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Thank you so much for the analysis of protein and its effects on horses. I
am a certified Equine Nutritionist through Purina, and they, along with the
vets I consulted when I came to Arizona about how to feed my horses here in
this desert (no grass!) told me horses should be on a low protein diet like
grass, with some supplement if needed for level of work, and in my case,
for the breeding mares and stallions I keep, and the growing young stock.
There was some talk about how there is no point in feeding high levels of
protein above the 12% or so that is normal for most horses, or the 16% for
lactating mares and babies. I was told that how excess levels of protein
would be excreted anyway, and so could cause kidney damage if very high
over a long period, but the mechanism by which this could occur was not
detailed. I have had at least one owner of a horse that the vet said was
showing signs of kidney damage that he attributed to a straight alfalfa
diet for the 9 years of the horse's life, to my store since we carry grass
hay, with the instructions to the owner to get that horse off alfalfa and
onto grass.
Alafalfa is what is fed to most horses here in Arizona, because it is more
readily available than grass hay, and because it is therefore less
expensive than grass hay. In the midwest, we just didn't feed alfalfa to
horses except heavily cut with grass, so that really suprised me when I got
here. The vets say the practise of feeding staight alfalfa to horses here
is not good for them, and is worse here than in the Midwest, because the
calcium to phosphorus ratios of the alfalfa here are in the 7 to 1, 8 to 1,
even 10 to 1 ratio, whereas in the midwest the alfalfa is at 4 to 1 or 5 to
1. Horses should be at 3 to 1, so the alfalfa here in Arizona is really out
of whack with what a horse should have. The protein levels are also very
high here. In the midwest protein levels of alfalfa of around 16% are
common, but here it usually runs closer to 20%, even 25%. So your comment
that the protein levels can be REALLY high is absolutely correct. I will
give advice to customers that ask, but those that don't ask don't want to
be told they are not feeding their horse right, they will just go somewhere
else. So, there is only so much I can do about that with my customers. I
keep grass hay on hand at all times, though, so that those who do want to
feed grass have someplace to get it.
Another effect of alfalfa over time is that because of the out of kilter
calcium to phosphorus ratio, the horses on alfalfa diets will be prone to
develop kidney and bowel stones. So, people try to counteract this by
feeding bran, with the idea that the phosphorus content of the bran will
put the calcium phosphorus ratio back into balance, and thus prevent the
stones. My vet told me that a study she read showed that feeding bran
unfortunately has the opposite effect, and in fact *promotes* the formation
of the stones! I asked her what the solution was. Her answer was one
word:grass. She did say that the same study tested whether the use of
vinegar could prevent the stones from forming or reduce them if they had
started to form. The researchers were suprised to find that it actually
does reduce the size of stones already formed and does prevent formation,
1/2 C in the feed twice a day. She said I could use that if I was going to
feed alfalfa. I have opted to feed mostly grass, with a bit of alfalfa
thrown in to help "stretch" the grass. But of course, I still have to stock
bran at the feed store for all the people who ask for it along with the
bales of alfalfa loaded on their trucks for their horses.
Annette
----------
> From: Susan F. Evans <suendavid@worldnet.att.net>
> To: henslee <henslee@triax.com>
> Cc: ridecamp@endurance.net
> Subject: Re: Minerals
> Date: Friday, April 18, 1997 9:32 PM
>
> henslee wrote:
> >
> > Thanks for your response, Susan. No, the potassium levels are not high
enough to
> > cause muscle weakness nor cardiac arrest, thank goodness. It only
> > happened one time and he had been fed alfalfa cubes the night before,
> > so I thought maybe the alfalfa had something to do with it; but the
> > potassium scenario was a possible explanation given by a feed rep--who
> > knows nothing about endurance horses. My husband was the one doing the
> > discussing with the rep and I'm wondering if the rep said phosphorous
> > instead of potassium.
> >
> > Anyway, appreciate the time you took to give me your input.
>
>
> Hi again,
>
> Well, phosphorus doesn't sound like the culprit causing slow
> recoveries either, BUT when you mentioned alfalfa, that rang a big bell.
> Alfalfa, especially if it's really green and rich, is high in protein,
> sometimes really REALLY high. All that protein gets degraded to
> nitrogen in the blood plasma in the form of ammonia (yup, same stuff you
> clean windows with). Ammonia (surprise surprise) is not only of no use
> to the horse, it's toxic and so the body wants to get rid of it.
> Primarily it's going to be excreted through the kidneys via urine, which
> is why horses in box stalls on high-alfalfa diets stink to high heaven.
> (By the way, don't get worried at the thought of window cleaner in your
> horse's system---it's in low concentrations and the body is well
> designed to deal with it. Not a big deal, just a nuisance).
>
> However, here's the POSSIBLE connection to slower recovery/cooling
> rates. The body will also attempt to get rid of the excess nitrogen
> through the skin via sweat. The resulting sweat is thick and lathery,
> instead of being thin, clear and relatively odorless. The lathery sweat
> takes longer to evaporate, so the cooling effect is decreased.
>
> In addition, the metabolic process of converting excess protein to
> energy is more "expensive" than are the processes that convert fats or
> carbohydrates to energy. So horses on a high protein diet tend to have
> slightly higher body temperatures, and therefore are already at a slight
> cooling disadvantage against horses on a low protein diet that are
> running at a lower body temp. So the high-protein horse will have to
> sweat more to cool himself, but then again runs into the barrier of not
> getting maximum cooling from sweating, because the sweat is thick and
> lathery. During an endurance ride, this could make the horse more prone
> to dehydration, or at least needing more water to maintain and cool
> himself.
>
> Last, but not least, because the excess nitrogen/ammonia is primarily
> excreted through the urine, the body will produce more urine than normal
> to get rid of the ammonia. Normally horses will just drink more water
> to avoid dehydration, BUT what if that horse happens to be out doing an
> endurance ride on a hot day and doesn't have free access to all the
> water he needs? It's not life-threatening, but again, this horse is
> more prone to dehydration, and therefore the associated problems like
> colic and impaction, than is the horse on a low-protein diet. Again,
> nothing to panic about, it's just a disadvantage.
>
> I don't know what your horse normally eats, but some horses are more
> intolerant to high protein levels than others. If you fed him alfalfa
> cubes the night before, and then observed a marked difference in his
> recoveries the next day, it MIGHT be the protein that's causing it, and
> it MIGHT be that your horse is more sensitive to it than other horses
> might be. Alfalfa cubes are usually around 15-16% protein which is not
> incredibly rich, so if you saw an effect from just cubes, you might want
> to try it again (not before a race, of course) to see if the same thing
> happens again. If it does, then it sounds like your horse doesn't
> tolerate alfalfa well.
>
> I hope this answers the question/mystery for you. Let me know if I can
> help answer any questions for you, I'm happy to help.
>
> Susan Evans
>
>
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