Perfil hematológico de búfalas da raça Murrah, criadas ao sol e à sombra, em clima tropical da Amazônia Oriental

Abstract

ResumoForam avaliadas as respostas hematológicas de 20 búfalas, criadas ao sol (grupo -SS) e à sombra (grupo -cS), em Belém, Pará. os animais do grupo cS (n = 10) estavam em sistema silvipastoril, com Racosperma mangium e os do SS (n = 10), em piquetes sem sombra, em pastagem de Brachiaria humidicola, água para beber e sal mineral. Foram mensuradas temperatura do ar (tA), umidade relativa do ar (UR) e temperatura de globo negro, em cada tratamento. A coleta de sangue para eritrograma e número total de leucócitos foi realizada a cada 14 dias, às 13 h, durante o ano de 2009. Através da análise de variância constatou-se que em todos os períodos do ano, a tA e índice de temperatura de globo e umidade (itGU) foram diferentes (P < 0,05), com níveis mais elevados no grupo SS. no período mais chuvoso, o grupo cS apresentou valores elevados de leucócitos, enquanto nos períodos de transição e menos chuvoso, foram maiores no grupo SS. no período menos chuvoso do ano, o grupo SS apresentou maiores valores de hemácias. o teor de hemoglobina teve maiores níveis (P < 0,05) nos períodos de transição e menos chuvoso. Somente a hemoglobina teve correlação significativa e negativa (P < 0,05) com a UR. conclui-se que as novilhas búfalas Murrah estão sujeitas a um ambiente hostil e o período menos chuvoso é o mais propício a causar estresse térmico. PalavRas-chave: hematologia, búfalos, bioclimatologia.Hematologic profile of murrah buffalo cows, raised in the sun and under shade, at tropical climate of the eastern amazon aBsTRacT We evaluated the hematologic responses of 20 female buffaloes raised under full sun (group nS) and shade (group SG) at Belem, Para, Brazil. The animals in the SG group (n = 10) were maintained in paddocks under a silvopastoral system with Racosperma mangium, and the ones in the nS (n = 10), in paddocks with Brachiaria humidicola, with drinking water and mineral salt, but without access to shade. Air temperature (At), relative air humidity (RH) and black global temperature (BGt) were measured for each treatment. Blood sampling for erythrogram and leukocyte count were undertaken at intervals of 14 days, and carried out at 1:00 p.m., during 2009. At and black global temperature and humidity index (BGHi) were different (P < 0.05) throughout the year, and their highest values were observed in the nS group. During the rainier period, the SG group presented the highest values of leukocytes (P < 0.05), although in the transition and low rainy periods, the highest values were observed in the nS group. in the low rainy period, the erythrocytes count showed the highest values in the nS group. The highest levels of hemoglobin (P < 0.05) were observed during the transition and low rainy periods. only hemoglobin presented a significant and negative (P < 0.05) correlation with RH. We concluded that the female Murrah buffaloes are subject to a hostile environment, and that the low rainy period is the most favorable for causing heat stress.

<b>Assessment of indices of thermal stress indicators among male buffaloes reared in the Eastern Brazilian Amazon

“…In the present research, BST values are similar to those reported by Silva, Araújo, Lourenço Júnior, Viana et al (2011) and are higher in the afternoon (33.12 ± 0.78) than in the morning (29.17 ± 1.16) in the less rainy season of the year, when air temperature is higher. In these conditions, blood flow from the body core to the periphery increases in an attempt to eliminate heat, which contributes to raising BST .…”

“…Several studies have shown the effects of ambient temperature on buffalo RT as a function of thermal stress (Barros et al, 2015;Moraes Júnior et al, 2010;Silva, Araújo, Lourenço Júnior, Viana et al, 2011). The higher RT means (p < 0.05) in the afternoon are in agreement with the results from Silva, Araújo, Lourenço Júnior, Silva, Araújo, Lourenço Júnior, Viana et al (2011), who reported higher RT for female Murrah buffaloes in the afternoon than in the morning throughout the year, regardless of access to shade. In the afternoon, the animals are more exposed to direct and indirect solar radiation, which leads to unfavorable environmental conditions.…”

“…Silva, Araújo, Lourenço Júnior, Viana et al (2011) report that BST is strongly correlated with the climatic variables in buffaloes, which shows that this variable can be considered a good indicator to make up index formulas aiming to assess thermal stress in this species. On the other hand, the strong correlations of the new indices with BST (p < 0.01) and the moderate correlation with RT and RR (p < 0.01) show that these indices are efficient and can indicate the clinical status of comfort, stress, danger, or emergency.…”

Testicular thermoregulation, scrotal surface temperature patterns and semen quality of water buffalo bulls reared in a tropical climate

“…In fact, in the transitional period, there is a change in rainfall patterns, gradual decrease in relative air humidity associated with increased global solar radiation. In association, these factors create a transitional environment that is very challenging to the animals bred in a humid tropical climate (Silva et al., ). The increase in RR, as a consequence of panting, and the increase in HR are the most obvious signs of thermoregulation activation in buffaloes (Gudev et al., ; Marai & Haeeb, ).…”

Perfil hematológico de cabras Saanen e mestiças (1/2 Saanen e 1/2 Anglo-nubiana) criadas em clima tropical do Ceará

“…Em um estudo realizado em búfalas no Norte do Brasil não foi verificado correlação significativa entre variáveis hematológicas e ambientais, exceto entre a hemoglobina e a umidade do ar, que mostraram uma correlação significativa e negativa (r=0,57; p<0,01) (Silva et al 2011).…”