Table 2.

Effects of strain and temperature on feed intakes, body weights, feed conversion ratios, and mortality rate in broiler chickens from 1 to 35 days of age

Variable	Strain		SEM	Temp1)		SEM	p-value
	Cobb 500	Ross 308		Normal	Heat stress		Strain	Temp	Strain×Temp
Feed intake (g/bird)
Day 1 to 21	1,287	1,285	48.0	NA	NA	-	0.904	NA	NA
Day 22 to 35	2,281	2,339	167	2,418a	2,202b	127	0.269	<0.001	0.319
Day 1 to 35	3,568	3,624	151	3,697a	3,494b	112	0.236	<0.001	0.524
Body weight gain (g)
Day 1 to 21	1,044	1,042	36.0	NA	NA	-	0.932	NA	NA
Day 22 to 35	1,301b	1,372a	147	1,461a	1,210b	76.7	0.018	<0.001	0.205
Day 1 to 35	2,345b	2,414a	137	2,495a	2,263b	72.7	0.018	<0.001	0.512
FCR (feed/gain)
Day 1 to 21	1.23	1.23	0.03	NA	NA	-	0.988	NA	NA
Day 22 to 35	1.75	1.70	0.11	1.66b	1.82a	0.08	0.145	<0.001	0.993
Day 1 to 35	1.52	1.50	0.05	1.48b	1.54a	0.04	0.211	<0.001	0.872
Mortality (Day 22 to 35)	21.6	19.2	12.4	10.0b	31.4a	8.60	-	-	-

SEM, standard error of the mean for main effects (n = 12); Temp, temperature; NA, not applicable; FCR, feed conversion ratios.

¹⁾The heat stressed birds were exposed to 34°C for 6 h daily.

^a,bMeans within a row-subgroup with no common superscripts are significantly different at p<0.05.