Table 1.

Phenotypes of three beef breeds used in the present study

	Angus (n = 16)	Charolais (n = 16) (mean ± SEM)	Kinsella composite hybrid (n = 16)	P value¹
Residual feed intake (RFI; kg/day)
Overall	0.15 ± 0.21	0.06 ± 0.24	− 0.10 ± 0.24	0.73
L-RFI (n = 8)	− 0.58 ± 0.10	− 0.81 ± 0.10	− 0.96 ± 0.10
H-RFI (n = 8)	0.88 ± 0.15	0.92 ± 0.12	0.76 ± 0.13
P value²	1.46e−06	1.87e−08	6.43e−08
Dry matter intake (DMI; kg/day)
Overall	10.73 ± 0.27^a	10.33 ± 0.28^a	9.27 ± 0.28^b	3.23e−03
L-RFI (n = 8)	10.19 ± 0.34	9.49 ± 0.24	8.98 ± 0.34
H-RFI (n = 8)	11.35 ± 0.31	11.17 ± 0.29	9.67 ± 0.43
P value²	0.03	5.80e−04	0.23
Eating frequency (n/day)
Overall	37.63 ± 1.61^a	36.59 ± 1.56^a	29.73 ± 1.99^b	6.30e−03
L-RFI (n = 8)	41.25 ± 1.53	35.56 ± 2.65	29.94 ± 2.02
H-RFI (n = 8)	33.49 ± 2.13	37.63 ± 1.77	29.44 ± 4.18
P value²	9.90e−03	0.53	0.91
Empty rumen weight (kg)
Overall	13.02 ± 0.59^a	11.29 ± 0.29^b	NA	1.36e-02
L-RFI (n = 8)	12.42 ± 0.80	11.15 ± 0.38	NA
H-RFI (n = 8)	13.62 ± 0.87	11.43 ± 0.47	NA
P value²	0.33	0.65	NA

NA not available

¹P values among three breeds were calculated using ANOVA, and values with different superscripts were significantly different (P < 0.05)

²P values between H- and L-RFI groups were obtained using t test within each breed