The reproductive issue is a sticky wicket. Certainly if all I wanted to do was protect fertility and be certain a cavalier maintained uterine health, I would breed early and often, and spay at about age 4. In beagle colony studies (Exp Anml July 01) 15% of beagles greater than 4 years of age developed pyometra.
But there is also the argument that pyometra has a genetic predisposition, and that by spaying early, we don't know which lines are more likely to develop pyometra. (This was mentioned privately by one of the geneticists.) There are studies in horses to suggest that certain genetic haplotypes tend to be protective, and certain genetic haploytypes tend to make the horse more susceptible to endometritis.(Pemberton AD, John HA, Ricketts SW, Rossdale PD, Scott AM. Investigation of association between alpha-1 proteinase inhibitor haplotype and endometritis in the thoroughbred mare. (Equine Vet J. 1994 Mar;26(2):122-4.) For those of us who love our dogs, waiting to see who might develop pyometritis could be considered to be risky. Mortality may range between 5-10%, higher if it goes unrecognized for any length of time, and some studies, between 25-50% of the intact cavalier bitches develop it in their lifetime. In Sweden, studies (data on over 200,000 dogs) showed that more than 20% of intact bitches (all breeds) will develop pyometritis by age 10. Cavaliers were a particularly high risk breed (along with Collies, Rotts, Goldens, Eng Cockers) with rates up to 54%. (J Vet Intern Med 2001 Nov-Dec;15(6):530-8 Breed risk of pyometra in insured dogs in Sweden.Egenvall A, Hagman R, Bonnett BN, Hedhammar A, Olson P, Lagerstedt AS.) The large incidence in particular breeds supports the suggestion of a genetic predisposition. Besides the genetic predisposition, there are risk factors for pyometra, such as skipping breeding cycles. From Tilley and Smith, DVMs Veterinary Consult; ref Hardy, RM, Osborne, CA, Canine Pyometra: pathophysiology, disagnosis and treatment...J Am Anim Hosp Assoc: "Repeated exposure of the endometrium to high concentrations of estrogen followed by high concentrations of progesterone in the absence of pregnancy leads to cystic endometrial hyperplasia." and "Pyometra develops secondary to cystic endometrial hyperplasia when bacterial invasion of the abnormal endometrium leads to an intraluminal accumulation of purulent exudate." I don't know how to resolve the issues. I might be tempted to use a little younger bitch with a much older heart clear dog, if I could find a good match. For now, I'll just throw out the available info in hopes that it helps some of you make your breeding decisions. Leanne ---Original Message--- Read my earlier post about reproductive issues. Best, Suze ========================================================= "Magic Commands": to stop receiving mail for awhile, click here and send the email: mailto:[EMAIL PROTECTED]?body=SET%20CKCS-L%20NOMAIL to start it up gain click here: mailto:[EMAIL PROTECTED]?body=SET%20CKCS-L%20MAIL E-mail [EMAIL PROTECTED] for assistance. Search the Archives... http://apple.ease.lsoft.com/archives/ckcs-l.html All e-mail sent through CKCS-L is Copyright 2002 by its original author.
