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Updated: Apr 24, 2026
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The Use of an Automated System GreenFeed to Monitor Enteric Methane and Carbon Dioxide Emissions from Ruminant Animals
Published on: September 7, 2015
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Modelling ruminant grazing systems based on native grasslands. 2. Evaluation of the animal dynamics module
A Ruggia1, W A H Rossing2, P Soca3
1Instituto Nacional de Investigación Agropecuaria (INIA), Programa Nacional de Investigación en Producción Familiar, Estación Experimental INIA Las Brujas, Ruta 48 km 10, Canelones, Uruguay; Farming Systems Ecology, Wageningen University and Research, Wageningen, the Netherlands.
Animal : an International Journal of Animal Bioscience
|April 22, 2026
Summary
This study introduces the PASpALuM model, a tool for ecological intensification in beef cow-calf systems on native grasslands. It accurately simulates animal dynamics, linking herbage conditions to farm management for improved sustainability.
Area of Science:
- Livestock Science
- Ecology
- Agricultural Modeling
Background:
- Ecological intensification of beef cow-calf systems requires quantitative tools.
- Existing models may not adequately link herbage condition, animal physiology, and farm management.
Purpose of the Study:
- To present and evaluate the animal dynamics module of the PAmpa Sustainable grAzing Livestock Management (PASpALuM) model.
- To provide a farm-scale model for high-diversity Pampas grasslands that simulates individual animal performance based on herbage availability and management.
Main Methods:
- Developed the animal dynamics module of PASpALuM, simulating herbage intake, energy balance, body weight (BW), body condition score (BCS), and reproduction.
- Validated the model using experimental data on heifer intake and weight gain, and on-farm data from cow-calf operations for BW, BCS, pregnancy, and herbage height.
- Utilized herbage height and BCS as key farmer-measurable state variables.
Main Results:
- Simulated herbage intake showed strong agreement with experimental data (MAD=0.44 kg DM/animal/day, RMSE=0.52 kg DM/animal/day).
- Daily weight gain was well reproduced (MAD=0.05 kg/animal/day, RMSE=0.06 kg/animal/day), with modeling efficiency (EF) of 0.6 for both intake and gain.
- Model accurately predicted cow BW, BCS, and herbage height over 90 days (EF=0.6, 0.5, 0.7 respectively) and pregnancy rates within 95% confidence intervals on most farms.
Conclusions:
- The PASpALuM model, with its individual-animal approach and use of measurable variables like herbage height and BCS, is a distinct tool for grassland production systems.
- The model demonstrates strong performance in simulating key animal and herbage variables, supporting its use for ecological intensification in Pampas cow-calf systems.
- PASpALuM offers a quantitative approach to link herbage condition, animal physiology, and management at the whole-farm level for sustainable grazing management.
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