The basics about Ca and P (and everything else) can be found in the National Research
Council's Nutrient Requirements of Horses. It Its an inexpensive publication that can
be obtained from the National Academy Press, 2101 Constitution Ave., NW, Washington, DC
20418. This is one of a series that cover everything from dogs to non human primates.
It contains references to the studies underlying the feeding recommendations.
When it comes to more subtle issues, especially those specifically involving endurance
horses, Susan can point you to appropriate papers.
With regard to protein, the ability of the kidneys of the horse being able to handle
protein is not the problem. The average horse will survive quite well on alfalfa.
However, alfalfa is suspect with respect to enterolith formation. Magnesium and ammonia
are both constituents of the stones. Alfalfa contains high magnesium levels and creates
high ammonia as breakdown product of protein. No final answer here, just a caution
flag. Protein also requires more water (to aid the kidneys in eliminating the breakdown
products of excess protein). Susan can do a better job of pointing other possible
problems as they specifically relate to endurance.
The percent of protein in the feed is not the whole story. For example if I were to
feed oats as the only food (this is not a real feeding protocol, but for the sake of
illustration) at 13.3% protein for a horse requiring 25 Mcal DE, I would need to feed
17.2 lbs of oats and the horse would receive 2.3 lbs of protein. If I were to substitute
mid bloom timothy at 9.7% protein, I would need to feed 27.8 lb and the horse would
receive 2.7 lb protein. Because of the much lower energy density of timothy, one needs
to feed more and the horse receives more protein despite the lower protein percentage.
Using this same example, if I were to substitute mid bloom alfalfa the horse would
receive 4.5 lb protein.
One of the great mysteries of feeding "manufactured foods" is that the labeling laws
don't require digestible energy figures. Without knowing that number, the other numbers
become less meaningful. The closer the food is to its natural feed components, the
easier it is to estimate that number based on those components.
Duncan Fletcher
dfletche@gte.net
Gwen Dluehosh wrote:
>
> I guess I'll be the devil's advocate here for a minute... what papers... I
> want to read them too. As far as protein goes, it has NOT been proven to be
> a problem in kidneys according to all the wonderful stuff the IAMS people
> are sending us at Vet school... However, I don't consider 12% protein to be
> "high" protein, which is what i assume most endurance riders are probably on
> if they are feeding a premixed feed. ( DOn't recall exactly what was in the
> post about protein since I wasn't responding to that particular item)
> At the tracks I have had my horse at, and been around, most people were
> feeding straight alfalfa and or good mixed hay, plus Athlete in Omolene 300.
> At this one barn in particular, it doesn;t appear to me to have been a
> problem in racehorses- never had a tie up, and it sure didnt' slow them
> down- in fact one horse kept winning so much the guys in charge of
> handicapping wante d to weigh him down too much (he had a recovered knee
> injury) HOrses always look super good too, and never seem to have any problems.
> Ammonia is not made out of water... it is a protein by product.
> ANd I'd be willing to bet that most endurance horses are on quite a bit of
> turn out...
> so the stinky stall issue really isn't one...
> I wasn't addressing the protein issues in teh first post anyway.
> Just the Ca P stuff. Please do help me find info on the Ca:P stuff... it's
> interesting!
>
> Gwen
> >Yes, however there is some research that suggests excessive calcium may
> >be a factor in oseochondrosis and hypercalcitoninism. . Also, excessive
> protein has been shown to decrease
> >speed of racing Thoroughbreds, while requiring more water intake to get
> >rid of all that nitrogen. If a horse is fighting dehydration during a
> >ride anyway, I'd rather he didn't have to use that water making ammonia.
> >
> >Also, more ammonia means more urine, stinkier stalls, more bedding
> >costs. Finally, protein is the most expensive nutrient, so feeding
> >excessive amounts is not cost-effective, especially if a better, more
> >balanced ration can be formulated that provides the same benefits and
> >less of the detriments.
> >
> >Susan Evans
> >
> Gwen Dluehosh
> Desert Storm Arabians
> 1156 Hightop Rd, #89
> Blacksburg, VA 24060
> 540/953-1792