Risk factors associated with indicators of dairy cow welfare during the housing period in Irish, spring-calving, hybrid pasture-based systems.

In a dairy production system where cows are grazing for a large portion of their lactation, little attention has been afforded to investigating multiple indicators of welfare for risk factors associated with the housing period. Yet regardless of the length of the housing period, cows still experience the positive and negative welfare impacts of both indoor and outdoor environments in a hybrid system. Thus, the objective of this study was to identify risk factors for indicators of dairy cow welfare during the housing period in a spring-calving, hybrid pasture-based system. Herd-level scores for seven indicators of welfare (locomotion, body condition, ocular and nasal discharge, integument damage, tail injury and human avoidance response) were collected from 82 Irish dairy farms during the housing period (October - February). Data were analysed using multiple beta regression or zero-inflated beta regression to identify associations between these welfare indicators and measured herd-level housing, resource and management factors. Thirty-six unique risk factors were associated with one or more welfare indicators (P < 0.05). Analyses identified two risk factors for body condition < 3.0 and four for body condition > 3.5, the target range during the housing period. Four risk factors were identified for each of ocular discharge, nasal discharge and avoidance response of > 1 m from human approach. Six risk factors each were associated with the proportion of lame cows and integument damage to the head-neck-back or hindquarter regions. The greatest number of risk factors, 12, were associated with tail injury (broken, lacerated or incomplete tails). Risk factors associated with multiple indicators of welfare were cow comfort index (tail lacerations and hindquarter integument damage), cubicle width (broken and incomplete tails), shed floor slipperiness (lameness and head-neck-back integument damage), shed light-level (tail lacerations, avoidance response and below target body condition), shed passage width (broken tails and head-neck-back integument damage) and presence (incomplete tails) or absence (broken tails) of a collecting yard backing gate. With the large number of risk factors associated with tail injury, continued research is necessary to identify causes and determine prevention methods to contribute to improved overall welfare of dairy cows. Housing features meeting recommended guidelines from the literature were frequently associated with greater negative indicators of welfare. In light of this, housing guidelines may benefit from regular re-evaluation to ensure facilities meet the welfare needs of cows during the housing period.