RESUMO

The objective of the study was to characterize the adaptive profile of Ibero-American sheep of the Canaria breed, evaluating the possible changes in thermoregulatory responses and coat characteristics to which the animals are exposed in the different seasons of the year. Data collected over a period of 12 months were analyzed, with information being observed in the interval of 15 days of each month, in 23 adult ewes kept in an intensive breeding system. The rectal temperature (RT) of Canaria ewes was higher (P < 0.001) in the summer and spring seasons. In contrast, the respiratory rate (RR) of the animals was higher in autumn. The surface temperature (ST) of the herd was lower during the spring. It was observed that the hair length (HL) and the hair density (NH) did not vary during the seasons. However, the hair diameter (HD) and the coat thickness (CT) varied, being in the spring, the season in which the animals had the highest HD and autumn, the season in which they had the lowest. The performance was similar throughout the seasons (P > 0.05). The morphological variables of the coat presented 63.8% of original cases grouped, which may characterize the morphological responses of the coat of these animals as an important trait of the adaptive profile of the breed, whereas the opposite occurred for thermoregulatory responses. The variables most used by the herd and that were most important were autumn (CT, NH, HD, HR, RT, and HL), summer (ST and RR), spring (RR, ST, and RT), and winter (RT, HD, HR, and RR). Sheep of the Canaria breed have an adaptive profile that dynamically uses thermoregulatory and morphological responses, molding themselves according to climate changes resulting from seasonal periods on the Island of Tenerife, Spain. The Canaria sheep stood out for the modification of the morphological characteristics of the coat, especially during autumn and spring, and can be considered an excellent genetic resource with excellent adaptive characteristics for arid environments such as those found in the Canary Islands.

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The purpose of this study was to evaluate the relationship between adaptive and productive performance and determine which characteristics related to adaptation could be included as criteria for the selection of Brahman bulls managed in a tropical region. Fifty Brahman bulls were evaluated in relation to productive performance and adaptive capacity to a hot environment. The animals were grouped according to the following characteristics: Respiratory rate (RR), Sweating rate (SR) and coat traits. Three clusters were formed with these different characteristics related to thermoregulation after that these clusters were compared with productive performance that includes weighing of animals, carcass and scrotal circumference. The high adapted group corresponded to the animals with higher productive performance, with heavier animals in terms of weight at 550 days and carcass weight. The principal components analysis (PCA1) showed that carcass weight (0.95), weight at 550 days (0.92) and gain weight (0.71) were characteristics strongly correlated with the performance of the animals. These sets of characteristics were analyzed together (productive characteristics) in a multiple regression. The animals with better productive performance presented shorter hair, a greater capacity to heat dissipate by sweating and a lower rectal temperature. These characteristics were most suitable to inclusion in the breeding programs, resulting in higher economic gains. It is possible to simultaneously select resistant animals to thermal stress as well as to maintain the productivity of the flocks.

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The principal focus of this study was to describe how the coat characteristics could affect the heat exchanges in animals managed in a hot environment. The Morada Nova ewes were monitored once a month, during 10 consecutive months, in three commercial flocks. Initially, an analysis was performed to measure the differences regarding the coat color in the thermoregulation mechanisms. The animals were grouped into 4 different groups according to coat tonality, as follows: dark red animals (group 1, N = 23), intermediate red color (group 2, N = 27), light red animals (group 3, N = 30), and white-coated animals (group 4, N = 30). The data were collected from 1100 to 1400 h, after the animals were exposed to 30 min of direct sunlight. The cluster analysis was performed considering the hair structural characteristics such as coat thickness (CT, cm), hair length (HL, mm), hair diameter (HD, m), and number of hairs (NH, hairs per unit area), after that these clusters were compared in relation to thermoregulatory mechanisms that include rectal temperature (RT, °C), respiratory rate (RR, breaths min-1), cutaneous evaporation (CE, °C), and respiratory evaporation (RE, W m-2). The groups were characterized and compared using mean and standard deviation, and the differences between the clusters were compared using the Tukey test with a 5% probability of error. In relation to coat color, no differences were found in groups 1, 2, and 3 regarding the activation of the thermoregulation mechanisms. The most different was observed in the totally white coat that presented different thermoregulatory responses as the highest sweating rate. White-coated animals showed a non-pigmented epidermis, and the hair structure is responsible to promote skin protection as necessary, such as a dense coat (1242.7 hair cm-2), long hair (14.2 mm), and thicker coat (7.38 mm). In red-coated animals, the hair structure favored heat loss to the environment, such as short hairs, less thick coat, and less hairs per square centimeter. All evaluated animals showed the rectal temperature within the reference limits for the ovine species, regardless of the coat color. In the analysis of clusters related to the physical structure of hair, it was possible to observe that the animals with thick hair, short hair, and less dense coat tended to have a higher capacity to eliminate heat through their respiratory rate and showed less intense heat loss by cutaneous evaporation. We verified that coat color presents a direct influence on the hair structure and the activation of mechanisms related to thermoregulation.

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RESUMO

The present study aimed evaluate possible modifications of thermoregulatory morphophysiological responses of Morada Nova sheep throughout the year in 4 properties of the nucleus of participatory genetic breeding. In the months of March, June, September and December, respiratory rate (RR), rectal temperatures (RT) and surface (ST) were recorded as well as the environmental variables air temperature (airT), relative humidity (RH) wind (Ws). Calculated the radiant heat load (RHL) and the Black Globe Humidity Index (BGHI). The coat thickness was measured and hair samples were collected and determined hair density, hair length and hair diameter. Blood collection was collected for determination of T3 and total T4 concentrations. In the rainy season, which includes the months of March and June, higher values of RR and RT, probably due to the combination of high RH, associated to RHL, BGHI and airT were recorded, as these hamper loss and heat. All values of RT independent of month and flocks remained within values considered normal for the species. September and December are inserted in the dry season, with a low RH factor that can facilitate heat loss through evaporation. In these months, lower values of RT and RR were observed when compared to the rainy season, lower values of RR were recorded between 40 and 60 mov.min-1. The secretion of thyroid hormones was greater in the environmental conditions considered more comfortable. The homeothermia was maintained by Morada Nova sheep at different times evaluated as indicated by the normal physiological parameters. The rainy season was considered the most stressful for the animals, since they used a more intense set of variables in order to thermoregulate and maintain the homeothermia, which justifies the importance of providing shelters, with the objective of reducing the overheating, even in view of their great adaptive capacity, already demonstrated in previous studies...(AU)

