Optimal Age for Spay and Neuter of Cats and Dogs
Dr Gail C. Golab, PhD, DVM, Director of the Animal Welfare Division of the American Veterinary Association, member of the Pet-Law forum, has secured free public access to the following PDF from the Journal of American Veterinary Medical Association.
Citation
Journal of the American Veterinary Medical Association
December 1, 2007, Vol. 231, No. 11, Pages 1665-1675
doi: 10.2460/javma.231.11.1665
Determining the optimal age for gonadectomy of dogs and cats
Margaret V. Root Kustritz, DVM, PhD, DACT
Department of Veterinary Clinical Sciences, College of Veterinary Medicine, University of Minnesota, Saint Paul, MN 55108. (Kustritz)
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Neutering Male and Female Dogs
Here is an article to consider. Reprinted with permission.
NEUTERING MALE AND FEMALE DOGS
There is some confusion in the minds of the public today regarding recommendations for neutering. In the bitch, or female dog, it is true that there is a genuine statistical advantage for bitches spayed before they come in heat for the first time, as regards the possibility of developing mammary cancer later in life.
While the breeder doesn't often see mammary cancer in their older bitches which remain un-spayed, this may be a reflection of a protective effect from nursing puppies. Certainly not all intact bitches develop mammary cancer. Certainly all bitches spayed before 6 months of age are not protected from getting mammary cancer. But there is a statistically significant advantage to this procedure in bitches which are not part of a breeding program.
The situation in dogs (male dogs), is not equivalent. It is no longer medically justifiable to castrate dogs for prevention of cancer. The overwhelming mass of data to the contrary can no longer be ignored, and publications are out there so that no veterinarian can use the excuse of ignorance. Castration predisposes to highly malignant prostatic cancer. Nearly all dogs afflicted with this nasty tumor are neutered individuals. Testicular cancers are very rare and almost always benign. Perianal adenoma can be treated by castration if and when it arises. It too is benign although messy.
I have always held that male-to-male dog-to-dog aggression is the only justification for castration. Many owners wish to castrate their male puppies thinking that all sorts of behavioral problems will be solved. Such as roaming. Most of these behaviors can only be altered by husbandry and training. Others are convinced that by castrating their dog, they will be doing the right thing regarding 'population control' - the fact is, males do not have puppies, females do. Castration is the search for the "quick fix" for people who don't wish to invest the time and effort necessary to care for their dogs properly. And, it may help; if not, the obesity which develops may achieve the desired effect.
With large breeds, early castration often results in an animal with an insufficient breadth of chest for orthopedic health. Seeing the number of giant breeds that I do, I am very aware of the tragic effects of castration on young males. The narrow chests which result are inadequate to support the weight that so many neutered animals, male or female, put on. These dogs then have to develop a 'toe-out' stance, with valgus deformity of the carpus, in an attempt to broaden their base for weight bearing. Once you've seen the harm caused by this practice in person, you quickly change that 'knee-jerk' reaction so often seen, of 'neuter everything that breathes'. If you do choose to castrate your male dog, by all means wait until he is at least one year old for small to medium size breeds, or at least 2 years old for giant breeds.
Spaying helps to reduce the incidence of mammary tumors, if performed before the first heat. It does not eliminate the possibility, but does statistically reduce the risk. So, however, does lactation, as in humans. A bitch which is not a breeding candidate should usually be spayed before the first heat. As for older bitches, they may be spayed after their reproductive careers are over, or they may stay healthy - in terms of uterine health - by monitoring the white blood count after each heat period. You will not miss a uterine infection if you consistently monitor the WBC at this time, and at other times when an older intact bitch goes off feed. Remember, however, that you must be as aware of the reproductive cycles in these older bitches as you are of younger ones!
For certain, pet owners who think of their dogs along the lines of a piece of furniture should have their bitches spayed. It's very hard to overstate the ignorance of the general public, in respect to their own and their pets' biology. This results in a lack of critical observation regarding their pets' health. Dealing with breeders nearly all the time as I do, the difference in the observational abilities of these two different groups is truly staggering. To be fair, pet owners do not usually have the opportunity to observe enough different individuals to form a valid picture of a 'normal' dog.
If you wish to retain the choice of breeding a bitch at a later date, the use of mibolerone (formerly Cheque drops) will shut down the cycling of the ovary. This removes the progesterone influence which is responsible for promoting uterine infections, and the estrogen responsible for stimulating some mammary tumors. The only caveat here, as with any steroid medication, is that liver values may be elevated in some individuals. These levels may be monitored in older bitches; I have not yet, in 22 years of practice - 12 of them concentrating on canine reproduction - had an instance where this became an issue with Cheque drop medication. When the medication is discontinued, the bitch resumes her normal cycling and may be bred if desired. Steroids can be divided into two general categories; the catabolic steroids - cortisone and it's relatives - and anabolic steroids - reproductive hormones and analogs. The anabolic steroids can promote better skin and muscle development, and a metabolism which in general terms can be thought of as 'building up' the body. Catabolic steroids tear down the body - damage muscle and connective tissue, suppress the immune system, as well as retaining water. It's disconcerting that pet owners and veterinarians think nothing of loading dogs up with these harmful catabolic steroids, yet aren't familiar with, and thus are reluctant to use Cheque drops, which can do so much good where indicated. Should you wish to spay the bitch later, her tissue tone and condition will be better if she's been on Cheque drops, and will be easier to suture without tearing. The most common use of this medication is to lengthen the inter-estrous interval in bitches which cycle too frequently, i.e. every 4 months. The heat cycle of the bitch is not 3 weeks, it is 4 months. Every bitch has a false pregnancy, based on circulating hormone levels, whether the behavior is there or not. The effect of bitches cycling every 4 months is that the uterus never gets any time off, and is more subject to disease. Fertility of bitches cycling every 4 months is adversely affected.
Mary C. Wakeman, D.V.M.
©2003 for BREEDERVET
