Ca:Phos ratio

[Sarah Ralston <ralston@AESOP.RUTGERS.EDU>]

Grain is higher in phosphorus than calcium, unless calcium 
has been added to the mix by the manufacturer (read the 
labels). Adding a lot of grain will increase the
phosphorus intake, reducing the Ca:Phos ratio. You never
want to feed more phosphorus than calcium (Ca:P ratio 
less than 1:1). The 0.65% Ca in beet pulp is not excessively
high-just high in relation to the phosphorus content. Most 
alfalfa hays are >1.0% Ca with only 0.25% Phos. Most grass
hays are between 0.4 and 0.65% Ca with 0.25-0.3% Phosphorus. 
Straight grains are around 0.35% phosphorus with virtually no 
Calcium. So, if feeding only grass hay and a lot of grain, 
especially with added bran (Both rice and wheat brans are
 >1.0% Phosphorus with virtually no Ca) you run the risk of
getting higher phosphorus than Ca intake. Some rice bran products
now have added Ca to balance out the high Phosphorus. Read the labels!
Adult horses need only 0.25% Phosphorus and 0.4% Ca in their total
ration. Some Calcium but no phosphorus is lost in sweat, so 
our exercising horses may have slightly higher Ca requirements 
than a sedentary horse would. I would not fret about a slightly 
high Ca intake. Anywhere up to about 1.0% in the total ration is 
well tolerated by healthy horses (even higher in many cases). 
Only horses with kidney disease would need to have it really 
restricted to the required levels...)! They can tolerate
excess calcium a lot better than excess phosphorus. 
Vegetable and other oils contain no minerals-only 
calories-so adding oil as an energy source will do nothing
to the Ca:Phos ratio.

Sarah and Fling (Mom-stop pontificating and get out here and ride me!)