Estimating Energy Values of Feedstuffs Approaches & Problems. Galen E Erickson

Transcription

1 Estimating Energy Values of Feedstuffs Approaches & Problems Galen E Erickson

2 Estimating Energy Values of Feedstuffs Approaches & Problems Galen E Erickson University of Nebraska-Lincoln gerickson4@unl.edu

3 Energy Terms NASEM, 2016 Calorie = heat to raise 1 g of water 17.5 to 18.5 degrees C 1 calorie = joules, 1,000 cal = kcal, 1,000,000 cal = Mcal 1 kg of TDN = 4.4 Mcal of DE

4 California Net Energy System

5 Determining Energy of Feed Difficult (rare) ways Calorimetry o Direct calorimetry: measure heat given off o Indirect calorimetry: measure O 2, CO 2, CH 4 gases, urinary energy, fecal energy Long-term feeding at maintenance Comparative slaughter With assumption on requirements!

6 Determining Energy of Feed Measure DE or ME and calculate NE. GEI(Mcal) = (4.15 Carbohydrate Protein Fat) DMI/100 Measure DE & TDN (bomb feces and diet) Gross Energy intake - Gross Energy feces Convert DE to TDN (4.4 Mcal/1 kg TDN) Measure ME (urine energy, gaseous losses)

7 Determining Energy of Feed Measure DE or ME and calculate NE. Measure DE DE*0.82 = ME Can measure ME (urine/gas) Calculate NEm and NEg from ME

8 Determining Energy of Feed Performance of beef cattle can be predicted from feed intake and NE values of the diet being fed (NRC, 1984; 1996). NE for maintenance = Mcal/kg MBW NE for gain = (DMI feed for maintenance)*diet NE g ADG = *EBW *NE for gain Using these equations in reverse, diet and ingredient NE values can be predicted from DMI and average feeding BW (Hayes et al., 1987; Owens et al., 1997; Zinn et al., 2002).

9 Adjusting for breed/size

10 Challenge 1: DE to ME conversion static? Big issue for feedlot diets

11 Challenge 2: from performance? Assumption that requirements are known Can t solve for 2 unknowns Either requirements known, and calculate diet energy Or diet energy known, measure requirements Another challenge, use linear relationship of NEm & NEg, when probably curvilinear Small issue

12 California Net Energy System

13 Determining Energy of New Feed Measure performance, calculate NE. Dietary treatments evaluating SYT-EFC and Conventional corn with or without added enzyme (Exp 2). Ingredient CON 1 SYT-EFC 2 BLEND CON-E 3 Conventional Dry Rolled Corn SYT-EFC 2 Dry Rolled Corn WDGS Corn silage Liquid Supplement 4, Nutrient Composition, % Starch NDF CP Fat

14 Determining Energy of New Feed Measure performance, calculate NE. Effect of corn hybrid and inclusion of an alpha amylase enzyme supplement on finishing steer performance and carcass characteristics (Exp 2) Dietary Treatment 1 Item CON SYT-EFC BLEND CON-E SEM F-Test 2 Animal Performance Initial BW, kg Final BW, kg b 590 a 589 a 589 a 3.37 < 0.01 Final Live BW, kg 573 b 589 a 587 a 588 a 2.57 < 0.01 DMI, kg/d ADG, kg b 1.79 a 1.78 a 1.78 a < 0.01 G:F b a a a < 0.01 Energy Values 4 NEm, Mcal/kg 1.93 b 2.01 a 2.03 a 2.04 a < 0.01 NEg, Mcal/kg 1.28 b 1.36 a 1.37 a 1.38 a < 0.01

15 Challenge 3: associative effects influence performance? Positive or Negative associative effects Will impact energy of the diet, what feed is assigned the lower/higher dietary energy impact? 2 examples Forage:Grain ratio, grain supplementation in forage diets Big issue

16 Challenge 3: associative effects influence performance? DRC 83% TDN WDGS: 108% TDN Exp 2: 34% DRC; 25% WDGS Exp. 3: 41% DRC; 25% WDGS Exp. 4: 22 & 50% DRC; 15 & 30% DGS

17 Challenge 3: associative effects influence performance? Positive or Negative associative effects Will impact energy of the diet, what feed is assigned the lower/higher dietary energy impact? 2 examples Forage:Grain ratio, grain supplementation in forage diets Ratio of HMC:DRC Big issue

18 Feed:Gain Associative Effect of Processing DRM:HMC DRC:HMC Ratio of grain/processing Stock et al., 1991 J. Anim Sci.

19 Feed:Gain Associative Effect of Processing DRM:HMC DRC:HMC ? Ratio of grain/processing Stock et al., 1991 J. Anim Sci.

