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ANSC 3375

Composition tables. A

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ANSC 3375

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    1. ANSC 3375 Laboratory 2 Composition and requirement tables

    2. Composition tables A ‘warehouse’ of chemical composition of feedstuffs An average of many laboratory analyses that are compiled over time Even though the avg or mean CP for a feed may be 10%, it could range from 8 to 12% In practice, better to use values determined for your location, etc. if feasible

    3. Composition tables Available from a number of sources Popular, professional magazines (Beef, Feedstuffs) National Research Council – specie nutrient requirements and feed composition

    4. Composition tables Feedstuff names – note that the table we use has some unusual feeds Names also indicate the form of the feed – reflects any processing Not all feeds listed will be relevant for a particular region

    5. Composition tables DM, % = 100 - the percentage of moisture or water normally found in the feed Determined by completely drying a sample and measuring the remaining weight – moisture evaporated This influences as-fed nutrient concentrations In this table, all other compositional values are on a DM basis

    6. Composition tables Measures of energy content Total digestible nutrients (TDN) – an early measure that describes the digestibility of the nutrients (carbohydrate, lipid, protein) as a % Similar to digestible energy (DE), but DE expressed as calories

    7. Composition tables Measures of energy content Net energy for maintenance (NEm) – the energy value of a feed when used to support animal maintenance functions respiration, body temperature, locomotion Net energy for gain (NEg) – energy value of a feed when used for productive purposes (e.g., weight gain) smaller than NEm – why’s that?

    8. Composition tables Measures of energy content Net energy for lactation (NEl) – one NE used for dairy cows because the efficiency of using calories for maintenance and lactation are similar

    9. Composition tables Crude protein - % N x 6.25, includes N from true protein and NPN in the table, this reflects % CP on a DM basis Bypass, % - describes the proportion of CP that is not degraded in the rumen dependent on a number of factors, so it is not really a constant in practice currently, the term undegraded intake protein (UIP) is used more commonly

    10. Composition tables Interpreting the bypass value - describes the proportion of CP that is not degraded in the rumen alfalfa cubes contain 18% CP on average, and 30% of this CP is considered UIP Thus, 5.4% of alfalfa cube DM is UIP (18 x 0.3) and 12.6% of alf cube DM is DIP (degraded intake protein, 18 x 0.7)

    11. Composition tables Crude fiber – the standard for feed labeling, but not as useful as other measures to describe fiber utilization Detergent fiber neutral detergent fiber (NDF) – plant cell wall; hemicellulose, cellulose, lignin acid detergent fiber (ADF) – cellulose and lignin effective NDF (eNDF) – describes the ability of NDF to maintain optimum ruminal pH; incorporates particle size

    12. Composition tables EE, % - describes the crude fat fraction, often referred to as ether extract fats, oil, waxes, complex lipids Ash, % - the inorganic material (crude mineral fraction) after oxidizing or combusting the organic fraction a necessary step before assaying individual minerals ppm – commonly used in the US, but = to mg/kg

    13. Requirement tables Pay close attention to units in columns and rows Feed intake or DM intake – approximate amount of DM that an animal should consume each day Table 13-2, rows 6 and 7 ME intake, kcal/day kcal ME/kg of DM

    14. Requirement tables Pay close attention to units in columns and rows Table 14-1, columns 4 and 5 col 4 – conc of protein in the diet with the assumed feed intake col 5 – quantity of protein/day with the assumed feed intake (see footnote)

    15. Requirement tables Pay close attention to units in columns and rows Table 17-4 mature cow maintenance – Mcal/day for the cow nutrients for milk production – amount/kg of milk

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