Longitudinal study assessing antimicrobial usage in broiler production cycles in northern Vietnam in 2022 to 2023
8 affiliations
- 1Centre for Applied One Health Research and Policy Advice (OHRP), City University of Hong Kong, Hong Kong SAR, China; Department of Infectious Diseases and Public Health, Jockey Club College of Veterinary Medicine and Life Sciences, City University of Hong Kong, Hong Kong SAR, China.
- 2Vietnam Institute of Animal and Veterinary Science (VIAVS), Ha Noi, Vietnam.
- 3Department of Pathobiology and Population Sciences, The Royal Veterinary College, UK.
- 4French Agricultural Research Centre for International Development (CIRAD), Ha Noi, Vietnam.
- 5Centre for Applied One Health Research and Policy Advice (OHRP), City University of Hong Kong, Hong Kong SAR, China; French Agricultural Research Centre for International Development (CIRAD), UMR ASTRE, Harare, Zimbabwe; Animals, Health, Territories, Risks, Ecosystems (ASTRE), Univ Montpellier, CIRAD, INRAE, Montpellier, France.
- 6Department of Infectious Diseases and Public Health, Jockey Club College of Veterinary Medicine and Life Sciences, City University of Hong Kong, Hong Kong SAR, China.
- 7Department of Pathobiology and Population Sciences, The Royal Veterinary College, UK; INRAE, VetAgro Sup, UMR EPIA, Université de Lyon, Marcy I'Étoile, France; INRAE, VetAgro Sup, UMR EPIA, Université Clermont Auvergne, Saint Genès Champanelle, France.
- 8Comparative Biomedical Sciences, The Royal Veterinary College, London, UK; Clinical Services and Sciences, The Royal Veterinary College, London, UK. Electronic address: [email protected].
Abstract
Antimicrobial drugs (AMDs) are commonly used in chicken production in Vietnam for both preventive (prophylactic) and therapeutic purposes. Characterizing how the frequency of antimicrobial usage (AMU) changes from flock placement to harvest, varies by purpose, and may be influenced by production stage and mortality levels, can guide antimicrobial stewardship interventions to mitigate the risk of antimicrobial resistance (AMR) in broiler production.We investigated daily AMU and mortality patterns in production cycles of slow-growing broiler chicken flocks raised on 60 farms in two provinces (Ha Noi and Bac Ninh) in northern Vietnam at the end of 2022 and the beginning of 2023. The association between the daily probability of AMU and mortality risk was evaluated using generalized additive mixed models (GAMMs). The dynamic process of initiating a new treatment, and the expected duration of that episode, were further assessed using a two-state semi-Markov process (SMP) within a Bayesian framework. A total of 569 treatment events (70.5% preventive vs. 29.5% therapeutic) were recorded across all 60 monitored cycles. A median value of 185.8 mg/Population Correction Unit (PCU) AMDs was used for prophylaxis, while 116.8 mg/PCU was used for therapeutic treatment per production cycle. The most frequently administered AMDs for preventive treatments were colistin (23.2%), amoxicillin (19.2%), and doxycycline (11.7%). Therapeutic treatments mostly involved doxycycline (26.8%), florfenicol (17.9%), and amoxicillin (13.7%). The main effect of within-flock mortality was not significant, but the interaction between mortality and broiler age was associated with AMU both in the case of preventive and therapeutic AMU (p-value <0.05), suggesting that the effect of mortality on AMU may have varied depending on the broiler age. Broiler age was strongly and non-linearly associated with AMU (p<0.05), with distinct temporal patterns for preventive and therapeutic use. At the start of a production cycle, initiation of preventive treatment was substantially more likely than initiation of therapeutic treatment (day 0: risk ratio [RR] = 8.6), and prophylactic treatment remained dominant during the early cycle (RR > 2 before day 22). These findings indicate that preventive treatment is the primary driver of AMU during the early cycle, highlighting the need for stewardship interventions at this stage, focused on reducing non-essential prophylactic use and promoting lower-risk alternatives.