O presente estudo objetivou avaliar possíveis modificações de respostas morfofisiológicas termorreguladoras de ovelhas da raça Morada Nova, ao longo do ano, em 4 propriedades do núcleo de melhoramento genético participativo. Nos meses de Março, Junho, Setembro e Dezembro foram registradas as frequências respiratórias (FR), temperaturas retais (TR) e de superfície (TS) assim como as variáveis ambientais temperatura do ar (Tar), umidade relativa (UR) e velocidade do vento (Vv). Calculada a carga térmica radiante (CTR) e o índice de temperatura de globo e umidade (ITGU). Foi medida a espessura da capa de pelame e amostras de pelo foram coletadas e determinadas a densidade numérica, o comprimento médio e o diâmetro médio. Coleta de sangue foi realizada a para a determinação das concentrações de T3 e T4 total. Na estação chuvosa que compreende os meses de Março e Junho, foram registrados maiores valores de FR e TR, provavelmente pela combinação de alta UR, associada a CTR, ITGU e Tar, pois estas dificultam a perda e calor. Todos os valores de TR independente de mês e rebanho mantiveram-se dentro de valores considerados normais para a espécie. Setembro e dezembro estão inseridos na estação seca, com baixa UR fator esse que pode facilitar as perdas de calor via evaporação. Nestes meses foram observados menores valores de TR e FR se comparados com o período chuvoso, foram registrados menores valores de FR entre 40 a 60 mov.min-1. A secreção dos hormônio tireoidianos foram maiores nas condições ambientais consideradas mais confortáveis. A homeotermia foi mantida pelos ovinos Morada Nova, nas diversas épocas avaliadas conforme indicado pelos parâmetros fisiológicos normais...(AU)

Assuntos

RESUMO

The present study aimed evaluate possible modifications of thermoregulatory morphophysiological responses of Morada Nova sheep throughout the year in 4 properties of the nucleus of participatory genetic breeding. In the months of March, June, September and December, respiratory rate (RR), rectal temperatures (RT) and surface (ST) were recorded as well as the environmental variables air temperature (airT), relative humidity (RH) wind (Ws). Calculated the radiant heat load (RHL) and the Black Globe Humidity Index (BGHI). The coat thickness was measured and hair samples were collected and determined hair density, hair length and hair diameter. Blood collection was collected for determination of T3 and total T4 concentrations. In the rainy season, which includes the months of March and June, higher values of RR and RT, probably due to the combination of high RH, associated to RHL, BGHI and airT were recorded, as these hamper loss and heat. All values of RT independent of month and flocks remained within values considered normal for the species. September and December are inserted in the dry season, with a low RH factor that can facilitate heat loss through evaporation. In these months, lower values of RT and RR were observed when compared to the rainy season, lower values of RR were recorded between 40 and 60 mov.min-1. The secretion of thyroid hormones was greater in the environmental conditions considered more comfortable. The homeothermia was maintained by Morada Nova sheep at different times evaluated as indicated by the normal physiological parameters. The rainy season was considered the most stressful for the animals, since they used a more intense set of variables in order to thermoregulate and maintain the homeothermia, which justifies the importance of providing shelters, with the objective of reducing the overheating, even in view of their great adaptive capacity, already demonstrated in previous studies...

O presente estudo objetivou avaliar possíveis modificações de respostas morfofisiológicas termorreguladoras de ovelhas da raça Morada Nova, ao longo do ano, em 4 propriedades do núcleo de melhoramento genético participativo. Nos meses de Março, Junho, Setembro e Dezembro foram registradas as frequências respiratórias (FR), temperaturas retais (TR) e de superfície (TS) assim como as variáveis ambientais temperatura do ar (Tar), umidade relativa (UR) e velocidade do vento (Vv). Calculada a carga térmica radiante (CTR) e o índice de temperatura de globo e umidade (ITGU). Foi medida a espessura da capa de pelame e amostras de pelo foram coletadas e determinadas a densidade numérica, o comprimento médio e o diâmetro médio. Coleta de sangue foi realizada a para a determinação das concentrações de T3 e T4 total. Na estação chuvosa que compreende os meses de Março e Junho, foram registrados maiores valores de FR e TR, provavelmente pela combinação de alta UR, associada a CTR, ITGU e Tar, pois estas dificultam a perda e calor. Todos os valores de TR independente de mês e rebanho mantiveram-se dentro de valores considerados normais para a espécie. Setembro e dezembro estão inseridos na estação seca, com baixa UR fator esse que pode facilitar as perdas de calor via evaporação. Nestes meses foram observados menores valores de TR e FR se comparados com o período chuvoso, foram registrados menores valores de FR entre 40 a 60 mov.min-1. A secreção dos hormônio tireoidianos foram maiores nas condições ambientais consideradas mais confortáveis. A homeotermia foi mantida pelos ovinos Morada Nova, nas diversas épocas avaliadas conforme indicado pelos parâmetros fisiológicos normais...

