 
Allie, our twenty month old lab is in heat for the first time, so she is in lock down. Man, that’s a pain. We have to keep her and her brother Zeke well separated. She has a lid on the kennel and we wrapped the sides with chicken wire to prevent any through-the-fence visitors. And she sulks in the house when she has to wear a pair of kids underwear with a hole cut for her tail. The kids thought that was funny looking. To tell the truth, the neighbors think it kind of strange as well.
Some things to remember about the heat cycle: it usually occurs for the first time between 6 to 12 months, but may be as late as 24 months. The full cycle usually take about six months, so the actual estrous period comes about twice a year. However, a friend’s German Shorthair has had her last two cycles 3 months apart. There are 4 parts to the cycle: 1.) proestrous – begins with vaginal bleeding and lasts 4 to 9 days. Males become very interested in the female, but she does not accept them. They often feel kind of mopey and lie around. 2.) Estrus – discharge shifts to more yellowish than bloody and is ususlly lasts for 4 to 12 days. The vulva will usually swell and may even be flagged or winked around a male. This is the period when she is most fertile and willing to willing to accept the male. By nature, she will stand and hold her tail to the side when you press on her back or when the male tries to mount. 3.) Metestrus and anestrus are periods of the ovarian cycle, but with no outward signs.
Keep in mind that you may easily miss the first day or two of the heat, and they may take longer or shorter than the norm to move through the cycle. Consider her to be in season for 21 days: 7 early heat, 7 days in season, and 7 days late season. Though conception is most likely to occur when they are in full season, due to individual variation and sperm life, it may occur anytime during the 21 days, so you have to keep them confined the whole time. Something else to remember is that she may attract dogs from all over town and males during this period like to mark everything that seems like a good scent post, like kennel corners, house corners, fence posts, standing bags of dog food, the car tire, whatever.
I have also heard many stories of neighborhood dogs (several specific to Australian Shepards) climbing a 6’ kennel and breeding a female in heat. I have also heard stories of dog breeding through chain link kennels, so be aware. Please think through breeding your dog very carefully before breeding your dog. Think of your young female’s health first, and remember that there are lots of very good, proven breeders out there. Visit the local animal shelter and see how many puppies end up there before you proceed.
