Associating body condition score and parity with sub-optimal mobility in pasture-based dairy cows

Sub-optimal mobility in dairy cows can be broadly defined as abnormal gait which causes a deviation from the optimal walking pattern of a cow. Sub-optimal mobility is also associated with significant economic and environmental consequences, which have yet to be extensively researched or quantified in pasture-based systems. However, to quantify sub-optimal mobility in terms of its impacts economically and environmentally, and indeed to aid in the development of automated detection sensors for sub-optimal mobility, a clear understanding of the characteristics of a cow with sub-optimal mobility is required. So far, automated detection sensors have been successful for detecting moderate to severe forms of sub-optimal mobility. However, there is a need for a better understanding of the cow-level traits associated with all forms of sub-optimal mobility, including mild forms, to incorporate this into future development of automated detection sensors for sub-optimal mobility. Therefore, the aim of our study was to determine the associations between hoof disorders (both type and presence), body condition score, and all levels of sub-optimal mobility in pasture-based dairy cows using data from a large sample of Irish dairy farms. Mobility scores, body condition scores (BCS), claw disorder (presence and severity), and parity records were available for 6,927 dairy cows from 52 pasture-based herds. Binomial logistic regression analysis was completed to determine the associations between claw disorder (presence and severity), BCS, parity and sub-optimal mobility. The output variable was sub-optimal mobility (mobility score ≥ 1) and the predictor variables were specific claw disorders and their severities, BCS, and parity. Our results indicate that all severities of claw disorders, low BCS, and higher parity cows are all associated with an increased risk for sub-optimal mobility.