Bitches have two heat periods per year,every 6 months,each lasting 2 to 3 weeks.Females living together is often cyclent each other and therefore their heat at the same time.The first heat occurs between 6 and 15 months and the dog can be fertilized at the undergraduate level.The onset of oestrus occurs later in large breeds that have a longer growing.
The bitch is a bitch to spontaneous ovulation,unlike a cat that has induced ovulation. This means that ovulation is independent of the projection.It takes place no matter what happens every 6 months (while in the cat,ovulation is triggered by the projection).Heats or more spaced closer together than a month however,are not abnormal.The cycle time varies from one animal to another and from one race to another but remains between 150 and 300 days.
The sexual cycle in females
This cycle has four phases: proestrus and estrus,which is the period of heat itself,and then metoestrus anoestrus,which are phases of sexual rest.Behavior,physiology and anatomy of the animal undergo changes during each stage of heat.
Over a period of 7 to 10 days,it indicates the onset of heat.One can observe the first blood loss and a very visible increase of the vulva.At this stage males are attracted by the female,but she refuses the projection.Within the reproductive tract,hair follicles,which will release the egg during ovulation,grow.
This phase follows the previous and lasts 5 to 10 days.Losses at the vulva decrease to stop completely.The male is accepted.Ovulation occurs during this period,usually 2 to 3 days after the acceptance period of the male.This notion is very important because it means that the ideal time of reproduction is that of acceptance of the projection by the female.
This stage lasts from 110 to 140 days. The bitch is pregnant,or sexual rest if it has not been fertilized.
This phase precedes the new heat period and is of variable duration given that on average a bitch is in heat twice a year.
The sexual cycle in the male
The dog does not have a sexual cycle accurate: it is in heat when a bitch in heat before it.Mature dogs recently (between 8 and 10 months),sperm are often few and sometimes show abnormalities.Its fertility is not at its maximum and it is better to wait the age of 10 to 15 months for the first projection.During these cycles,many hormones are secreted.It does not pass in review all these molecules,but it is necessary to take note of the most important hormones to understand cycle regulation and its disorders.