Your Puppy: Months 9-12

PetMD Editorial
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PetMD Editorial
Published: September 30, 2013

From the moment your puppy is born till he or she becomes an adult, they’re learning, growing and developing into the happy, healthy dogs that hopefully will be a part of your life for the next 10 to 15 years. Prepare to welcome them home — or make the first months together easier — by learning about their early development, care needs and training tips from nine to 12 months.

Puppy Physical Development

If your pup is a smaller breed, it will have reached emotional maturity by the 12-month mark, while larger breeds tend to take a bit longer to mature, says Victoria Wells, senior manager of behavior and training at the ASPCA adoption center.

Your puppy will also continue to grow at this age, but the rate at which they grow will begin to slow and will vary depending on your dog’s size and breed, with most breeds reaching their adult size around 12 months. According to the American Kennel Club (AKC), most male puppies will begin to lift their leg to urinate by 12 months and, if they haven’t been neutered, will experience a surge in hormones. This spike may cause some males to go through a temporary mounting period.

Your puppy should feel comfortable being groomed regularly at this age, with a routine in place for brushing their teeth and clipping their nails in addition to bathing and grooming their coats. When it comes to cleaning your pup’s teeth, Louise Murray, DVM and vice president of the ASPCA Animal Hospital suggests daily brushing either with a pet toothbrush or some moistened gauze wrapped around your fingertip. Your puppy may feel uncomfortable with this at first, so make sure they become accustomed to it gradually to keep you from being bitten and your puppy from dashing at the sight of their toothbrush.

Puppy Behavior

Owners that have socialized their puppy to a variety of people, environments and other animals should not notice a change in their attitude towards these stimuli at this age, Wells says. Rebellious or adolescent behavior may decrease between nine and 12 months, she said, especially when boundaries have been set for your pup and proper training has been established. Any changes in routine or stressful situations at home may cause minor setbacks in your puppy’s housetraining, according to the AKC, so be sure to be reinforce the basics and provide your pup with lots of positive rewards to encourage them to remember and keep up with their good manners. Separation anxiety may develop during this period and become a source of stress for your dog. Help them cope with your comings and goings by not making a scene when you depart for the day.

Puppy Food

Your dog can continue to be fed puppy-formulated food twice a day until they’re at least a year old. If you have specific questions about your puppy’s diet, Dr. Murray suggests discussing them with your veterinarian. Talk to your vet about the ideal weight for your full-grown dog and work to maintain that weight as your pup continues to age. Even if your puppy’s energy level has begun to taper, you’ll want to make sure they’re still getting plenty of exercise each day to keep unwanted pounds from creeping up.

Puppy Health

If you haven’t done so already, this is the time to spay or neuter your pup. According to petMD, spaying greatly reduces the chance of mammary cancer and eliminates the possibility of uterine or ovarian cancer, while neutering will decrease the possibility of prostate disease and eliminates testicular cancer in your dog. Spaying and neutering can also help to lessen the development of certain behavioral issues in your puppy as he or she continues to grow, Dr. Murray says. 

By this point, your puppy should have all of their vaccinations and will only need boosters one year after the final round of puppyhood vaccines are completed, Dr. Murray says. Talk with your veterinarian about a vaccination schedule for your dog after the first year and, if you haven’t already done so, ask about your options for monthly heartworm and flea and tick prevention.

Puppy Training

With the mature body of an adult, this is an ideal time to engage your puppy in active sports and agility exercises to keep them engaged and excited as you continue the training process.

“If your dog has a high energy level, teaching them to play sports (like fetch, fly ball or agility training) is a great way to expend energy so that your dog doesn’t spend it chewing up your shoes and furniture,” Wells said.

Another fun challenge to consider is the AKC’s Canine Good Citizen (CGC) test, which can be administered to puppies that have completed all of their immunizations and boosters. The test, designed to be an easy and fun way to reward well-behaved dogs for good manners, stresses responsible pet ownership and basic good manners while strengthening the bond between owners and their dogs. Completing the CGC test will also help you to determine if further training or competition—like agility, show or other performance events — is something you’d like to pursue with your pup.

A Few Other Puppy Care Tips

Although your once squirmy puppy has reached adulthood, they’ll still need refresher courses in training, physical and mental stimulation, and rules, Wells said. Teenage puppies may try to push their limits at home so consistency and a strong hand in training is key.

If you’re taking home a puppy for the first time at this age, prepare for a pet with a much more distinct and established personality than a younger puppy might have. Although you can certainly work to correct unwanted behavior in your teenage pup, certain tendencies—like a preference for lounging on the couch or running non-stop—are more likely to stick with an older puppy, Wells said. 

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Photo courtesy of the ASPCA. 

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