ISSUE FOCUS FEED & ADDITIVE MAGAZINE March 2023 39 Figure 1. Pearson Square model for diet formulation using crude protein. 0.2 parts Chopped Hay Chopped Hay Corn Silage Corn Silage 1.25 parts 1.45 total parts 12.25% 10.8% 11.0% When developing a ration for livestock, especially when using only a few ingredients, a Pearson Square may be easiest to use. A Pearson Square is a simple and easy way to develop a total mixed ration (TMR) for livestock. The main consideration is knowing the final requirement or percentage of the nutrient needed in the ration. This article will explain how to use a Pearson Square effectively to formulate a ration. PEARSON SQUARE The Pearson Square is an easy and simple way to calculate livestock rations, especially when using only a few ingredients. Figure 1 is the main model for the Pearson Square. In Figure 1, we are formulating a ration to meet crude protein (CP) requirements using chopped hay and corn silage. In this example a final diet formulation of 11% CP is required. HOW TO USE A PEARSON SQUARE 1. The value in the middle MUST be intermediate between the two values used in the left side of the square. In this example, 11% is the CP requirement for the animals. Chopped hay has 12.25% CP and corn silage has 10.8% CP. 2. Disregard any negative numbers during subtraction. FORMULATING ANIMAL FEED RATIONS WITH A PEARSON SQUARE Megan Van Emon Extension Beef Cattle Specialist Montana State University
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