20 Summary of Grain Combination Trials Grain Sources ADG Efficiency SF Corn & W Corn DR Wheat & DR Corn (6) DR Wheat & DR Corn DR Wheat & DR Sorghum DR or DG Corn & W Corn HM Corn & SR Wheat DR Corn & SR Barley SF Corn & W Corn DR Wheat & HM Corn HM Corn & SR Barley SF Corn & SF Sorghum DR Corn & DR or DG Sorg DR Barley & W Corn

21 Forages & Silages Determining Energy of Forages & Silages Common to use fiber (ADF) as predictor Legumes %TDN = ( x NEL) ENE (Mcal/100 lb) = NEL x 82.6 NEL (Mcal/lb) = ( x ADF) Grasses %TDN = ( x NEL) ENE (Mcal/100 lb) = NEL x 82.6 NEL (Mcal/lb) = ( x ADF) Corn Silage %TDN = (53.1 x NEL) ENE (Mcal/100 lb) = NEL x 82.6 NEL (Mcal/lb) = ( x ADF)

22 Determining Energy of Forages & Silages Forages & Silages (appendix: Foragetesting.org) Common to use fiber (ADF) as predictor Comparison of TDN prediction equations ADG NRC Midwest PSU NY Mertens

23 Forages & Silages Determining Energy of Forages & Silages Common to use fiber (ADF) as predictor Terrible to extrapolate to fibrous byproducts/concentrates Never use predicted TDN from fiber for distillers (gluten, beet pulp, citrus pulp, soyhulls, etc) Other methods being considered Use digestible NDF (in vitro, in situ)? Digestibility trials (without DE)

24 1 lb of TDN = 2000 Calories DE (Swift, 1957) Thus, 1 kg of TDN = 4.4 Mcal of DE TDN is an energy measure But measured 2 ways Relationship of DE, TDN, and digestible OM Direct determination of total feed & feces by bomb calorimetry TDN based on proximate analysis of diets Works well for corn, fat, most forages Not good for byproducts or new feeds TDN estimated from OM digestion

25 DE, Mcal/kg Relationship of DE, TDN, and digestible OM Zinn et al. JAS ( ) 1 4,00 3,75 3,50 3,25 3,00 2,75 2, OMDig, % 1 67:11; 67:1038; 91:1801; 89:136; 74;2310; 78:1768; 73:1239; 72:2209; 68:776

26 DE, Mcal/kg Relationship of DE, TDN, and digestible OM Zinn et al. JAS ( ) 4,00 3,75 y = 0.033x R² = ,50 3,25 3,00 2,75 2, OMDig, %

27 Relationship of DE, TDN, and digestible OM Relationship of OM digestion to DE Established for corn based diets with fat Not established for byproducts, like distillers grains In general, feeding WDGS or MDGS, increases G:F while decreasing or not changing OM digestion

28 DGS impact on G:F and OMD Reference Inclusion Corn Control Traditional Distillers De-oiled Distillers CON OMD DGS OMD Vander Pol et al, 40 Corrigan et al., 27.5 Meyer et al. 25 Luebbe et al Luebbe et al., 2 30 Watson et al. WDGS 30 Watson et al. MDGS 30 Jolly et al., % Jolly et al., % Bremer et al., % Bremer et al., % Burhoop et al., % Average 38% a b b a b b a b b a b b a b b

29 Relationship of DE, TDN, and digestible OM Materials and Methods Compare OM digestion to measured DE 3 previous digestion trials Bombed feed/feces for DE Samples were analyzed for DE using a Parr 1281 Bomb Calorimeter Dietary DE calculated from heat of combustion Converted to TDN using 4.4 Mcal DE/kg TDN

30 TDN, % DM Relationship of DE, TDN, and digestible OM Experiment 1 Results: 40% corn gluten, HMC diets 90 TDN vs DIGOM in finishing diets w/o DGS y = 0.97x R² = ppt 2 Control Enzyme DIGOM, % DM 2 percentage unit 1 Individual data points represent animal

