DR. LYDIA GRAY: Hey, SmartPak fans
welcome to a special edition of Ask The Vet.
You may notice I'm sitting on this side not that side.
I'm Dr. Lydia Gray, the Staff Veterinarian and Medical
Director at SmartPak.
This is Nerida Richards, PhD.
I'm going to let you introduce yourself.
DR. NERIDA RICHARDS: Sure.
Thanks Lydia.
So I'm Nerida.
I'm an equine nutritionist from Australia, which is probably
quite obvious given my accent.
DR. LYDIA GRAY: I was going to say, "far."
DR. NERIDA RICHARDS: Yes.
DR. LYDIA GRAY: Obvious, true.
DR. NERIDA RICHARDS: I work as a consulting
nutritionist in Australia.
I formulate feeds and supplements
for companies all over the world.
And I also run the FeedXL.com website
which is a nutrition calculator that horse owners use to put
their horses' diets together.
DR. LYDIA GRAY: Yeah, great.
We asked you to submit your horse nutrition questions
specifically, and then this segment
we'll answer one of those questions-- you'll
answer one of those questions.
I'm helping.
And then to see the other questions,
just click on the playlist at the end the video,
and you get to see them all.
So ready?
Miss Callie Rose on-- from Instagram
says, "When feeding a lot of alfalfa,
what is the best way to keep a horse's calcium to phosphorus
ratio where it should be?"
Can we first say what the calcium:phosphorus ratio should
be, so we're all on the same page here.
DR. NERIDA RICHARDS: Sure.
Yeah, so it's interesting, you know.
The calcium:phosphorus ratio is one of the oldest nutritional
concepts that has been around.
And still to this day, even with all this amazing research
that's happening in the states in pigs with calcium:phosphorus
we still don't actually know how calcium affects the absorption
of phosphorus.
Isn't that amazing?
DR. LYDIA GRAY: Someday.
DR. NERIDA RICHARDS: It's amazing.
I mean, we know what happens.
But we don't actually know the mechanism.
So it's a good question, one I'm really familiar with.
So the calcium:phosphorus ratio for a mature horse needs to be
below 6 to 1.
So below 6 parts calcium to 1 part phosphorus.
And above a minimum of 1 to 1.
So 1 to 1 is an absolute minimum.
DR. LYDIA GRAY: So there should be
more calcium than phosphorus.
DR. NERIDA RICHARDS: Should always
be more calcium than phosphorus.
So if you have more phosphorus than calcium,
the phosphorus somehow obstructs the absorption of the calcium
so that you become calcium deficient.
If you go above the six parts calcium to one part phosphorus,
the calcium then starts interfering
with phosphoruses absorption.
They just, they don't play well together.
I mean, they're so important and they go together,
but in the gut they just don't play well together.
Now for a growing horse, it has to be kept above one part
calcium to one part phosphorus.
The same as mature horses.
But it needs to be below three parts
calcium to one part phosphorus.
DR. LYDIA GRAY: So it's a smaller window.
DR. NERIDA RICHARDS: It's a much smaller window.
And it's a lot harder when you're
feeding a really alfalfa rich diet,
it's a lot harder to keep it within that window.
So I guess the easiest solution to this problem,
and the one that I would go for first, is feeding less alfalfa.
And I'm really familiar with that being quite difficult
sometimes, because in parts of Australia
it's almost impossible to grow.
It's changing, but it was almost impossible to buy any hay other
than alfalfa.
DR. LYDIA GRAY: And parts of the US are like that as well.
DR. NERIDA RICHARDS: It's the same.
DR. LYDIA GRAY: Yeah.
DR. NERIDA RICHARDS: So if you can,
try and find a different hay to kind of bring
some of your alfalfa out of the diet.
And then that, especially if the horse is a box at a reduced
protein intake.
Horses on pure alfalfa have such wet boxes
because they urinate a lot.
So try and bring in a different hay, a grassy hay of some kind.
And that will just naturally bring the calcium intake down.
And generally will bring the phosphorus intake up too,
because grasses tend to have a little bit more phosphorous.
DR. LYDIA GRAY: Right.
DR. NERIDA RICHARDS: Not strictly as a rule,
but they tend to have more phosphorus in them.
If you can't get away from using that much alfalfa, what
you might have to do, depending on whether you feed grain,
all the commercial grain mixes that you buy, as nutritionists
we would never put a grain mix on the market that has
more phosphorus than calcium.
You just wouldn't do it.
So all of the grain mixes you're going to buy
are going to have more calcium than phosphorus.
DR. LYDIA GRAY: So adding a grain mix alone
is not going to bring it back into balance.
DR. NERIDA RICHARDS: It generally won't.
Like if your ratio is a long way out,
you'll add more phosphorus, but you probably won't add enough.
Because you're adding calcium at the same time
to bring the ratio back to where it needs to be.
So you can look at using something like rice bran,
which is known as being really high in phosphorus and very low
in calcium, and can cause calcium:phosphorus ratio
problems, but--
DR. LYDIA GRAY: They tell you to be careful with this.
Right.
DR. NERIDA RICHARDS: Exactly.
But in this situation it's useful
because it has very low calcium.
It adds a lot of phosphorus.
So it's a really useful one for bringing things back down.
DR. LYDIA GRAY: What about beet pulp?
DR. NERIDA RICHARDS: Beet pulp is
going to push your ratio the other way.
So because of the way the sugar is extracted,
it's extracted using limestone water.
So it actually has limestone of calcium carbonate added to it.
So it's calcium content is really high,
so it's going to make the problem even worse.
Grains, so just you know feeding straight oats
is going to add phosphorus.
Not as much as rice bran, but it will certainly
add a lot more phosphorus than calcium.
So again, you might need to look at switching
from a commercial grain.
DR. LYDIA GRAY: A fortified grain.
Yeah.
DR. NERIDA RICHARDS: To an oat grain,
and then using it just a vitamin mineral supplement.
So not a ration balancer, because ration balancers
again are almost always formulated
with twice the calcium that they have phosphorus.
And the other thing you can do is, and it's not ideal again,
because you're still adding calcium,
but you can add something like dicalcium phosphate.
And so dicalcium phosphate is 22% calcium,
but it's 18% to 19% phosphorus.
So you're still adding calcium, but it's almost a one to one
ratio.
So you might be able to pull your ratio back
in line with dicalcium phosphate.
DR. LYDIA GRAY: Really, it comes from--
if she can get a different kind of hay than alfalfa.
That's going to be easiest.
DR. NERIDA RICHARDS: That, yeah.
Yeah.
And the other thing I would add just
on the end of that is guessing all of this is really hard.
So I would say use a nutrition calculator.
So this is where FeedXL really comes into its own, in that you
can put what you're feeding in, and it will show you
exactly what the ratio is, and it will show you
if you add rice bran, how much rice bran do
you need to add to get the ratio back to being balanced.
DR. LYDIA GRAY: You can play with it a little bit.
DR. NERIDA RICHARDS: Or if you know if you use rice bran
and oats, how much of each do you need to add to stay within
calorie requirements, but to balance your calcium:phosphorus
ratio up.