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RESUMO

The aim of this research was to evaluate the sensitivity and specificity of the FAMACHA© (F©) system in Morada Nova ewes. The conjunctivae of 562 ewes were evaluated using the F© system. Packed cell volume (PCV) served as the gold standard for clinical F© evaluation. To calculate the sensitivity and specificity of the F© system, different criteria were adopted: animals classified as (I) F© 4 and 5 or (II) 3, 4, and 5 were considered to be anemic and animals classified as (I) F© 1, 2, and 3, or (II) 1 and 2 were considered to be non-anemic. Three standard values of PCV, namely, ≤ 19%, ≤ 18%, or ≤ 15%, were used to confirm anemia. The percentage of correct treatments was always high when the F© values 4 and 5 were used as criteria for positive tests. For all the PCV cut-off values, more animals were classified as false positives when evaluated using F© 3, 4, and 5 as criteria for a positive test and more true negative animals when evaluated using only F© 4 and 5 as criteria for a positive test. For both sets of criteria for the positive tests, few animals were classified as false negatives and true positives. Eliminating the classification of F© 3 as anemic decreased the sensitivity and increased the specificity for all the PCV cut-off values for the ewes. The F© system can be used as a reliable alternative to reduce selection pressure for anthelmintics in relation to routine non-selective blanket treatment for worm control in the Morada Nova ewes.

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RESUMO

Well adapted animals are characterized by maintain homeostasis under natural conditions. The present study aimed to evaluate physiological and morphological responses, as well as identify the relationship between these parameters in order to maintain homoeothermic status, in the dry and rainy season. Measurements were taken from 383 Morada Nova hair ewes, under dry and rainy season. The studied variables included rectal temperature (RT), respiratory rate (RR), coat thickness (CT), hair length (HL), hair diameter (HD) and hair density (D). Blood samples were collected for determining biochemical, erythrogam and hormone concentration. The evaluated blood parameters from the Morada Nova breed did not demonstrate any variation from the reference interval established for sheep, confirming its adaptability profile even under high radiation and air temperatures. Multivariate analyses were performed in order to determine relationship between morphological, biochemical, erythrocyte and hormonal traits in each season. Differences correlations were observed according to season of the year. In the dry season, the correlations were significant among RT, RR, Packed cell volume (PCV), thyroxine (T4), Glucose (GLU), CT, HL, Globulin (GLO) and Total Protein (TP), whereas in dry season the characteristics that showed greater correlation were Mean corpuscular volume (MCV), thyroid hormones, Creatinine, GLO, TP, PCV and GLU. In conclusion, Morada Nova ewes was able to maintain homeothermy, even in the most stressful environmental conditions. Their hematological, biochemical and hormonal profile were within the normal range for sheep, confirming the adaptability of this local breed to the Brazilian semiarid environment.(AU)

Os animais bem adaptados são caracterizados por manter a homeostase em condições naturais. O presente estudo teve como objetivo avaliar as respostas fisiológicas e morfológicas, bem como identificar a relação entre esses parâmetros a fim de, manter o estado homeotérmico, na estação seca e chuvosa. As medições foram tomadas em 383 ovelhas da raça Morada Nova, na época seca e chuvosa. As variáveis estudadas incluíram temperatura retal (TR), frequência respiratória (FR), espessura do pelame (EP), comprimento do pelo (CP), diâmetro do pelo (D) e densidade numérica (DN). Foram coletadas amostras de sangue para determinar a concentração bioquímica, eritrogama e hormonal. Os parâmetros de sangue avaliados da raça Morada Nova não demonstraram variação do intervalo de referência estabelecido para ovinos, confirmando que seu perfil de adaptabilidade, mesmo sob alta radiação e temperaturas do ar. Foram realizadas análises multivariadas para determinar a relação entre características morfológicas, bioquímicas, eritrocitárias e hormonais em cada estação. As correlações de diferenças foram observadas de acordo com a estação do ano. Na estação seca, as correlações foram significativas entre TR, FR, PCV, T4, GLU, CT, HL, GLO e TP, enquanto que na estação seca as características que apresentaram maior correlação foram MCV, T4, T3, CRE, GLO, TP PCV e GLU. Em conclusão, as ovelhas Morada Nova conseguem manter a homeotermia, mesmo nas condições ambientais mais estressantes. Seu perfil hematológico, bioquímico e hormonal permanecem dentro da faixa de normalidade para ovinos, confirmando a adaptabilidade dessa raça local ao ambiente semiárido brasileiro.(AU)

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RESUMO

The present paper aimed to show the thermoregulatory responses of locally adapted Morada Nova sheep with different coat colors that were exposed to direct solar radiation in an equatorial semiarid region. Animals were classified into four groups according to the coat color as follows: (1) dark red, (2) intermediate red, (3) light red, and (4) white coats. Forty Morada Nova ewes were observed in for 7 consecutive months. The experimental variables measured were rectal temperature (RT), skin surface temperature (ST), respiratory rate (RR), skin surface evaporation (CE), respiratory evaporation (RE), and heat exchange by convection (HC) and radiation (R). Data were collected from 1100 to 1400 h after the animals were exposed to 30 min direct sunlight. The results showed that all groups maintained homeothermy. The RR was higher in the animals of groups 1 to 3, which also showed higher values for ST when compared to the white-coated animals. Sensible heat exchange mechanisms were not important for heat loss, and R was a significant source of heat gain from the environment for the animals. Groups 1, 2, and 3 used RR more intensely than group 4 (P value = 0.001); however, CE was higher for the white-coated animals. It was concluded that Morada Nova sheep are well adapted to the semiarid environment, regardless of coat color.

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RESUMO

This study aimed to evaluate the effects of heat stress and characterize the coat characteristics of red and white varieties of Morada Nova sheep raised in the semiarid region of Brazil during the rainy and dry seasons. The following variables were investigated: coat thickness (CT), inclination angle of the coat (θI), hair coat density (HDE), hair length (HL) and hair diameter (HD), in conjunction with the physiological responses of rectal temperature (RT) and respiratory rate (RR). The data were tested with an analysis of variance, a Tukey test at a 5% significance level and a correlation analysis. The season of the year (dry and rainy) and the variety (red and white) were used as fixed effects in the analysis of variance. HL, HDE and HD were significantly greater in the dry season than in the rainy season (P 0.05), but CT and θI did not differ between seasons (P > 0.05). HL, HDE and HD were lower and 0I was greater (P < 0.05) for the red variety, but CT was statistically equal (P > 0.05) for the two varieties. It was concluded that the coat characteristics of the Morada Nova ewes favor the adaptation of the sheep to a semiarid environment, including the improved protection of the skin against ultraviolet radiation. In general, the white variety presented characteristics reflecting a higher degree of adaptation to the conditions of the Brazilian semiarid region.(AU)

