There are chemicals that can stop the heat cycle. They may make a dog more masculine and aggressive and are typically only used if you plan to breed the dog but want to control the timing.
You can read about using megestrol (Ovaban) here
http://www.peteducation.com/article.cfm?c=0+1303+1466&aid=1470
The spay operation (ovariohysterectomy) provides some health benefits as well as some negatives but would be my choice among the three surgeries you list.
This site goes over positives and negatives of spaying
http://avmajournals.avma.org/doi/pdf/10.2460/javma.231.11.1665
If you do not intend to breed and if this is not a giant breed dog then spaying now would be a reasonable choice. If this is a giant breed dog there may be benefits to waiting until she is over three before spaying to ensure the growth plates are closed.
Hope this helps you!
Sure take a look here about what happens to the uterine lining
http://www.marvistavet.com/html/body_pyometra.html
Progesterone is what causes the break down of the uterine lining. Removing the ovaries simply removes the estrogen source.
From a holistic point of view, the best option is to permit the dog to breed each heat cycle or at least one heat cycle a year for life. This causes complete shed of the uterine lining in most cases which helps reduce chances of infection.
From a responsible owner or breeder point of view, if a dog is not going to be bred then removing the organs is safer for the dog and ensures only wanted puppies come into the world. The timing of when that is done is controversial.
Dog Expert:Rescue, Train,Breed,Care
30+ yrs dog home vet care & nursing, rescue, behavior&training, responsible show breeding, genetics
You are welcome and good luck with her!
Thanks for the above accept!