The Ruminant Farm Systems Animal Module: A Biophysical Description of Animal Management

Abstract

Dairy production is an important source of nutrients in the global food supply, but environmental impacts are increasingly a concern of consumers, scientists, and policy-makers. Many decisions must be integrated to support sustainable production—which can be achieved using a simulation model. We provide an example of the Ruminant Farm Systems (RuFaS) model to assess changes in the dairy system related to altered animal feed efficiency. RuFaS is a whole-system farm simulation model that simulates the individual animal life cycle, production, and environmental impacts. We added a stochastic animal-level parameter to represent individual animal feed efficiency as a result of reduced residual feed intake and compared High (intake = 94% of expected) and Very High (intake = 88% of expected) efficiency levels with a Baseline scenario (intake = 100% of expected). As expected, the simulated total feed intake was reduced by 6 and 12% for the High and Very High efficiency scenarios, and the expected impact of these improved efficiencies on the greenhouse gas emissions from enteric methane and manure storage was a decrease of 4.6 and 9.3%, respectively.

Investigating the effect of temporal, geographic, and management factors on US Holstein lactation curve parameters

“…We chose the Wood's model for this study because of its simplicity and flexibility, for which it has been selected by a variety of studies on milking performance (Silvestre et al, 2009;Cole et al, 2011) and many simulation analyses (Rotz et al, 1999;Calsamiglia et al, 2018). We also plan to use these results for simulation with the Ruminant Farm System Model (RuFaS; Hansen, et al, 2021).…”

“…The findings of this study may contribute to a more accurate representation of current animal performance in a dairy farm system model, such as RuFaS (Li et al, 2018;Kebreab et al, 2019;Hansen et al, 2021). The RuFaS model is a daily time-step, process-based, whole-farm model that simulates individual animal production, growth, and life events daily.…”

A conceptual framework for modelling the role of livestock systems in sustainable diets and a sustainable planet

“…Biophysical models are a key tool for assessing environmental and economic sustainability at the animal and farm-system scales (Dougherty et al 2019a;Tedeschi 2023). Some existing whole-farm models designed to assess economic and environmental sustainability, such as GrassGro (Freer et al 2012), APSIM (Holzworth et al 2018), the Australian farm-optimisation model (Young and Young 2022; Young 2023), RuFaS (Hansen et al 2021), the IFSM (Rotz et al 2022), and CLEM (APSIM Initiative 2023), also incorporate some degree of decision-making modelling by allowing users to set rules for buying/selling/managing resources depending on the internal state of the model, or including social aspects such as labour constraints, or cultural and community values. These existing decision-making models could serve as examples of a starting point for developing the holistic modelling framework discussed here.…”

The Ruminant Farm Systems Model: A decision-support tool for whole farm efficiency and sustainability

“…An example of a methodological choice that distinguishes RuFaS from other dairy farm models is in the Animal Module that simulates each individual animal as they move through their life cycle in a dairy herd. 4 This choice allows RuFaS to compare how management decisions related to breeding, animal health and culling impact herd efficiency and thus environmental outcomes like enteric emissions and manure production. The choice to represent individual animals is one example of our general approach to build a flexible and scalable model that is capable of representing the diversity of management practices in the U.S. dairy industry.…”