Meeting and mating: the reproductive cycles in pets. Pete the Vet on Newstalk’s Pat Kenny Show

This week’s podcast discusses reproduction in dogs and cats, from coming into season through to pregnancy. Listen to the podcast below.

Female cycle in dogs

The first season (oestrus) in a dog usually happens between 10 and 18 months of age.and they tend to come into season around twice a year
The reproductive cycle of the bitch is divided into four stages: proestrus, estrus, diestrus, and anestrus.
Most bitches are non-seasonally polyoestrous, whereas wild dogs (including foxes) are seasonally monooestrous. This means that female pet dogs come into season continuously, every 6 months or so, while wild dogs come into season once a year, in the early springtime.

Bitches are spontaneous ovulators i.e. they don’t depend on being mated to ovulate (cats do)

The four stages of a female dog’s cycle are as follows, and they happen continuously in this order, one after the other.

  • Proestrus
    Prooestrus starts with the onset of swelling of the vulva, with a small amount of bleeding. The average length of prooestrus is 9 days; however it may range from 0-27 days.
    Estrogen causes hypertrophy and hyperplasia of the uterus, vagina, and vulva. The bitch becomes attractive to male dogs but will not let mating take place. She refuses to stand still and may even be aggressive if approached by a male dog.
  • Oestrus
    Oestrus is the time when ovulation takes place; the vulva continues to be swollen, blood stops dripping and is replaced by a straw-coloured fluid, and the bitch will now stand placidly if mounted by a male dog. Oestrus on average lasts for 9 days but can be as short as 4 days or as long as 24 days.
    Mating is likely to happen at this time and may result in pregnancy (although the chance of pregnancy following a single mating is just 38%)
  • Dioestrus
    The bitch becomes unreceptive to mating during this stage. This period lasts two months and a bitch may develop a false pregnancy towards the end of this time.
  • Anestrus
    Anestrus follows diestrus and is the time of hormonal inaction. This is the “recovery period”,  allowing the uterus to recover after the active phase of oestrus. It usually lasts for around 4 months.

How can you tell what stage of the cycle a female dog is at?

Microscopic evaluation of vaginal smears by a vet is the clearest way to judge the stage of cycle of a bitch. These are often done by vets in the practice laboratory. The vet stains these smears, examining the cells present under a microscope. The population of cells varies according to the stage of the cycle, allowing a judgement to be made.

How long does pregnancy last in a female dog?

Pregnancy lasts 64 days on average

Female cycle in cats

The first oestrus in queens usually occurs between 4 and 12 months of age.
Queens are seasonally polyestrous. They normally cycle when there is 14-16 hours of light (either natural or artificial) light every day (i.e. from spring to autumn).
When exposed to natural lighting, cats in Europe typically cycle from early-February to mid-October.
As with dogs, the oestrous cycle includes proestrus, estrus, diestrus, and anestrus.

  • Prooestrus only lasts 1-2 days, and because it is so short, it may not be noticed.
  • Oestrus typically lasts 7 days (range 2-19 days). During this phase, oestrogen levels are raised and behavioral signs are usually obvious (such as increased affection, playfulness, rolling, loud vocalisation and sexual receptivity).
  • If a queen has not ovulated, an interoestrus period of approximately 13-18 days occurs, and then pro-oestrus and oestrus happen again. Ovulation is stimulated by the act of mating. If mating does not happen, ovulation does not happen, and the cycle of pro-oestrus, oestrus and interoestrus keeps being repeated.
  • If a queen has ovulated (stimulated by the act of mating), dioestrus occurs.
  • If conception and implantation (i.e. pregnancy) does not take place, a pseudopregnancy follows, lasting 25-45 days, and then the cycle of pro-oestrus and oestrus starts again
  • If pregnancy does follow mating (i.e. if conception and implantation take place), gestation lasts 63-68 days.
  • The anoestrus phase (when the reproductive system is quiescent) occurs during winter, when daylight is short, which means from October to late January in Europe.

Pregnancy diagnosis in pets

There are several ways of diagnosing pregnancy in dogs and cats. Simple urine or blood tests (as in humans) are not available due to the different type of hormonal changes in animals.

  • Abdominal palpation. Uterine enlargement can usually be felt by a vet manually palpating the abdomen by day 24 to 30 after ovulation in dogs and cats.
  • X-rays. An enlarged uterus can sometimes be seen between days 21 and 42 after ovulation, but the skeletons of the pups and kittens cannot be seen till day 45 or so.
  • Ultrasound. Ultrasound is the earliest and most accurate way to diagnose pregnancy, sometimes being possible by 20-22 days after ovulation, and becoming clear by day 28. However it is not possible to count the number of pups or kittens accurately.
  • Blood tests for pregnancy diagnosis are not as simple as you’d expect compared to humans and they are not often used in practice

Questions from listeners about pets

Listeners texted in their questions as usual: the following were answered on air:

  • I’ve got two 4 month old kittens who keep each other entertained when my partner and I are in work. What’s your opinion on letting them watch ‘cat tv’!? There are lots of YouTube channels specifically designed for cats showing videos of mice, birds, fish etc. They seem to love it but I’ve heard it might be cruel and could cause them to become frustrated or stressed. What do you think? Thank You.
  • We have recently moved house and our previously well behaved 4 yr old miniature schnauzer has started peeing on my daughters bedroom floor and our 2 year old Cat (a ragdoll) has found a spot on the living room. We have attempted restricting both pets in the tiled areas of the house, but with two kids the doors often get opened and they go directly back to their spots! We have a litter tray which the cat uses and the dog goes out to garden regularly and otherwise they both seem happy and not stressed by the move, but we are pulling our hair out particularly with the cat pee, it is very hard to get rid of the smell in the room . Any help appreciated! Jane.
  • My two cats have started peeing and pooing on my bed and my son’s bed whilst he was asleep in it, and also in the bath, they’ve never done it before, they are both male and are outside during the day, what should I do. Thanks Caroline
  • We are lucky to have up to five grey squirrels in our small garden every day. I love to see them but we have two small children (1 and 3) and am wondering if squirrels pose any health risk we should be aware of. We always make sure our children wash hands after playing in the garden.

To listen to the answers, and to hear the rest of the podcast, click on the link below

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