O objetivo desse trabalho foi avaliar as características de pelame de ovelhas da variedades vermelha e outra branca da raça Morada Nova, criadas no ambiente semiárido brasileiro, durante as épocas seca e chuvosa. Foram avaliada espessura de pelame (CT), ângulo de inclinação do pelo (I), número de pelos (HDE), comprimento do pelo (HL) e diâmetro do pelo (HD), em conjunto com as respostas fisiológicas temperature retal (RT) e frequência respiratória (RR). Foram realizados análise de variância e teste de Tukey a 5% de probabilidade. A estação do ano (seca e chuvosa) e variedade (vermelha e branca) foram usadas como fatores fixos. HL, HDE e HD foram significativamente maiores na estação seca (P < 0,05), mas CT e θI não diferiram. HL, HDE e HD foram menor e θI foi maior na variedade vermelha, CT não apresentou diferença em relação a variedade. Conclui-se que as características de pelame das ovelhas Morada Nova favorecem a adaptação a ambiente semiárido, incluindo proteção da pele contra o excesso de raios ultravioleta, com a variedade branca apresentando-se mais favorável à adaptação nas condições da região semiárida brasileira.(AU)

Assuntos

RESUMO

This study aimed to evaluate the effects of heat stress and characterize the coat characteristics of red and white varieties of Morada Nova sheep raised in the semiarid region of Brazil during the rainy and dry seasons. The following variables were investigated: coat thickness (CT), inclination angle of the coat (θI), hair coat density (HDE), hair length (HL) and hair diameter (HD), in conjunction with the physiological responses of rectal temperature (RT) and respiratory rate (RR). The data were tested with an analysis of variance, a Tukey test at a 5% significance level and a correlation analysis. The season of the year (dry and rainy) and the variety (red and white) were used as fixed effects in the analysis of variance. HL, HDE and HD were significantly greater in the dry season than in the rainy season (P 0.05), but CT and θI did not differ between seasons (P > 0.05). HL, HDE and HD were lower and 0I was greater (P 0.05) for the two varieties. It was concluded that the coat characteristics of the Morada Nova ewes favor the adaptation of the sheep to a semiarid environment, including the improved protection of the skin against ultraviolet radiation. In general, the white variety presented characteristics reflecting a higher degree of adaptation to the conditions of the Brazilian semiarid region.

O objetivo desse trabalho foi avaliar as características de pelame de ovelhas da variedades vermelha e outra branca da raça Morada Nova, criadas no ambiente semiárido brasileiro, durante as épocas seca e chuvosa. Foram avaliada espessura de pelame (CT), ângulo de inclinação do pelo (I), número de pelos (HDE), comprimento do pelo (HL) e diâmetro do pelo (HD), em conjunto com as respostas fisiológicas temperature retal (RT) e frequência respiratória (RR). Foram realizados análise de variância e teste de Tukey a 5% de probabilidade. A estação do ano (seca e chuvosa) e variedade (vermelha e branca) foram usadas como fatores fixos. HL, HDE e HD foram significativamente maiores na estação seca (P < 0,05), mas CT e θI não diferiram. HL, HDE e HD foram menor e θI foi maior na variedade vermelha, CT não apresentou diferença em relação a variedade. Conclui-se que as características de pelame das ovelhas Morada Nova favorecem a adaptação a ambiente semiárido, incluindo proteção da pele contra o excesso de raios ultravioleta, com a variedade branca apresentando-se mais favorável à adaptação nas condições da região semiárida brasileira.

Assuntos

RESUMO

Well adapted animals are characterized by maintain homeostasis under natural conditions. The present study aimed to evaluate physiological and morphological responses, as well as identify the relationship between these parameters in order to maintain homoeothermic status, in the dry and rainy season. Measurements were taken from 383 Morada Nova hair ewes, under dry and rainy season. The studied variables included rectal temperature (RT), respiratory rate (RR), coat thickness (CT), hair length (HL), hair diameter (HD) and hair density (D). Blood samples were collected for determining biochemical, erythrogam and hormone concentration. The evaluated blood parameters from the Morada Nova breed did not demonstrate any variation from the reference interval established for sheep, confirming its adaptability profile even under high radiation and air temperatures. Multivariate analyses were performed in order to determine relationship between morphological, biochemical, erythrocyte and hormonal traits in each season. Differences correlations were observed according to season of the year. In the dry season, the correlations were significant among RT, RR, Packed cell volume (PCV), thyroxine (T4), Glucose (GLU), CT, HL, Globulin (GLO) and Total Protein (TP), whereas in dry season the characteristics that showed greater correlation were Mean corpuscular volume (MCV), thyroid hormones, Creatinine, GLO, TP, PCV and GLU. In conclusion, Morada Nova ewes was able to maintain homeothermy, even in the most stressful environmental conditions. Their hematological, biochemical and hormonal profile were within the normal range for sheep, confirming the adaptability of this local breed to the Brazilian semiarid environment.

Os animais bem adaptados são caracterizados por manter a homeostase em condições naturais. O presente estudo teve como objetivo avaliar as respostas fisiológicas e morfológicas, bem como identificar a relação entre esses parâmetros a fim de, manter o estado homeotérmico, na estação seca e chuvosa. As medições foram tomadas em 383 ovelhas da raça Morada Nova, na época seca e chuvosa. As variáveis estudadas incluíram temperatura retal (TR), frequência respiratória (FR), espessura do pelame (EP), comprimento do pelo (CP), diâmetro do pelo (D) e densidade numérica (DN). Foram coletadas amostras de sangue para determinar a concentração bioquímica, eritrogama e hormonal. Os parâmetros de sangue avaliados da raça Morada Nova não demonstraram variação do intervalo de referência estabelecido para ovinos, confirmando que seu perfil de adaptabilidade, mesmo sob alta radiação e temperaturas do ar. Foram realizadas análises multivariadas para determinar a relação entre características morfológicas, bioquímicas, eritrocitárias e hormonais em cada estação. As correlações de diferenças foram observadas de acordo com a estação do ano. Na estação seca, as correlações foram significativas entre TR, FR, PCV, T4, GLU, CT, HL, GLO e TP, enquanto que na estação seca as características que apresentaram maior correlação foram MCV, T4, T3, CRE, GLO, TP PCV e GLU. Em conclusão, as ovelhas Morada Nova conseguem manter a homeotermia, mesmo nas condições ambientais mais estressantes. Seu perfil hematológico, bioquímico e hormonal permanecem dentro da faixa de normalidade para ovinos, confirmando a adaptabilidade dessa raça local ao ambiente semiárido brasileiro.

