How Old Is a Puppy When Their Balls Drop? A Vet‘s Perspective

As a veterinarian and lifelong dog lover, I know that getting a new puppy is an exciting time filled with many "firsts". One of the key milestones that owners of male puppies watch for is waiting for their dog‘s testicles to descend. But what is the normal timeline for this process? When should you expect to see your pup‘s balls "drop" – and what happens if they don‘t?

In this article, I‘ll share my veterinary expertise on everything you need to know about testicle development in male puppies. We‘ll cover the typical age range for the balls to descend, how to recognize if there‘s an issue, and what it means for your dog‘s health. Plus, I‘ll address some common myths and questions owners have about their male pup‘s "family jewels".

The Typical Timing of Testicle Descent in Puppies

From a medical standpoint, the process of a puppy‘s testicles moving into the scrotum is called testicular descent. Although puppy balls may seem to "drop" suddenly, it‘s actually a gradual process that begins before birth.

Here‘s a timeline of how the testicles develop in male dogs:

• In the womb (gestation): The testicles first form near the kidneys in the abdomen. They are connected to the scrotum by a ligament called the gubernaculum.

• At birth (0-2 weeks): The testicles are still located in the abdomen, high up near the bladder. The scrotum is visibly empty. Internally, the gubernaculum is gradually shortening.

• 2-8 weeks: The gubernaculum pulls the testicles through the inguinal canal toward the scrotum. They may "bounce" in and out of the scrotum as the muscles develop. The scrotum becomes more prominent.

• 8-16 weeks: In most puppies, both testicles are now fully descended into the scrotum. The scrotum looks fuller and the testicles are easily palpable. Hormonal changes of puberty begin.

• 4-6 months: Rarely, descent of one or both testicles may be delayed until this age range. After 6 months, the testicles are considered permanently retained or cryptorchid if not in the scrotum.

• 6-12 months: The descended testicles continue to grow and mature. Sperm production begins around 7-10 months on average. The dog is now fertile.

So in the vast majority of male dogs, the testicles will be completely descended into the scrotum by 4 months of age. For some small breeds, it may take a bit longer, up to 6 months. But once a puppy reaches 6 months old, the testicles are as low as they‘ll go – what you see is what you get!

How to Tell If Your Puppy‘s Balls Have Dropped

Want to check if your puppy‘s testicles have both descended properly? Here are some tips on what to look for and how to do a "self-exam" at home:

Visual Check

Start by looking at your puppy‘s rear end under the tail. By 8-16 weeks, you should see an obvious scrotum – a pouch of slightly wrinkled, fur-covered skin. The scrotum is usually darker in color and bald compared to the surrounding skin. An empty or barely-there scrotum suggests the testicles are not fully in place yet.

Manual Palpation

Using gentle pressure, carefully feel the scrotum with your fingers. You should be able to palpate two distinct, oval-shaped balls inside moving freely. The testicles are typically symmetrical in size and position. It should not be painful for your dog when you examine the scrotum.

In a puppy under 6 months, the testicles may periodically retract into the groin due to the muscle tone still developing. However, you should still be able to manipulate them back into the scrotum relatively easily.

Once your puppy reaches 6 months old, the testicles should remain consistently descended in the scrotum. One or both testicles not being readily palpable is a red flag that warrants a vet visit. You may notice an asymmetrical scrotum with one side fuller than the other, or the scrotum may seem to be completely flat and empty.

It‘s important for your vet to examine your puppy‘s testicles as part of their routine wellness care. This allows for early diagnosis and treatment of any abnormalities in descent. Make note of what you find at home and report it to your vet.

Cryptorchidism: The Most Common Testicle Issue in Puppies

What happens when a puppy‘s testicles don‘t drop by the time they‘re 6 months old? This condition is known as cryptorchidism – and it‘s actually quite common in dogs.

Cryptorchidism is when one testicle (unilateral) or both testicles (bilateral) fail to descend into the scrotum. With unilateral cryptorchidism, one testicle is retained while the other is descended normally. Bilateral cryptorchidism means the dog has no testicles palpable in the scrotum at all.

How Many Dogs Are Affected By Cryptorchidism?

According to a large retrospective study, the overall prevalence of cryptorchidism in dogs ranges from 0.8% to 10%, depending on the breed¹. Rates are much higher in certain breeds, particularly small and toy dogs.

Some of the breeds with the highest incidence of cryptorchidism include:

Breed	Prevalence of Cryptorchidism
Toy Poodle	11.3%
Pomeranian	7.1%
Yorkshire Terrier	6.6%
Miniature Schnauzer	5.8%
Chihuahua	5.7%
Maltese	4.3%
English Bulldog	4.2%
French Bulldog	3.8%
Boxer	3.6%
Pug	2.6%

It‘s theorized that the genes controlling testicle descent are linked to the genes for smaller body size, which may explain the higher rates in toy and miniature breeds.

Unilateral cryptorchidism is significantly more common than bilateral. In most studies, 68-75% of cryptorchid dogs had one retained testicle while 25-32% had both testicles undescended². The right testicle also tends to be affected about twice as often as the left.

Where Are Retained Testicles Located?

There are three main locations where an undescended testicle may be retained:

1. Abdominal: The testicle remains in the abdomen near the bladder or kidney (40-50% of cases)

2. Inguinal: The testicle is "stuck" partway through the inguinal canal in the groin (40-50% of cases)

3. Subcutaneous: The testicle is under the skin in the groin area, often palpable as a firm lump (10% of cases)

This diagram shows the difference between a normal, scrotal testicle and the potential locations of a cryptorchid testicle:

[Illustration of normal vs retained testicles – https://bit.ly/3LTK1Hk]

Health Risks of Retained Testicles

Cryptorchidism is much more than a cosmetic issue – it poses serious health risks to affected dogs, even those with only one retained testicle. The two major complications are testicular cancer and spermatic cord torsion.

