This week's point to ponder - horse BMI

[puddicat]

According to the welfare organisations, perceptions of 'good condition' have changed in recent years such that many leisure horses carry more than the ideal weight. See the ILPH Right Weight page for more info. To a lesser extent there are also horses that are underweight not due to any deliberate intention of their owners.

Condition in humans is determined by the body mass index (BMI) which is the number you get if you divide your weight by the square of your height. If the number is between 19.1 and 25.8 (slightly higher for blokes) you are in the ideal weight bracket.

Would it be useful to have a BMI for horses? That is, a number that can be calculated easily and regardless of breed and size would fall within an upper and lower limit if the horse was an ideal weight.

(and the tricky bit) Is it possible to formulate a horse BMI and how would do it - or at least how would you go about doing it?

 

[vicijp]

Weight / bone x girth?

 

[Weezy]

I think an equine BMI is a fantastic idea (even though the human ones are sometimes WAY out) - will leave it up to you clever people to devise HOW to do it though!

 

[puddicat]

I see where you're coming from and it's a very nice idea, I don't think it would quite work but I'll explain why later.

One interesting difference between humans and horses is that humans can use weight scales to get a pretty accurate weight, most horse owners aren't going to have access to a weighbridge so if the calculation included weight they would have to use a weigh tape to get an estimate of weight and that will introduce 5 - 10% error. Mind you I have a feeling my cheap household scales are about 10% out.

 

[vicijp]

TBH, I have no idea how you would work it out, but that is what goes through my head when I assess a horse.
I have no interest in tapes, or indeed the actual weight of the horse - it is all relative to what is fat and what is muscle.
Its called an eye.

 

[puddicat]

Yep couldn't agree more. I think if you know what you're doing that is always going to be the best way and you wouldn't need to use a BMI. I think the possible application of a BMI would be for people who aren't that experienced at looking at horses.

The bit about how you work is out was really just a puzzle for those who know a bit about the maths behind the analysis of shapes and sizes of animals

 

[RachelB]

Argh no is this a maths question??!

I may have to sleep on this one!

Has got me thinking though...

 

[puddicat]

"Argh no is this a maths question??! "

Errrrrr well I prefer to think of it as a horse question that you need to know a bit of maths to be able to answer. But essentially you're right, it is.

It turns out my bathroom scales are only 2% out which is pretty good since they cost about 10 quid from Argos. So they are better than a weigh-tape - phew.

 

[crabbymare]

Would be an interesting idea, although it would need to be a simple formula otherwise people would simply give up trying to calculate it.

I would imagine that some would get a shock if they found how obese their horses really were!

 

[spaniel]

An interesting concept PC. Not quite sure how you could formulate a BMI using the height/weight method with a horse.

I would be more inclined to try skin fold caliper testing which would not rely on knowing the actual height and weight of the horse.

 

[puddicat]

Thanks, it is possible and you could do it using the same two measures, height and weight, but using a slightly different formula. The complication in horses is that breed affects body shape and this may require a 3rd measurement to allow for it. There's no absolute answer at the moment because it would need some work doing that nobody has done yet.