Assessing the inhibitory effect and intervention mechanism of food traceability system on reducing hog farmers’ overuse of animal antibiotics in China

The use of animal antibiotics is a double-edged sword. It can be used for disease treatment, health protection, and growth promoters. It also creates antibiotic residues and resistance, poses risks, and damages food safety, ecosystems, and public health. Under the pressure of disease risk and expected losses, farmers' overuse of animal antibiotics exacerbates this dual objective incompatibility. In this study, we employ the endogenous switching regression (ESR) model and the mediating effect method to empirically analyze the inhibitory effect and intervention mechanism of the food traceability system (FTS) on reducing farmers’ overuse of antibiotics by using the survey data of hog farmers from China. This paper measures the “dose” unit of antibiotics farmers use regarding cost and the active ingredients of antibiotics per kilogram of treated infected hogs. The study finds evidence that the FTS exerts a significant inhibitory effect on the overuse of antibiotics by farmers. The counterfactual hypothesis unveils that non-participation in the FTS by the involved farmers will increase the cost of antibiotics overuse by 0.080 yuan/kg, while if the farmers currently not participating are to engage with the FTS, the price will decrease by 0.126 yuan/kg. This effect persists across control variables controlled in turn and the unit doses of active ingredients of tetracycline, sulfonamides, $\beta$-lactam, chloramphenicol, and macrolide antibiotics. Moreover, our results reveal that the inhibitory effects of the FTS on over-the-counter and broad-spectrum antibiotics are more significant than on prescription and narrow-spectrum antibiotics. The results show that the inhibition effect of the FTS on the overuse of antibiotics by free-range, professional, and large-scale farmers exhibits an approximately inverse-U curvilinear relationship. Besides, the intervention mechanism of the FTS on the overuse of antibiotics by farmers mainly consists of social reputation maintenance, liability traceability for antibiotic residues, and biosafety enhancement, and the proportion of their mediating effects in the total impact are 24.22%, 21.84%, and 10.87%, respectively. Our empirical study has yielded several implications, such as strengthening the FTS construction, improving farmers’ antibiotic use skills, promoting standardized breeding levels, and increasing the market premium for food products that adhere to antibiotic residue standards. These outcomes not only contribute to the improvement of livestock production safety but also reduce the problem of antibiotic overuse.