2.5.2 Calculating the energy expenditure
We calculated the EE of collared sheep using previously derived
relationships between triaxial accelerometer data and animals’
energetics from experimental trials of various types of animal species
as well as farm ruminant animals (Halsey et al., 2011; Miwa et al.,
2015). The link between sheep energetics and collar data is given by
\begin{equation}
\text{VO}_{2}=15.139M^{0.794}+{38.467M}^{0.835}(ODBA)\nonumber \\
\end{equation}\begin{equation}
r^{2}=0.908\nonumber \\
\end{equation}here \(\text{VO}_{2}\) \((ml/min)\) amount of oxygen consumed over 1
min, and overall dynamic body acceleration ODBA (g ) is
the sum of the absolute value of each accelerometer axis summed over 1
min (Miwa et al., 2015). Oxygen consumption was then converted to
kilojoules expended per 20.46 J /ml (McLean, 1972). We then
estimated the sum of energy expenditure (kilojoules) as the sum of
kilojoules expended per minute over each 1-min period between successive
data collection.