Unwanted pregnancies Print E-mail
News - Rubrieke
Thursday, 22 May 2014 23:53
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Dr Liesel van der Merwe is a small animal medicine specialist. Send her your questions: This e-mail address is being protected from spambots. You need JavaScript enabled to view it .

Dr Liesel van der Merwe

I adopted an eight to ten-weeks-old kitten two months ago. I could not believe what I was seeing over Easter weekend. She was on heat, and she couldn’t have been more than four and a half months old.

Never mind all the rules about cats coming into heat later in autumn. After one night of howling, I took her into the practice on Easter Sunday and spayed her. Things settled down after 12 hours and she was back to normal two days later.

You need to pick up on early signs of heat. In dogs, the smaller breeds come onto heat at five to six months, with larger dogs showing their first heat at eight to nine months and in the giant breeds, such as Great Danes, at about 10 to 12 months. 

Most dogs will have a heat cycle every six months with the giant breeds every eight to 12 months. The signs of heat differ and the heat period is two to three weeks long, with mating in the last few days, as this is when the female is receptive.

Initially there is swelling of the vulva and the female pays increased attention to her rear end. There is also a mild amount of bloody vulva discharge. Depending on the volume and how fastidious your dog is, you may not easily notice the bleeding.

From the beginning of the heat period she will be attractive to male dogs due to pheromones in her urine, but will usually not allow mating until about 11 days into the heat. The discharge will usually become less bloodstained at this time and the vulva may also appear less swollen.

Sterilisation of the bitch protects against later development of mammary tumours if done before the second heat. There are no personality changes whether they’re allowed a heat or a litter or not. Obesity is a possibility after sterilisation, as the metabolism slows down. If caloric intake is reduced by up to 30%, weight can be managed by exercise.

If you want to breed with your bitch, don’t breed on the first heat, as females are not mature yet. You need a strategy to prevent her from falling pregnant. High walls help, but small dogs can scale them. If you have a male on the property and cannot separate them, consider kennelling her.

Canine sperm is viable for up to seven days in the female reproductive tract, so she can fall pregnant even if mated three to four days before ovulating. Her litter can have several different fathers if she is mated by different dogs.

The only way to determine when she has ovulated is by doing serial vaginal smears to determine the day she goes off heat and into di-oestrus. The day of mating cannot be used to determine day one of pregnancy or the due date.

It is not necessary for the female to 'tie' with the male dog to get pregnant. There is little point in trying to separate animals that are locked in this way. Buckets of cold water and cap guns do little to speed up the process of separation and merely upset the dogs. Forced separation can result in serious injury to the female.

We used to dispense a course of hormone pills within three days of mis-mating, but this predisposes them to uterine infection, which is treated by sterilisation or major antibiotics, hormones and flushing if you want to try to retain breeding potential.

We do not use this pill anymore. There is an injection which can be given up to four weeks after a mis-mating and causes abortion. We can diagnose pregnancy from 21 days by scanning and about four weeks by feeling, which is more accurate in smaller dogs and if the dog is relaxed. 

X-rays are only used later when the puppies’ skeletons are developed and to check the size of the litter. There is a blood test to confirm pregnancy or abortion. It can only be used after 22 days of pregnancy and needs to be repeated after seven days.

Cats will keep coming into heat every two weeks until they are mated. There are no physical changes to indicate heat, so you need to look at their behaviour – vocalising, rolling, kneading and lifting the rump.


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