I have a beautiful girl i show and i planned to keep a pup from her first litter back to also show but due to timing i couldnt,i was very disappointed because there were a couple of pups that looked very promising however i  decided to keep one from her 2nd litter .I had to use a different sire but one i was very keen on and has sired many litters that have gone on to do very well in the show ring .It was quite a large litter but was horrified when one by one they came out with various defects ranging from deformed limbs/tails,cleft palate,extra toes.many didnt make it,2 were stillborn and the ones that did make it have had problem..4 have cateracts and one a heart murmur and im absolutely devastated because the first litter were perfect! How can one litter be so perfect then this? I was desperate to keep my line going through this girl but now i dont know what to do..would this be hereditary or something environmental although i just cant think of anything that couldve caused this.Any help would be great because i am baffled.

Multiple deformities like this, in several pups, tend to happen because of outside influence. I.e. something happened during the pregnancy. Can you think of anything unusual? Or even just different to normal? I had this happen in a litter of Persian kittens many years ago and I contacted the geneticist Roy Robinson. It's difficult to know for sure what the cause was but in my case, the house next door had been totally gutted and renovated and a LOT of dust came into our house, and that was the one different thing. The next litter was normal.

I agree with Goldmali.  When a whole litter is affected like this, it suggests some kind of environmental toxin - could be weed killer, maybe you walked through a field a farmer had just sprayed (I know of an entire litter with birth defects as a result of that), perhaps you used some medications during pregnancy (tick, worming, ABs?) which are not safe during pregnancy...