RESUMO

To evaluate the bromatological composition and ruminal degradability of dry matter (DM), crude protein (CP), neutral detergent fiber (NDF) and acid detergent fiber (ADF) of Xaraés palisade grass (Urochloa brizantha ‘Xaraes’ syn Brachiaria brizantha) under grazing in integrated crop, livestock (ICL), and forest (ICLF) systems, we conducted an in situ degradability trial in randomized blocks with three non-lactating 3/4 Gyr × 1/4 Holstein cows, provided with ruminal cannula. The management of Xaraés palisade grass was similar in both systems, differing only regarding shading in the ICLF system provided by eucalyptus trees (average 65% crown cover). Grass samples were incubated for 0, 3, 6, 9, 12, 24, 36, 48, 72, and 96 hours. Considering the passage rate 2% h-1, the Xaraés palisade grass of ICL system had greater NDF effective degradability in relation to ICLF (46.38% vs 44.98%). However, the palisade grass CP potential degradability was greater in the ICLF than in the ICL system (68.92% vs. 65.40%). The presence of trees in the pasture has effect on nutritional traits of the Xaraés palisade grass, increasing its protein content and degradability and reducing its fiber degradability.

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RESUMO

To evaluate the bromatological composition and ruminal degradability of dry matter (DM), crude protein (CP), neutral detergent fiber (NDF) and acid detergent fiber (ADF) of Xaraés palisade grass (Urochloa brizantha ‘Xaraes syn Brachiaria brizantha) under grazing in integrated crop, livestock (ICL), and forest (ICLF) systems, we conducted an in situ degradability trial in randomized blocks with three non-lactating 3/4 Gyr × 1/4 Holstein cows, provided with ruminal cannula. The management of Xaraés palisade grass was similar in both systems, differing only regarding shading in the ICLF system provided by eucalyptus trees (average 65% crown cover). Grass samples were incubated for 0, 3, 6, 9, 12, 24, 36, 48, 72, and 96 hours. Considering the passage rate 2% h-1, the Xaraés palisade grass of ICL system had greater NDF effective degradability in relation to ICLF (46.38% vs 44.98%). However, the palisade grass CP potential degradability was greater in the ICLF than in the ICL system (68.92% vs. 65.40%). The presence of trees in the pasture has effect on nutritional traits of the Xaraés palisade grass, increasing its protein content and degradability and reducing its fiber degradability.(AU)

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RESUMO

To compare the integrated crop-livestock-forest (ICLF) and crop-livestock (ICL) systems in relation to thermal comfort and grazing behavior of Girolando heifers, a 2 × 2 crossover trial (two system and two periods) was carried out with eight – Holstein × » Gyr heifers in Xaraés-palisade grass pasture under intermittent stocking with 10 days of occupation period and 20 days of resting. In ICLF, crown cover of eucalyptus planted in rows was 65% at the beginning of the experiment. Animal behavior was assessed through bioacoustics by recording heifers’ sounds for 48 hours. Concomitantly, heifers’ internal temperature (IT, °C) was recorded every 10 min using data logger thermometers adapted to hormone-free intravaginal devices. Air temperature and humidity data were collected by thermohygrometers located in the center of ICLF and ICL for calculating Temperature-Humidity Index (THI). According to THI values, ICLF and ICL did not vary in terms of thermal comfort. However, THI indicated moderate stress (82.26±4.40) during day (06:00 to 17:59h) and mild stress (75.76±4.38) at night (18:00 to 05:59h) in both systems. During day, heifers from ICL had significantly (p < 0.05) higher IT (39.51±0.56oC) than those from ICLF (39.41±0.56oC); the former spent more time grazing and less time drinking water in ICLF (581.35±30.1 and 4.87±1.09 min, respectively) when compared with those from ICL (436.88±28.1 and 10.25±1.09 min, respectively). Therefore, although thermal comfort index did not vary between the systems, under moderate stress, crossbred heifers have lower internal temperatures, resulting in longer diurnal grazing and shorter water drinking time in Eucalyptus-shaded pastures.

