ANSC304 LABI Problems: IMPORTANT - SHOW ALL YOUR CALCULATION STEPS NAME: Problem 1A: DATE: You need to find good quality alfalfa hay to feed to your horse. You take samples from 2 sources. A sample from a source south of Las Cruces weighod 8,00 g before drying and 6,56 g after drying. The second sample from a source north of Las Cruces weighed 9.00 g before drying and 7.92 g after 2. You need to buy 2 tons (I ton 2000 lb) of as fed feed. How many pounds of dry hay do you get drying. 1. Determine the DM concentration (percentage) of both sources from each source? Problem I B You also sent a sample of alfalfa from cach source in problem 1A to the State Chemists Laboratory for a crude protein (CP) analysis. The report from the lab showed that the sample of hay from the source south of town contained 15.58% CP on an as fed basis, and the sample from north of town contained 16.28% CP on an as fed basis. Compare the protein concentration of the two sources on a dry matter basis using the DM concentrations from Problem 1A DATE: ANSC 304 - FEEDS AND FEEDING Laboratory 1 Dry matter and as fed conversions Obiectives To learn the difference between feed analysis presented on a dry matter (DM) or as fed (AF) basis. Also, to learn how to convert to a dry matter or as fed basis. Introduction: All feeds contain water. However, the water content among different feeds is highly variable. If we wish to compare the nutrient content of one feed to another, it should be done on a constant water basis. Reason: Water does not contribute to the nutritive value of a feed, but directly affects its nutrient content. The more water present in a feed, the less there is of other nutrients. To fairly compare the nutritive value of foods, it should be measured on a dry matter basis (without water). water. On an as fed basis, the com silage contains 4% crude protein, while the com grain contains when we determine the protein content on a dry matter basis (without water), both foods contain the 10.5% crude protein. At first glance the com gruin appears to be a higher protein feed. However, same amount of crude protein (11.4%), Definitions: Dry matter: - The portion of a feed remaining after water is removed (by drying in an oven). As fed: - feed as it would be fed to the animal. Calculations: (THINK DRY MATTER) Dry matter (DM) is determined by grinding a feed sample and drying it in an oven until all the moisture has evaporated. On a DM basis, feed contains 0% water. (sample wt after drying/sample weight before drying) * 100 1) Converting composition of feed Useful rule #1: The concentration (percentage) of a nutrient on a dry matter basis will always be higher than it will be on an as fed basis. % nutrient (dry) % nutrient (as fed) (% dry matter/100) % DM-100% -% water % nutrient (as fed) % nutrient (dry) (% dry matter/100) 2) Converting amounts of feed Useful rule #2: The amount of feed on a dry matter basis will always be lower than it will be on an as fed basis. Feed amount (dry) feed amount (as fed)x % dry matter/100) Feed amount (as fed) = feed amount (dry) (% dry matter/100) AND ANSC304 LAB1 NAME: Calculation examples: 2 DATE: weight is achieved (all water has evaporated). The sample weighed 1.0520 g after drying. What is the Example 1 A ground hay sample weighs 1.1520 g and is placed in a 100 C oven until a constant dry matter content of the hay? %DM Sample waflet drying 100 sample wt before drying %DM - (1.0520g/1.1520 g) 100 91.3% Example 2. A sample of com silage analyzed by a feed laboratory was reported to be 35% crude protein (as fed basis) and 30% DM. What is the crude protein content on a DM basis? % nutrient (dry) - % nutrient (as fed) (% dry matter/100) % CP (dry) = 3.5% CP (as fed)/(30% DM/100) - 11.67% CP (dry) Example 3: A sample of alfalfa hay was analyzed to contain 18.5% crude protein on a DM basis. The hay was found to be 92% DM. What is the crude protein content on an as fed basis? % nutrient (as fed) - % nutrient (dry) % dry matter/100) % CP (as fed) - 18.5% CP (dry) (92%DM / 100) 17.0% CP (as fed) Example 4: We have determined that we need to feed 10 lbs of alfalfa hay on a DM basis to our animals to meet their requirements. The alfalfa hay that we have purchased is 89% DM. How much alfalfa hay (as fed) do we need to add to the feed bunks for each animal to cat? Feed amount (as fed) feed amount (dry) (% dry matter/100) Lbs of alfalfa (as fed) 10 lbs (dry) / (89% DM / 100) - 11.2 lbs (as fed) Example 5: A diet contains 90% com silage and 10% supplement on a DM basis. The com silage and supplement were analyzed to contain 40% and 90% DM, respectively. What is the composition of the dict on an as fed basis? Diet Ingredients Com silage Supplement % in the diet DM basis 90 10 100 % DM (40/100) (90/100) Mixing parts 225 11.1 236.1 +236.1 x 100 +236.1 x 100 % in the diet As fed basis 95.3 4.7 100.0 +