Ask the Vet: When Do Puppy Growth Plates Close?
Dr. Ivana Crnec
Knowing when puppy growth plates close is important for puppy owners considering certain activities or interested in enrolling their pups in canine sports. Knowledge is power when it comes to protecting a pup's vulnerable joints from potential harm. Veterinarian Dr. Ivana shares guidelines on when puppy growth plates close and how to safeguard them.
Puppy Growth Plates
The steel-strong yet aluminum-light bony framework of the skeleton is responsible for supporting the dog’s weight and facilitating movement.
A dog's skeleton is composed of bones. Bones come in many shapes and sizes, ranging from flat plates that anchor large muscle masses, such as the shoulder blades, to hollow, thick-walled tubes that support weight or act as lever, such as those in the dog's limbs.
Long bones have so-called growth plates, also known as epiphyseal plates. But what exactly are growth plates and what are they made of? Growth plates are relatively soft areas located at the ends of all long bones. The growth plates are made of fast multiplying cells which enable the bones to grow in length and strengthen in density. Only puppies and young dogs have growth plates.
When Do Puppy Growth Plates Close?
When growth plates close varies based on the type of bone involved and a dog's size. Larger dogs’ growth plates tend to close later than those of small dogs.
In general, growth plates close when the dog fully matures (usually around 12 to 18 months of age). At that point, the fast multiplying cells have already filled the entire soft area and that area has become a stable bone part.
In simple words, the term "growth plate closing" means ossifying or transforming into bone tissue. The growth plate therefore continues to add to the length of the bone up until the age at which it's genetically programmed to close.
Growth Plate Problems in Puppies
Generally speaking, when it comes to growth plates, there is one major problem – growth plate injuries. In a nutshell, during the intense multiplying phase, the growth plates are soft and particularly vulnerable to injuries.
If a growth plate injury occurs, the fast multiplying cells might respond to the injury by slowing down their growth. In more extreme cases, if enduring a more severe injury, the cells may even completely cease their multiplication and just stop growing.
For example, let us assume that the right leg’s femoral bone (more precisely, its proximal growth plate) sustained an injury. The cells in that growth plate will stop multiplying or at least slow down. The growth plates in the other three extremities though will continue to grow at a normal rate.
When the dog outgrows its puberty phase and the growth plates close, that dog will have three properly developed legs (the two front and the left hind leg) and one shorter leg (the right hind leg).
This problem has long-term consequences – the uneven pressure the body weight exerts on the underdeveloped leg increases the risk of developing arthritis later on in life.
Types of Growth Plate Injuries in Puppies
There are two types of growth plate injuries: acute and chronic. Let's take a look at both.
Acute growth plate injuries in puppies are due to a traumatic event such as being hit by a car or jumping off of a high couch.
Chronic growth plate injuries in puppies are due to too much physical activity which causes extreme bone exhaustion, so extreme, that it reaches the point of injury.
A pup with a growth plate injury is likely to manifest the following signs and symptoms:
- Stiffness of the affected limb
- Decreased appetite
- Reluctance to be physically active.
Acute growth plate injuries are easier to prevent since we rarely leave our young pups unsupervised and unattended. On the flip side, chronic growth plate injuries are harder to anticipate since most puppy parents are unaware of the risks associated with too much physical activity.
The Puppy's Five-Minute Rule
To limit the amount of physical exercise for young and growing puppies, veterinarians agreed on a so-called five-minute rule. The rule was invented to provide pups with age and breed-suitable exercise regimens while preventing unwanted injuries.
The five-minute rule states that every puppy should be assigned with five minutes of physical exercise (twice a day) per month of age. The rule applies for puppies and young dogs that are still growing. Once fully grown, they can be physically active for much longer.
Following that rule, a one-month-old pup should have two, five-minute lasting sessions of physical activity per day. A two-months-old pup should have instead two, ten-minute lasting sessions of physical activity per day, while a three months old pup can be physically active for 15 minutes, twice a day.
Last but not least, it is worth mentioning that by physical activity we mean lead walking, not ball chasing, not playing with older dogs and definitely no running in the park.
Puppy Physical Exercise Alternatives
As a dog parent you probably know that pups have go-all-day stamina, and in such cases, implementing the five-minute rule can be challenging.
If your pup is a hyperactive bundle of adventure and spirit, it is highly advisable to start practicing activities that require zero physical engagement while sharpening the mind and offering a fair amount of mental stimulation.
· Encourage your pup’s exploration inclinations – it is in every pup’s nature to be curious so this method is quite easy to implement. Take your puppy in the garden and let him investigate the new environment. Alternatively, you can place him in a new room that was previously out of reach. Just make sure he is not left unsupervised at any moment. The new surroundings can be dangerous to a small puppy.
· Start basic training your pup – puppy training classes will keep your pup’s mind engaged, and contrary to popular belief, tiring the mind is also tiring on the body. Not to mention that early basic training goes a long way when raising a well-behaved dog.
· Make your pup follow scent trails – this method is particularly good for food-motivated pups. All you need to do is hide some of your pup’s tasty and irresistibly smelling treats around the room and let your pup use its nose to locate them. Once again, it is important to supervise your pup while treat hunting.
The best way to reduce risks to a puppy's growth plates is to minimize stresses on bones and joints.
While your pup is growing, avoid rough games that involve vigorous physical activity (like jumping) such as ball catching.
Feed your pup carefully so that its skeleton grows slowly.
Do not feed an excessively calorie-rich or mineral-rich diet. Such over-nutrition will cause the bones to grow faster but have lower density, and the skeleton will be less able to withstand stresses from the increasing muscle mass and body weight.
Basically, growth plate problems are best prevented through light-exercise regimens and healthy, well-balanced nutrition plans.
About the Author
Dr. Ivana Crnec is a graduate of the University Sv. Kliment Ohridski’s Faculty of Veterinary Medicine in Bitola, Republic of Macedonia.