Re: formula for energy expenditure

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

31 Mcals of energy would be provided by roughly 5-6 large coffee cans of
Omalene.  I don't feed Omalene, I'm guessing that a large coffee can
weighs about four pounds, and you'd need to feed somewhere around 22
pounds (I'm also making an educated guess at the exact energy content of
Omalene---maybe Amber has the exact data on that.)

Susan

Angela C. McGhee wrote:
> 
> Could you please translate that into coffee cans of Omalene?
> 
> Angie
> 
> On Thu, 05 Mar 1998 15:10:05 -0800 Susan Evans Garlinghouse
> <suendavid@worldnet.att.net> writes:
> >Hiya,
> >
> >A bunch of people have been asking me lately about replacing the
> >calories burned by the horse during a ride and I thought everyone
> >might
> >be interested in seeing a nifty formula that was published in the
> >journals from Pagan and Hintz (both widely respected) that pretty
> >accurately calculates the calories expended by a horse during
> >exercise.
> >This is the formula that is much more accurate than the formulae
> >currently used in the NRC books to calculate energy required for work
> >above maintenance levels.
> >
> >It's interesting, if nothing else, to see the calories required for an
> >average horse to cover 50 miles---a 900 lb horse carrying a 165 lb
> >rider
> >and covering 50 miles in 6 hours actual riding time burns up 18.3
> >Mcals.  The same horse carrying a 210 lb rider and covering the same
> >fifty miles in four hours would burn 26 Mcals.  A 1000-lb thoroughbred
> >carrying 112 pounds and running a mile in two minutes (sorry, Tom, I
> >don't know average times for a mile) would burn 4.6 Mcals in just two
> >minutes, which is pretty damn impressive considering he's providing
> >almost all of that energy in the form of glucose (endurance horses get
> >at least a large portion of their energy requirements from fats, which
> >are in greater supply.)  And since feed efficiency is only around 60%
> >efficient for a typical ration (that means that only 60% of the
> >calories
> >ingested actually get utilized in energy production, the rest is
> >burned
> >in metabolism or lost heat, etc), that means that you would have to
> >feed
> >30.5, 7.7 and 43.4 Mcals, respectively, to make up the energy burned
> >during that ride.  Incredible, considering that the same horse would
> >only use 13.4 Mcals a day for daily maintenance.  Another good
> >argument
> >for making sure your horse is in good body condition before you start
> >a
> >heavy ride season---he's going to need those extra stores of fat!
> >
> >(And, by the way, please don't take this as a recommendation to try to
> >feed back those calories right after the ride, or we'll all going to
> >have a whole lot of colicky, foundering horses).
> >
> >Anyway, here's the formula.  The engineers and math whizzes on the
> >list
> >can take it and run with it.  For the rest of us, below are directions
> >on how to actually get useable numbers.  Again, this is just for fun,
> >not an indication that anyone should make major changes to their
> >horse's
> >diet...unless you're riding 50 miles every weekend, only providing 10
> >lbs of hay a day and scratching your head as to why ol' Flash is
> >looking
> >a little peaky. :-D
> >
> >The formula is: Y = e (superscript)3.20 + .0065x; where x is the speed
> >is meters/minute, and Y equals the calories expended per kg per
> >minute.
> >
> >Here's how to actually get an answer if you're not a math genius---you
> >will need a calculators that does logarithms, natural logs, etc, just
> >the cheapy kind they give out at the gas station won't do it.
> >
> >First you need to calculate the average speed ("x")you're traveling
> >at.
> >It's okay if you change speed alot, the formula still works.  Figure
> >out
> >how many miles you traveled and how long it took you to get there.
> >Convert the miles to meters by multiplying miles times 1609.35 (the
> >number of meters in a mile).  Fifty miles is 80,467.5 meters.  Divide
> >this number by how many minutes you took getting there.  This will
> >give
> >you your average speed in meters per minute.  For example, if you took
> >six hours to travel fifty miles than x= 80,467.35 divided by 360 =
> >223.54 meters/min.
> >
> >Multiply x by .0065 and add 3.20.  For example, 223.54 times .0065,
> >plus
> >3.2 equals 4.65.  If you have a memory function on the calculator, put
> >this number into the memory, or at least write it down.
> >
> >Find on the calculator the inverse function for the natural log.  The
> >primary function on the caculator button will say "LN", and the
> >inverse/2nd function will have an "e" with an "x" superscript.  Take
> >the
> >number you just calculated above (in the example, the 4.65), push the
> >2nd function key, and then the LN key to get the inverse function.  In
> >the above example, the result would be 104.89.  This number is the
> >number of calories your horse is burning PER minute, PER kilogram of
> >weight getting moved down the trail.  This is "Y".  Put this number
> >into
> >memory or write it down.
> >
> >To calculate the total expenditure of energy, you need to know the
> >kilograms.  Take your horse's weight in pounds and add the number of
> >pounds he's carrying in rider and tack weight.  For example, a 900
> >pound
> >horse carrying 165 pounds of rider and tack totals1065 pounds.  Divide
> >this number by 2.2 to convert to kilograms. 1065 pounds equals 484
> >kilograms.
> >
> >Take the number of kilograms and multiply it by the Y number you
> >calculated above, and then calculate THAT number by the minutes you
> >were
> >riding.  In the on-going example, if you took six hours to do a 50
> >mile
> >ride, you rode for 360 minutes.  So the total expenditure of calories
> >was 18,650,000 calories.
> >
> >To convert this number into units you're more familiar with, divide
> >this
> >number by 1,000,000 (one million) to give you Mcals, or by 1000 to
> >give
> >Kcals, the unit most people are thinking of when they think calories,
> >as
> >in "that piece of cake is 500 calories".
> >
> >Divide the number of Mcals by .60.  For example, 18.65 Mcal divided by
> >.60 equals 31.08 Mcals.  This is the number of extra caolries you
> >would
> >have to actually feed just to replace the calories burned during this
> >ride, IF you wanted to maintain weight---remember, the horse has
> >already
> >supplied the energy he needed from fat stores, as well as a small
> >amount
> >from what he ate during the ride.  Hopefully, if you're competing,
> >then
> >you are already feeding more than just a flake of hay.  Just to give a
> >general idea, you would have to feed 20 pounds of corn to supply the
> >18.65 Mcals, or about 15 cups of vegetable oil, or 23 pounds of oats.
> >So if you're competing alot, you might use this formula to give you
> >just
> >a general idea of how many extra calories you need to be providing in
> >the daily ration (obviously, you would spread the extra calories over
> >a
> >number of days, and make sure the horse keeps exercising, so you don't
> >run into azoturia problems).  If you don't provide enough calories,
> >the
> >horse isn't going to drop dead or his ears fall off, he's just going
> >to
> >lose weight throughout the season, which IS eventually going to affect
> >his performance.
> >
> >This formula seemed to be pretty accurate in the study, but probably
> >is
> >only a rough estimate for endurance horses that will be expending more
> >or less energy depending on factors like terrain, temperature, the
> >skill
> >of the rider and individual factors like temperament, keeping
> >qualities,
> >type of feed provided and feed efficiency factors.  But for those
> >riders
> >that like knowing the details of what's going on, this formula might
> >be
> >something interesting for you to keep around just for grins.
> >
> >Seeya,
> >
> >Susan Garlinghouse
> >
> >
> 
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