Hi Home2strays,
In this case, many of the researchers and specialists would disagree with you about early age neutering. There have been a number of studies that have not shown any connection between early neuter and smaller urethras. Here are a couple quotes:
1) From an article on the Winn Feline Foundation website by Dr Susan Little who is a well known and respected Board Certified Feline Specialist with a special expertise in reproductive medicine. You can read the whole article here:
http://www.winnfelinehealth.org/Pages/Early_Age_Spay_Neuter.pdf In it she wrote:
However, several scientific studies have now shown these concerns are unwarranted. For example, it is has been shown that early-age altering of cats:
"022 does not cause stunted growth in cats (University of Florida study, 1996).
"022 does not contribute to increased surgical and anesthetic risks or post-surgical complication rates (University of Texas studies, 1997 and 2000).
"022 does not cause serious behaviour problems in cats (University of Cornell study, 2004, and Mercer University study, 2001).
"022 does not contribute to feline lower urinary tract disease (University of Minnesota study, 1996, and University of Texas study, 2000).
"022 does not cause obesity (University of Minnesota study, 1996).
In fact, a large-scale study from Cornell University of over 1,600 cats—adopted from a humane society in New York State and followed for up to 11 years—showed early-age altered cats had less risk of certain health problems including gingivitis, asthma and abscesses—than cats altered at traditional ages.
2) From a 2007 article in the Journal of the AVMA by Margaret V. Root Kustritz who is Board Certified in reproductive medicine, which you can read at:
http://avmajournals.avma.org/doi/pdf/10.2460/javma.231.11.1665 "Despite numerous vehemently declared anecdotes of an increase in the incidence of urethral obstruction in male cats castrated when young, numerous studies (35,132,135) have failed to detect a correlation between gonadectomy of cats at any age and a decrease in diameter of the urethra or an increase in incidence of FLUTD, with or without urethral obstruction."
3) The American Association of Feline Practitioners (AAFP) have a Position Paper on early spay/neuter and are in support of the practice. You can read it at:
http://www.catvets.com/uploads/PDF/EarlySpayCastration2010NEW.pdf The AAFP Statement begins:
"The American Association of Feline Practitioners supports neutering early in life as a safe and effective method of decreasing cat overpopulation, and one which confers long-term medical and behavioral benefits to the individual cat."
If you know of a study that shows that early neutered males have smaller urethras, I'd be interested in a reference.
As I'm sure you know, there are two primary types of crystals that cats get (struvite & calcium oxalate) one caused by too high pH and the other by too low. I think many of the "crystal" diets now aim to get the pH in the optimal range that will help prevent either type of crystal ... rather than just trying to raise or lower the pH to prevent one type of crystal.
Hope that helps.
Stephanie in Montreal