“Phosphorus Needs”
by Chris Reinhardt, feedlot specialist
Phosphorus is a critical, essential nutrient in the diet of all livestock. And like any other essential nutrient, meeting the animal’s requirement is an investment, while supplying beyond the requirement is a wasted cost.
We’ve learned an expensive lesson about excess phosphorus in confinement feeding. We need to find an approved home for any phosphorus we feed beyond the animals’ needs because it winds up on the pen surface and needs to be captured and managed. For many decades, we formulated beyond the animals’ requirements, either out of ignorance or ‘cheap insurance’. It’s just not ‘cheap’ anymore—either as a feed nutrient or a waste nutrient.
Also, modern cattle diets contain a great deal more non-supplemental phosphorus than in decades past, mainly from feed byproducts from the corn milling industries. This has greatly reduced the amount of supplemental phosphorus we include in cattle diets. And even so, we are still oftentimes feeding in excess of the animals’ needs, simply because the energy and protein content dictate feeding levels the force phosphorus levels upward.
Beef cows are not immune from this same situation. The difference between a cow and a feedlot animal is that the cow’s requirement varies much more widely due to gestation and lactation. If we match the nutrient supply in our feed resources (pasture plus supplemental feed) to the rising needs of the cow, there may be limited need for supplemental phosphorus. But we won’t know how much phosphorus we’ll need until we know what we have. If a rancher is feeding distillers byproducts, it is likely extra supplemental phosphorus will not be needed.
As always, know what you have, learn what the cow needs, and do your best to make the two fit together. This will ensure maximum productivity and minimum wasted inputs and cost.
