Estimating the Economic Impact of Neonatal Calf Diarrhea Agents With Decision Tree Analysis and the Monte Carlo...

Neonatal calf diarrhoea (NCD) is a major health problem in livestock, causing significant economic losses due to treatment costs, growth retardation, and mortality. Accurately estimating these losses is crucial for effective herd management. Decision tree analysis and Monte Carlo simulation are powerful tools for evaluating the economic impact of different etiological agents. This study aims to determine the economic impacts of the major agents causing diarrhea in newborn calves using Monte Carlo simulation and decision tree analysis.

The material used in this study consisted of neonatal period (1-28 days) data of 1,497 calves born on a dairy farm in Türkiye. Health records, including cases of diarrhoea and causative agents, were collected and analysed. An immunochromatographic rapid diagnostic test (BoviD-5 Ag, Bionote, South Korea) was used to identify the agents causing diarrhea. To estimate the economic impact of the main pathogens causing neonatal calf diarrhoea (bovine rotavirus [BRV], bovine coronavirus [BCoV], and Cryptosporidium spp.), a decision tree model and a Monte Carlo simulation were applied. These approaches allowed a general assessment of the financial losses associated with each pathogen and enabled comparison between different disease scenarios (expected and pessimistic). The modelling process was carried out using Python 3.13.

In calves without diarrhea (healthy), following only preventive measures, the cost per animal was $13.7. In calves with diarrhea (diseased), the economic loss per animal ranged from $36.82 to $1,519.58, depending on the agent (single or co-infection) and scenario (severity). In single infections, the economic losses ranged from $82.98 to $1,072.72 for Cryptosporidium spp., $61.01 to $1,183.56 for BRV, and $65.74 to $1,170.38 for BCoV. In co-infections, the losses were higher and ranged from $79.34 to $1,246.67 for BRV + BCoV; $142.32 to $1,519.58 for Cryptosporidium spp. + BCoV; $124.90 to $998.25 for BRV + Cryptosporidium spp., and $170.00 to $1,336.52 for the triple infection (Cryptosporidium spp. + BCoV + BRV). The total economic loss of diarrhea for a farm with 1,497 calves born annually was estimated at $130,502.52 (95% CI: $96,391.72-168,419.85).

Economic losses due to calf diarrhea agents were estimated separately for single and co-infections under recovery (expected) and mortality (pessimistic) scenarios using Monte Carlo simulation and decision tree analysis. The results provide a decision support tool for farm management, resource planning, and veterinary health policy.