Índices De Tolerância Ao Calor De Vacas Leiteiras No Período Chuvoso E Seco No Ceará

Rocha, David R. da; Salles, María Gorete Flores; Moura, Arlindo de Alencar Araripe; Araújo, Aírton Alencar de

doi:10.7213/academica.7739

Cited by 14 publications

(8 citation statements)

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“…The correlations between IHTI and the physiological variables found in the present research match the results by Rocha et al (2012), who found similar results in tropical conditions when researching dairy cows, with a strong negative correlation between IHTI and RT (P<0.01) for both seasons.…”

Section: Discussionsupporting

confidence: 93%

Thermal comfort indices of female Murrah buffaloes reared in the Eastern Amazon

et al. 2015

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The study aimed to develop new and more specific thermal comfort indices for buffaloes reared in the Amazon region. Twenty female Murrah buffaloes were studied for a year. The animals were fed in pasture with drinking water and mineral supplementation ad libitum. The following parameters were measured twice a week in the morning (7 AM) and afternoon (1 PM): air temperature (AT), relative air humidity (RH), dew point temperature (DPT), wet bulb temperature (WBT), black globe temperature (BGT), rectal temperature (RT), respiratory rate (RR), and body surface temperature (BST). The temperature and humidity index (THI), globe temperature and humidity index (GTHI), Benezra's comfort index (BTCI), and Ibéria's heat tolerance index (IHTI) were calculated so they could be compared to the new indices. Multivariate regression analyses were carried out using the canonical correlation model, and all indices were correlated with the physiological and climatic variables. Three pairs of indices (general, effective, and practical) were determined comprising the buffalo comfort climatic condition index (BCCCI) and the buffalo environmental comfort index (BECI). The indices were validated and a great agreement was found among the BCCCIs (general, effective, and practical), with 98.3 % between general and effective a.nd 92.6 % between general and practical. A significant correlation (P < 0.01) was found between the new indices and the physiological and climatic variables, which indicated that these may be used in pairs to diagnose thermal stress in buffaloes reared in the Amazon.

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Section: Discussionsupporting

confidence: 93%

Thermal comfort indices of female Murrah buffaloes reared in the Eastern Amazon

et al. 2015

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“…In the afternoon experimental periods, the average THI values were 79.9 and 83.6 in the shade and in the sun, respectively, which characterized this experimental period as moderate heat stress. Similar results were reported by Rocha et al (2012), who also found differences between times of day, with higher THI values found in the afternoon. The authors attributed this to the increased AT throughout the day, with a positive correlation detected between AT and THI (r = 0.89).…”

Section: Resultssupporting

confidence: 90%

Consumo, produção de leite e parâmetros fisiológicos de vacas em lactação alimentadas com dietas contendo diferentes quantidades de xiquexique (Pilosocereus gounellei)

et al. 2016

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Consumo AbstractThe aim of the present study was to evaluate the effect of substituting Tifton-85 grass hay with different quantities of xiquexique (Pilosocereus gounellei) (0, 12, 24, and 36%) on the nutrient intake and physiological responses of lactating dairy cows. Eight multiparous crossbred cows at approximately 100 days in milk, with an average milk yield of 15 kg of milk per day -1 , and an average body weight (BW) of 465.20 ± 39.37 kg, were distributed in a 4 × 4 double Latin square design. Each experimental period lasted 16 days, consisting of 10 days for adaptation and 6 days for data collection, giving a total of 64 experimental days. The roughage: concentrate ratio was 60:40, on a dry matter (DM) basis. The DM intake, expressed in kg day -1 , was affected quadratically by the levels of xiquexique in the diets. The intakes of DM, expressed in % BW and g kg -0.75, and neutral detergent fiber (NDF) in the three units analyzed (kg day -1 , % BW, and g kg -0.75 ), as well as the intakes of organic matter (OM), crude protein (CP), ether extract (EE), and total carbohydrates (TC), expressed in kg/day -1 , decreased linearly with the levels of xiquexique in the diet. Milk yield (kg day -1 ) was reduced by the addition of xiquexique into the diet, but feed efficiency was not influenced. Water intake from feed (WI Feed ), expressed in kg day -1 and % BW, incresed linearly with increasing levels of xiquexique in the total diet, while voluntary water intake, expressed in kg day -1 and % BW (WI Voluntary ), decreased linearly. The total water intake (WI Total ) was not affected by experimental treatments. Participation of WI Voluntary in the WI Total linearly reduced with Xiquexique levels in the diet. The respiratory rate and surface temperature during both periods of the day (morning and afternoon), and rectal temperature during the morning were not influenced by the levels of xiquexique in the diet. Therefore, xiquexique can be utilized in the feeding of medium and high producing dairy cows, as a means of reducing nutrient intake, milk yield, and voluntary consumption of water without changing feed efficiency or the animals' physiological responses. ResumoO presente estudo foi conduzido com o objetivo de avaliar o efeito de diferentes níveis de xiquexique (0, 12, 24 e 36%) em substituição ao feno de capim Tifton 85 sobre o consumo de nutrientes e respostas fisiológicas de vacas leiteiras em lactação. Foram utilizadas oito vacas mestiças pluríparas, com aproximadamente 100 dias em lactação, produção média de 15 kg de leite dia -1 e com peso corporal (PC) médio de 465,20 ± 39,37 kg. Os animais foram distribuídos em delineamento em quadrado latino 4x4, duplo. Cada período teve duração de 16 dias, sendo 10 dias de adaptação e 6 dias de coleta de dados, totalizando 64 dias experimentais. A relação volumoso:concentrado foi de 60:40, com base na matéria seca (MS). O consumo de MS, expresso em kg dia -1 , foi influenciado de forma quadrática pelos níveis de xiquexique nas rações. O consumo de MS expresso em % PC e g...

