. 2024 Apr 2;14(7):1076. doi: 10.3390/ani14071076

Table 1.

Effect of the temperature–humidity index (THI) on the performance of laying hens.

Item	Treatment ¹					SEM ²	p-Value
Item	THI 68	THI 72	THI 78	THI 81	THI 85	SEM ²	p-Value
Egg production (%)
Day 7	99.38	97.4	97.51	96.89	94.4	1.48	0.222
Day 14	97.51 ^a	98.76 ^a	98.81 ^a	96.89 ^a	92.85 ^b	1.28	0.010
Day 21	96.27 ^a	98.05 ^a	98.81 ^a	95.65 ^a	85.70 ^b	1.56	<0.001
Day 28	98.70 ^a	96.89 ^a	95.83 ^a	95.03 ^a	88.30 ^b	1.79	0.002
Feed intake (g/day/bird)
Day 7	129.5 ^a	125.2 ^a	120.3 ^ab	110.6 ^b	88.3 ^c	4.26	<0.001
Day 14	127.5 ^a	123.2 ^a	119.0 ^a	101.7 ^b	91.2 ^c	2.86	<0.001
Day 21	127.2 ^a	118.2 ^ab	115.4 ^b	108.4 ^b	81.4 ^c	3.45	<0.001
Day 28	121.2 ^a	122.0 ^a	118.3 ^a	114.2 ^a	95.1 ^b	3.12	<0.001
Egg weight (g)
Day 7	58.0 ^a	55.7 ^b	55.5 ^b	56.1 ^ab	52.0 ^c	0.68	<0.001
Day 14	57.8 ^a	57.8 ^a	57.2 ^a	55.4 ^a	48.9 ^b	0.89	<0.001
Day 21	59.1 ^a	56.7 ^b	57.3 ^ab	56.5 ^b	50.1 ^c	0.78	<0.001
Day 28	59.7 ^a	57.3 ^ab	55.8 ^bc	53.6 ^c	48.1 ^c	0.87	<0.001
Feed conversion ratio (g/g)
Day 7	2.40 ^a	2.33 ^a	2.08 ^b	2.08 ^b	1.78 ^c	0.069	<0.001
Day 14	2.31 ^a	2.23 ^ab	2.06 ^bc	1.82 ^d	1.88 ^cd	0.069	<0.001
Day 21	2.26	2.12	2.06	2.00	1.64	0.116	0.337
Day 28	2.19	2.23	2.18	2.07	2.12	0.061	0.353
Body weight gain (g/day/bird)
Day 0 to 7	2.57 ^ab	4.14 ^a	2.43 ^ab	$-$ 3.94 ^b	$-$ 22.56 ^c	2.48	<0.001
Day 7 to 14	7.07 ^a	0.99 ^b	0.27 ^b	$-$ 0.53 ^a	$-$ 8.68 ^c	1.91	0.001
Day 14 to 21	4.32 ^a	$-$ 1.95 ^ab	$-$ 3.27 ^b	$-$ 0.44 ^ab	$-$ 12.57 ^c	2.27	0.003
Day 21 to 28	2.05	4.39	−0.37	$-$ 0.76	$-$ 2.40	1.75	0.097
Day 0 to 28	15.62 ^a	8.49 ^ab	$-$ 0.94 ^bc	$-$ 5.67 ^c	$-$ 46.21 ^d	4.05	<0.001

¹ THI 68 (21 °C, 68% RH); THI 72 (25 °C, 58% RH); THI 78 (29 °C, 63% RH); THI 81 (29 °C, 82% RH); THI 85 (33 °C, 66% RH); ² SEM, standard error of the means; ^a–d Different letters within rows differ significantly (p < 0.05).