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RESUMO

To compare the integrated crop-livestock-forest (ICLF) and crop-livestock (ICL) systems in relation to thermal comfort and grazing behavior of Girolando heifers, a 2 × 2 crossover trial (two system and two periods) was carried out with eight Holstein × » Gyr heifers in Xaraés-palisade grass pasture under intermittent stocking with 10 days of occupation period and 20 days of resting. In ICLF, crown cover of eucalyptus planted in rows was 65% at the beginning of the experiment. Animal behavior was assessed through bioacoustics by recording heifers sounds for 48 hours. Concomitantly, heifers internal temperature (IT, °C) was recorded every 10 min using data logger thermometers adapted to hormone-free intravaginal devices. Air temperature and humidity data were collected by thermohygrometers located in the center of ICLF and ICL for calculating Temperature-Humidity Index (THI). According to THI values, ICLF and ICL did not vary in terms of thermal comfort. However, THI indicated moderate stress (82.26±4.40) during day (06:00 to 17:59h) and mild stress (75.76±4.38) at night (18:00 to 05:59h) in both systems. During day, heifers from ICL had significantly (p < 0.05) higher IT (39.51±0.56oC) than those from ICLF (39.41±0.56oC); the former spent more time grazing and less time drinking water in ICLF (581.35±30.1 and 4.87±1.09 min, respectively) when compared with those from ICL (436.88±28.1 and 10.25±1.09 min, respectively). Therefore, although thermal comfort index did not vary between the systems, under moderate stress, crossbred heifers have lower internal temperatures, resulting in longer diurnal grazing and shorter water drinking time in Eucalyptus-shaded pastures.(AU)

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The relationship between the indices of thermal comfort and internal temperature in lactating cows was evaluated inRondônia, western Amazonia in a 2 × 2 crossover trial carried out with eight Girolando cows, ½ Holstein × ½ Gyr (n=4) and Holstein × » Gyr (n=4), grazing palisade grass supplemented with or without soybean oil concentrates. Data logger thermometers adapted to intravaginal devices (hormone free) were used to measure internal temperatures (IT) every 10 min over 48 h. Concomitantly, environmental parameters (air temperature, relative humidity, wind speed, and solar radiation) were collected for the estimation of the temperature-humidity index (THI), equivalent temperature index (ETI), and predicted respiratory rate (PRR). Supplementation with soybean oil did not affect the internal temperature of the cows. IT varied significantly between the genetic groups, with the highest mean observed at night in the Holstein × » Gyr cows, compared with that in the ½ Holstein × ½ Gyr cows (39.54 °C vs 39.06 °C, respectively). THI, ETI, and PRR were significantly and positively correlated with the IT of the Girolando cows; however, the PRR was not found to be adequate in indicating the night-time heat stress in cows.(AU)

A relação entre índices de conforto térmico com a temperatura interna de vacas lactantes foi avaliada em Rondônia, na Amazônia Ocidental, em um ensaio crossover 2x2 utilizando oito vacas Girolando, ½ Holandês x ½ Gir (n=4) e Holandês x » Gir (n=4) pastejando capim-marandu suplementadas com concentrados contendo ou não óleo de soja. A temperatura interna (TI) dos animais foi aferida com termômetros eletrônicos adaptados em dispositivos intravaginais (livres de hormônio) a cada 10 minutos durante 48h. Concomitantemente, dados climáticos (temperatura do ar, umidade relativa do ar, velocidade do vento e radiação solar) foram coletados para cálculo dos índices de temperatura e umidade (ITU), índice de temperatura equivalente (ITE) e o índice de frequência respiratória predita (PFR). A suplementação com óleo de soja não afetou a temperatura interna das vacas. A TI variou significativamente entre os grupos genéticos, com a maior média observada à noite nas vacas Holandês × » Gir em relação às ½ Holandês × ½ Gir (39,54 °C vs 39,06 °C, respectivamente). ITU, ITE e PFR tiveram correlação significativa e positiva com a TI de vacas Girolando, mas o PFR não foi adequado para indicar estresse térmico em vacas no período da noite.(AU)

