Are there any disadvantage of spaying an older bitch in terms of health?
Many vets say that chances of cancer of the breast is decreased with spaying.
This is real undisputed truth?
Are there balanced viewed on spaying an older bitch?
"Pyometra is a result of hormonal and structural changes in the uterus lining. This can happen at any age, whether she has bred or not, and whether it is her 1st or 10th heat (although it becomes more common as the dog gets older). The main risk period for a female is for eight weeks after her peak standing heat (or estrus cycle) has ended. Normally during this period, the cervix, which was open during her heat, begins to close, and the inner lining begins to adapt back to normal. However, cystic hyperplasia of the endometrium (inner lining of the uterus) – known as cystic endometrial hyperplasia (CEH) – may occur at this time for some animals, as an inappropriate response to progesterone.
Under these circumstances, bacteria (especially E. coli) that have migrated from the vagina into the uterus find the environment favorable to growth, especially since progesterone also causes mucus secretion, closes the cervix (preventing uterine drainage), and decreases uterine contractility. The condition of the cervix is a major factor in the severity of the condition.
Living with… pyometra
Written by: Linda Aronson, DVM
Pyometra is a relatively common disorder of older intact bitches. Either estrogen or progesterone can cause thickening of the inner lining of the uterus (cystic endometrial hyperplasia - CEH). Exposure first to estrogen and then progesterone (as in the normal heat cycle) produces maximal thickening. As bitches age the likelihood and level of thickening increase progressively, and by age 9 two-thirds of bitches will have some signs. Bitches that receive estrogen or progesterone to terminate pregnancy or suppress estrous are more likely to develop CEH. During proestrus and estrus the cervix opens allowing bacteria normally present in the vagina to ascend into the uterus. These bacteria are the ones that invariably cause pyometra. It has nothing to do with the stud dog, and this process occurs whether or not the bitch is bred. In bitches with CEH, bacteria colonize the thickened uterine lining and aren’t expelled as they would be in a normal bitch. Once diestrus begins the cervix closes and bacteria can no longer exit. Progesterone prevents uterine contraction while stimulating secretion by uterine glands to nourish the fetuses, but also the accumulated bacteria. White blood cells, secretions and bacteria fill the uterus, and antibiotics cannot diffuse into this sea of pus. The pressure of the fluid may cause the cervix to open (open pyometra), but this doesn’t occur in all cases. The infection may cause secondary kidney damage, which may be irreversible. Pyometra also causes suppression of the immune system by direct effect on the immune cells. While pyometra is more common as bitches age, it has been reported in bitches under a year old. It is also more common in bitches that have never had puppies. Clinical signs are usually seen within 12 weeks of estrus. The most common sign is a thick, creamy discharge that is usually foul smelling and sometimes resembles tomato soup. Closed cervix pyometras generally produce more severe signs including fever, abdominal distension, vomiting, increased thirst and urination. After 24 days ultrasound can be used to distinguish pyometra from pregnancy in a bred bitch. An elevated white blood cell count, with young cells predominating, indicates active infection. Anemia may be present. Diagnosing a mild infection can be problematic. Spaying is by far the preferred treatment. Pyometra is progressive and CEH is irreversible. The dog will be predisposed to pyometra for life. Medical treatment should only be attempted in young bitches that seem healthy with open cervix pyometras. It consists of antibiotics to control infection – which are not very effective, along with either prostaglandins to cause uterine contraction, or antiprogestogens (like RU486) to lower progesterone concentration. The former is more commonly used in North America. In theory, the increased pressure of the contractions will cause further opening of the cervix and the uterus will expel the infected fluid. However, if the uterus fails to open fully it may result either in uterine rupture or backflow into the abdomen, both will cause peritonitis and usually death. The antibiotics are ineffective until the pool of pus and bacteria is cleared from the uterus, and meanwhile the toxins they produce continue to damage the bitch. The infection is never completely eradicated but reduced to a subclinical level. If medical intervention is attempted not only should the bitch be young, in good body condition, show no signs of secondary illness and have an open cervix pyometra she should be a very valuable member of a breeding program – even for appropriate candidates the treatment is painful, and many vets will not at
by Blitzen on 10 October 2011 - 03:10Posts: 12316
Joined: Mon Aug 09, 2004 06:49 am
attempt it. She should be bred on her next season, monitored closely for likely pyometra and then spayed after the puppies are weaned, assuming she makes it through the pregnancy, whelping and lactation successfully.
We are lucky to have not one but two detailed accounts of breeders whose bitches developed pyometra. Both were open cervix, both had been bred, both breeders were extremely attuned to their dogs. Neither bitch had experienced a prior pyometra. Provided the bitch is stabilized prior to spaying the prognosis is good. Provided the above guide-lines are followed in choosing candidate animals prognosis for fertility in medically treated bitches is fair to good. If medical treatment fails, the bitch can still be spayed.
Linda Aronson, DVM
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