Intake, physiological parameters and behavior of Angus and Nellore bulls subjected to heat stress

被引：31

作者：

Lisboa Valente, Eriton Egidio ^{[1
]}

Chizzotti, Mario Luiz ^{[2
]}

Ribeiro de Oliveira, Cristhiane Viol ^{[3
]}

Galvao, Matheus Castilho ^{[3
]}

Domingues, Silas Sebastiao ^{[4
]}

Rodrigues, Aline de Castro ^{[3
]}

Ladeira, Marcio Machado ^{[5
]}

机构：

[1] Univ Estadual Oeste Parana, UNIOESTE, Marechal Candido Rodondo, PR, Brazil

[2] Univ Fed Vicosa, Vicosa, MG, Brazil

[3] Univ Fed Lavras, Discentes Zootecnia, Lavras, MG, Brazil

[4] Univ Fed Lavras, Zootecnia, Lavras, MG, Brazil

[5] Univ Fed Lavras, Lavras, MG, Brazil

来源：

SEMINA-CIENCIAS AGRARIAS | 2015年 / 36卷 / 06期

关键词：

Beef cattle; intake regulation; temperature; BODY-TEMPERATURE; THERMAL-STRESS; BOS-INDICUS; CATTLE; ADAPTATIONS; RESPONSES; STEERS; TAURUS;

D O I：

10.5433/1679-0359.2015v36n6Supl2p4565

中图分类号：

S [农业科学];

学科分类号：

09 ;

摘要：

Genetics differences between breeds may determine the tolerance to high temperature, effect dry matter intake and consequently cattle performance. The effect of temperature and humidity index (THI) on diurnal, nocturnal and daily intake, water intake, physiologic parameters and behavior of Nellore (B. indicus) and Angus (B. taurus) bulls were evaluated. Eight Angus and eight Nellore young bulls (337 +/- 7.4 kg and 16 months of age) were allocated in two climate-controlled rooms for 32 days. In the period 1, all bulls were housed in thermoneutral conditions (TN, THI = 72.6) for 10 days. In period 2 (10 days), four Angus and four Nellore bulls were subjected to low heat stress (LHS, THI = 76.4) in daytime, and four Angus and four Nellore bulls were subjected to high heat stress (HHS, THI = 81.5) in daytime. The diurnal and daily dry matter intake (DMI) of Nellore were not affected (P>0.05) by heat stress. However, Angus bulls decreased diurnal DMI by 24% and daily DMI decreased (P<0.05) by 15% on HHS. In TN Angus bulls had higher (P<0.05) daily DMI (36.2 g/kg of BW) than Nellore (29.1 g/kg of BW), but in HHS they had similar (P>0.05) daily DMI (31.6 and 30.2 g/kg of BW, respectively). We observed an increase (P<0.05) in respiratory frequency, but water intake was not affected (P>0.05) by heat stress. The heart rate decreased (P<0.05) with heat stress. No differences were found (P>0.05) in feeding behavior. Therefore, THI stress threshold should distinct for Angus and Nellore bulls. The use of feed intake information may improve the prediction of thermic discomfort on specific climate condition.

引用

页码：4565 / 4574

页数：10