Factors influencing recovery from and duration of lameness in Michigan (USA) horses

The objective of this study was to identify factors that may affect recover y from and duration of a case of lameness in a stratified random sample of Michigan horses. This was done using data from Phase-II of the Michigan equ ine monitoring system (MEMS Phase-II), the equine health-monitoring study [ Kaneene er at., Prev. Vet. Med. 29 (1997b) 277-292; Ross and Kaneene, Prev. Vet. Med, 28 (1996a) 209-224; Ross and Kaneene, Prev. Vet. Med. 29 (1996b) 59-75; Ross et al., Am. J. Vet. Res. 59 (1997) 23-29]. In this study, stat istical modelling was conducted to evaluate risk factors affecting recovery from and duration of lameness using multivariable logistic regression and Cox's proportional hazards regression, respectively. Of 357 incident lamene ss cases reported during MEMS Phase-II, 280 (78.6%) were reported to have r ecovered. The median duration of a lameness case was 18 days (1st quartile (Q): 1, maximum (Max): 360). A total of 296 of 357 (82.9%) incident lamenes s cases received some type of treatment. Of 619 total treatments used, 329 (53.2%) were administered, conducted or applied by a veterinarian. Horses experiencing other types of lameness were less likely to recover tha n those experiencing hoof lameness (odds ratio (OR) = 0.48; 95% CI: 0.25, 0 .93). Horses that had participated in exercise-related activities during th e study period and prior to the lameness were more likely to recover (OR = 1.91; 95% CI: 1.05, 3.50). Treatment of the lameness was associated with an increased likelihood of recovery (OR = 1.82; 95% CI: 0.97, 3.45). Cases wi th a veterinarian involved in the diagnosis were associated with a decrease d risk of recovery (OR = 0.48; 95% CI: 0.27, 0.84) ana a longer duration la meness (HR = 0.58; 95% CI: 0.45, 0.73)-which might indicate that these case s were more complex or severe. Although cases treated for lameness were mor e likely to recover (OR = 1.82; 95% CI: 1.05, 3.50), treatment was not asso ciated with lameness duration (HR = 0.58; 95% CI: 0.45, 0.73). (C) 1999 Els evier Science B.V. All rights reserved.