Re: tall vs short horses

["Susan Garlinghouse" <suendavid@worldnet.att.net>]

> Now do shorter horses like Polaris burn up more energy trying to cover
> more ground or do taller horses use less energy covering more ground
> with there long legs?


The energy requirement isn't based so much on height as it is on body
mass---a tall horse of equivalent build and in good body condition is
naturally going to weigh more than the "same" horse standing six or eight
inches shorter.  In general terms, a horse and rider on level ground on
decent footing is going to expend about .07 Mcal/mile/100 lb mass traveling
between 5-7 mph.  So an 800 lb horse with a 180 lb rider is going to require
34.3 Mcal of energy to cover 50 miles in 7-10 hours actual riding time.  A
1150-lb horse (presumably the tall one) with the same rider at the same
speed would require 46.55 Mcals of energy, or more than a third more energy
than the smaller horse.

So yeah, the tall horse is usually going to have a longer stride length and
maybe a faster trot, but he's *always* going to be burning more calories per
mile than the smaller horse, just because he has an extra 350 pounds of body
mass he has to transport down the trail (and this is why it's such a hoot to
hear riders getting all worried over weighing 20 pounds more than the next
rider, without taking the size of the horse into consideration).

And just because so many people have suggested this, you aren't gaining an
advantage by keeping the tall horse really lean and 150 pounds lighter than
he otherwise would be---there's good data to verify that skinny horses are
alot more prone to metabolic shutdown than they would be at a decent weight.
So you have to keep them at the weight they're supposed to be and not try to
cheat by starving them down to a lighter weight.

And the other thing to consider is that size of the supporting structures
such as cannon bones and feet don't increase proportionately with the
increase in body mass, so bigger (endurance) horses as a whole are
statistically more prone to lameness problems than smaller horses are.
That's an important point to consider when bringing along a taller
horse---lots and lots and LOTS of long, slow distance is even more important
to them, or I can guarentee they won't stay sound.  There are other possible
factors as well, ie the bigger horse has proportionately a smaller
surface-to-body mass ratio and so is less efficient at dissipating heat; the
trails encountered may favor horses with a shorter stride length (ie steep
mountains and rocks instead of long stretches of 'racetrack') and the
increased length of the taller horse's back may or may not make him more
prone to back soreness.  And undoubtedly many others that I haven't
mentioned.

And you also have to consider the individual horse, obviously.  The bigger
horse may not be as energetically efficient as a smaller horse, but if the
bigger horse is a better eater and drinker, is more experienced and has a
smarter rider, you can bet he'll beat the nervous, don't-wanna-eat-or-drink
little guy with the dumbass rider every time.

And lastly, you have to consider what works for the rider.  A small horse
may be more efficient, but I'm almost 6' tall and I can't get into the
rhythm riding a short-strided horse.  So I like my Anglos, because their
trot is comfortable, even though they'll have some barriers to overcome
against smaller horses.

Hope this made sense.

Susan G