Table 2. Main effects of parasite exposure treatment, body size and horn size on PPO and PO activity.

	PPO activity				PO activity
	Parameter		Likelihood		Parameter		Likelihood
Model Term	Estimate	S.E.	Ratio χ2	p	Estimate	S.E.	Ratio χ2	p
Intercept	−0.16	6.877	0.001	0.982	0.378	0.61	0.384	0.535
Treatment	0.063	0.165	0.145	0.704	0.023	0.015	2.524	0.112
BodyMass	0.181	0.584	0.096	0.757	−0.002	0.052	0.002	0.969
BodyLength	<0.001	0.001	0.153	0.696	<0.001	<0.001	0.742	0.389
HornLength	0.005	0.006	0.701	0.403	<0.001	0.001	0.03	0.862

Fully factorial GLM also indicated no significant interaction among these main effects. Degrees of freedom = 1 in all cases (i.e. testing the full model versus the one with the designated effect removed).