Estresse tÃrmico em fÃmeas bovinas girolando: ÂHolandÃs ÂGIR vs. ÂHolandÃs ÂGIR, criadas em clima semiÃrido no estado do CearÃ

• Autor(a) principal: AntÃnio NÃlson Lima da Costa
• Data de Publicação: 2014
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UFC
• Texto Completo: http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=11428
• topic: Adaptabilidade; bioclimatologia; fisiologia bovina; hormÃnios; vacas de leite; Adaptability; bioclimatology; bovine physiology; hormones; dairy cows.; ZOOTECNIA

The mainly goal of this study was to compare the two most common breed groups of Girolando (ÂHol ÂGir vs. ÂHol ÂGir) through rectal temperature (RT), respiratory rates (RR), surface temperature (ST), hormonal profiles (T3, T4 and cortisol), milk production, number of inseminations (AI) per pregnancy and pregnancy rates (PR). We used 240 primiparous cows, 120 of each breed group. Physiological data were collected in March, April and May, and in September, October and November. The environmental parameters were: relative humidity (RH), ambient temperature (AT) and the temperature and humidity index (THI). The means of RH, AT and THI were 62.5%, 29.4 &#61616;C and 71 in rainy period, and 37.4%, 37 &#61616;C and 85 in the dry period, respectively. The RT means and frequencies for ÂHol cows remained within normal ranges in both periods and shifts with differences (p < 0.05) in means inside the rainy period between breed groups. The ÂHol cows had RT means above of normal ranges in both periods. The RR means and frequencies of ÂHol cows remained within the normal range in both periods and shifts with differences (p < 0.05) between periods. The ÂHol RR means were above normal ranges during the dry period and differed (p < 0.05) of another group and between periods. In relation to T3, both groups of animals showed higher concentrations in rainy period with differences (p < 0.05) between groups, and there were differences between periods (p < 0.05) in ÂHol group. With the T4 hormone, there were differences (p < 0.05) between the groups in the rainy period and between periods in the group of ÂHol. In relation to cortisol, there were differences (p < 0.05) in the dry period between the groups of animals and, between periods, for ÂHol animals. In relation to production, there were differences (p < 0.05) in the dry period and, differences between periods, in the other group. At lactation peaks there were differences (p < 0.05) only between periods. In the number of AI there were differences (p < 0.05) between the groups in the dry period and, between periods, in the animals of the group ÂHol. There were differences (p < 0.05) in PR during the dry season between the groups and, between periods, ÂHol group had a significant decrease in PR in the dry period. The animals best suited to the farm system without cooling are those of the breed group of ÂHolstein ÂGir.