The general opinion of the majority of veterinary circles is that the “responsible” dog-owners, should sterilise their animals at 6 months. In some countries, it is much earlier.
But we must not forget that sex hormones play a crucial role in maintaining the growth of muscles and bones of the body.
Sexual maturity (puberty) occurs between 6 and 15 months for both males and females, with peak fertility, between 11 and 15 months, once they are fully mature physically.
For some large breeds, this can be delayed up to 2 years.
I argue in favour of these 3 progressive Scandinavian countries, Sweden, Norway and Denmark, because according to them, surgical sterilization is perceived as MUTILATION !!!
Removing reproductive organs - from dogs and cats - is considered an illegal act and should only be performed for medical reasons.
If a Scandinavian veterinarian ignores this, he would be found guilty of professional misconduct!!!
Unfortunately, in most countries, veterinarians do their best to motivate pet owners to rush out with the procedure.
The side effects of early sterilization, are scientifically proven and shouldn’t be overlooked by the “responsible” pet-parents.
What Are the Risks
- Abnormal Bone Growth
- Decreased Longevity
- Increased risk of Hypothyroidism
- Increased risk of Incontinence
- Increased risk of Disease
- Behavioral Issues
Gonadal and mammary cancer is quite rare in the dog population, in general and it is known that dogs recover very well from testicular cancer, following early diagnosis and castration.
In addition, while 30-50% of breast cancers are malignant, the prognosis is very good in dogs when they are detected early and surgically removed (Brody et al., 1983, Meuten, 2002).
Many studies show that removal of the sex organs at the beginning of the animal 's developmental period, causes cancer but not in the testes or ovaries - because they are already removed.
A 13-year study of the Journal of Veterinary Internal Medicine revealed exactly that:
"Sterilized dogs appear to increase the risk of heart tumour in both sexes".
After careful examination, using 683 male and female Rottweilers castrated or sterilized before the age of one year:
"Both sexes were significantly more likely to develop bone cancer, undergoing early sterilization, 25% more likely to have bone cancer than intact dogs."
A study done on 759 intact and sterilised Golden Retrievers, (Torres de la Riva and others 2013) has highlighted an important problem in the sterilised dogs:
"A lymphosarcoma was diagnosed in nearly 10% of early sterilised males, 3 times more than in intact males".
Testosterone and eostrogen play a crucial role in the development of muscles and bones.
Testosterone controls the growth, height and muscle mass of the individual.
In adults continues to work to maintain strength and muscle mass and promote bone density, as well as reduction of adipose tissue (one of the reasons that sterilized pets can gain weight).
Eostrogen also plays a role in skeletal growth.
At puberty, estrogen promotes skeletal maturation and progressive closure of growth plates.
Oestrogen also helps in maintaining bone mineral acquisition.
In other words, oestrogen tells the epiphyseal plates to stop growing.
By removing testosterone and oestrogen from the vital phase of puberty growth, it will affect the size, muscle mass and bone formation of the individual, compared to an intact animal of the same size and breed. Research shows that this is absolutely the case.
The study by Stubbs and Bloomberg (1995):
"Thus, if you remove the oestrogen-producing organs in immature dogs, female and male, you could expect cause epiphyseal plates to remain open and the dog to grow longer bones".
Late closure of the epiphyseal plaques results in longer, heavier bones, which increases the risk of Cruciate Ligament Rupture and Hip Dysplasia.
For example, if the femur has reached its normal length, determined at 8 months when a dog is spayed or neutered, but the tibia, which normally ceases development between 12 and 14 months, continues to grow, an abnormal angle may develop in the knee.
Moreover, with additional growth, the leg below the knee probably becomes heavier (because it is longer) and may result in increased stress on the cranial cruciate ligament.
This is verified by a study by Slauterbeck et al. (2004).
A study from the College of Veterinary Medicine at Cornell University published in the Journal of the American Veterinary Medical Association, showed that male and female dogs sterilised at an early age were more prone to hip dysplasia.
Females that keep their ovaries the longest, are 9 times more likely to achieve exceptional longevity (13 years and older).
A sterilisation study on Rottweiler females, before the age of 4, showed a reduction in longevity of 30%.
Waters et al. (2009) found:
“like human females, female dogs in our study had a distinct survival advantage over males, but taking away ovaries during the first four years of life completely erased the female survival advantage”.
When a hormone producing organ is removed, other organs are forced to work.
This may overload an organ that consequently will suffer.
Panciera (1994) and Glickman et al. (1999) found that:
"Spayed and neutered dogs are more likely to develop hypothyroidism."
Spain et al. (2004) and Stöcklin-Gautschi et al. (2001) found that early sterilization increased the risk of urinary incontinence from 4 to 20% in bitches.
Aaron et al. (1996) noted that:
"Neutering it is associated with an increased likelihood of urethral sphincter incontinence in males also."
Very early sterilisation increases the risk of illness in dogs.
A study conducted by the College of Veterinary Medicine at Texas A & M University on shelter dogs, concluded that:
"Infectious diseases were more common in dogs that were sterilised at less than 24 weeks of age."
Spain et al. (2004) also noted that precocious gonadectomy was associated with an increase in unwanted sexual behavior, but also an increase in mental imbalance and noise phobias.
Even more worrying, Spain et al. (2004) noted:
"Increase in aggression towards family members, barking or growling at visitors, and excessive barking member in male dogs neutered before 5 and a half months."
In another study, Hart (2001) found that the number of dogs with Cognitive Impairment (a problem to remember, learn, focus and make decisions) was significantly higher for neutered than sexually intact male dogs.
In other words, mental problems can aggravate in sterilised dogs.
That being said, i would like to quote that in Switzerland, you must pass a theoretical and practical test, before approving the ownership of a dog.
In these progressive and well-informed countries, Switzerland, Denmark and Norway, owning a dog is not synonymous with that of a right, but rather of a privilege.