Navegando por Assunto "Ambiente tropical"

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Acesso aberto (Open Access)
Características quantitativas e qualitativas do capim-mombaça, submetido a doses crescentes de nitrogênio em clima tropical úmido – classificação AF
(Universidade Federal do Pará, 2016-02-29) OLIVEIRA, Joelma Kyone Silva de; DOMINGUES, Felipe Nogueira; http://lattes.cnpq.br/1461187309835749
The productive chain of ruminant in northern Brazil has its base sustained by forages being its management and fertilization, grasses perpetuity, extremely important for the high biological value protein final production for human intake. The study aimed to evaluate trades of Panicum maximum cv. Mombaça fertilized with increasing doses of nitrogen at Af weather conditions being this condition classified by frequent rainfall along every month of the year, so, showing no seasonality in rain scheme. There were evaluate productive trades, morphogenetic, structural and chemical of Mombaça grass in parcels. Being the experiment outlined in random blocks with six treatments (0, 10, 20, 30, 40 e 50 kg of N ha-1 aplication-1), each application performed after each cut and four repetitions, a repetition by block totalizing 24 plots and the cut done at a height of 40 cm, whenever the parcels high achieved 90 cm to be considered the time when the canopy intercepts 95% of incident light. The data were submitted to variance and regression analysis, with significance of 5% taken from the linear and quadratic coefficients of determination. Nitrogen fertilization affected (p<0,05) stretching rates, appearance, number of leaves alive by tillers and dry mass production. The forage quality was also affected by N doses (p<0,05), being the levels of CP positively affected and values of TC negatively. The fiber levels and lignin were not influenced by fertilization (p<0,05) being this result positive from the forage nutritional pint of view, once fiber and lignin high levels do not benefit consumption and cause a digestive limitation. The nitrogen provides better qualitative and quantitative results to Mombaça grass in tropical climate areas.
Acesso aberto (Open Access)
Respostas termográficas em touros bubalinos submetidos à coleta de sêmen e avaliados sob condições agrometeorológicas no trópico úmido
(Universidade Federal do Pará, 2014-04-30) BARROS, Daniel Vale; LOURENÇO JÚNIOR, José de Brito; http://lattes.cnpq.br/2919433679918544; GARCIA, Alexandre Rossetto; http://lattes.cnpq.br/2678267039338224
Buffalo (Bubalus bubalis) livestock is mostly performed in the intertropical zone, where high temperatures prevail. Therefore the knowledge about buffaloes physiology on tropical environments and their possible responses due to tropical climate changes are essential. The objective of the study was to evaluate the variation in thermal comfort, physiological, hematological, seminal parameters and the superficial temperatures of buffalo bulls raised on humid tropical climate (Afi, Köppen classification). Ten buffaloes were kept in collective paddocks with free access to shade. During five months, data were registered from climatological meteorological station and three distinct dataloggers installed inside the stalls for calculating the Temperature and Humidity Index (THI). Respiratory rate (RR), heart rate (HR), rectal temperature (RT), superficial temperature of the eye (GLO), superficial temperature of the scrotum (ESC), superficial temperature of the right flank (FLd) and left flank (FLe) were registered. The Benezra´s Comfort Index (ICB) was also calculated. Semen collection was performed weekly by artificial vagina and blood sampling for assessment of blood counts were done monthly. The mean maximum of air temperature was 31.5°C and maximum a verage relative humidity was 93.2%. The THI was different only between periods (P<0.05). The RR, HR and ICB showed significant difference over the months and between shifts (P <0.05). RT differed between periods and reduced along months with lower value in August (37.8 ± 0.7°C). RT, GLO, FLd, FLe and ESC showed no diffe rence (P<0.05) for both periods and months. The hematocrit, mean corpuscular volume, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, gross motility and sperm vigor showed significant differences (P<0.05) along the months. The highest correlations between THI and superficial temperatures were between ITUmed and FLdmed (0.77; P<0.0001), ITUmed and FLemed (0.75; P<0.0001), ITUmed and GLO (0.72; P<0.0001), and ITUmed and ESC (0.41; P<0.0001). The highest correlation between internal temperature and surface temperature was TR and GLOmax (0.58; P<0.0001). Significant correlations were found between ICB and FR (0.97; P<0.0001), ICB and FC (0.89; P<0.0001), FC and FR (0.87; P<0.0001), THI and integrity of the plasma sperm membrane (-0.17; P<0.05). The results showed that animals had variations in thermal comfort and increased superficial temperature in the hottest periods of the day, however they were able to maintain homeothermy. Finally, the infrared thermography can be used as a noninvasive and auxiliary technique in studies about animal physiology and thermoregulation.
Acesso aberto (Open Access)
Respostas termolíticas e qualidade seminal de ovinos naturalizados criados em ambiente tropical
(Universidade Federal do Pará, 2015-10-30) KAHWAGE, Priscila Reis; GARCIA, Alexandre Rossetto; http://lattes.cnpq.br/2678267039338224
The study aimed to deepen knowledge about anatomical and physiological features related to body heat loss ability and relation to semen quality of naturalized sheep Morada Nova and Santa Ines on tropical environment. Nine male Santa Inês and seven Morada Nova breed were subjected to two experiments. The first test included monitoring of coat features (amount of melanin, thick, length and diameter of the fibers), sweat rate, physiological indicators of thermal comfort (respiratory rate, heart rate, rectal temperature, surface temperature, skin temperature and scrotal surface temperature), sperm quality (sperm concentration, progressive motility, plasma membrane integrity, major defects, minor defects and total defects) and testicular parenchyma integrity coupled with the meteorological variables measured throughout the year. Statistical analysis was performed using the GLM and LSMEANS procedures of SAS software, version 9.1.3. Significant differences (P <0.05) were observed between the summer and fall and winter, with increase in termolitics parameters during the hot season. Already sperm quality did not vary throughout the year. The second experiment evaluated the capacity of rams to maintain body and testicular homeothermy under thermal challenge. Animals were subjected to heat tolerance test, which consists maintenance in the shade (period 1), followed by exposure to the sun (period 2) and return to the shadow (period 3). In the three periods were measured: respiratory rate, heart rate, body surface temperature, back, eyeball and scrotum, by infrared thermography. Adaptability of the animals was measured by heat tolerance index calculation. Sperm quality and testicular parenchyma integrity were evaluated before and after the heat challenge. In Period 1, the variables had baseline values for both genotypes. In Period 2, the variables involved in thermolysis significantly increased (P<0.05), which matches a thermal discomfort situation. In Period 3, the variables returned to baseline values and some values were lower than those in Period 1. Seminal and ultrasonographic variables did not share with thermal insult. It is concluded that MN and SIN rams had efficient thermolytic mechanisms that favor preserving gonadal functionality. The animals were considered resilient to a thermal challenge.