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“…Uma vez que ocorre acréscimo nos valores dessa variável fisiológica, é reflexo de falha ou esgotamento nos mecanismo de perda de calor (roCha et al, 2012). Neste trabalho, pode-se observar então que os animais utilizaram os mecanismos de perda de calor de forma eficientemente, uma vez que os parâmetros fisiológicos não demonstraram alteração acima da normalidade.…”

Section: Tabela 1 Valores Médios De Temperatura Do Ar (Tar) Umidadeunclassified

Respostas fisiológicas e adaptabilidade de vacas ¾ holandês x zebu ao clima do semiárido

Moreira¹,

Carvalho²,

Santos³

et al. 2017

Bol. Ind. Anim.

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RESUMO: A região Norte de Minas possui a produção de leite limitada, principalmente em função da seca, no entanto, esta é a base econômica da agricultura familiar que sustenta a região. Assim, realizou-se um estudo com o objetivo de avaliar o efeito do ambiente térmico sobre as respostas fisiológicas de vacas ¾ Holandês-Zebu, na região do semiárido mineiro a fim de se verificar a adaptabilidade destes animais. O experimento foi conduzido no verão e inverno, na fazenda Bela Vista localizada no município de Verdelândia (MG), onde foram avaliadas 10 vacas ¾ Holandês x Zebu (HxZ), em cada época. O ambiente térmico foi caracterizado por meio de medições diárias da temperatura do ar, umidade relativa do ar, índice de temperatura de globo e umidade e carga térmica radiante. Os parâmetros fisiológicos: frequência respiratória e cardíaca, temperatura de superfície corporal e temperatura retal, espessura, cor e densidade do pelame, e comprimento dos pelos foram mensurados antes da ordenha matutina, em função das estações do ano, diariamente, durante 15 dias. As variáveis e índices climáticos foram superiores no verão e no período da tarde. A frequência respiratória e a espessura do pelame não diferiram estatisticamente, no entanto as demais variáveis foram superiores no verão. As variáveis climáticas induziram diferenças nos parâmetros fisiológicos, mas foram assimiladas pelos animais, o que permite concluir que as vacas ¾ HxZ adaptam-se ao clima do semiárido mineiro sem manifestarem situação de estresse térmico.Palavras-chave: agricultura familiar, ambiência, bovinos leiteiros, cruzamento genético. PHYSIOLOGICAL RESPONSES AND ADAPTABILITY OF ¾ HOLSTEIN X ZEBU COWS TO SEMIARID CLIMATEABSTRACT: The northern region of Minas Gerais has limited milk production, mainly due to drought, however, this is the economic base of family agriculture that sustains the region. Thus, a study was carried out to evaluate the effect of the thermal environment on the physiological responses of Holstein-Zebu cows in the semi-arid region of Minas Gerais in order to verify the adaptability of these animals. The experiment was conducted in the summer and winter at the Bela Vista farm located in the Verdelândia city (MG), where 10 cows ¾ Holstein x Zebu (HxZ) were evaluated in each season. The thermal environment was characterized by means of daily measurements of air temperature, relative humidity, air temperature index and humidity and radiant thermal load. The physiological parameters: respiratory and heart rate, body surface temperature and rectal temperature, thickness, hair color and density, and hair length were measured before morning milking, as a function of the seasons of the year for 15 days. Climatic variables and indexes were higher in the summer and in the afternoon. The respiratory rate and the pelt thickness did not differ statistically, however the other variables were higher in the summer.

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Índices De Tolerância Ao Calor De Vacas Leiteiras No Período Chuvoso E Seco No Ceará

Cited by 14 publications

References 5 publications

Thermal comfort indices of female Murrah buffaloes reared in the Eastern Amazon

Thermal comfort indices of female Murrah buffaloes reared in the Eastern Amazon

Consumo, produção de leite e parâmetros fisiológicos de vacas em lactação alimentadas com dietas contendo diferentes quantidades de xiquexique (Pilosocereus gounellei)

Respostas fisiológicas e adaptabilidade de vacas ¾ holandês x zebu ao clima do semiárido

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