Please help - Is my puppy too small?

I recently purchased a 5 month old cavalier puppy. She is now 6 months old and weighs 7.7 lbs. We recently met two 4.5 month old Cavlier puppies (the two puppies were unrelated to each other). I was amazed and shocked at how much smaller my dog was than the two pups. They were almost twice her size, and she was dwarfed beside them. (BTW, my vet also told me how tiny she was. I really thought he was referring to the fact that she was skinny and not that she was tiny, until we met the other two pups.)

This is my first Cavalier. Should I be concerned about her size?

No you don't need to be concerned My pup is a year old and only weighs 9 lbs. We met a 13 week old cavalier the other day who was about her same size - the other family didn't believe me when I told them that my pup was a year old! I think that size is just fine for a 6 month old puppy. Most of the cavaliers out there these days are bigger than they should be from bad breeding and being overfed, etc so comparatively yours may seems small but as adults they are only supposed to be in the range of 13 - 18 lbs so 8lbs at 6 months is just fine I think. But they come in all sizes based on many factors so as long as she is healthy otherwise I'm sure she's fine!

Not necessarily.My cavalier is just over a year old and I always considered her dainty.I've seen other cavaliers and even fosterd two and they all completely dwarfed her and I began to wonder if my cav was tiny.
Happily it seems that she's the correct size as regards the breed standard and that very many cavs are much bigger than the breed standard.( mY hubby met karlin's Jasper and he's exactly the same size and appearance so I was happy to hear that) My mother has a cav who would make a springer feel insecure, he's massive!
So if your pup is eating well and is generally thriving and healthy I wouldn't worry.
Sins

Well it is hard to say as many dogs get a growth spurt later, some early, all depending on the line, the number of puppies in the actual litter, and so on. So the answer is this is not necessarily a concern, as long as your vet says she is fine and healthy. And she my well reach breed standard anyway, she is still very young. and that isn't all that small, either, just slightly smaller. Girls are usually about half their adult size at around 14 weeks but this is just a rough gauge and there are many variables (eg puppies from large litters may start off a lot smaller).

Have you discussed your concerns with her breeder? Any reputable, health focused breeder will only aim to breed dogs that fit breed conformation -- 13-18 lbs in the US, 12-18lbs in the UK -- but some will always be a bit smaller and a bit larger. Talking to your breeder should reassure you of the size of parents and whether her size should be of any concern. Also it may be useful to the breeder to know that she remains small.

Unfortunately there are also many unscrupulous breeders who do not care about what the breed looks like or whether they breed for health, and some even deliberately breed for extra small dogs (eg teacup cavaliers -- there's no such thing). If puppies are well off conformation (a lot smaller or a lot larger), and you don't know much about the breeder, chances are they also did nothing to ensure breed health and just bred any two dogs, in which case there could be longer term implications -- so that is one possible worry with an extra small dog. Breeders who deliberately breed small dogs are really dicing in a cruel way with genetics. First off if they are breeding in this way you can be sure they do no health testing at all and do not understand the genetic problems they can be introducing. Second they may well be selecting dogs that are already health compromised as that may be producing the smaller dog to begin with -- open fontanels, for example, or liver misfunction... or breeding litter runts, which are usually pretty poor breed examples and often are small due to poorer health than siblings.

And that's the last possible concern -- that an actual physical problem may be the cause of a dog not reaching normal size. However, if the dog is otherwise healthy and your vet isn't concerned, then an immediate physical problem is really probably not something to be concerned about.

I agree with Karlin, the best course of action is to discuss this with the breeder she came from, could easily be that the lines are just slower to mature, or that many of the cavaliers you see are larger then they should be. I've had several people comment on Amber's size - She's 4 years old, and about 14-15 lbs now (she was slightly underweight when I got her), which is about perfect for a health female cavalier according to breed standard, yet she does look tiny around many of the cavaliers in this area, because they aren't bred to the standard (mostly because very few people around here care ). I have little experience with the breed as a puppy, but a 6 month 7.7 lb cavalier doesn't sound horribly tiny. It never hurts to have her checked for heart problems and liver shunts just to make sure there's nothing medical that's leading her to be so tiny, but I also wouldn't panic at that age, especially if you discuss it with the breeder and she feels she's at an appropriate weight for her age, the breeder should know her bloodlines well enough to know if that's normal or not.

I was wondering if my boys were small for their age too. They went to the vet last week and he said they weigh 6.3 each. I've read that they should have an hourglass figure but I wish I had something to compare them to I guess.