Conforto ambiental de bezerros bubalinos (Bubalus bubalis Linnaeus, 1758) em sistemas silvipastoris na Amazônia Oriental

Abstract

Foi analisado o efeito de dois sistemas silvipastoris nos índices de conforto ambiental e alterações nos parâmetros fisiológicos de bezerros bubalinos criados na Embrapa Amazônia Oriental, Belém-PA (clima Afi), no Período 1 (abril a setembro/2007) e Período 2 (outubro/2007 a março/2008). Foram inseridos onze bezerros no Sistema Silvipastoril 1 (SSP1), que apresentava sombreamento útil nas pastagens de 18 a 21%, e oito no Sistema Silvipastoril 2 (SSP2), sem sombreamento, com lago para banho. Foram mensuradas as variáveis fisiológicas: temperatura retal (TR), frequência respiratória (FR), temperatura da pele (TP), e calculados o Índice de Temperatura e Umidade (ITU) e Índice de Conforto de Benezra (ICB), nos dois períodos experimentais, comparados pelo Teste Tukey (P < 0,05). O ITU apresentou diferença estatística entre horários (P < 0,05) e período do ano (P < 0,05), e oscilou de 73,5 ± 1,3 até 82,2 ± 0,8. A TR apresentou diferença estatística entre horários e períodos do ano (P < 0,05), com amplitude de 38,3 ± 0,26 a 39,3 ± 0,38 °C. A FR apresentou diferença significativa entre horários (P < 0,05), com amplitude de 32,2 ± 9,2 a 56,5 ± 19,0 mov min-1, consideradas acima dos níveis normais, enquanto a TP foi diferente estatisticamente entre períodos e horários (P < 0,05) e variou de 23,6 ± 8,3 a 31,7 ± 5,4 °C. Nos Períodos 1 e 2 e nos dois SSP's, os ICBs estiveram acima do valor ideal, variando de 2,46 ± 0,33 a 3,31 ± 0,62 (SSP1) e 2,42 ± 0,30 a 3,45 ± 0,66 (SSP2).

Hormonal changes in female buffaloes under shading in tropical climate of Eastern Amazon, Brazil

“…These results show how important silvopastoral systems are in buffalo farming in hot, high-humidity regions such as the Amazon, since it is known that air temperature under tree canopies can be 2 to 3 °C below that under full sunlight due to the positive interference of leaves in the passage of solar radiation (Moraes Júnior et al, 2010). AT -air temperature; RH -relative humidity; GTHI -index of globe temperature and humidity.…”

“…This result emphasises the importance of using trees in management systems to provide greater thermal comfort for animals (Moraes Júnior et al, 2010;Silva et al, 2011) and improve their yield (Castro et al, 2008;Moraes Júnior et al, 2010;Garcia et al, 2011). Incorporating trees into pastures in hot, humid climate regions favors the microclimate and provides better thermal comfort conditions, since shading can lower GTHI compared with areas under full sunlight (Garcia, 2013).…”

“…However, buffaloes can become stressed when exposed to high temperatures and direct sunlight, which consequently decreases their productive and reproductive performance. Thus, the adoption of production systems such as the silvopasture system (SPS) is important because the trees located in the pasture decrease the intensity of direct solar radiation, thereby providing greater thermal comfort and hence more productive buffaloes (Castro et al, 2008;Moraes Júnior et al, 2010).…”

Assessment of surface temperatures of buffalo bulls (Bubalus bubalis) raised under tropical conditions using infrared thermography

“…However, the findings in the current study did not indicate a thermal stress situation. Likewise, previous research conducted in the Afi type climate demonstrated that buffalo did not present heat stress or reduction of growth performance when THI was between 73.5 and 82.2 (Moraes Júnior et al, 2010) or when THI varied from 75.0 to 81.0 . Regarding ICB, the values found in the present study were similar to those reported by for adult buffalo (1.7 to 2.4).…”

“…The buffalo is a homeothermic animal, but when submitted to elevated temperatures and relative humidity may undergo heat stress (Moraes Júnior et al, 2010). However, around 85% of domestic buffaloes are raised in the intertropical zone, which predisposes these animals to a situation of permanent thermal challenge (Garcia, 2013).…”