Evaporação cutânea e respostas fisiológicas de caprinos Canindé em ambiente equatorial semiárido

Silva, Juliana Jéssica Ferreira Coelho; Torquato, Jânio Lopes; Filho, Geovan Figueirêdo de Sá; Souza, João Batista Freire de; Costa, Leonardo Lélis de Macedo

doi:10.14269/2318-1265.v01n01a03

Cited by 6 publications

(9 citation statements)

References 10 publications

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“…The results of this study confirm those reported by Silva et al [29], according to which maintenance of body temperature occurs by exchange of heat with the environment. Consequently, under low ambient temperatures, the heat is dissipated to the environment in sensible form via a temperature gradient formed between animal and environment.…”

Section: Discussionsupporting

confidence: 92%

“…The skin plays a key role in body heat dissipation, since there is a constant exchange of heat between the body and the environment. Body temperature is dependent not only on environmental factors such as temperature and humidity, but also on physiological characteristics such as vascularization and evaporation of sweat [29]. Thus, the external surface of the body constitutes a boundary between the body and the environment, and allows the conduction of heat from the internal medium of the body to the body surface, where it can be transferred to the environment [29].…”

Section: Introductionmentioning

confidence: 99%

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Heat Stress and Body Temperature in Brown Swiss Cows Raised in Semi-Arid Climate of Ceará State, Brazil

Leles

Rodrigues

Neto

et al. 2017

Acta Scientiae. Vet.

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Background: In tropical countries like Brazil, air temperature and relative humidity have a significant effect on animal physiology; there is a great impact of solar radiation on physiological parameters, especially on body temperature. This study evaluated the occurrence of heat stress in Brown Swiss cows in a tropical semi-arid climate, and checked for the correlation between internal body temperatures [rectal temperature (RT) and vaginal temperature (VT)] with surface temperature (ST) to determine if these variables are associated.Materials, Methods & Results: Twenty-eight Brown Swiss cows at three stages of the lactation cycle were used in this study: 10 nonpregant lactating (NPL) cows, 8 dry pregnant (DP) cows, and 10 pregnant lactating (PL) cows. These animals were between the second and third calving, weighed between 346 and 720 kg, and had ages between 2 and 13 years. During the experimental period, air temperature and relative humidity (RH) at the experimental site were measured using a digital thermohygrometer. The temperature and humidity index (THI) was calculated according to methodology described by Thom (1958), and was used as an environmental comfort parameter. For the evaluation of RT and VT, two digital clinical thermometers, one inserted in the vagina and the other in the rectum, were used simultaneously to minimize stress. Surface temperature (ST) was assessed using a digital infrared laser thermometer at a distance of 50 cm from the animal. Surface temperature was measured in the forehead (FST), thorax (TST), flank (FLST), and legs (LST). During the study period, the ambient temperature (AT) was significantly higher outside (in the sun) than inside of the facilities (in the shade) (P < 0.05). RH was inversely proportional to AT, and was significantly higher inside than outside the facilities (P < 0.05). Like AT, THI was significantly higher outside (in the sun) than inside the facilities (in the shade), with significant differences between these locations (P < 0.05). The amplitudes of the differences between the locations were as follows: 3.8°C for AT, 6.2% for RH, and 2.6 for THI. Mean values of rectal and vaginal temperatures were not significantly different from each other independent of lactation cycle stage, and were almost always significantly higher than the measured surface temperatures (P < 0.05). The maximum values obtained for each lactation cycle stage in this study were higher when compared to the mean values, showing that they are more representative of the occurrence of heat stress. Correlations between internal temperatures (RT and VT) and surface temperatures (TSF, TST, TSFL, and TSP) were weak and non-significant. ST values exhibited mostly weak, non-significant correlations, with the exception of FST with FLST and LST, which had moderate, significant correlations, as shown by the following coefficient factors: FST x FLST, 0.34; LST x FST, 0.415; and LST x FLST, 0.37.Discussion: A temperature of 34°C with RH ranging from 46% to 80% (i.e., a THI between 83 and 89) has been reported to have a significant thermal impact on dairy Brown Swiss cows; the THI values found in the present experiment were close to those. Body temperatures exhibited significant variations depending on the lactation cycle stage of the cows. Lactation concomitant with pregnancy significantly increases internal temperatures (RT and VT) in DP and NPL cows. This finding may be explained by the fact that pregnancy concomitant with lactation accelerates the metabolism, which results in higher food intake and increased production of body heat with consequent increase in internal body temperature. The maximum values of internal body temperatures (RT and TV) at all stages of the lactation cycle were higher than their corresponding average values, which indicates that some cows exhibited, at given moments, hyperthermia.

