Hamid Sharifi - Department of Food Hygiene and Public Health, Faculty of veterinary medicine. Shahid Bahonar University of Kerman, Kerman, Iran and Research Center for Modeling in Health, Institute for Futures Studies in Health, Kerman University of Medical
Nima Ghalekhani - Faculty of Veterinary Medicine, Shahid Bahonar University of Kerman, Kerman, Iran.
Mahshid Hashemi - Faculty of Veterinary Medicine, Shahid Bahonar University of Kerman, Kerman, Iran.
Zohre Abbaspour-Benhengi - Faculty of Veterinary Medicine, Shahid Bahonar University of Kerman, Kerman, Iran.
Hanie Rahimifard - Faculty of Veterinary Medicine, Shahid Bahonar University of Kerman, Kerman, Iran.
Saeid Tabatabaei - Department of Microbiology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran.
Saeedeh Shojaeipour - Faculty of Veterinary Medicine, Shahid Bahonar University of Kerman, Kerman, Iran.
Parham Razavi - Faculty of Veterinary Medicine, Shahid Bahonar University of Kerman, Kerman, Iran.
Fereshte Kavousi - Faculty of Veterinary Medicine, Shahid Bahonar University of Kerman, Kerman, Iran.

Objective- Locomotor disorders are prevalent health problems in dairy herds that negatively affect milk production, reproduction performance and animal welfare. The ultimate cost of locomotor disorders in dairy cattle is substantially greater than treatment costs alone. As limited information is available on incidence of feet and leg disorders in Iran, the objective of this study was to determine cumulative incidence of locomotor disorders in dairy herds of Tehran province. Design- Historical cohort study Study population and procedures- Totally, ۱۰۵۰۶ Holstein cows, from ۳۲ Iranian dairy herds, which calved from March ۲۰۰۷ to March ۲۰۰۸, were followed until the next calving or culling and cumulative incidence of locomotor disorders was calculated based on registered data. Results- Cumulative incidence of locomotor disorders in the studied cows was ۲۳.۲% (۹۵% CI: ۲۲.۴- ۲۳.۹). This index was ۲۰.۰% (۱۸.۷-۲۱.۲), ۱۹.۶% (۱۸.۲- ۲۱.۰), ۲۹.۳% (۲۷.۱-۳۱.۵), ۲۹.۳% (۲۷.۱-۳۱.۵), ۳۵.۶% (۳۱.۶-۴۹.۳) and ۲۳.۸% (۱۹.۲-۲۸.۴) in the first to sixth and more than sixth lactation, respectively. This showed, locomotor problems are important issue in this area. Moreover, with increasing parities cumulative incidence of locomotor disorders increased; this increase could be due to weight gain, increased milk production and culling susceptible animals to these health disorders before sixth lactation. Conclusion and Clinical Relevance- Our findings confirm the results of previous studies that dairy herd-health programs should emphasize the control of feet and leg disorders.

Incidence, Locomotor disorders, Dairy cattle, Tehran Province