EFFECTS OF CHANGING HOUSING ON OPEN-FIELD BEHAVIOR OF CALVES

The open-field behavior of 25 Holstein bull calves maintained in one of four housing treatments was quantified weekly for 8 weeks to investigate the effects of different methods of confinement on motivation for locomotor and other behaviors, and behavioral ontogeny. Data were modeled as a repeated measures design and analyzed as a split plot in which housing treatment was the whole-plot factor and week was the split-plot factor. Treatment effects were found for trotting, cantering and investigating, and week effects were found for cantering and investigating. Standing, walking, grazing and bucking exhibited significant (P <0.05) treatment × week interactions. Motivation for highly active locomotor behavior in general increased with increasing degree and duration of movement restraint, and decreased in response to less restrictive housing. Motivation for locomotor and investigatory behaviors decreased in response to weaning, although all calves were consuming grain and hay prior to weaning. Calves maintained in the most restrictive housing for the majority of the duration of the experiment tended to stumble and fall more frequently than calves housed less restrictively. Results illustrate that the use of only in situ behavior to evaluate animal well-being is inadequate when the in situ environment precludes an animal's performance of one or more fixed ("modal") action patterns. © 1990.