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Section: Discussionsupporting

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Heat Stress and Body Temperature in Brown Swiss Cows Raised in Semi-Arid Climate of Ceará State, Brazil

Leles

Rodrigues

Neto

et al. 2017

Acta Scientiae. Vet.

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“…Knizkova et al (1996) also found high temperatures in dairy cows and Silva et al (2013) in goats without defined breed, but no difference between this region and the body.…”

Section: Resultsmentioning

confidence: 96%

“…The semi-arid region of Brazil is characterized by high temperature and solar radiation levels throughout the year, which is an obstacle to the cattle industry. These environmental factors directly affect the thermoregulation of animals (Silva et al, 2013), and the provision of a favorable environment becomes essential, especially for calves. Young animals are particularly vulnerable and the continuous exposure to a hot environment raises the rectal temperature and respiratory rate, while decreases feed intake, resulting in less body development.…”

Section: Resultsmentioning

confidence: 99%

“…The semi-arid region of northeastern Brazil is characterized by high temperatures and high levels of solar radiation (Silva et al, 2013;Oliveira et al, 2014;Queiroz et al, 2014) and the seasons are divided into dry and rainy. In the rainy season, solar radiation is lower than in the dry season, but the air temperature and air humidity are high.…”

Section: Introductionmentioning

confidence: 99%

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Evaluation of Physiological Responses of Calves During Rainy Season in the Semiarid Environment

Dantas¹,

Souza²,

Lima³

et al. 2016

Acta Vet Bras

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The relationship between corn particle size and thermoregulation of laying hens in an equatorial semi-arid environment

et al. 2014

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Heat stress is one of the main factors affecting egg production. One way to improve egg production is physical processing of the feed ingredients, allowing for better utilization of nutrients. In this study, the relationship between the corn particle size, measured as the geometric mean diameter (GMD), and thermoregulation was evaluated by determining the effect of the GMD on performance, egg quality, and physiological responses. Feed intake, eggshell quality (weight and thickness), rectal temperature (T R), respiratory rate (R R), and surface temperature (T S) were recorded in sixty 20-week-old naked neck laying hens that were fed corn of different particle sizes. Ambient temperature (T A) was also recorded during the trial. The GMD of corn particles was determined using a screens granulometer, resulting in sizes of 605, 1,030, and 2,280 μm. The analysis of variance (ANOVA) of a completely randomized design showed a significant effect (P < 0.05) of GMD on feed intake, shell weight, and shell thickness. The ANOVA performed by the least squares method showed a highly significant effect (P < 0.01) of GMD on T R and R R. T A, categorized into three classes (24.0-26, 26.1-28.9, and 29.0-31.0 °C), had a significant effect (P < 0.01) on T R and T S. The interaction between the GMD of corn particles and the T A classes was not statistically significant. Coarser corn particles cause an increase in the rectal temperature of naked neck hens, and these birds increase their respiratory rate to dissipate excess metabolic heat. This increase in the respiratory rate causes a decrease in the eggshell quality.

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Evaporação cutânea e respostas fisiológicas de caprinos Canindé em ambiente equatorial semiárido

Cited by 6 publications

References 10 publications

Heat Stress and Body Temperature in Brown Swiss Cows Raised in Semi-Arid Climate of Ceará State, Brazil

Heat Stress and Body Temperature in Brown Swiss Cows Raised in Semi-Arid Climate of Ceará State, Brazil

Evaluation of Physiological Responses of Calves During Rainy Season in the Semiarid Environment

The relationship between corn particle size and thermoregulation of laying hens in an equatorial semi-arid environment

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