Data/hora: 02/06/2024 14:46:08

Provedor de dados: | 96
País: | Brazil
Título: | Hormonal changes in female buffaloes under shading in tropical climate of Eastern Amazon, Brazil
Autores: | Silva,Jamile Andréa Rodrigues da; Araújo,Airton Alencar de; Lourenço Júnior,José de Brito; Santos,Núbia de Fátima Alves dos; Viana,Rinaldo Batista; Garcia,Alexandre Rossetto; Rondina,Davide; Grise,Márcia Mascarenhas.
Data: | 2014-01-01
Ano: | 2014
Palavras-chave: | Bioclimatology; Cortisol; Ruminant; Silvopasture system; Thyroid hormone.
Resumo: | The hormonal responses of 20 female buffaloes raised under the sun (SS group) or in the shade (CS group) in Belém, Pará, Brazil, were assessed. The CS group (n = 10) was kept in a silvopasture system featuring Racosperma mangium, whereas the SS group (n = 10) was kept in paddocks without shade featuring Brachiaria humidicola, drinking water, and mineral salt. The following parameters were measured for each treatment: dry-bulb temperature (AT), relative humidity (RH), and black-globe temperature in order to calculate the globe temperature and humidity index (GTHI). Blood sample collections to quantitatively determine levels of cortisol, triiodothyronine (T3), and thyroxine (T4) were performed every 14 days, at 13.00 h. Different seasons of the year were also assessed: rainy (January-April), transition (May-July), and less rainy (August-December). Analysis of variance revealed that AT and the index of global temperature and humidity (GTHI) differed between groups; specifically, higher values were found in the SS group, which shows how important silvopastoral systems are in buffalo farming in tropical climates. Relative humidity was significantly different across seasons and particularly high in the rainy season. The treatments influenced cortisol such that higher values were observed in the SS group. The highest mean cortisol levels were recorded during the rainy and less rainy seasons, whereas the highest T3 and T4 levels were recorded only during the rainy season. Triiodothyronine and thyroxine were negatively correlated with AT and GTHI and positively correlated with RH. Silvopastoral systems provide thermal comfort to buffaloes, and the less rainy season is more likely to cause heat stress.
Tipo: | Info:eu-repo/semantics/article
Idioma: | Inglês
Identificador: | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-35982014000100007
Editor: | Sociedade Brasileira de Zootecnia
Relação: | 10.1590/S1516-35982014000100007
Formato: | text/html
Fonte: | Revista Brasileira de Zootecnia  v.43 n.1 2014
Fonte: | info:eu-repo/semantics/openAccess