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RESUMO

The aim of the present study was to evaluate the changes in physiological responses and serum biochemical panel in crossbred dairy cow populations kept in a hot climate environment. We used a population of 384 dairy cows of genetic groups ½Holstein × ½Guzerá (n = 105) and ¾Holstein × »Guzerá (n = 279) derived from the Brazilian semiarid region. The physiological responses analyzed were: respiratory rate (RR, movements/minute), rectal temperature (RT, C), free thyroxine (T4, µg/mL) and thyroid-stimulating hormone (TSH, µUI/mL). The values of RR, RT, T4, TSH and serum levels of glucose, cholesterol, total protein, urea and creatinine were determined and correlated with milk production for 305 days, correlation lying only with TSH. Significant differences were observed just in milk production, RR and TSH comparing the genetic groups ½Holstein × ½Guzerá and ¾Holstein × »Guzerá. In conclusion, ¾Holstein × »Guzerá cows showed higher thyroid activity and milk production than ½Holstein × ½Guzerá cows, and may therefore be a better option for dairy production systems in semiarid regions.(AU)

O objetivo do presente estudo foi avaliar as mudanças de algumas respostas fisiológicas e dos parametros bioquímicos séricos em vacas leiteiras mestiças mantidas em um ambiente de clima quente. Utilizou-se uma população de 384 vacas leiteiras de grupos genéticos ½Holstein × ½Guzerá (n = 105) e ¾Holstein × »Guzerá (n = 279) criadas no semiárido brasileiro. As respostas fisiológicas analisadas foram: freqüência respiratória (RR, movimentos/minuto), temperatura retal (RT, C), tiroxina livre (T4, ug/mL) e hormônio estimulante da tireóide (TSH, ?UI/mL). Os valores de RR, RT, TR, T4, TSH e níveis séricos de glicose, colesterol, proteínas totais, uréia, creatinina foram determinados e correlacionados com a produção de leite corrigida para os 305 dias, encontrando-se correlação apenas com TSH. Foram observadas diferenças significativas apenas na produção de leite, RR e TSH entre os grupos genéticos ½Holstein × ½Guzerá e ¾Holstein × »Guzerá. Concluiu-se que, vacas ¾Holstein × »Guzerá apresentaram maior atividade da tireóide e produção de leite do que as vacas ½Holstein × ½Guzerá, podendo ser uma melhor opção para sistemas de produção leiteira no semiárido.(AU)

Assuntos

RESUMO

The aim of the present study was to evaluate the changes in physiological responses and serum biochemical panel in crossbred dairy cow populations kept in a hot climate environment. We used a population of 384 dairy cows of genetic groups ½Holstein × ½Guzerá (n = 105) and ¾Holstein × »Guzerá (n = 279) derived from the Brazilian semiarid region. The physiological responses analyzed were: respiratory rate (RR, movements/minute), rectal temperature (RT, C), free thyroxine (T4, µg/mL) and thyroid-stimulating hormone (TSH, µUI/mL). The values of RR, RT, T4, TSH and serum levels of glucose, cholesterol, total protein, urea and creatinine were determined and correlated with milk production for 305 days, correlation lying only with TSH. Significant differences were observed just in milk production, RR and TSH comparing the genetic groups ½Holstein × ½Guzerá and ¾Holstein × »Guzerá. In conclusion, ¾Holstein × »Guzerá cows showed higher thyroid activity and milk production than ½Holstein × ½Guzerá cows, and may therefore be a better option for dairy production systems in semiarid regions.

O objetivo do presente estudo foi avaliar as mudanças de algumas respostas fisiológicas e dos parametros bioquímicos séricos em vacas leiteiras mestiças mantidas em um ambiente de clima quente. Utilizou-se uma população de 384 vacas leiteiras de grupos genéticos ½Holstein × ½Guzerá (n = 105) e ¾Holstein × »Guzerá (n = 279) criadas no semiárido brasileiro. As respostas fisiológicas analisadas foram: freqüência respiratória (RR, movimentos/minuto), temperatura retal (RT, C), tiroxina livre (T4, ug/mL) e hormônio estimulante da tireóide (TSH, ?UI/mL). Os valores de RR, RT, TR, T4, TSH e níveis séricos de glicose, colesterol, proteínas totais, uréia, creatinina foram determinados e correlacionados com a produção de leite corrigida para os 305 dias, encontrando-se correlação apenas com TSH. Foram observadas diferenças significativas apenas na produção de leite, RR e TSH entre os grupos genéticos ½Holstein × ½Guzerá e ¾Holstein × »Guzerá. Concluiu-se que, vacas ¾Holstein × »Guzerá apresentaram maior atividade da tireóide e produção de leite do que as vacas ½Holstein × ½Guzerá, podendo ser uma melhor opção para sistemas de produção leiteira no semiárido.

