Lying behavior might indicate how the animal interacts with its environment
and is an important indicator of cow and calf comfort. Measuring behavior can
be time consuming; therefore, behavioral recording with the help of loggers
has become common. Recently, the Hobo Pendant G data logger (Onset Computer
Corp., Bourne, MA) was validated for measuring lying behavior in cows but no
work to date has validated this logger for measuring lying behavior in calves.
The objective of this study was to test the accuracy of the Hobo Pendant G
data logger for measuring total lying time and frequency of lying bouts in
dairy calves. In 2 experiments (experiment 1: thirty-seven 2-h observation
periods; experiment 2: nineteen 24-h observation periods), we tested the
effect of 2 different recording intervals, the effect of attachment to
different legs, and the effect of removing short, potentially erroneous
readings. We found an excellent relationship when comparing the 30-s and 60-s
recording intervals. For total lying time and bout frequency, the highest
correlation was found when the logger was attached to the hind legs and
recording was conducted with a 60-s sampling interval. In experiment 2,
average total lying time was 1,077 ± 54 min/24 h (18.0 ± 0.9h/24h), with an
average frequency of 19.4 ± 4.5 bouts per day. Predictability, sensitivity,
and specificity for experiment 2 were >97% using the 60-s recording interval
and removing single readings of lying or standing from the data set compared
with direct observation as reference. The data logger accurately measured
total lying time and bout frequency when the sampling interval was ≤ 60 s and
short readings of lying and standing up to 1 min were converted into the
preceding behavior. The best results were achieved by attaching the logger to
the right hind leg