Abstract
Research, extension, and education communities often focus on the adoption of single strategies because they lack the tools to integrate opportunities at a farm level. Modeling is the best approach to synchronize the complex linkages between animal health, animal-based protein production, water resources, and soil health on dairy farms. Available farm systems models have limitations that prevent scalability and adaptation to evolving technologies and scientific knowledge. Participatory modeling with corporate partners and farmers is being used to create the Ruminant Farm Systems (RuFaS) model. RuFaS tracks the flows of nitrogen, carbon, and phosphorus through four biophysical modules: soil and crop, feed storage, animal herd, and manure. Users input farm variables through tiered files, from general farm information (e.g., crop type, animal numbers, field characteristics) to advanced inputs (e.g., soil characteristics, milk production parameters). The soil and crop module predicts alfalfa, corn, and soybean growth. The animal module uses a Monte-Carlo approach to determine individual animal characteristics and production, incorporating breed traits, reproduction protocols, and animal management decisions. RuFaS calculates animal nutrient requirements from NRC equations, which are averaged on a pen basis to reflect industry practices. A nutritional grouping algorithm can allocate lactating cows to different pens. Manure processing and feed storage modules are currently being developed. RuFaS is coded in python, a general-purpose programming language emphasizing readability. Pool and flux values are stored daily and transferred to an output generator before being cleared annually. Simulation data can be summarized to determine resource use, greenhouse gas emissions, and the cost of production. RuFaS will be available as open-source software to radically change users’ access to dairy farm systems models. The completed RuFaS model will be an essential tool for researchers to evaluate strategies for farm sustainability, and we anticipate the first version of RuFaS will be available in 2021.
The Impact of Somatotropin, Milking Frequency, and Photoperiod on Dairy Farm Nutrient Flows