What can be the reasons for a bitch missing. When you breed dogs you pretty much expect them to be pregnant so when they aren't it can come as a bit of a surprise but what are the reasons for missing. Having both male and female and letting them decide when the time is right I would imagine you have a better rate of them getting the right time.?   I fully expected my bitch to catch this time and its come as a shock im now ( probably worrying over nothing) but worried that one of them may have something wrong.  Earlier this year by boy got ill, he had severe sickness and diarhea and was on a drip for 3 days in the vets.  Can something like this affect fertility ?

Goodness almost anything can cause a bitch to miss the most usual being mistiming and from the sires side overheating in the last 3 months or so. But they are no more fertile than any other mammal, how many times have you heard that a zoo is disappointed that their charge is not carrying and they are the experts so it is not surprising that all breeders will tell you that they have had a bitch miss or abort, if the timing is wrong or anything is not right then nature steps in and stops the process.

Can't remember what the conception rate in canines is but I think I read it's around 85% of mated bitches go on to produce puppies.

Even Rabbits miss, and they ovulate due to stimulation of mating (so you can't get timing wrong).

The most common reason for no pups is mistiming, a bitch not ovulating that season or some reason, underactive thyroid can be a reason for this (though often you won't get a mating).  Then there is something going wrong in actual pregnancy resulting in fertilised eggs not implanting, or pups being absorbed later, hormone levels out of wack (can be stress).

I think I read it's around 85% of mated bitches go on to produce puppies.

That may be right I can't remember either but it is by no means a forgone conclusion except when the bitch or a stray, very unsuitable dog, get through the fence then it would seem to be 100%. Some dog and bitch pairs seem never to produce a viable litter with one another although they are able to with different partners.

I do believe if a dog has had illness it can affect their fertility around 6 months later - at least this may be a reason why your bitch missed - many of us have no idea why a proven bitch who was ovulation tested and had 2 good mating 48 hours apart missed to a proven stud.

Better luck next time....

Suppose like most things in nature procreation is not 100% nor a given right. And agree a dog that has been sick may well suffer a blip in it's fertility particularly if the temperature has been raised, forget the detail now but sperm die if subjected to a temperature above a certain level so being left in hot conditions or having a fever will effect fertility.

I have also heard that antibiotics can affect male fertility. I'm sure my vet told me this when one of my boys had to go on a long course for a nasty bladder infection. But others have said it's rubbish!

Not sure about the ABs but the infection would cause a problem because of the raised temperature and white cell count.

Think it is by far the best practice to only use dogs who are and have been top notch for at least the last 6 months if a litter is important at that time which one would hope it is or you would not be mating at all.

I'm pretty sure I was told that either being on any meds containing steroid including things like ear drops can affect fertility

http://www.thedogplace.org/REPRODUCTION/Mechanics-of-Mating_Andrews-09.asp you may find of interest,

This one is a warning to what could happen to a pet male http://www.thedogplace.org/REPRODUCTION/Mating-Dance-0910_Gammill.asp

thank you everyone. It was only in February and he was running a high temp and had AB too so maybe thats the reason she didnt take this time. She will be coming back into season in December so maybe we will be able to try again then.