Livestock and Poultry Environmental Learning Center Webcast Series September 20, 2013

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1 Livestock and ultry Environmental Learning Center Webcast Series September, 13 Mark Hanigan, in Feng, Partha Ray, Jamie Jarrett, Chao Shang, Rory Maguire, and Katharine Knowlton Departments of Dairy Science and Crop, Soil, and Environmental Science, Virginia Tech 1) Nutrition is the SOURCE of the problem ) Solution? DON T FEED MORE THAN NEEDED Reduce feed waste Properly balance rations Properly mix rations Less overfeeding for insurance Improve knowledge of P availability and requirements 1) Absorption is regulated to meet needs only inorganic P is absorbed Bone buffers P deficiencies Excess P is excreted in feces ) Digestion can limit availability? Phytate () Organic () Inorganic () Taylor et al., 7

2 Livestock and ultry Environmental Learning Center Webcast Series September, 13 P, % of DM 1.8% 1.5% 1.3% 1.%.8%.5% Non phytate P Phytate P.3%.% Corn Oats Wheat Corn Gltn Fd Barley Corn DDG Cottonseed meal SBM Wheat midds release, ug/ml RF/min Beef Study 1% hay 55% barley 9% barley release, ug/ml RF/min Dairy Study b a 65% forage 35% forage Yanke et al., 1998 Knowlton et al., 4 Classical phytate analysis 1) Ion exchange chromatography Nitric & perchloric acid digestion Colorimetry ) Works very well for feed!! 3) Doesn t work for digesta and feces Partially degraded phytate co-elutes with phytate

3 This image cannot currently be displayed. Livestock and ultry Environmental Learning Center Webcast Series September, 13 1) NMR Spectroscopy Improved separation of peaks to more clearly define phytate ) High Performance Ion Chromatography Improved acid & base extractions to clean up samples Used NMR to verify HPIC separation Reliably measure IP 6, IP 5-1, and Feed Digesta Feces 1) Cows, heifers, and steers ) 5 digestion studies Varying intake Varying forage to concentrate Ileal Phytate infusion Abomasal infusion Dietary variation 3) Intake, omasal flow, ileal flow, fecal output Pt,,, (by difference)

4 487* Livestock and ultry Environmental Learning Center Webcast Series September, 13 Diet 3 4* 3 Rumen Pm 14* Salivation 53* 19* 8* 57* 64* 1) Use data to estimate digestibities by ingredient Blood 5* Small Intestine 8* 5* 34* 8* 483 ) Calculate P bioavailability on a range of ingredients Large Intestine * 3) confidence in the system Pm 8* 7* 3* 1* 5* PT PT Feces Urine Milk Hill et al., 8 Parameter Description Estimate STDev. K Rum Ruminal phytate degradation, d K Rum Ruminal organic phosphorus degradation, d V Sal Vmax for salivary phosphorus secretion, g/kg DM 58.6 K SI Small intestinal organic P degradation, g/g. - K AbsSI Small intestinal phosphorus absorption, g/g.86. K DegLI Large intestinal phytate degradation, g/g K LI Large intestinal organic P degradation, g/g K AbsLI Large intestinal phosphorus absorption, g/g.133. K BldUrn Renal phosphorus clearance, L/d K BldBone Bone P deposition rate, L/d K Gain Phosphorus retention in gain, g/d 6..3 Residual Fecal Total P Flow Predicted Fecal Total P Flow Residual Phytate P Flow Predicted Fecal Phytate P Flow

5 Livestock and ultry Environmental Learning Center Webcast Series September, 13 Residual Fecal Total P Flow Feed Phosphorus (% of DM) Residual Fecal Phytate P Flow Feed Phosphorus (% of DM) Residual Fecal Total P Flow Feed Phytate (% of DM) Residual Fecal Phytate P Flow Feed Phytate (% of DM) Site --- % of input --- Rumen SI 8 LI Total Microbial synthesis removed Microbial formation is balanced with degradation 3 N for total tract is greater than for Rumen and SI

6 -8 Livestock and ultry Environmental Learning Center Webcast Series September, 13 Digestion Coefficients, g/g Phosphorus Balance, g/d DCSI DCPtSI DCPtTT P-Balance Milk Yield, lbs/d Digestion Coefficients, g/g Phosphorus Balance, g/d DCSI DCPtSI DCPtTT P-Balance Dietary Phosphorus, % of DM, 1 6,, 5,, 6,,,,,,,,,, 1,,,,,,, 1,, 1,,, 1,, Feed P Digestibility Total Tract Absorption Small intestine Large intestine Corn silage Alfalfa silage Almond hulls Grass hay Western hay Wet Citrus Pulp Alfalfa hay Mixed Legume/Grass Silage Citrus pulp Wet DGS DDGS HMSC Corn gluten Brewers grain Soy Hull Dry Barley SBM 48% Wet brewers Corn grain Whole cottonseed Canola Hominy

7 Livestock and ultry Environmental Learning Center Webcast Series September, 13 1) Feed phytate is highly available in the rumen ) Inorganic P absorption is high and highly regulated Large changes in P availability have small effects on P balance Large bone reserves mitigate any P deficiency for long periods of time 3) Recycling to the rumen is an important aspect of P excretion 4) High phytate ingredients should not be of concern 5) Will exogenous phytase help? 6) Knowledge gaps Regulation of bone P balance Regulation of P excretion into the rumen 1) Tzu-Hsuan Yang, Jamie Jarrett, in Feng, and Partha Ray, MS and PhD students ) Drs. Chao Shang and Rory Maguire, Analytical Techniques 3) CSREES U.S. Department of Agriculture, Award No ) Departmental Funding provided by the Virginia State Dairymen s Association Next Speaker: Dr. Bob James Dept. of Dairy Science

8 Livestock and ultry Environmental Learning Center Webcast Series September, 13 1) High phytase activity in the rumen 8+% of phytate degraded ) % phytate digestion in the small intestine 3) 1% phytate digestion in the large intestine 4) Phosphorus absorption from SI is 8% Responds to need, high of 1% and low of 5% 5) Low phosphorus absorption from the LI, 5% 6) Huge salivary recycling (>x P Intake) a lot of buffering of supply 7) Newer NRC requirements are generally adequate Rarely need to add inorganic P on normal diets 8) New P bioavailability values for ingredients Diet 3 3 Rumen 4* Pm 19* 14* Salivation 53* 1) Phytate digestibilty Change with quantity fed? All ingredients the same? ) Very limited data!! Only a couple of diets 8* 57* 64* 75% Phytate Degradation =phytate P, =non-phytate organic P, =inorganic P 1) Comprehensive information, inorganic & organic P compounds ) Time-consuming, expensive, insensitive

9 Livestock and ultry Environmental Learning Center Webcast Series September, 13 7 % of Observed Mean or of MSPE RMSPE Mean Bias Slope Bias Pt SI SI SI Pt LI LI LI Pt Feces Feces Feces Blood