livestock chute (yes/no),
milking parlour(yes/no),
stables (yes/no),
type of bedding (pas-ture/ground/concrete/wood chips) and perimeter fence(yes/no). In reference to the variable “ventilation”, it depended on the variable absence of housing in the nextway: when there was no housing the ventilation was considered always as good. By contrast, it was considered a bad ventilation when inside the houses an odour of ammonia was detected.