Assuntos

RESUMO

The goal of this study was to evaluate the daily rhythmicity of the thermoregulatory responses of Morada Nova ewes that were raised in a semiarid environment. The experiment was conducted during the dry season. Data were collected from 5:00 a.m. to 4:00 a.m.. Samples were taken over the course of 8 days, with a 1-week interval between sampling periods. During each day that the data were collected, animals were measured once an hour for 24 h in an area directly exposed to solar radiation. The environment was characterized by measuring the following variables: air temperature (TA), relative humidity (RH), Black Globe Humidity Index (BGHI), radiant heat load (RHL), and wind speed (WS). Physiological variables that were measured included rectal temperature (RT, °C), respiratory rate (RR, breaths/min), surface temperature (ST, °C), and sweating rate (SR, g m2 h-1). We observed that RT, RR, and ST increased as environmental conditions became more stressful. Specifically, environmental conditions became more stressful as RHL, air temperature, and BGHI increased, while RH decreased. All physiological variables of the animals were strongly affected by the time of the day: environmental variables changed drastically between nighttime and noon. Physiological parameters increased sharply from the morning (7:00 a.m.-10:00 a.m.) until noon (11:00 a.m.-2:00 p.m.), except for sweating rate. After noon, these variables began to drop until nighttime (11:00 p.m.-6:00 am), and values of the main physiological indexes were stable during this period. The Morada Nova breed exhibited daily cyclic variations in thermoregulatory responses. Evaporative heat loss mechanisms were triggered during the most stressful times of the day. The first mechanism that animals used was panting, which was an immediate response to environmental heat stress. Cutaneous evaporation had a slower response mechanism to environmental heat stress. Homeothermy conditions were restored to the animals at approximately 5:00 p.m.; however, these findings confirm the importance of providing environmental protection during critical periods of the day, even for locally adapted breeds. These responses suggest that the use of thermal storage allowed the animals to achieve equilibrium with the environment and maintain a stable body temperature.

Assuntos

RESUMO

The aim of the present study was to evaluate the changes in physiological responses and serum biochemical panel in crossbred dairy cow populations kept in a hot climate environment. We used a population of 384 dairy cows of genetic groups ½Holstein × ½Guzerá (n = 105) and ¾Holstein × »Guzerá (n = 279) derived from the Brazilian semiarid region. The physiological responses analyzed were: respiratory rate (RR, movements/minute), rectal temperature (RT, C), free thyroxine (T4, µg/mL) and thyroid-stimulating hormone (TSH, µUI/mL). The values of RR, RT, T4, TSH and serum levels of glucose, cholesterol, total protein, urea and creatinine were determined and correlated with milk production for 305 days, correlation lying only with TSH. Significant differences were observed just in milk production, RR and TSH comparing the genetic groups ½Holstein × ½Guzerá and ¾Holstein × »Guzerá. In conclusion, ¾Holstein × »Guzerá cows showed higher thyroid activity and milk production than ½Holstein × ½Guzerá cows, and may therefore be a better option for dairy production systems in semiarid regions.

O objetivo do presente estudo foi avaliar as mudanças de algumas respostas fisiológicas e dos parametros bioquímicos séricos em vacas leiteiras mestiças mantidas em um ambiente de clima quente. Utilizou-se uma população de 384 vacas leiteiras de grupos genéticos ½Holstein × ½Guzerá (n = 105) e ¾Holstein × »Guzerá (n = 279) criadas no semiárido brasileiro. As respostas fisiológicas analisadas foram: freqüência respiratória (RR, movimentos/minuto), temperatura retal (RT, C), tiroxina livre (T4, ug/mL) e hormônio estimulante da tireóide (TSH, ?UI/mL). Os valores de RR, RT, TR, T4, TSH e níveis séricos de glicose, colesterol, proteínas totais, uréia, creatinina foram determinados e correlacionados com a produção de leite corrigida para os 305 dias, encontrando-se correlação apenas com TSH. Foram observadas diferenças significativas apenas na produção de leite, RR e TSH entre os grupos genéticos ½Holstein × ½Guzerá e ¾Holstein × »Guzerá. Concluiu-se que, vacas ¾Holstein × »Guzerá apresentaram maior atividade da tireóide e produção de leite do que as vacas ½Holstein × ½Guzerá, podendo ser uma melhor opção para sistemas de produção leiteira no semiárido.

RESUMO

The aim of the present study was to evaluate the changes in physiological responses and serum biochemical panel in crossbred dairy cow populations kept in a hot climate environment. We used a population of 384 dairy cows of genetic groups ½Holstein × ½Guzerá (n = 105) and ¾Holstein × »Guzerá (n = 279) derived from the Brazilian semiarid region. The physiological responses analyzed were: respiratory rate (RR, movements/minute), rectal temperature (RT, C), free thyroxine (T4, µg/mL) and thyroid-stimulating hormone (TSH, µUI/mL). The values of RR, RT, T4, TSH and serum levels of glucose, cholesterol, total protein, urea and creatinine were determined and correlated with milk production for 305 days, correlation lying only with TSH. Significant differences were observed just in milk production, RR and TSH comparing the genetic groups ½Holstein × ½Guzerá and ¾Holstein × »Guzerá. In conclusion, ¾Holstein × »Guzerá cows showed higher thyroid activity and milk production than ½Holstein × ½Guzerá cows, and may therefore be a better option for dairy production systems in semiarid regions.

O objetivo do presente estudo foi avaliar as mudanças de algumas respostas fisiológicas e dos parametros bioquímicos séricos em vacas leiteiras mestiças mantidas em um ambiente de clima quente. Utilizou-se uma população de 384 vacas leiteiras de grupos genéticos ½Holstein × ½Guzerá (n = 105) e ¾Holstein × »Guzerá (n = 279) criadas no semiárido brasileiro. As respostas fisiológicas analisadas foram: freqüência respiratória (RR, movimentos/minuto), temperatura retal (RT, C), tiroxina livre (T4, ug/mL) e hormônio estimulante da tireóide (TSH, ?UI/mL). Os valores de RR, RT, TR, T4, TSH e níveis séricos de glicose, colesterol, proteínas totais, uréia, creatinina foram determinados e correlacionados com a produção de leite corrigida para os 305 dias, encontrando-se correlação apenas com TSH. Foram observadas diferenças significativas apenas na produção de leite, RR e TSH entre os grupos genéticos ½Holstein × ½Guzerá e ¾Holstein × »Guzerá. Concluiu-se que, vacas ¾Holstein × »Guzerá apresentaram maior atividade da tireóide e produção de leite do que as vacas ½Holstein × ½Guzerá, podendo ser uma melhor opção para sistemas de produção leiteira no semiárido.

