Scientific Abstract
Nutrient requirements of growing-finishing pigs are influenced by a complex interplay of factors, including feed intake, metabolism, and environmental conditions. To better understand these dynamics, a comprehensive agent-based model (ABM) was developed and implemented to simulate the growth performance and nutrient requirements of growing-finishing pigs. The ABM was built upon the principles and mechanistic equations from Nutrient Requirements of Swine (NRC, 2012), providing a detailed representation of individual pig behavior and interactions within their environment. The model consisted of pig agents capable of movement, feed consumption, nutrient metabolism, and growth based on their nutritional balance status. The proposed ABM was developed using NetLogo, allowing for the dynamic simulation of feed intake, metabolism, and growth processes of pigs with stochasticity included via a triangular distribution function. Key variables, such as body weight gain, starting and finishing weights, pig sexes, and environmental conditions are incorporated into the model; outputs were calibrated using results of pig growth rates and feed conversion ratios from the NRC (2012) computer model to ensure accuracy and reliability. Hence, the ABM is a comprehensive computer framework for simulating and understanding the complex dynamics governing the growth and development of pigs. Further, program-generated result reports of pig outputs allow users to account for and analyze individual variations among the agents (pigs) of the simulation to enhance the model’s applicability and utility in practical swine production settings. The model accurately estimates foundational parameters of pigs’ biological growth, including body weight, feed intake, metabolizable energy (ME) intake, maintenance ME requirements, protein deposition (Pd), and lipid deposition (Ld). In addition, the daily requirements such as amino acid, calcium (Ca), and phosphorus (P) requirements were calculated separately for each pig. For purpose of model validation, the growth of pigs of three different sexes (barrow, gilt, and entire male) from 20 kg to 130 kg was simulated. As expected, barrows experienced the least daily protein deposition, the greatest daily lipid deposition, and the greatest time to market weight (i.e., date of pig attainment of the rule to exit the simulation). Daily lipid deposition reached a peak of roughly 409 g/day, 359 g/day, and 314 g/day in barrows, gilts, and intact males, respectively. The results of this project are anticipated to impact the enhancement of feeding and management strategies within commercial swine production systems, leading to greater production efficiency and sustainability in the pork sector. This method has potential to help swine producers and decision makers to not only quantify but also improve feed efficiency while minimizing feed waste and nutrient excretion, resulting in more sustainable practices in swine production that support environmental stewardship and profitable pig production.
