N. F. A. Santos

Sistema silvipastoril na Amazônia: ferramenta para elevar o desempenho produtivo de búfalos

Agroforestry systems are alternative techniques for the soil used, involving forest species, agricultural crops and livestock. Silvopastoral Systems are a less aggressive alternative, contributing to the reversion of altered areas and to raise biodiversity. These systems explore natural resources, controlled erosive process, improve the soil structure and balance the microorganisms activity, promote better quality of the pastures, providing animal ambience, due to the efficient shade of pastures. Thus, provide barrier against the winds, decreasing thermal stress and improving animal performance. This review describes the silvopastoral system as a strategy for management of buffaloes, aiming to raise productive performance.

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

Foi analisado o efeito de dois sistemas silvipastoris nos indices de conforto ambiental e alteracoes nos parâmetros fisiologicos de bezerros bubalinos criados na Embrapa Amazonia Oriental, Belem-PA (clima Afi), no Periodo 1 (abril a setembro/2007) e Periodo 2 (outubro/2007 a marco/2008). Foram inseridos onze bezerros no Sistema Silvipastoril 1 (SSP1), que apresentava sombreamento util nas pastagens de 18 a 21%, e oito no Sistema Silvipastoril 2 (SSP2), sem sombreamento, com lago para banho. Foram mensuradas as variaveis fisiologicas: temperatura retal (TR), frequencia respiratoria (FR), temperatura da pele (TP), e calculados o Indice de Temperatura e Umidade (ITU) e Indice de Conforto de Benezra (ICB), nos dois periodos experimentais, comparados pelo Teste Tukey (P < 0,05). O ITU apresentou diferenca estatistica entre horarios (P < 0,05) e periodo do ano (P < 0,05), e oscilou de 73,5 ± 1,3 ate 82,2 ± 0,8. A TR apresentou diferenca estatistica entre horarios e periodos do ano (P < 0,05), com amplitude de 38,3 ± 0,26 a 39,3 ± 0,38 °C. A FR apresentou diferenca significativa entre horarios (P < 0,05), com amplitude de 32,2 ± 9,2 a 56,5 ± 19,0 mov min-1, consideradas acima dos niveis normais, enquanto a TP foi diferente estatisticamente entre periodos e horarios (P < 0,05) e variou de 23,6 ± 8,3 a 31,7 ± 5,4 °C. Nos Periodos 1 e 2 e nos dois SSPs, 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).

Conforto térmico de búfalas em sistema silvipastoril na Amazônia Oriental

The objective of this work was to evaluate the effects of a silvipasture system on the thermal comfort of 20 female buffaloes, from which 10 raised in under nonshaded paddocks (SS) and 10 in paddocks shaded by Racosperma mangium (CS), in Belem county, PA, Brazil. All animals were fed in pastures with Urochloa humidicola, and had free access to drinking water and mineral salt. Every three days, measurements were made for air temperature (TA), relative humidity ( UR ), black globe temperature (TGN), rectal temperature (TR), respiratory rate (FR), heart rate (FC), and body surface temperature (TSC), in the morning (7 AM) and in the afternoon (1 PM). The values of TR, TSC, RR and FR, mainly for the SS group, were higher in the afternoon. The TR, TSC and FR showed a significant and positive correlation with TA and the temperature and humidity index (ITGU), and a negative correlation with UR . These correlations were higher for the less rainy period. The FR showed significant and positive correlations with TA and ITGU, during both the most and the less rainy seasons, and negative correlations with UR only in the rainy season. The forestation of pasture areas is efficient to increase the thermal comfort for Murrah females, especially in the afternoon.

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

Foram avaliadas as respostas hematologicas de 20 bufalas, criadas ao sol (grupo - SS) e a sombra (grupo - CS), em Belem, Para. 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, agua 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 numero total de leucocitos foi realizada a cada 14 dias, as 13 h, durante o ano de 2009. Atraves da analise de variância constatou-se que em todos os periodos do ano, a TA e indice de temperatura de globo e umidade (ITGU) foram diferentes (P < 0,05), com niveis mais elevados no grupo SS. No periodo mais chuvoso, o grupo CS apresentou valores elevados de leucocitos, enquanto nos periodos de transicao e menos chuvoso, foram maiores no grupo SS. No periodo menos chuvoso do ano, o grupo SS apresentou maiores valores de hemacias. O teor de hemoglobina teve maiores niveis (P < 0,05) nos periodos de transicao e menos chuvoso. Somente a hemoglobina teve correlacao significativa e negativa (P < 0,05) com a UR. Conclui-se que as novilhas bufalas Murrah estao sujeitas a um ambiente hostil e o periodo menos chuvoso e o mais propicio a causar estresse termico.

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

The hormonal responses of 20 female buffaloes raised under the sun (SS group) or in the shade (CS group) in Belem, Para, 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.