How much phosphorus does a cow need?

Phosphorus content is variable, depending on the age, weight, type and level of production of your bovine. The maximum amount of phosphorus a bovine should have is 1% of DM (dry matter) ration. Phosphorus should be given ad libitum (free access), and come in the form of the following:

• Dicalcium phosphate
• Defluorinated phosphate
• Bone meal (highly unrecommended to feed because of concerns of Mad Cow Disease)
• Soft phosphate
• Sodium phosphate
• Ammonium polyphosphate
• Orthophosphates
• Metaphosphates
• Pyrophoshates
• Tripolyphosphates

Oilseed meals and animal and fish products contain large amounts of P. Phytate phosphorus is not well utilized by nonruminants, but ruminants appear to use considerable quantities of this form of P. Grains, grain by-products and high-protein supplements are fairly high in phosphorus. Rations high in such ingredients require little or no P supplementation.

Calcium-phosphorus ratiOS of 2:1 are beneficial in reducing urinary calculi; and even higher levels of calcium may be necessary when urinary calculi is encountered. RatiOS between calcium and phosphorus of 7:1 have been reported to be satisfactory for cattle.

Note: Avoid feeding animal by-products like bone meal because for one, these products are outlawed to be fed to ruminants, and because these products fed to cattle have been known to be the source of BSE concerns in ruminants.