ASN-ASAS SYMPOSIUM: FUTURE OF DATA ANALYTICS IN NUTRITION: Modeling complex problems with system dynamics: applications in animal agriculture1

Abstract

Many problematic outcomes in agricultural and food systems have important dynamic dimensions and arise due to underlying system structure. Thus, understanding the linkages between system structure and dynamic behavior often is important for the design and implementation of interventions to achieve sustained improvements. System dynamics (SD) modeling represents system structure using stock-flow-feedback structures expressed as systems of differential equations solved by numerical integration methods. System dynamics methods also encompass a broader methodological approach that emphasizes model structural development and data inputs to replicate one of a limited number of problematic behavioral modes, anticipates dynamic complexity, and focuses on feedback processes arising from endogenous system elements. This paper highlights the process of SD modeling using 2 examples from animal agriculture at different scales. A dynamic version of the Cornell Net Carbohydrate and Protein System (CNCPS) that represents outcomes for an individual dairy cow is formulated as an SD model illustrates the benefits of the SD approach in modeling rumen fill and animal performance. At a very different scale, an SD model of the Brazilian dairy supply chain (farms, processing, and consumers) illustrates the country-level impacts of efforts to improve cow productivity and how impacts differ if productivity improvement occurs on small farms rather than large farms. The paper concludes with recommendations about how to increase awareness and training in SD methods to enhance their appropriate use in research and instruction.

Feed intake, fiber fraction digestibility and milk yield of lactating goats fed banana peel in the diet

“…The primary factor impacting ration utilization in dairy ruminants that are lactating are nutritional content and digestibility [24,25]. Table 5 shows that the digestibility values of the fiber fraction and dry matter were not significant different (P>0.05).…”

Can the Tragedy of the Commons be Avoided in Common-Pool Forage Resource Systems? An Application to Small-Holder Herding in the Semi-Arid Grazing Lands of Nigeria

“…The models are mathematical representations of the mechanisms governing natural phenomenon that are not easily understood or managed [46,47]. This approach has been used in previous agricultural systems research, including natural resource, livestock production and grazing management problems [15,27,[47][48][49][50][51][52][53][54], as well as Nigerian beef supply problems [55]. A mathematical SD model was constructed in the Vensim ® modeling environment (Ventana Corp., Harvard, MA, USA) to link common forage, animal population, crops and the net worth of herders (stylized in Figure 2).…”