The goal of feed formulation is to combine various feed ingredients which contain varying amount of nutrients to achieve the animal requirements for these nutrients. A report in the March/April issue of Feed Management discusses the impact of natural nutrient variability on feed formation. The natural variation in nutient composition of a feedstuff can reduce the ability to accurately formulate a ration that precisely meets the animal’s requirement for optimum performance. The author discusses the impact of nutrient variability on animal performance and reasons that this natural variation in a feed ingredient can often be the reason why some groups of animals fail to meet performance standards even though the rations formualtion are similar to those achiving greater productivity.

The paper also discusses standard deviations: Assuming a feed ingredient’s nutrient compositon is normal and follows a standard bell-shaped curve; 68% of the ingredient’s analyses will be within one standard deviation of the “true mean” and 95% of the analyzed values within 2 standard deviations within that “true mean”. Understanding natural variation in an ingredient’s compositon is an esssential for formualting productive rations. Some feed ingredients are by nature quite variable and present many challenges in developing formuated feeds that precisely meet the minumum nutrient standards. Reviewer’s note: Soybean meal has normal variation in nutrient levels due to differences in growing environments, seed genetics, and processing variables. The soybean industry benefits from having several large soybean processing companies that purchase and blend soybeans from a wide geographical region and a defined/precise large-volume crushing operation that results in a consistent meal that is one of the feed industry’s most uniform products.