NorFor – Nordic feed evaluation system - with focus on estimation of degradation parameters in practice
AARHUS
Martin Riis Weisbjerg Faculty of Agricultural Sciences, University of Aarhus, Denmark & Harald Volden TINE BA Norwegian University of Life Sciences U N I V E R S I TNorFor ET project group
Faculty of Agricultural Sciences
A common Nordic feed evaluation system for cattle Developed in cooperation between dairy farmer organizations in Island, Norway, Sweden and Denmark Based on earlier model developed by Harald Volden, TINE/UMB, Norway
NorFor Plan
A semi mechanistic model •Feed intake •Rumen, intestinal and hind gut digestion •Energy value based on Dutch energy evaluation system (van Es) Predict •Feed intake, energy value, rumen protein balance and absorbed amino acids, milk production and milk protein
What is included in NorFor Feed evaluation system Animal requirements Feed table (http://www.norfor.info/) Standardized feed analysis and ring tests IT development, computer tools, separate user interface in the different countries. Non-linear optimization tool
Some model interactions Sugars+starch
NDF degradation
Roughage level
Digesta passage
Intake
Microbial efficiency
Net energy
AA uptake
pdNDF
iST
pdST
Rest sST
Rest CHO
Lipids FPF
Protein
LI
iCP
Grf. 0,5 Krf. 0,1
RUMEN
kdløys. / kpvæske (TS/lev.vekt, grf:krf) kdløys. / kpvæske (TS/lev.vekt, grf:krf) kdPNST / kpKRF (TS/lev.vekt, grf:krf)
kdNDF / kp1 + kp2 / kpkrf (NDF/lev.vekt, grf:krf)
pdCP
sCP
Kdløys. / kpvæske (TS/lev.vekt, grf:krf)
iNDF
Starch
kdPNCP / kpKRF /kpGRF (TS/lev.vekt, grf:krf)
FEED
Fibre
NH3
ol , er e ys tos l G lak ga
UREA 4,6% av CPfôr
Energy and nitrogen for microbial growth
INTERMEDIARY METABOLISM
PBV
Energy
Microbal growth
Endogenous urinary-N
MCP * 0,63
iST
pdST
SMALL INTESTINE
pdNDF
sST
Rest CHO
LI
pdCP
mST
mLI
mCP
eCP
30g / kg OM to duodenum
Endogenous N
+ 60 g in intestine
AAT for hair and skin
Grf. 0,7
0,9
Krf. 0,85
Energy
0,9
0,2 0,85
0,5 0,73 0,95 Grf 0,65 Kkrf 0,85
HIND GUT
0,09
0,1
iNDF
0,1
iST
0,01
Grf. 0,3 Krf 0,15
Microbial growth
iCP
g 38 g /k
5g 10 BH gK /k
AAT to milk Utilization
4
% H 30 KB kg / 5g
0,35
H KB
AAT
0,1
Energy and nitrogen for microbial growth
0,9
0,9
Gain / mobil.