RESUMO

Objetivou-se avaliar as respostas fisiológicas e a produção de leite de vacas da raça Holandesa, puras, nas épocas seca e chuvosa. Durante o período de março a outubro foram tomadas, duas vezes por semana, em onze vacas, a temperatura retal (TR), a frequência respiratória (FR) e a produção de leite (PL) às 7 h e às 15 h. Nos mesmos horários foram também registradas as temperaturas do ar e do globo negro, a umidade do ar e calculado o Índice de Temperatura de Globo e Umidade (ITGU). As análises estatísticas foram realizadas pelo método dos quadrados mínimos e revelaram efeitos significativos de animal, período do ano e mês de coleta dentro de período do ano sobre as variáveis registradas, com maiores TR e FR no período chuvoso, quando a PL foi superior. Houve efeito da interação hora e animal apenas para a PL e da interação coleta e período para PL e TR. Os efeitos do ITGU à sombra e ao sol foram diferentes apenas para FR. A produção de leite foi extremamente baixa em todos os períodos do ano e na estação seca, no período da tarde, ocorreu um maior aquecimento corporal, sendo no período chuvoso intensificado o uso dos mecanismos de termólise evaporativa respiratória.(AU)

This study aimed to evaluate the physiological responses and the production of milk cows of the Holstein breed, pure, in the dry and rainy seasons. During the period from March to October rectal temperature (TR), respiratory rate (FR) and milk production (PL) were taken at 7 am and at 3 pm twice a week, in eleven cows. At the same time, in these cows there were also recorded temperatures of air and black globe, humidity and it was calculated the Globe and Humidity Temperature Index (ITGU). Statistical analyzes were performed by the method of least squares and this revealed significant effects of the animal, also the year of the period and month collection period within the year on the variables recorded, with higher TR and FR during the rainy season, when the PL was higher. There was a significant time interaction and animals just for the PL and the interaction time of collection and time for PL and TR. The effects of ITGU in the shade and the sun were different only concerning the FR. Milk production was extremely low in all periods of the year and in the dry season, in the afternoon, there was a higher body heat, and in the rainy season the use of the mechanisms of respiratory evaporative heat loss was intensified.(AU)

Assuntos

RESUMO

Objetivou-se avaliar as respostas fisiológicas e a produção de leite de vacas da raça Holandesa, puras, nas épocas seca e chuvosa. Durante o período de março a outubro foram tomadas, duas vezes por semana, em onze vacas, a temperatura retal (TR), a frequência respiratória (FR) e a produção de leite (PL) às 7 h e às 15 h. Nos mesmos horários foram também registradas as temperaturas do ar e do globo negro, a umidade do ar e calculado o Índice de Temperatura de Globo e Umidade (ITGU). As análises estatísticas foram realizadas pelo método dos quadrados mínimos e revelaram efeitos significativos de animal, período do ano e mês de coleta dentro de período do ano sobre as variáveis registradas, com maiores TR e FR no período chuvoso, quando a PL foi superior. Houve efeito da interação hora e animal apenas para a PL e da interação coleta e período para PL e TR. Os efeitos do ITGU à sombra e ao sol foram diferentes apenas para FR. A produção de leite foi extremamente baixa em todos os períodos do ano e na estação seca, no período da tarde, ocorreu um maior aquecimento corporal, sendo no período chuvoso intensificado o uso dos mecanismos de termólise evaporativa respiratória.

This study aimed to evaluate the physiological responses and the production of milk cows of the Holstein breed, pure, in the dry and rainy seasons. During the period from March to October rectal temperature (TR), respiratory rate (FR) and milk production (PL) were taken at 7 am and at 3 pm twice a week, in eleven cows. At the same time, in these cows there were also recorded temperatures of air and black globe, humidity and it was calculated the Globe and Humidity Temperature Index (ITGU). Statistical analyzes were performed by the method of least squares and this revealed significant effects of the animal, also the year of the period and month collection period within the year on the variables recorded, with higher TR and FR during the rainy season, when the PL was higher. There was a significant time interaction and animals just for the PL and the interaction time of collection and time for PL and TR. The effects of ITGU in the shade and the sun were different only concerning the FR. Milk production was extremely low in all periods of the year and in the dry season, in the afternoon, there was a higher body heat, and in the rainy season the use of the mechanisms of respiratory evaporative heat loss was intensified.

Assuntos

RESUMO

The effect of the natural weather conditions on respiratory rate, rectal temperature and hematologic parameters such as glucose, total cholesterol, triacylglycerol, total protein, albumin, globulin, red blood cells, microhematocrit, mean corpuscular volume, serum triiodothyronine (T3) and thyroxine (T4) levels was evaluated in red (RMN) and white (WMN) coat colored Morada Nova ewes, of different class of body condition score (CBCS), during the dry (from july to december) and wet (from january to june) seasons, which exhibited different (P 0.05) air temperature, relative humidity and radiant thermal load averages. Tukeys test was used and the difference considered was to P 0.05. Significant greater averages of respiratory rate were observed in the dry period compared to the rainy period (42.26±8.96 and 36.89±8.20 breaths min-1, respectively), mainly in the RMN (45.54±8.23 breaths min-1) compared with the WMN (39.27±8.57 breaths min-1). No differences were observed in rectal temperature measurements between the dry and the wet periods (38.59±0.58 and 38.60±0.56 oC, respectively), but the WMN had higher values than the RMN (38.77±0.54 and 38.40±0.54 oC, respectively). The glucose and total cholesterol were higher in the wet season, with no variation due to breed variety and CBCS. The triacylglycerol did not change between breed varieties and seasons. The albumin was similar between varieties and in different seasons, being different in CBCS. Total protein and globulin serum were higher during the wet season, but total protein was higher and globulin was lower in better CBCS. T3 and T4 levels were higher in the rainy season (0.25±0.07 and 6.74±11.37 μg dL-1, for T3 and T4, respectively) than in the dry season (0.18±0.08 and 6.31±1.64 μg dL-1, for T3 and T4, respectively). The red blood cells showed no difference, but microhematocrit was higher in WMN and in the better CBCS and mean corpuscular volume was higher in the dry season.(AU)

