Desempenho e concentrações hormonais de novilhas Nelore e ½ Girolando ½ Nelore criadas em sistemas de integração pecuária floresta

• Autor(a) principal: Duarte, Julia Paschoareli Ferro
• Data de Publicação: 2021
• Tipo de documento: Trabalho de conclusão de curso
• Idioma: por
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://hdl.handle.net/11449/215622
• topic: Thermal comfort; Animal welfare; Silvipastoral system; Thermal stress; Cattle; Cortisol; Crossbreeding; Conforto térmico; Bem-estar animal; Sistema silvipastoril; Estresse térmico; Bovinos; Cortisol; Cruzamento

Considering the negative effects of heat stress on animal production, the provision of shade is very eficiente to improve the animal comfort and trees are the best and most economical resources to provide better welfare to animals. The objective of the study was to evaluate the performance and hormonal parameters of Nellore and ½ Girolando and ½ Nelore heifers in an integrated livestock-forest system with 187 trees/ha and Nelore heifers in conventional system (without trees). The experimental design was completely randomized with three treatments and five repetitions. The treatments were: Nelore heifers in integrated livestock forestry system, with eucalyptus planted in single lines at a density of 187 trees / ha; Heifers from the crossing of ½ Nelore ½ Girolanda in integrated livestock forestry, with eucalyptus planted in single lines at a density of 187 trees / ha; Nelore heifers in conventional system in full sun, without the presence of trees. We used heifers with an average age of 11 months and an average initial weight of 261 kg. Average daily weight gain, total protein, albumin, globulin, cortisol, triiodothyronine (T3) and thyroxine (T4) were evaluated. Data were submitted to analysis of variance and Tukey's test at 5% probability. Albumin, globulin and total protein concentrations were lower in Nelore animals kept in SC. The hormones T3 and T4 showed no difference between treatments. Cortisol levels were higher in Nellore animals kept in the sun. No differences were observed in weight gain. The integration system livestock forest provides lower temperatures and consequently better thermal comfort in the hottest hours of the day, than the conventional system. The greater thermal comfort did not alter the daily weight gain of heifers, but heifers that were in the conventional system, without the presence of trees, showed changes in blood and hormonal parameters.