When your mild-mannered dog is quietly snoozing in his bed, it's hard to believe it's the same guy who could scale a fence to meet up with a dog in heat. A dog in heat emits powerful odors, strong enough to entice suitors from 3 miles away. If your dog isn't neutered, you'll have to be clever and determined about calming him during the female's estrus cycle.
The typical dog experiences two heat cycles a year, each lasting approximately two to three weeks. Depending on the dog, you may not notice she's in heat right away; often a bloody discharge is the first thing to clue you in. A dog can't get pregnant early in her cycle, but after a week to 10 days, she enters the estrus phase of her heat cycle. At this point her discharge becomes more watery and she often begins to mark, depositing urine on various spots in and out of the house, signalling her receptiveness to mating. During this time, her urine contains hormones and pheromones easily detected by male dogs, who can detect her scent and condition from great distances.
Not So Gentlemanly Responses
Dogs have a sharp sense of smell that helps them perpetuate the species. Once an intact male gets a whiff of his potential new girlfriend, he'll do just about anything to find his way to her, including digging under and jumping over fences and dodging his way across a busy highway. The male also will urine mark if he picks up the scent of a female in estrus, signaling his availability. If there's competition for her affections, there may be some aggressive behavior as two male suitors battle it out for her attentions.
Chances are good if an intact male encounters a female in estrus, there will be a litter of puppies. Spaying and neutering is the only way to ensure neither becomes a parent. Otherwise, you'll have to keep your dogs separated until she's completed her heat cycle. If a tryst has taken place and you aren't ready for little ones, your vet can perform an abortion.
If you cannot neuter and spay your dogs and you don't want puppies, keeping them separated is mandatory. Consider kenneling your male dog for the duration. He won't be present to pick up on the scents the female is emitting, nor will he be spending all of his time trying to hook up with his girlfriend. If kenneling is out of the question, dog breeder and nutritional consultant Linda Arndt recommends giving the female liquid chlorophyll twice a day to mask her odors. According to Arndt, the male's interest wanes a bit because he's not picking up the masked scent. If you choose to try this option, check with your vet to determine the appropriate dose. If your male's potential suitor isn't in the same house but lives next door or up the street, do your best to avoid the other dog.