In middle aged rats; neutering male rats were not found to have a negative impact upon bone density. Yet in middle aged female rats, altering resulted in significant bone reabsorption and spinal osteoporosis.

Our study confirmed that middle-aged female rats on a normal diet develop osteoporosis after castration; similar findings have been made by Saville (1969) and Kalu (1983).
In juvenile male rats, neutering was also found to result in ostoporosis, because the full level of male hormones that peak at puberty must be sustained till adulthood to achieve full calcium bone density.

Young castrated male rats have a reduction in femoral and lumbar BMD due to the mixture of two detrimental factors: young castrated male rats did not reach peak BMD, and increased bone turnover caused bone resorption to exceed bone formation.
When it is necessary to spay a female squirrel, or neuter a male squirrel prior it reaching adulthood; raising the (Ca:P) whole diet ratio by adding additional calcium to the diet, will help to offset the drop in calcium absorption in the diet caused by the drop in sex hormones from altering.

In older squirrels, lowering the main source of protein and phosphorus in the diet of older squirrels where their kidney function has lowered, is also needful. This can be done by reducing the amount of rodent block by a third portion daily and adding back the amount of calcium reduced by this reduction, plus additional calcium to support a higher (Ca:P) whole diet ratio, which takes the pressure of aging kidneys lending to the extension of their kidney function, and potentially their lifespan also.

We fed (Teklad) Rodent Diet with organic fresh foods, which we supplemented with additional vitamin and mineral supplement added to the drinking water, and a, "Manu" mineral clay. which our squirrel would gnaw on the stone directly after finishing her meal. Approaching middle age, her heats were lasting longer and were occurring two times a year. Our vet explained that this is normal in rats and other rodents for heats to last longer as they age. Yet with the additional issue of her having a vaginal discharge that our first vet explained was a vaginal yeast infection, not a UTI, our then vet advised she be spayed as the AB failed to resolve this form of yeast infection.

At 7 years we took her to an exotic vet who did a successful spaying. Sadly, this younger vet didn't leave any follow up instructions in regard to our increasing the level of calcium in her diet. In just two years she developed osteoporosis in her spine in the form of, 'degenerative disc disease' from the drop of estrogen from the spaying that lowered the absorption of calcium from her diet and supplements. Our last vet and their senior member confirmed by x-ray, what I read years later to be the same result that has even found to result from spaying middle aged female rats. Worst of all, this destabilization of the spine resulted in spasms occurring in her lower body and legs, which required medication given orally two times a day by non needle syringe. If only the vets looked into the research that went back as far 1960 and the late 1980s; she would not have been caused to suffer with this preventable condition, and the advanced MBD two years later that reached her jaw which was then needful to humanely end her life.