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Ruminant Livestock

Livestock Analysis Model User Manual

LAM TOC | LAM Introduction | Using the LAM | LAM Tutorial

Introduction to the Livestock Analysis Model
Overview of Main Model Elements
Using LAM

Population Model and Methane Emissions Model

This is a brief summary of the Livestock Analysis Model (LAM) Version 1.01, developed by ICF Incorporated. This initial version of the model is available for review and comment. Please provide your comments to the address listed below.


The purpose of the Livestock Analysis Model (LAM) is to provide a tool for:

  • Characterizing cattle and buffalo populations driven by the supply and demand for livestock products: milk, meat, and draft power.
  • Evaluating the impact of changes in production characteristics on the population of cattle and buffalo.
  • Evaluating baseline and future methane emissions from cattle and buffalo populations.

Overview of Main Model Elements

LAM is divided into four main elements as follows:

  1. Production Targets. Target levels of production are set for milk, meat, and draft power. These production targets may be sub-divided into the following sectors: up to four separate milk herds, two separate draft power herds, and one meat producing herd. LAM links the sectors together so that the production of multiple products from one herd (e.g., both milk and meat) affects the targets for the other herds in all sectors.
  2. Production Characteristics. This portion of the model is used to define the production characteristics of each herd, such as the rate of milk production and mortality rates. LAM uses these production characteristics to generate the size and composition of each sector and the overall population of cattle and buffalo.
  3. Methane Characteristics. This portion of the model is used to define the characteristics that affect methane emissions rates. The data required and the method used is based on the IPCC/OECD Emissions Inventory Guidelines (1994).
  4. Results. This portion of the model presents the results of the calculations, including descriptions of the livestock populations by sector and methane emissions.

Using LAM

LAM is designed to be used as an assessment tool in the following manner:

  • Calibration. Using data on production levels and animal characteristics for a recent historical year (e.g., 1990), simulate the population and productivity of the relevant livestock. The inputs should be checked and verified to ensure that the model produces a simulation of the livestock population that is consistent with the data available for the historical year.
  • Baseline. Using projected production levels and animal characteristics for a future year (e.g., 2000), simulate a baseline of the expected livestock population and methane emissions.
  • Simulated Intervention. To simulate the implications of an intervention, first define how the intervention would affect production targets, production characteristics, or methane characteristics. For example, providing improved nutrients to rural dairy cows would increase milk production per lactation, reduce the inter-calving interval between lactations, and increase feed digestibility. The new characteristics are then entered into LAM to simulate the population and methane emissions that would result from the implementation of the intervention.
  • Impact. The impact of the intervention is estimated as the difference between the baseline simulation and the intervention simulation.


LAM implements an equilibrium population model based on the approach in Hallam (1983). The model cannot simulate how the livestock population will evolve over time as its characteristics change. Therefore, the year of the assessment must be far enough in the future to allow the livestock population to adjust to its changed characteristics. The model is not suitable for simulating livestock populations with rapidly changing characteristics.

The estimates produced by LAM are only as good as the inputs used to describe the livestock populations. Care must be taken in developing and using the necessary data and checking the data using a calibration step as discussed above.


LAM is currently under development, and all comments are welcome regarding its usefulness and suitability as an assessment tool. Please provide comments to:

Michael J. Gibbs
ICF Consulting Associates, Inc.
10 Universal City Plaza, Suite 2400
Universal City, CA 91608-1097
Voice: 818/509-3186
FAX: 818/509-3137

LAM TOC | LAM Introduction | Using the LAM | LAM Tutorial

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