Table 2.

The impact of body weight and range usage on tibia mineral concentration and the relative proportion of different bone parameters obtained from hens at the age of 74 wk housed in commercial free-range system.

Main effect			Bone dry matter	Total ash (%)	Ca (%)	Mg (%)	P (%)	S (%)	Relative proportion of cortical bone to total bone volume (%)	Relative proportion of tibia bone marrow (%)	Relative proportion of blood vessels to total bone volume (%)	Bone mineral density (mg/cm3)
Range use (RU)	Rangers		9.80 ± 0.95	45.4 ± 2.06	41.6 ± 0.15	0.49 ± 0.01	17.62 ± 0.07	0.08 ± 0.01	0.46 ± 0.02	0.49 ± 0.03	0.03 ± 0.001	0.53 ± 0.02
	Stayers		8.49 ± 0.23	48.3 ± 2.97	41.7 ± 0.09	0.48 ± 0.01	17.61 ± 0.06	0.07 ± 0.01	0.48 ± 0.02	0.49 ± 0.03	0.002 ± 0.002	0.51 ± 0.01
Body weight (BW)		Light	8.99 ± 0.58	48.7 ± 3.21	41.7 ± 0.01	0.49 ± 0.01	17.61 ± 0.07	0.08 ± 0.007	0.47 ± 0.03	0.488 ± 0.02	0.025 ± 0.001	0.50 ± 0.01
		Heavy	9.72 ± 0.89	44.4 ± 0.70	41.6 ± 0.01	0.48 ± 0.01	17.61 ± 0.05	0.07 ± 0.004	0.46 ± 0.02	0.49 ± 0.03	0.026 ± 0.002	0.54 ± 0.02
Two-way interaction
RU*BW	Rangers	Light	9.70 ± 1.11	45.7 ± 4.17	41.6 ± 0.28	0.48 ± 0.01	17.63 ± 0.12	0.08 ± 0.01	0.48 ± 0.03	0.48 ± 0.03	0.03 ± 0.002	0.50 ± 0.02
	Rangers	Heavy	10.6 ± 1.62	45.1 ± 0.84	41.5 ± 0.15	0.49 ± 0.01	17.61 ± 0.06	0.08 ± 0.01	0.44 ± 0.04	0.50 ± 0.05	0.03 ± 0.001	0.57 ± 0.03
	Stayers	Light	8.28 ± 0.28	51.7 ± 4.90	41.8 ± 0.10	0.49 ± 0.01	17.60 ± 0.09	0.08 ± 0.01	0.47 ± 0.04	0.49 ± 0.04	0.028 ± 0.003	0.51 ± 0.02
	Stayers	Heavy	8.51 ± 0.43	43.8 ± 1.21	41.7 ± 0.17	0.48 ± 0.01	17.62 ± 0.08	0.06 ± 0.01	0.49 ± 0.03	0.48 ± 0.03	0.02 ± 0.003	0.50 ± 0.03
P-values
Range use			0.487	0.515	0.403	0.512	0.912	0.304	0.582	0.975	0.910	0.323
Body weight			0.326	0.239	0.479	0.913	0.982	0.154	0.813	0.992	0.601	0.259
RU*BW			0.261	0.307	0.897	0.384	0.877	0.449	0.328	0.764	0.458	0.197

The following abbreviations are used: Ca: calcium, Mg: magnesium, P: phosphorus, S: sulfur, RU: range usage, BW: body weight.