Evaluation of thermal stress indexes for dairy cows in tropical regions

Silva, Alexandre Rodrigues; Morais, Débora Andréa Evangelista Façanha; Guilhermino, Magda Maria

doi:10.1590/s1516-35982007000500028

Cited by 90 publications

(86 citation statements)

References 10 publications

(7 reference statements)

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“…The results demonstrated that T a was nearly as good a predictor of rectal temperatures of lactating Holsteins as any of the THI equations (R 2 =0.41 versus 0.43). Similarly, da Silva et al (2007), looking at six different indicies, found THI and BGTHI had the lowest correlations with rectal temperature and respiration rate. In Missouri, percent relative humidity is relatively low in comparison to southern United States.…”

Section: Discussionmentioning

confidence: 95%

Determinants of bovine thermal response to heat and solar radiation exposures in a field environment

et al. 2010

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Continuous exposure of cattle to summer heat in the absence of shade results in significant hyperthermia and impairs growth and general health. Reliable predictors of heat strain are needed to identify this condition. A 12-day study was conducted during a moderate summer heat period using 12 Angus x Simmental (Bos taurus) steers (533± 12 kg average body weight) to identify animal and ambient determinations of core body temperature (T core ) and respiration rate (RR) responses to heat stress. Steers were provided standard diet and water ad libitum, and implanted intraperitoneally with telemetric transmitters to monitor T core hourly. Visual count of flank movement at 0800 and 1500 hours was used for RR. Dataloggers recorded air temperature (T a ), and black globe temperatures (T bg ) hourly to assess radiant heat load. Analysis was across four periods and 2 consecutive days averaged within each period. Average T a and T bg increased progressively from 21.7 to 30.3°C and 25.3 to 34.0°C, respectively, from the first to fourth periods. A model utilizing a quadratic function of T a explained the most variation in T core (R 2 =0.56). A delay in response from 1 to 3 h did not significantly improve R 2 for this relationship. Measurements at 0800 and 1500 hours alone are sufficient to predict heat strain. Daily minimum core body temperature and initial 2-h rise in T a were predictors of maximum core temperature and RR. Further studies using continuous monitoring are needed to expand prediction of heat stress impact under different conditions.

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Section: Discussionmentioning

confidence: 95%

Determinants of bovine thermal response to heat and solar radiation exposures in a field environment

et al. 2010

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“…For instance, Holstein cows bred in tropical and subtropical conditions have differences in their hair coat characteristics compared with those bred in temperate regions [6,55].…”

Section: Discussionmentioning

confidence: 99%

“…HLINew is also suggested for fat and protein content in the spring. Silva et al suggested HLI for tropical regions, and Moran and Epstein evaluated ESI for hot/dry and hot/wet climates [6,35].…”

Section: Discussionmentioning

confidence: 99%

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A Survey of the Relationship between Climatic Heat Stress Indices and Fundamental Milk Components Considering Uncertainty

Milani

Hense

Rahmani

et al. 2015

Climate

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Abstract:The main purpose of this study is to assess the relationship between four bioclimatic indices for cattle (environmental stress, heat load, modified heat load, and respiratory rate predictor indices) and three main milk components (fat, protein, and milk yield) considering uncertainty. The climate parameters used to calculate the climate indices were taken from the NASA-Modern Era Retrospective-Analysis for Research and Applications (NASA-MERRA) reanalysis from 2002 to 2010. Cow milk data were considered for the same period from April to September when the cows use the natural pasture. The study is based on a linear regression analysis using correlations as a summarizing diagnostic. Bootstrapping is used to represent uncertainty information in the confidence intervals. The main results identify an interesting relationship between the milk compounds and climate indices under all climate conditions. During spring, there are reasonably high correlations between the fat and protein concentrations vs. the climate indices, whereas there are insignificant dependencies between the milk yield and climate indices. During summer, the correlation between the fat and protein concentrations with the climate indices decreased in comparison with the spring results, whereas the correlation for the milk yield increased. This methodology is suggested for OPEN ACCESSClimate 2015, 3 877 studies investigating the impacts of climate variability/change on food and agriculture using short term data considering uncertainty.

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“…242, Art. 1601, Outubro, 2013 2.3.2 Efeito do manejo e de variáveis bioclimáticas sobre a taxa de gestação em vacas receptoras de embriões Nos ambientes tropicais, as elevadas temperaturas do ar, ligada à umidade e radiação alta, diminui consideravelmente a eficiência da perda de calor e, com isso, incrementa o estresse térmico (Silva et al, 2007), o que se torna limitante ao desenvolvimento, a reprodução e produção animal (Torres Júnior et al, 2008). O animal tem a capacidade de se ajustar fisiologicamente mediante estresse por calor, em função de alta umidade do ar e temperatura(o que se observa são a temperatura retal e a frequência respiratória), utilizando esses mecanismos fisiológicos o animal está tentando perder o calor absorvido (Azevedo et al, 2005;Morais et al, 2008).…”

Section: Seleção De Receptoras Aptas Ao Processo De Transferência De unclassified

Importance of choosing a program receiving embryo transfer in cattle

Honorato¹,

Ferro²,

Ferro³

et al. 2015

Pubvet

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ResumoA utilização de biotecnologias reprodutivas representa cada vez mais a evolução da produção animal no Brasil e no mundo. A Inseminação Artificial em bovinos veio como a pioneira dessa evolução, seguida pela Transferência de Embriões (TE) convencional que trouxe a Aspiração Folicular guiada por ultra-sonografia para produção in vitro de embriões bovinos, possibilitando o incremento da genética dos rebanhos, em quantidade e qualidade.Objetivou-se descrever os aspectos relacionados a um programa de transferência de embriões, relatando que em posição de destaque encontram-se as receptoras responsáveis pela gestação de animais de genética superior. O programa de Aspiração Folicular veio como a evolução da TE convencional, tornando os processos mais práticos, viáveis e eficientes, porém não se deve esquecer que os envolvidos nos processos devem possuir experiência e habilidade profissional, pois eles são

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Evaluation of thermal stress indexes for dairy cows in tropical regions

Cited by 90 publications

References 10 publications

Determinants of bovine thermal response to heat and solar radiation exposures in a field environment

Determinants of bovine thermal response to heat and solar radiation exposures in a field environment

A Survey of the Relationship between Climatic Heat Stress Indices and Fundamental Milk Components Considering Uncertainty

Importance of choosing a program receiving embryo transfer in cattle

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