A linear programming model to optimize diets in environmental policy - - PowerPoint PPT Presentation

▶
a linear programming model to optimize diets in
SMART_READER_LITE
LIVE PREVIEW

A linear programming model to optimize diets in environmental policy - - PowerPoint PPT Presentation

May 17, 2023 132 likes •351 views

A linear programming model to optimize diets in environmental policy scenarios Paper by: L.E. Moraes, J.E. Wilen, P.H. Robinson, J.G Fadel (2012) Presented by: Dan Jensen Advanced Quantitative Methods in Herd Management 12/09 2018

slide-1
SLIDE 1

A linear programming model to optimize diets in environmental policy scenarios

Paper by: L.E. Moraes, J.E. Wilen, P.H. Robinson, J.G Fadel (2012) Presented by: Dan Jensen

Advanced Quantitative Methods in Herd Management – 12/09 2018

slide-2
SLIDE 2

Introduction

  • Problem: (Dairy)-farming is messy!
  • Goal: Tool for optimizing dairy cattle diet
  • Status of this research: Preliminary!

Dias 2

  • Agriculture: 6.3 % total US GHG emissions (2009)
  • Enteric fermentation (): 20 % of US human GHG
  • Also nitrogen, phosphor, etc.
  • Effect of emission taxes
  • Forced (assumed) reduction
  • Sensitive to constraints. E.g. feed prices
slide-3
SLIDE 3

Methods General Background

  • Linear Programming Model (LPM)
  • Reminder - an LPM is:
  • Method to achieve best outcome given certain

constraints

  • Constraints are represented by linear

relationships

Dias 3

slide-4
SLIDE 4

Methods The models

  • Three scenarios – three models:
  • BASEM: Cheapest possible feed (baseline)
  • TAXM: what if there was an emission tax?
  • … of 5 $ per tonne?
  • … of 17 $ per tonne?
  • … of 250 $ per tonne?
  • REDM: what if you were forced to reduce

emissions?

Dias 4

slide-5
SLIDE 5

Methods The models, Assumptions 1

Dias 5

−

slide-6
SLIDE 6

Methods The models, Assumptions 2

Dias 6

Locally collected kg/kg DM $/kg DM − − −

slide-7
SLIDE 7

Methods The models, Assumptions 2.1

Dias 7

slide-8
SLIDE 8

Methods The models, specifics

  • BASEM/REDM:

Remember: j = feed c = cost of feed a = animal class

Dias 8

slide-9
SLIDE 9

Methods The models, specifics

  • TAXM:

Remember: j = feed c = cost of feed a = cow category Notice: e = expected emission (tonnes) p = tax price per tonne

Dias 9

slide-10
SLIDE 10

Methods The models, Outputs

Dias 10

55.65 MJ/kg

  • How big is the mess?

Feed composition – absorbstion Excrete composition

slide-11
SLIDE 11

5 minute break

slide-12
SLIDE 12

Methods The models, Constraints 1

Dias 12

Nutrient req.

  • Diet. Feed Limits

Methane Restrictions DMI Other Limits, 1

  • Diet. Barley Limits

Other Limits, 2

  • Diet. Forage Proportions
slide-13
SLIDE 13

Methods The models, Constraints 2

Dias 13

Nutrient req.

Remember: j = feed a = cow category (7 kinds) i = nutrient (14 kinds)

Amount Nutrient content Requirement

7 x 14 = 98 eq.

slide-14
SLIDE 14

Methods The models, Constraints 3

Dias 14

  • Diet. Feed Limits

Remember: j = feed a = cow category (7 kinds) l = limit (for 10 kinds of j)

≤ ∙

  • 7 x 10 = 70 eq.
slide-15
SLIDE 15

Methods The models, Constraints 4

Dias 15

Methane Restrictions (REDM) Total feed (all cows, all feed) 1-Reduction BASEM emission Max. Emission Total NDF Total ME Methane prediction

slide-16
SLIDE 16

Results

  • REDM:

Dias 16

Neutral Detergent Fiber consumption given Methane reduction Metabolisable energy proportion given Methane reduction Crude protein consumption given Methane reduction

slide-17
SLIDE 17

Results

  • REDM:

Dias 17

↓ → ↓ ! ∴ ↓ → ↑ $%!

slide-18
SLIDE 18

Results

  • REDM:

Dias 18

Consumption Excretion

slide-19
SLIDE 19

Results

  • Shadow prices, Feed stuff:

Dias 19

%&! '( )*!%' )%!+:

  • .)*!'* / -0 !(1*%'+
slide-20
SLIDE 20

Results

  • Shadow prices, Methane emissions:

Dias 20

slide-21
SLIDE 21

Conclusions

  • Cost of low emission diet exceeds cost of taxes

TAXM ~ BASEM

  • Reduction of emissions yields increase in

Nitrogen-excretion

  • Further studies are needed!

Dias 21