chloelogoa

                    The Canine 'Season'                    

talalogoa

Female dogs become sexually mature between 6 and 12 months of age. Smaller breeds reach puberty at a younger age than larger breeds. Most bitches will come 'into season' 'on heat' or  'oestrus' when they reach puberty at 6-7 months of age, but possibly as early as 4 months or as late as 2 years.  Generally it is around the 12 months mark. The objective of the estrus cycle is to produce eggs, stimulate the bitch into accepting the male, and prepare the reproductive tract to nurture fertilized eggs and the foetal puppies as they develop in the uterus.  Most dogs go through a heat or estrous cycle every 5 to 10 months (7 months = average) throughout their lives.  Some breeds like the German Shepherds may cycle once every four months where as others will cycle once every 12 months.  More frequent heats, that is at intervals of less than four months, are often associated with infertility. 

The first sign is likely to be a slight discharge of white or pale yellow mucus from the vulva (the opening to the womb) which may also swell slightly.  Conception is more likely to occur if mating takes place 10-12 days after the first obvious signs of heat are noticed but can occur earlier or later.  After a day or so, the discharge becomes blood-stained and the vulva swells much more.  The main discharge continues for the first 5 to 10 days of the season, which is technically called "pro-oestrus". After this it will gradually reduce until it dries up altogether - this part of the cycle is officially called "oestrus". 

Some bitches may show signs of abdominal discomfort, increased excitability and be less inclined to eat for a few days before heat commences.  Some will start territory marking just before and during proestrus, by passing small amounts of urine at frequent intervals around the garden or when they are taken for walks.  Bitches become attracted to dogs, usually from the first day of heat, but mostly they are not interested in their admirers untill 7-10 days have passed.  At this stage she is equally anxious to escape to meet the male. 

Straight after her season is the time of "metoestrus". Slight physical or behavioural changes (e.g. milk glands enlarging, 'nursing' toys) May occur at the time when the puppies would have been born if she had been mated. If this is severe, see your vet as she may need hormone treatment to correct it.

Remember the first season is often irregular and not typical and it may be 'silent' or shorter than usual.  Some bitches can take up to a year or longer to settle into a regular cycle.  Split heats where the bitch bleeds, stops bleeding and then returns to heat around 6 weeks later are common during the first estrus.  It is advisable not to breed on first heat as it may increase the risk of dystocia.  The life threatening condition called pyometra occurs most commonly one to two months after the bitch has been in season.

Some Important Points
    * You should consider your pet to be "in season" for 21 days: 7 days coming into heat, 7 days in heat, 7 days going out. Conception is most likely during the middle 7 days, but doesn't always follow the rules.  Be more vigilant and confine your pet for the entire 3 weeks.

    * Remember that the above information is general. Not all females follow these patterns. Consult with the veterinary surgeon if your pet does not seem typical. Cycling problems may indicate more serious problems, and they are best dealt with sooner rather than later.

    * If a bitch of two years old has never had a season please seek veterinary advice.

    * Bitches housed in close proximity tend to synchronize their estrus cycles, probably as a result of the excretion of pheromones. 

There are four stages in the canine heat cycle (estrus) in dogs based on the dog's behaviour and physical signs:


Stages Of The Estrous Cycle
Stage of Cycle
 Duration
Proestrus
 Average 9 Days
(range 2-27 days)
 The period of time when a female dog attracts males but is not receptive to breeding unfortunately the males will not take no for an answer but the female will make it plain that she is not interested.  Proestrus is the time when a bitch's reproductive tract is preparing for the possibility of breeding with a male dog. Females usually have a blood tinged vaginal discharge and a swollen firm vulva.  A bitch that cleans herself can be hard to detect for a few days, so it is a good practice to lift her tail and check every day.  Also the bitch will usually have an increase in the need for urination and her coat can become soft with the increase of hormones.  Her temperament can also change, becoming scatty and resistant to human direction.  If you are considering mating she will become more calm and secretive once she has accepted the male and is pregnant.
Estrus
 Average 9 Days
(range 3-21 days)
 This second phase is the actual fertile phase and is when the female dog will accept the male and stand for breeding. Generally she will continue to accept the male for approximately 4-10 days, but can vary between 3 days -3 weeks. The vaginal discharge decreases and has usually gone from bright red - to pink- almost clear (some dogs will continue to have a bloody discharge throughout) and the vulva, although still swollen, is softer. The bitch will display the behaviour called "flagging" where she holds her tail off to the side when any male approaches.
Diestrus Average 90 days
 Diestrus starts when the female will no longer allow breeding. She will either snap at the males or lie down when they try to mount her.  It ends when the ovaries stop producing the hormone progesterone and is considered the period when progesterone dominates the hormone scene. This period lasts about 65 days in the pregnant dog ending when the puppies are delivered, or 75 to 95 days in the non-pregnant dog. Progesterone may cause many false signs of pregnancy like nesting behaviour and milk production even if the dog is not pregnant. "False pregnancy" resolves on its own when progesterone levels decline.
Anestrus Variable - but on average 75 days
 The period between heat cycles when the uterus becomes smaller and inactive is known as Anestrus.  Anestrus lasts an average of 4 to 5 months. During this time the sex hormones are at very low levels, although they do continue to have small rises and declines throughout this stage. If you are thinking of having your bitch spayed this is the best time to do it.

source:
Doglopaedia - JM Evans & Kay White
Book of the Bitch - JM Evans & Kay White
Coming into Season - Harvey Caruthers
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The Normal Canine Estrous Cycle
 False Pregnancy
 Dystocia
 Events in The Estrus Cycle
Estrus and Hips





chloebutton     talabutton
  The above information is simply informational. It's intent is not to replace the advice of a veterinarian nor to assist you in making a diagnosis of your pet. Please consult with your own veterinarian for confirmation of any diagnosis. Your pets life may depend on it.