31 TDN, % DM Relationship of DE, TDN, and digestible OM Experiment 2 Results: Growing diets 18% DGS, 18% solubles and corn stalks 85 TDN v. DIGOM of growing diets with DGS 1. y = 1.10x R² = ppt negcontrol poscontrol pelletc pellets DIGOM, % DM 1 Individual data points represent animal

32 Relationship of DE, TDN, and digestible OM Experiment 3 Diet fed to steers in a digestibility experiment evaluating dietary fat sources (Bremer, 2010) 1. Ingredient, %DM Corn Corn Oil Tallow Solubles WDGS DRC Grass Hay Supplement Molasses Corn Oil Tallow Solubles WDGS Nebraska Beef Cattle Report pp , University of Nebraska Lincoln Extension

33 TDN, % DMI Relationship of DE, TDN, and digestible OM Experiment 3 Results 95 TDN v. DIGOM in five finishing diets ppt Tallow ppt 0.3 ppt WDGS ppt Corn Oil ppt Corn Solubles DIGOM, % DM 1 Individual data points represent animal WDGS: y=1.15x-0.89 R 2 =0.99 Solubles: y=1.25x-13.8 R 2 =0.99 Tallow: y=0.99x+1.09 R 2 =0.99 Corn Oil: y=1.18x-13.5 R 2 =0.99 Corn: y=1.11x-12.5 R 2 =0.99

34 Relationship of DE, TDN, and digestible OM Relationship of OM digestion to DE is consistent in cornbased diets with fat Relationship of OM digestion to DE is not good for byproducts consistent versus fit concerns with DGS DE increases as OM digestion increases OM digestion is not equivalent to TDN though Essential to determine DE in digestion trials with new feeds or alternative ingredients

35 Feeding value versus Net Energy calculations Evaluation of new feeds, compared to a feed (corn) Change in G:F, corrected for inclusion Feeding value [(G:F control G:F of test diet)/g:f control] decimal percentage

36 Feeding value versus Net Energy calculations Example: corn silage kernel processing, fed at 40% Item -KP +KP P-value Initial BW Final BW DMI ADG % G:F FV = [(( )/0.1344) 0.4] + 1 = 1.07 = 107% HCW LM area Fat Marbling

37 Feeding value versus Net Energy calculations Example: deoiled MDGS compared to corn, fed at 40% Treatment 1 CON DO MDGS MDGS + Oil FF MDGS F-TEST Initial BW, kg Final BW, kg b 645 a 640 a 636 ab 0.04 DMI, kg/d 10.3 b 10.8 a 10.0 b 10.2 b 0.01 ADG, kg 1.52 b 1.68 a 1.65 a 1.61 ab 0.06 G:F c b a ab <0.01 Feeding Value 3 5.4% FV = [(( )/0.148) 0.4] + 1 = 1.13 = 113.5%

38 Feeding value versus Net Energy calculations Example Treatment 1 CON DO MDGS MDGS + Oil FF MDGS F-TEST NEm, Mcal/kg 1.96 c 2.00 bc 2.09 a 2.05 ab <0.01 NEg, Mcal/kg 1.31 c 1.34 bc 1.43 a 1.38 b <0.01 NRC equations and Vasconcelos and Galyean, 2008 approach by pen NEm, Mcal/kg NEg, Mcal/kg Using measure DE and conversion to NE (NASEM, 2016) G:F c b a ab <0.01 Feeding Value FV = [(( )/0.148) 0.4] + 1 = 1.13 = 113.5% Note: NE increase is not 13% (about 6%)

39 Predicting performance; model requirement Summary of means for pens of cattle at the beginning, midpoint, and end of the feeding period. Item BW, kg ADG, kg DMI, kg/day NE adjusters DMI as % BW Beginning Calf-fed Short yearling Midpoint Calf-fed Short yearling End Calf-fed Short yearling

40 Feeding value versus Net Energy calculations Determining energy of new feeds or new situations is important Cattle never lie (feeding value, or calculated from performance is good) Key assumptions: requirements are known, change is G:F is not the same % change in NE, no positive, or negative associative effects Great for relative differences, comparing to known or common feed (i.e., corn) Measure DE in digestion trials, digestible OM alone can be deceiving Forages/Silages fairly accurately predicted from ADF (established) Can use calorimetry chambers, limited observations

41 Estimating Energy Values of Feedstuffs Approaches & Problems Galen E Erickson University of Nebraska-Lincoln gerickson4@unl.edu