Testicular Cancer:
Cryptorchid testicles are 13-14 times more likely to develop tumors compared to descended testicles. In one study of 1,345 dogs with testicular tumors, 25% involved retained testicles³. The most common tumor types arising in cryptorchid testicles are Sertoli cell tumors, seminomas, and interstitial cell tumors.

Spermatic Cord Torsion:
The spermatic cord suspends the testicle and contains the blood vessels supplying it. If the spermatic cord attached to a retained testicle twists on itself, it cuts off circulation. This causes sudden, severe abdominal pain that requires emergency surgery to remove the testicle. The risk of torsion is much higher in cryptorchid testicles compared to descended testicles.

In addition, retained testicles have no ability to produce viable sperm due to the higher temperature inside the body. Dogs with one descended and one cryptorchid testicle are still fertile, while dogs with bilateral cryptorchidism are sterile. Retained testicles are also prone to injury and infection if located in the groin area.

Given all of these factors, veterinary experts agree that neutering is the best treatment for any dog diagnosed with cryptorchidism, even if only one testicle is affected. Neutering involves surgically removing both testicles under general anesthesia, which eliminates the risk of cancer and other complications.

The Cryptorchid Neuter Surgery

The surgical procedure for neutering a dog with cryptorchidism is a bit different than a standard neuter. For the undescended testicle(s), the vet first has to locate where in the body the testicle is retained. This may involve imaging like an abdominal ultrasound prior to surgery.

The approach for removing the retained testicle depends on its location:

• Abdominal testicles are removed through a larger abdominal incision, often along the midline of the belly. The vet has to open the abdomen to access the testicle. Abdominal cryptorchid neuters have the longest surgery/anesthesia times.

• Inguinal testicles are removed through an incision in the groin area, over where the testicle is palpated. Sometimes inguinal testicles can be pulled through the inguinal canal into the scrotum to be removed.

• Subcutaneous testicles are removed through a skin incision directly over the lump in the groin, similar to a standard incision made in the scrotum.

For dogs with one normal testicle, that testicle is always removed too, through a typical scrotal incision. Post-operatively, cryptorchid dogs may have stitches in both the scrotum and the groin/abdomen incision. An E-collar is essential to protect the incisions.

Most dogs recover very smoothly after a cryptorchid neuter with proper post-op care. Complications like infection or incision dehiscence (opening) are rare. Just like a normal neuter, the behavioral and health benefits are significant.

Myths and Misconceptions About Puppy Testicles

There are quite a few old wives‘ tales and myths floating around out there about dog testicles! Let‘s debunk a few common misconceptions:

Myth: Male dogs with only one testicle are more aggressive or "macho".
Fact: There is no scientific evidence linking cryptorchidism with aggression or behavioral issues. Temperament in dogs is largely determined by genetics, socialization, and training.

Myth: Testosterone is necessary for male dogs to develop masculine physical traits.
Fact: Secondary sex characteristics in male dogs like larger body size, broader head shape, and urinary marking are dependent on exposure to testosterone during key developmental periods. Neutering later will not affect these male traits.

Myth: It‘s best to wait to neuter male dogs until after puberty or at least 12 months of age.
Fact: For dogs without an increased risk of joint/orthopedic issues (like hip dysplasia), there is no proven benefit to waiting to neuter past 6 months of age. Dogs with cryptorchidism should definitely be neutered sooner rather than later to mitigate the risk of cancer.

Key Points for Dog Owners

To recap, here are the most important things for owners of male puppies to know about testicle development and health:

• Most puppies will have two fully descended testicles by 8-16 weeks of age. It‘s abnormal if one or both testicles can‘t be felt in the scrotum by 6 months old.
• Undescended testicles have a high risk of cancer, torsion and other complications if left intact. Neutering is always the treatment of choice for cryptorchid dogs.
• Don‘t assume a swelling in the groin of an older unneutered male dog is "just a fatty lump" – get it checked out by a vet ASAP, as it could be a retained testicle!
• Regular vet visits during puppyhood are essential for monitoring the testicles and catching any abnormalities early. It‘s a good idea for owners to learn what normal puppy testicles look and feel like too.
• Cryptorchidism is considered an inherited defect. Dogs with retained testicles should not be bred, as they may pass on the trait to their offspring.

With knowledge and proactive veterinary care, you can ensure your precious male pup grows up with healthy balls! At the end of the day, the most important "manly bits" are the ones inside their head and heart, not in their scrotum. Love your dog for the unique individual he is, testicles and all.

References

¹ Zhao, X., Du, Z-Q. and Rothschild, M.F. (2010), Variation in RXFP2 Is Associated with Cryptorchidism in Several Dog Breeds. Sexual Development, 4: 279-280. https://doi.org/10.1159/000320935

² Yates, D., Hayes, G., Heffernan, M. and Beynon, R. (2003), Incidence of cryptorchidism in dogs and cats. Veterinary Record, 152: 502-504. https://doi.org/10.1136/vr.152.16.502

³ Hayes HM Jr, Wilson GP, Pendergrass TW, Cox VS. Canine cryptorchism and subsequent testicular neoplasia: case-control study with epidemiologic update. Teratology. 1985 Oct;32(2):51-6. doi: 10.1002/tera.1420320108.