Can metrics of acceleration provide accurate estimates of energy costs of locomotion on uneven terrain? Using domestic sheep (Ovis aries) as an example

Table 1 Structure of the various generalised linear mixed statistical models

	Dependent variable	Model structure	Random factor	AIC
Model 1a	Oxygen consumption (V̇O₂)-Intercept	VeDBA	ID	10.85*
Model 1b (null model)	Oxygen consumption (V̇O₂)-Intercept		ID	11.45
Model 2a	Oxygen consumption (V̇O₂)-Intercept	Speed:Pitch + Speed:Slope + Slope + Speed + Pitch	ID	13.79
Model 2b	Oxygen consumption (V̇O₂)-Intercept	Speed:Slope + Slope + Speed + Pitch	ID	12.16
Model 2c	Oxygen consumption (V̇O₂)-Intercept	Speed:Pitch + Slope + Speed + Pitch	ID	11.89
Model 2d	Oxygen consumption (V̇O₂)-Intercept	Slope + Speed + Pitch	ID	10.16
Model 2e	Oxygen consumption (V̇O₂)-Intercept	Speed + Pitch	ID	11.56
Model 2f	Oxygen consumption (V̇O₂)-Intercept	Slope + Pitch	ID	12.64
Model 2g	Oxygen consumption (V̇O₂)-Intercept	Speed + Slope	ID	8.46*
Model 2h	Oxygen consumption (V̇O₂)-Intercept	Speed	ID	12.76
Model 2i	Oxygen consumption (V̇O₂)-Intercept	Slope	ID	10.99
Model 3a	VeDBA	Speed:Slope + Pitch:Speed + Speed + Slope + Pitch	ID	− 123.80
Model 3b	VeDBA	Pitch:Speed + Speed + Slope + Pitch	ID	− 123.11
Model 3c	VeDBA	Speed:Slope + Speed + Slope + Pitch	ID	− 123.79
Model 3d	VeDBA	Speed:Slope + Pitch:Speed + Slope + Pitch	ID	− 57.77
Model 3e	VeDBA	Speed:Slope + Pitch:Speed + Speed + Pitch	ID	− 125.45
Model 3f	VeDBA	Speed:Slope + Pitch:Speed + Pitch	ID	− 59.69
Model 3g	VeDBA	Speed:Slope + Pitch:Speed + Speed	ID	− 125.44*

In the table, ‘:’ denotes an interaction and ‘+’ denotes a main effect between two independent variables. An asterisk, *, denotes the final model used as defiled buy the lowest Akaike Information Criteria (AIC) value. The intercept was set at a value of 3.67 mL O₂ kg⁻¹ min⁻¹ (measured resting V̇O₂). For each model, a Gamma error family was used

ISSN: 2050-3385