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Friday, November 21, 2014

How Small Is Too Small?

Here's a question I received from Ashley...
My question now is about the weight of my Newfoundland puppy, Olive. She was born 26 March and when I picked her up at 10 weeks, she only weighed 8kg (17.6lbs), a bit small for a Newfie of that age. Well, now at 22 weeks she weighs 21kg (46.3lbs), and people are commenting on how small she is for her age. Despite the fact that she has consistently been gaining 1kg/week since I picked her up, I am starting to worry that maybe her lighter weight is due to a deficiency or improper feeding. I know this may come across as a daft question (as she has always been on the smaller side), but do you feel my concerns are justified?
I wanted to answer this question because the basic principle can answer a lot of client concerns.  I will often have clients ask me if their dog is too big or too small.   The question then becomes "what is too small?  What is too big?"  And really it's not as simple as most people think.  Even within a breed there can be big differences in sizes of healthy, normal dogs.  Some individuals will be outside of the normal size range, yet still be healthy.
Think about human heights and sizes.  I stand about 5'7".  My wife is 2 inches smaller, and her sister is about 5'2".  Her father is around 6' tall, as is my best friend.  I'm sure all of you know people with similar differences in height.  Yet we wouldn't consider the 5' person to be extraordinarilly abnormal, any more than we would someone at 6'6".  yes, those are outside of the typical heights, but these people aren't likely to be unhealthy due to the size alone.
So what about dogs?  Yes, each breed has a certain typical weight and height range.  But this doesn't mean that every individual within the breed will be exactly in that range.  To me this is like a human couple who are both 6' tall having a child that grows to 5'4".  It's not expected, but it doesn't have to be bad.  That smaller person or dog can be just as healthy as the bigger one.
Most vets use body condition scoring (BCS) systems to determine proper weight.  These are systems where we look at certain physical characteristics to determine whether a pet is underweight, overweight, or at an ideal weight.  Because it deals in proportions and physical features, the height of the pet in comparison to others is irrelevant.  Personally I use a 5 point scale, where 3 is an ideal weight, 1 is severely underweight, and 5 is obese (as in this example on the Hill's website).  I've also seen 7 point and 9 point scales, but the prinicple is the same. 
If I was seeing Ashley's dog I'd look at her proportions and compare it to a BCS system.  If the dog was at an ideal score, I'd consider her healthy even if she was smaller than her littermates or others in the breed.  An unusually small dog like this may not meet breed standards and therefore shouldn't be bred, but she can certainly be healthy and normal.  Dramatic differences in size are typically due to genetic factors rather than nutrition, so as long as her BCS was normal, I wouldn't worry about changing the amount or kind of food she gets.