Risk factors associated with dairy cattle lameness and hock and knee injuries on Iranian dairy farms

Both lameness and hock and knee injuries represent significant welfare and economic concerns on dairy farms. However, there is a notable lack of data from certain housing systems, including bedded-pack farms and a few studies that compare free-stalls with bedded-pack farms. The objective of this study was therefore to utilise data collected during a welfare assessment to identify key risk factors for lameness and leg injuries in these housing systems. A generalised linear mixed model was used to identify risk factors associated with hock and knee injuries, whereas for lameness a binomial regression model was used. Lameness was associated with a range of measures, but a notable negative association was observed with the number of hoof trimmings per year (OR: 0.55 and 0.65 when comparing trimming >2 and 2 with <2 times a year), while using an external contractor increased the odds of lameness (OR: 1.71). All types of injuries of hock and knee were higher in free-stall farms compared to bedded-pack farms, but overall, the variation in the type of risk factors associated with the lesions indicates that their aetiologies may be distinct. A positive association was found between the number of cows with hock swelling (OR: 3.83) and ulcer (OR: 4.84) and bad stockmanship. These findings are a baseline for further studies and highlight the need for assessments specifically targeted at identifying risk factors associated with lameness and hoc and knee injuries.