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Consistency CountsInconsistency, Non-Conformance Yields Unaccepteable Performance
Dr. Steve Auman
Phosphorus is used directly or indirectly in nearly every biochemical pathway in a living organism. It is a component of both tissue and bone. Therefore, deficiency in dietary phosphorus has a dramatic effect on animal performance ? shown by reduced growth, reproduction and disease resistance. Precise nutrient management of dietary phosphorus is critical to raising healthy animals. It will provide optimal growth and reproduction and ensure efficient utilization of dietary energy, protein, vitamins and minerals, as well as reducing feed costs. Table 1 summarizes turkey research data which demonstrate the effect of Calcium to available Phosphorus ratio (Ca:Pav) on feed cost (Ferket, 1991). A 10 percent variation in dietary P content can result in increased feed:gain ratio and feed cost. Sources of Nutrient Variation - Dietary Phosphorus Nutrient Variability Animal nutritionists try to maximize feed performance and minimize formula feed costs by reducing variation of nutrient content in the feed in order to achieve a uniform nutrient profile. Degree of mixing uniformity is measured by timed incremental sampling of the mix discharge and calculating the coefficient of variation [%CV = (standard deviation/mean) X 100] of the nutrient analyzed. As a rule, a uniform mix should have a %CV below 10 percent. However, this is not achievable if the nutrient sources going into the mix have %CVs at or greater than 10 percent. So a good place to start improving mix %CVs is by reducing the nutrient variability of the source ingredients. In the case of phosphorus sources, there is concern for both variation in content and bioavailability. Plant Sources of Dietary Phosphorus Plant sources of phosphorus (see chart to the right) contain some phytate-bound phosphorus that is not available for uptake. Measures of phosphorus digestibility in corn, for example, range from 12 percent to 33 percent (Soares, 1995) and total phosphorus content can vary between 0.15 percent and 0.35 percent depending on soil moisture and fertility. Dried Distillers? Grains are increasingly being used in feed formulations. Due to different processing methods, total phosphorus content is reported to vary between 0.42 percent and 0.99 percent (with 19.4 percent CV) and phosphorus availability between 54 percent and 102 percent (Shurson, 2006, www.ddgs.umn.edu). Mineral Sources of Dietary Phosphorus Commercial inorganic mineral supplements contain some phosphorus bound as indigestible mineral salts. There are many mineral sources of phosphorus used as feed supplements. Phosphorus content can vary from 12 percent P and 17 percent P availability for soft phosphate rock to 21 percent P and 98 percent P availability for monocalcium phosphate monohydrate (Soares, 1995). Field sampling of P content of some commercial mineral sources shows %CVs greater than 10 percent, which can result in unacceptable animal performance and profit losses (PotashCorp research files). Bottom Line At PotashCorp, we understand the importance of consistently meeting phosphorus label guarantees. Our feed phosphate production plants use a quality management system that delivers product whose P content has a %CV of less than 1 percent. To ensure maximum P uptake, we routinely measure available phosphate content of our product using officially recognized bioassay procedures. Set up a meeting with your PotashCorp sales representative. We?ll be glad to tell you more about our highly bioavailable feed phosphate products.  Top
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