Energy
0,1
FAECES
sCP
AA in milk 0,15
0,4
NEL
Milk
Feed fractions Soluble Potentially degradable Total indigestible
”Soluble”
Protein NDF
Amino acids
Potentially degradable Total indigestible
Starch
Potentially degradable Total indigestible
Fermentation pr. Sugars Rest CHO Lipids Ash
Fatty acids
Effect of feed intake on passage rate and rumen degradation of NDF 3
70 KP NDF NDF degradability
65
2
60
1,5
55
1
50
0,5
45 10
12
14
16
18
20
Feed intake kg DM/d
22
24
26
NDF degradability, %
Passage rate, %/h
2,5
Sugar and starch in the diet
Affects the rumen environment
Rumen fermentation of NDF and microbial growth
Effect of sugars + starch on rumen degradation of NDF
68
NDF degradability, %
66 64 62 60 58 56 54 52 50 200
225
250
275
300
325
350
375
400
Sugars + starch, g/kg dry matter
425
450
Efficiency of microbial protein sythesis 220 10 kg DM
200
15 kg DM
Efficiency, g/kg TOMD
20 kg DM 25 kg DM
180
160
140
120
100 0
50
100
150
200
250
300
Starch+"rest CHO", g/kg DM
350
400
450
500
Energy supply. Net energy Calculated from total tract apparent digestibility Net energy lactation calculated from a modified version of the Dutch energy system (Van ES, 1975) Net energy growth calculated according to French, Dutch and English systems. Modifications made according to NorFor
Sensitivity analysis. NEL/kg DM 13 11 9
Sensitivity, %
7 5 3 1 -1 -3 -5 -7 -9 -11 -13 -15
kd pdCP (5.5-16.5 %/h)
sCP (600-800 g/kg CP)
iCP (1.9-5.7 g/kg CP)
iNDF (80-240 g/kg NDF)
kd pdNDF (2.3-7.0 %/h)
Sensitivity analysis. AAT, g/kg DM 11 9 7
Sensitivity, %
5 3 1 -1 -3 -5 -7 -9 -11 -13 -15
kd pdCP (5.5-16.5 %/h)
sCP (600-800 g/kg CP)
iCP (1.9-5.7 g/kg CP)
iNDF (80-240 g/kg NDF)
kd pdNDF (2.3-7.0 %/h)
Most important feed characteristics Energy value: Indigestible NDF (iNDF) Fractional rate of NDF degradation (kd NDF) Protein value: Soluble protein Indigestible NDF (iNDF) Fractional rate of NDF degradation (kd NDF)
How do we estimate these most important values on forage samples from practice ? iNDF → NIR (reference in situ) Kd NDF → ’Backwards calculation’ Soluble protein → NIR (reference buffer solubility)
iNDF (Ref), % DM
Prediction of iNDF by NIR in green samples of grass, clover and lucerne
iNDF (NIR), % DM
Eurofins Steins (2007)
’Backwards calculation’ Information needed OM digestibility Ash concentration NDF concentration iNDF concentration All except iNDF classical feed analysis Idea: NDS digestibility estimated using Lucas principle NDF digestibility calculated by difference Kd NDF ‘backwards’ calculated assuming 2 pool rumen model
kdNDF in roughage. The backward calculation method (Weisbjerg et al 2004, 2007) kd
kd kp
20 h
30 h
⎛ kd ⎛ kr ED = ⎜ ⋅ ⎜1 + ⎜ (kd + kr ⎜ (kd + kp ⎝ ⎝
kr
⎞⎞ ⎟ ⎟ ⋅ Pd ⎟⎟ ⎠⎠
Allen & Mertens, 1988
kdNDF = 1,21 ⋅ 100 ⋅ ( −0.041667 +
0.006944 +
0.0066667 ⋅ D 1− D ) − 1,24 2
Huhtanen et al, 2006
NDS = 1000 – Ash – NDF NDSFK = (101.3 – (902/NDS/10))/100 uOM = (1000 – Ash) *(1-OMD/100) uNDS = NDS*(1 – NDSFK) uNDF = uOM – uNDS NDFFK = (NDF – uNDF)/NDF pdNDF = NDF - iNDF D = NDFFK/(pdNDF/1000)
OMD estimated from sheep fed at maintenance
Status NorFor August 2008 System for dairy cows in use in practice in Norway, Sweden and Denmark, however still parallel use of old systems System for young stock planned to be introduced September 2008 Methods have been developed that enable us to analyse for most important feed degradation parameters on forage samples from practice
Some recent tests
Model test. OMD digestion 18000
16000
y = 0,981x + 259,25 2
R = 0,9885
14000
Predicted, g/d
12000
10000
8000
6000
4000
2000
0 0
2000
4000
6000
8000
10000
Observed, g/d
12000
14000
16000
18000
Model test. NDF digestion 8000,0
y = 0,96x + 180,91 R2 = 0,9734
7000,0
6000,0
predicted, g/d
5000,0
4000,0
3000,0
2000,0
1000,0
0,0 0
1000
2000
3000
4000 Observed, g/d
5000
6000
7000
8000
Model test. CP digestion 4500
4000
y = 1,0392x - 101,15 2
R = 0,9767
3500
Predicted, g/d
3000
2500
2000
1500
1000
500
0 0
500
1000
1500
2000 Observed, g/d
2500
3000
3500
4000
The end
