorder eventually leads to blindness. While no cure exists for PRA, understanding the genetic risk can help with early diagnosis and preparations for managing a visually impaired dog.

5. Nutrition and Obesity: Proper diet is crucial for a growing Border Collie puppy. Overfeeding can lead to obesity and associated health problems such as diabetes and joint stress. Feeding a balanced diet measured to the puppy’s age, size, and activity level is important for maintaining optimal health.

6. Behavioral Health: Mental health is as important as physical health. Border Collies are highly intelligent and energetic dogs requiring adequate mental stimulation and socialization to prevent behavioral issues. Lack of activity and engagement can lead to destructive behaviors and stress. Training, social interaction, and cognitive games are important throughout a Border Collie’s development.

7. Regular Vet Check-ups: Scheduled visits to the vet for check-ups allow for monitoring the puppy’s growth, weight, and overall health. These visits are opportunities to discuss concerns, update vaccinations, and receive advice on preventive care measures.

When to Neuter or Spay Border Collie: Impact on Growth

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Deciding when to neuter or spay a Border Collie is an important decision that can significantly affect the dog’s growth and overall health. Neutering or spaying involves the surgical removal of a dog’s reproductive organs and can impact various aspects of a Border Collie’s growth and development. Here’s an overview of the considerations and potential impacts:

Timing Considerations

The timing of spaying or neutering a Border Collie is a considerable debate among veterinarians and breeders. Traditionally, many veterinarians recommended spaying or neutering dogs before they reached sexual maturity, often between 6 and 9 months of age. However, recent studies suggest that waiting until a dog has reached physical maturity can benefit active breeds of working dogs like Border Collies.

Impact on Physical Growth

Spaying or neutering a Border Collie before physical maturity can affect the closure of the bone growth plates. Hormones play a significant role in signaling the growth plates to close, and removing these hormones too early can result in longer, thinner bones, potentially predisposing the dog to joint issues such as hip dysplasia or cruciate ligament tears. Waiting until the dog is fully grown (typically around 12 to 18 months for Border Collies) might prevent some of these issues.

Impact on Health

There are health benefits and risks associated with neutering or spaying. Spaying female Border Collies before their first heat significantly reduces the risk of mammary cancer and eliminates the risk of pyometra, a serious uterine condition. Neutering males can reduce the risk of benign prostatic hyperplasia and testicular cancer. However, studies also suggest that early neutering can increase the risk of certain other cancers and joint disorders.

Behavioral Considerations

Spaying and neutering can also impact behavior. It typically reduces behaviors driven by hormones, such as roaming, marking, and aggression toward other dogs. However, these behaviors are not guaranteed to disappear entirely as they can also be influenced by genetics and environment.


The decision on when to neuter or spay should be made in consultation with a veterinarian who can provide advice based on the latest research and the specific health, behavior, and lifestyle of the Border Collie breed. Some veterinarians now recommend waiting until the dog has reached physical maturity, particularly for breeds prone to joint disorders.

In conclusion, understanding when Border Collies stop growing is essential for providing the proper care and support as they mature. These active and intelligent dogs typically reach their full physical size around 12 to 15 months, but their emotional and mental development continues well into their later years. By ensuring they receive proper nutrition, regular health check-ups, and ongoing training, you can help your Border Collie thrive throughout all stages of growth. Stay attentive to their development needs and enjoy the rewarding journey of raising a well-rounded canine companion.


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