When does a female dog first come into "heat"?
Puberty or sexual maturity in the female dog usually occurs around six months of age. The smaller breeds tend to go into estrus or "heat" earlier and some females can have their first "heat" cycle as early as four months of age. On the other hand, the large and giant breeds can be up to two years old before they come into heat for the first time.
How often do female dogs come into heat?
On average, this occurs about twice a year, although it varies from dog to dog. When cycling first begins, there may be a great deal of variability in the time between cycles. This is normal. Some females take eighteen months to two years to develop a regular cycle.
Small breeds tend to cycle more regularly than the larger breeds. Three and occasionally four heat cycles per year can be normal in some females. Very large breeds may only cycle once every 12-18 months. In most giant breeds (Great Danes, Irish Wolfhounds, St Bernard', etc.) an estrus cycle every twelve months is common.
How long does a "heat" cycle or estrus last?
"Heat cycles vary, but average two to three weeks for most dogs."
"Heat" cycles vary, but average two to three weeks for most dogs. The heat cycle begins with the first signs of vulvar swelling or vaginal discharge. It ends when all discharge ceases and the vulva has returned to its normal size.
How can I prevent my female dog from coming into "heat" and having puppies?
There are two methods to prevent estrus or "heat" in a female dog:
Surgery - ovariohysterectomy
When a woman has a hysterectomy, the ovaries are not usually removed. Why is it necessary to remove the ovaries in my dog?
The reproductive cycle of the female dog is entirely different from that of woman. Female dogs come into "season" or "heat" twice a year on average and it is only at that time that they can conceive. The purpose of an ovariohysterectomy is to ensure that the estrus cycle does not occur. This has numerous health advantages for the dog, including reducing the risk of breast cancer and eliminating the risk of ovarian and uterine cancer. In addition, unwanted litters are prevented and the behavioral changes associated with "heat" are avoided.
Are there any other advantages to spaying?
Breast cancer (mammary neoplasia)
Medical control of estrus
There is currently a tremendous amount of research being conducted in this area. Novel approaches such as drug implants and vaccines to prevent ovarian development and pregnancy are being investigated.