Fiber Analysis and 6.5 Biology

Transcription

1 Fiber Analysis and 6.5 Biology Paul K. Sirois, Sarah E. Fessenden & Lynn Gilbert* Dairy One Forage Lab *AMTS Penn State Dairy Nutrition Workshop Grantville, PA November 15, 2017 Fiber the state of the union Where we are and how we got there Population statistics Incorporating new values into rations 1

2 Unless otherwise noted, all nutrient composition values are expressed on a dry matter basis as a percentage of the dry matter. NDFD values are expressed as a percentage of the NDF Comparison of detergent and crude fiber methods Cell contents Protein, Fat, Minerals NFC Starch, sugars, pectins, B-glucans, VFA Cell walls Hemicellulose NFE NDF Lignin Alkali soluble Alkali insoluble ADF Cellulose CF 2

3 Neutral Detergent Fiber (NDF) Procedure used to describe the total fiber content of feed (collectively cellulose, hemicellulose and lignin) Sample is boiled in ND solution for 1 hr to dissolve the unwanted nutrients leaving the fibrous residue behind Neutral Detergent Fiber (NDF) Various chemicals are employed to dissolve the unwanted nutrients Sodium dodecyl sulfate protein & fats EDTA (ethylene diamine tetra acetic acid) Ca, Mg, Zn, pectins Triethylene glycol starch Sodium borate - buffer Sodium phosphate dibasic - buffer 3

4 Neutral Detergent Fiber (andf) Mid 90 s, procedure modified to include the following Amylase - enzyme to breakdown starch Sodium sulfite - protein Neutral Detergent Fiber (andfom) It is now being advocated that NDF be performed on an organic matter or ash free basis 4

5 Neutral Detergent Fiber (andfom) Large harvesting equipment Neutral Detergent Fiber (andfom) Flood irrigation 5

6 Neutral Detergent Fiber (andfom) The elevated total ash content of some feeds can sometimes contribute to elevated NDF values This can lead to an underestimation and underfeeding of fiber and the problems associated with low fiber diets. Neutral Detergent Fiber (andfom) Ash free fiber involves taking the fiber residue remaining after ND extraction and ashing it at 550 C for 2 hrs The NDF value is then corrected for the ash content The organic matter (om) or ash free NDF is reported as andfom 6

7 Corn Silage [andf andfom] differences Percentage >5.0 andfom diff Legume Haylage [andf andfom] differences Percentage >5.0 andfom diff 7

8 Grass Haylage [andf andfom] difference Percentage >5.0 andfom diff andf andfom differences Forage n mean sd Corn Silage 5, Legume Haylage 2, Grass Haylage 3,

9 Forage Statistics Haylage n andf andfom diff Legume 3, MML 9, MMG 15, Grass 8, Hay Legume 36, MML 2, MMG 12, Grass 19, Corn Silage 35, Where it pays Forage andf% andfom% diff Ash% Corn Silage Legume Haylage Grass Haylage ADF > andfom% 9

10 Fiber Digestibility NDF Digestibility (NDFD) NDFD is the percent of NDF digested at a specific point in time NDFD24 NDFD30 NDFD48 10

11 NDF Digestibility (NDFD) NDFD24, 30, and or 48 were used in conjunction with NDF and lignin to calculate kd kd = rate of NDF digestion or disappearance expressed as %/hr The unavailable or undigestible fiber was estimated as (lignin x 2.4) NDF Digestibility (NDFD) Kd = rate of NDF digestion or disappearance expressed as %/hr 11

12 Corn Silage NDF Digestibility by NDF and Lignin Content NDF, %DM Lignin, %DM Courtesy M. Van Amburgh, Cornell University Corn Silage NDF Digestibility by NDF and Lignin Content NDF, %DM Lignin, %DM NDFD% (30hr) Est. NDF kd, %h Courtesy M. Van Amburgh, Cornell University 12

13 Indigestible fiber circa 1980 (Sniffen); indf = lignin x (Raffrenatto et al) Forage Factor Range Corn Silage BMR CS Grass Straw & Hay Afalfa Raffrenato, E. and M.E. Van Amburgh. CNC Indigestible Fiber Corn silage = lignin x 3.38 Legumes = lignin x 2.53 Grasses = lignin x