Neste estudo foram avaliados os efeitos da época do ano nas características fisiológicas de frequência respiratória e temperatura retal e nos parâmetros hematológicos glicose, colesterol total, triglicerídeos, proteínas totais, albumina, globulina, contagem total de hemácias, hematócrito, volume corpuscular médio, triiodotironina (T3) e tiroxina (T4) em ovelhas da raça Morada Nova das variedades vermelha (RMN) e branca (WMN), de diferentes classes de escore corporal (CBCS), durante os períodos seco (de julho a dezembro) e chuvoso (de janeiro a junho), assim caracterizados por exibirem diferenças estatísticas (P<0,05) na temperatura do ar, umidade relativa e carga térmica radiante. Na análise estatística foi usado o teste de Tukey a 5% de probabilidade (P<0,05). Diferenças significativas foram encontradas na frequência respiratória durante os períodos seco e chuvoso, sendo maior na variedade vermelha do que na branca. Não foram verificadas diferença na temperatura retal dos animais entre os períodos seco e chuvoso, mas a variedade vermelha apresentou maiores médias desta variável. A glicose e o colesterol total sérico foram maiores no período chuvoso, não apresentando diferença significativa entre as variedades nem entre animais de diferentes condições corporais. A dosagem sanguínea de triglicerídeos não foi diferente para nenhuma das fontes de variação. A albumina foi estatisticamente semelhante entre as variedades da raça e durante os períodos seco e chuvoso do ano, apresentando diferença somente em relação à condição corporal dos animais CBCS. A dosagem sérica de proteína total e globulina foram maiores durante o inverno, mas a proteína total foi maior e a globulina foi menor em animais com melhor CBCS. Os níveis séricos de T3 e T4 foram maiores no período chuvoso do que no seco e a concentração de T3 nas ovelhas de pelagem vermelha, enquanto T4 não diferiu entre as variedades.(AU)

Assuntos

RESUMO

The effect of the natural weather conditions on respiratory rate, rectal temperature and hematologic parameters such as glucose, total cholesterol, triacylglycerol, total protein, albumin, globulin, red blood cells, microhematocrit, mean corpuscular volume, serum triiodothyronine (T3) and thyroxine (T4) levels was evaluated in red (RMN) and white (WMN) coat colored Morada Nova ewes, of different class of body condition score (CBCS), during the dry (from july to december) and wet (from january to june) seasons, which exhibited different (P 0.05) air temperature, relative humidity and radiant thermal load averages. Tukeys test was used and the difference considered was to P 0.05. Significant greater averages of respiratory rate were observed in the dry period compared to the rainy period (42.26±8.96 and 36.89±8.20 breaths min-1, respectively), mainly in the RMN (45.54±8.23 breaths min-1) compared with the WMN (39.27±8.57 breaths min-1). No differences were observed in rectal temperature measurements between the dry and the wet periods (38.59±0.58 and 38.60±0.56 oC, respectively), but the WMN had higher values than the RMN (38.77±0.54 and 38.40±0.54 oC, respectively). The glucose and total cholesterol were higher in the wet season, with no variation due to breed variety and CBCS. The triacylglycerol did not change between breed varieties and seasons. The albumin was similar between varieties and in different seasons, being different in CBCS. Total protein and globulin serum were higher during the wet season, but total protein was higher and globulin was lower in better CBCS. T3 and T4 levels were higher in the rainy season (0.25±0.07 and 6.74±11.37 μg dL-1, for T3 and T4, respectively) than in the dry season (0.18±0.08 and 6.31±1.64 μg dL-1, for T3 and T4, respectively). The red blood cells showed no difference, but microhematocrit was higher in WMN and in the better CBCS and mean corpuscular volume was higher in the dry season.

Neste estudo foram avaliados os efeitos da época do ano nas características fisiológicas de frequência respiratória e temperatura retal e nos parâmetros hematológicos glicose, colesterol total, triglicerídeos, proteínas totais, albumina, globulina, contagem total de hemácias, hematócrito, volume corpuscular médio, triiodotironina (T3) e tiroxina (T4) em ovelhas da raça Morada Nova das variedades vermelha (RMN) e branca (WMN), de diferentes classes de escore corporal (CBCS), durante os períodos seco (de julho a dezembro) e chuvoso (de janeiro a junho), assim caracterizados por exibirem diferenças estatísticas (P<0,05) na temperatura do ar, umidade relativa e carga térmica radiante. Na análise estatística foi usado o teste de Tukey a 5% de probabilidade (P<0,05). Diferenças significativas foram encontradas na frequência respiratória durante os períodos seco e chuvoso, sendo maior na variedade vermelha do que na branca. Não foram verificadas diferença na temperatura retal dos animais entre os períodos seco e chuvoso, mas a variedade vermelha apresentou maiores médias desta variável. A glicose e o colesterol total sérico foram maiores no período chuvoso, não apresentando diferença significativa entre as variedades nem entre animais de diferentes condições corporais. A dosagem sanguínea de triglicerídeos não foi diferente para nenhuma das fontes de variação. A albumina foi estatisticamente semelhante entre as variedades da raça e durante os períodos seco e chuvoso do ano, apresentando diferença somente em relação à condição corporal dos animais CBCS. A dosagem sérica de proteína total e globulina foram maiores durante o inverno, mas a proteína total foi maior e a globulina foi menor em animais com melhor CBCS. Os níveis séricos de T3 e T4 foram maiores no período chuvoso do que no seco e a concentração de T3 nas ovelhas de pelagem vermelha, enquanto T4 não diferiu entre as variedades.

Assuntos