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BibTeX
@article{xin2026longitudinal,
title = {{Longitudinal study assessing antimicrobial usage in broiler production cycles in northern Vietnam in 2022 to 2023}},
author = {Chen Xin and Trang Nguyen and Quoc Hung Nguyen and Saira Butt and Huong Quynh Luu and Hoa Thi Thanh Pham and Anne Conan and Ngoc Thi Pham and Dirk Pfeiffer and Damer Blake and Fiona Tomley and Priscilla F Gerber and Beatriz Calvo-Urbano and Guillaume Fournié and Ludovic Pelligand},
journal = {Poultry Science},
year = {2026},
month = oct,
doi = {10.1016/j.psj.2026.107918},
url = {https://hal.inrae.fr/hal-05796496v2},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Longitudinal study assessing antimicrobial usage in broiler production cycles in northern Vietnam in 2022 to 2023
AU - Chen Xin
AU - Trang Nguyen
AU - Quoc Hung Nguyen
AU - Saira Butt
AU - Huong Quynh Luu
AU - Hoa Thi Thanh Pham
AU - Anne Conan
AU - Ngoc Thi Pham
AU - Dirk Pfeiffer
AU - Damer Blake
AU - Fiona Tomley
AU - Priscilla F Gerber
AU - Beatriz Calvo-Urbano
AU - Guillaume Fournié
AU - Ludovic Pelligand
PY - 2026
DA - 2026/10/06
JO - Poultry Science
DO - 10.1016/j.psj.2026.107918
UR - https://hal.inrae.fr/hal-05796496v2
AB - Antimicrobial drugs (AMDs) are commonly used in chicken production in Vietnam for both preventive (prophylactic) and therapeutic purposes. Characterizing how the frequency of antimicrobial usage (AMU) changes from flock placement to harvest, varies by purpose, and may be influenced by production stage and mortality levels, can guide antimicrobial stewardship interventions to mitigate the risk of antimicrobial resistance (AMR) in broiler production.We investigated daily AMU and mortality patterns in production cycles of slow-growing broiler chicken flocks raised on 60 farms in two provinces (Ha Noi and Bac Ninh) in northern Vietnam at the end of 2022 and the beginning of 2023. The association between the daily probability of AMU and mortality risk was evaluated using generalized additive mixed models (GAMMs). The dynamic process of initiating a new treatment, and the expected duration of that episode, were further assessed using a two-state semi-Markov process (SMP) within a Bayesian framework. A total of 569 treatment events (70.5% preventive vs. 29.5% therapeutic) were recorded across all 60 monitored cycles. A median value of 185.8 mg/Population Correction Unit (PCU) AMDs was used for prophylaxis, while 116.8 mg/PCU was used for therapeutic treatment per production cycle. The most frequently administered AMDs for preventive treatments were colistin (23.2%), amoxicillin (19.2%), and doxycycline (11.7%). Therapeutic treatments mostly involved doxycycline (26.8%), florfenicol (17.9%), and amoxicillin (13.7%). The main effect of within-flock mortality was not significant, but the interaction between mortality and broiler age was associated with AMU both in the case of preventive and therapeutic AMU (p-value <0.05), suggesting that the effect of mortality on AMU may have varied depending on the broiler age. Broiler age was strongly and non-linearly associated with AMU (p<0.05), with distinct temporal patterns for preventive and therapeutic use. At the start of a production cycle, initiation of preventive treatment was substantially more likely than initiation of therapeutic treatment (day 0: risk ratio [RR] = 8.6), and prophylactic treatment remained dominant during the early cycle (RR > 2 before day 22). These findings indicate that preventive treatment is the primary driver of AMU during the early cycle, highlighting the need for stewardship interventions at this stage, focused on reducing non-essential prophylactic use and promoting lower-risk alternatives.
SN - 0032-5791
SN - 0032-5791
SN - 1525-3171
ER -