Performance of chicks subjected to thermal challenge

Ferraz, Patrícia Ferreira Ponciano; Yanagi, Tadayuki; Lima, Renato Ribeiro de; Ferraz, Gabriel Araújo e Silva; Xin, Hongwei

doi:10.1590/S0100-204X2017000200005

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ZOOTECNIA • Pesq. agropec. bras. 52 (2) • Feb 2017 • https://doi.org/10.1590/S0100-204X2017000200005 copy

Performance of chicks subjected to thermal challenge

Desempenho de pintinhos submetidos a estresse térmico

Authorship SCIMAGO INSTITUTIONS RANKINGS

Abstract:

The objective of this work was to evaluate the effect of thermal challenge at different intensities and durations on the production responses of 3 to 21-day-old broiler chickens. Two hundred and ten Cobb chicks were subjected to dry-bulb temperatures (t_db) of 27, 30, 33, or 36°C for the duration of 0, 1, 2, 3, or 4 days from the second day of life onwards. The experiment was carried out in four identical environmentally-controlled wind tunnels. Data on body mass (BM), feed intake (FI), and water intake (WI), all in grams, were monitored daily; and body weight gain (BWG), in grams, and feed conversion (FC) were also calculated. The effect of duration was not statistically significant. Empirical models were adjusted to relate BM, FI, and WI with t_db and bird age. The performance of chicks at 21 days of age was analyzed using the BM, FI, WI, BWG, and FC values. Overall, the development of chicks at 33 and 36°C was better than that of those subjected to the lower t_db of 30 and 27°C. The exposure of chicks to cold thermal challenge in early life can have a carry-over negative effect on their production performance up to 21 days of age.

Index terms:
air temperature; broiler; carry-over effect; production responses; thermal stress.

Treatment	Dry-bulb temperature (°C)			Relative humidity (%)	Days in thermal challenge
Treatment	1^st week⁽²⁾	2^nd week	3^rd week	Relative humidity (%)	Days in thermal challenge
1	27±0.2	30±0.3	27±0.2	60±0.3	2^nd day of life
2	27±0.3	30±0.2	27±0.2	60±0.3	2^nd and 3^rd days of life
3	27±0.2	30±0.2	27±0.2	60±0.6	2^nd, 3^rd, and 4^th days of life
4	27±0.2	30±0.3	27±0.2	60±0.3	2^nd, 3^rd, 4^th, and 5^th days of life
5	30±0.3	30±0.2	27±0.2	60±0.4	2^nd day of life
6	30±0.3	30±0.2	27±0.2	60±1.0	2^nd and 3^rd days of life
7	30±0.3	30±0.2	27±0.2	60±0.7	2^nd, 3^rd, and 4^th days of life
8	30±0.2	30±0.2	27±0.2	60±0.3	2^nd, 3^rd, 4^th, and 5^th days of life
9,10,11,12 (control)	33±0.2	30±0.3	27±0.2	60±0.5	No day on week 1
13	36±0.6	30±0.3	27±0.6	60±0.3	2^nd day of life
14	36±0.5	30±0.2	27±0.5	60±1.0	2^nd and 3^rd days of life
15	36±0.6	30±0.3	27±0.6	60±0.5	2^nd, 3^rd, and 4^th days of life
16	36±0.5	30±0.2	27±0.6	60±0.4	2^nd, 3^rd, 4^th, and 5^th days of life
Chicks/Treatment	15	12	8

t_db (^oC)	BM (g)	FI (g)	WI (g)	BWG (g)	FC
27	455.0c	1,061.7b	2,430.5b	417.4b	2.550
30	507.0b	1,135.4ab	2,606.9ab	462.5a	2.467
33	553.0a	1,186.0a	2,595.6ab	506.2a	2.325
36	539.0a	1,184.9a	2,660.7a	492.3a	2.408
Average	507.3	1,134.5	2,568.7	463.8	2.459
CV (%)	0.01	0.09	7.91	0.22	0.25

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[TFN1] ⁽¹⁾
Air velocity at the animal-occupied zone was 0.2±0.1 m s^-1.

[TFN2] ⁽²⁾
Air temperature for the remainder of the first week, after the thermal challenge, was maintained at the thermoneutral level of 33°C.