14 Extended In Vitro time points 0, 6,12, 24, 30, 36, 48, 72, 96,120,144, 216, 240 hr Indigestible Fiber 2014: 240 hr undfom Indigestible fiber = lignin x 2.4 Indigestible fiber = undfom240 Indigestibility constant = undfom240/lignin 14

15 Legume Haylage n = 2,280 Lignin, avg = 7.21 undfom240 = undfom240/lignin = indigestibility constant 17.64/7.21 =

16 Epic 16

17 Moron Corn Silage Indigestibility Constants Percentage >5.0 Indig. Constant (undfom240/lignin) 17

18 Legume Haylage Indigestibility Constants Percentage >5.0 Indig. Constant (undfom240) Grass Haylage Indigestibility Constants Percentage >5.0 Indig. Constant (undfom240/lignin) 18

19 Table 7. Indigestibility constant summary table (historic = 2.4) Forage n mean sd min max Corn Silage 5, Legume Haylage 2, Grass Haylage 3, Table 6. indf* vs undfom240 Corn silage Legume haylage Grass Haylage undfom240 indf undfom240 indf undfom240 indf n 5,030 5,030 2,280 2,280 3,959 3,959 mean sd min median max *indf = lignin x

20 Corn Silage [lignin x 2.4] vs. undfom240 (n = 5,030) lignin x y = x R² = undfom Legume Haylage [lignin x 2.4] vs. undfom240 (n = 2,280) lignin x y = x R² = undfom240 20

21 Grass Haylage [lignin x 2.4] vs. undfom240 (n = 3,959) lignin x y = x R² = undfom240 Whether viewed as undfom240 or calculated indigestibility constants, sufficient variation exists within the population to justify routine analysis to enhance our ability to predict forage performance and utilization 21

22 Regional sample nos. Corn Legume Grass Region Silage Haylage Haylage NE SE MW SW W

23 Corn Silage Regional NDFDom Data Corn silage % andfom NDFDom30 NDFDom120 NDFDom240 NE SE MW SW W Legume Haylage Regional NDFDom Data Legume haylage % andfom NDFDom30 NDFDom120 NDFDom240 NE SE MW SW W 23

24 Grass Haylage Regional NDFDom Data Grass haylage % andfom NDFDom30 NDFDom120 NDFDom240 NE SE MW SW W Conventional vs. BMR NDFDom values (n = 70) NDFDom, % time, hrs Conv BMR 24

25 Forage Statistics Haylage n CP ADF andf andfom Lignin Ash Legume 3, MML 9, MMG 15, Grass 8, Hay Legume 36, MML 2, MMG 12, Grass 19, Corn Silage 35, Haylage NDFDom NDFDom% NDFDom30 NDFDom120 NDFDom240 Legume MML MMG Grass 25

26 Hay NDFDom NDFDom% NDFDom30 NDFDom120 NDFDom240 Legume MML MMG Grass Legume Haylage NDFDom NDFDom% NDFDom30 NDFDom120 NDFDom

27 Grass Haylage NDFDom NDFDom% NDFDom30 NDFDom120 NDFDom Corn Silage NDFDom NDFDom% NDFDom30 NDFDom120 NDFDom240 Axis Title all

28 Summary andfom correcting for ash will yield a cleaner NDF value and is most impactful in high ash samples When viewed as calculated indigestible rate constants (undfom240/lignin), the values are normally distributed about the mean. Graphs of (lignin x 2.4) vs undfom240 show a positive relationship between the two, though there is a large amount of variation within the population. Given the variation about the line, using undfom240 instead of the calculated indf should improve the determination of rate values. Some geographic differences exist in undfom values BMR corn silage had higher digestibilities at 30 hr and this carried through to 120 and 240 hr As the percentage of grass in a mixed forage increased, so did the digestibilities Differences in digestibilites across years were not immediately apparent. 28

29 Herd Demographics Three Forage Qualities 29

30 Corn Silage Sample 30

31 Low Quality Medium Quality 31

32 High Quality Rations without Any Timepoints 32

33 Rations 30 hr only 3 time points 33

34 Summary You don't know what you don't test Another tool to troubleshoot Multiple timepoints help define the feed 34