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RESUMO

The relationship between the indices of thermal comfort and internal temperature in lactating cows was evaluated inRondônia, western Amazonia in a 2 × 2 crossover trial carried out with eight Girolando cows, ½ Holstein × ½ Gyr (n=4) and Holstein × » Gyr (n=4), grazing palisade grass supplemented with or without soybean oil concentrates. Data logger thermometers adapted to intravaginal devices (hormone free) were used to measure internal temperatures (IT) every 10 min over 48 h. Concomitantly, environmental parameters (air temperature, relative humidity, wind speed, and solar radiation) were collected for the estimation of the temperature-humidity index (THI), equivalent temperature index (ETI), and predicted respiratory rate (PRR). Supplementation with soybean oil did not affect the internal temperature of the cows. IT varied significantly between the genetic groups, with the highest mean observed at night in the Holstein × » Gyr cows, compared with that in the ½ Holstein × ½ Gyr cows (39.54 °C vs 39.06 °C, respectively). THI, ETI, and PRR were significantly and positively correlated with the IT of the Girolando cows; however, the PRR was not found to be adequate in indicating the night-time heat stress in cows.

A relação entre índices de conforto térmico com a temperatura interna de vacas lactantes foi avaliada em Rondônia, na Amazônia Ocidental, em um ensaio crossover 2x2 utilizando oito vacas Girolando, ½ Holandês x ½ Gir (n=4) e Holandês x » Gir (n=4) pastejando capim-marandu suplementadas com concentrados contendo ou não óleo de soja. A temperatura interna (TI) dos animais foi aferida com termômetros eletrônicos adaptados em dispositivos intravaginais (livres de hormônio) a cada 10 minutos durante 48h. Concomitantemente, dados climáticos (temperatura do ar, umidade relativa do ar, velocidade do vento e radiação solar) foram coletados para cálculo dos índices de temperatura e umidade (ITU), índice de temperatura equivalente (ITE) e o índice de frequência respiratória predita (PFR). A suplementação com óleo de soja não afetou a temperatura interna das vacas. A TI variou significativamente entre os grupos genéticos, com a maior média observada à noite nas vacas Holandês × » Gir em relação às ½ Holandês × ½ Gir (39,54 °C vs 39,06 °C, respectivamente). ITU, ITE e PFR tiveram correlação significativa e positiva com a TI de vacas Girolando, mas o PFR não foi adequado para indicar estresse térmico em vacas no período da noite.

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RESUMO

Amiodarone, a benzofuran derivative, is a very effective antiarrhythmic medication, but has potential to cause side effects. Although its cytotoxicity potential is very well-known, there are few reports about its genotoxicity effects. Since amiodarone has not been investigated in genotoxicity studies, and the spontaneously hypertensive rat (SHR) is a well-characterized model for hypertension, the aim of the present study was to perform cytogenetic analysis on chromosome aberrations in bone marrow cells of SHRs and normotensive Wistar-Kyoto rats (WKYs) that received oral amiodarone treatment for 4 weeks. Amiodarone activity was also monitored using electrocardiograms. The presence of bradycardia in amiodarone-treated rats confirmed that this drug was really active. Metaphase analysis on bone marrow cells showed that there were significant differences in total chromosomal damage and percentage abnormal metaphase between WKY and SHR negative controls. In the SHR negative control, the frequencies of basal chromosomal aberrations and abnormal metaphases were significantly higher (p<0.05). There were high numbers of chromosomal aberrations in all amiodarone-treated groups, compared with negative controls. In amiodarone-treated groups, the most frequent chromosomal aberration was chromatid breaks. More chromosomal aberrations were found in WKYs that received amiodarone, with a statistically significant difference in comparison with negative controls (p<0.05). However, in SHR rats there was no significant difference between the amiodarone and negative groups regarding chromosomal damage induction. These results showed that treatment with amiodarone was genotoxic in WKYs, but not in SHRs. Further studies are needed to confirm whether amiodarone is genotoxic or efficient and harmless, among humans undergoing therapy.

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