XXXX via leg-mounted accelerometers on dairy @entity291 on four commercial farms.

@entity1273 @entity11535 @entity21604 @entity426 @entity291 @entity21603
UNASSIGNED: Lameness in dairy herds is traditionally detected by visual inspection, which is time-consuming and subjective. Compared with healthy @entity291 , lame @entity291 often spend longer time lying down, walk less and change behaviour around feeding time. Accelerometers measuring @entity291 leg activity may assist farmers in detecting lame @entity291 . On four commercial farms, accelerometer data were derived from hind leg-mounted accelerometers on 348 Holstein @entity291 , 53 of them during two lactations. The @entity291 were milked twice daily and had no access to pasture. During a lactation, @entity426 ( @entity426 ) was assessed on average 2.4 times (s.d. 1.3). Based on daily lying duration, standing duration, walking duration, total number of steps, step frequency, @entity11535 ( @entity11535 , i.e. total acceleration) for lying, standing and walking, eight accelerometer means and their corresponding coefficient of variation (CV) were calculated for each week immediately before an @entity426 . A principal component analysis was performed to evaluate the relationship between the variables. The effects of @entity426 and farm on the principal components (PC) and on the variables were analysed in a mixed model. The first four PC accounted for 27%, 18%, 12% and 10% of the total variation, respectively. @entity21603 corresponded to Activity variability due to heavy loading by five CV variables related to standing and walking. @entity21604 corresponded to Activity level due to heavy loading by @entity11535 walking, @entity11535 standing and walking duration. @entity21603 corresponded to Recumbency due to heavy loading by four variables related to lying. PC4 corresponded mainly to Stepping due to heavy loading by step frequency. Activity variability at LS4 was significantly higher than at the lower @entity426 levels. Activity level was significantly higher at LS1 than at LS2, which was significantly higher than at LS4. Recumbency was unaffected by @entity426 . Stepping at LS1 and LS2 was significantly higher than at LS3 and LS4. Activity level was significantly lower on farm 3 compared with farms 1 and 2. Stepping was significantly lower on farms 1 and 3 compared with farms 2 and 4. @entity11535 standing indicated increased restlessness while standing when @entity291 increased from LS3 to LS4. Lying duration was only increased in lame @entity291 . In conclusion, Activity level differed already between LS1 and LS2, thus detecting early signs of @entity1273 , particularly through contributions from walking duration and @entity11535 walking. @entity1273 models including walking duration, @entity11535 walking and @entity11535 standing seem worthy of further investigation.
