Physiological response to heat stress and ingestive behavior of lactating Jersey cows in silvopasture and conventional pasture grazing systems in a Brazilian subtropical climate zone

2021 ◽  
Vol 53 (2) ◽  
Author(s):  
Fernando Reimann Skonieski ◽  
Edenilson Robson de Souza ◽  
Luana Carolina Bachmann Gregolin ◽  
Ana Carolina Fluck ◽  
Olmar Antônio Denardin Costa ◽  
...  
Keyword(s):  
Heat Stress ◽  
Physiological Response ◽  
Ingestive Behavior ◽  
Subtropical Climate ◽  
Climate Zone ◽  
Grazing Systems ◽  
Jersey Cows

scholarly journals Critical Temperature-Humidity Index Thresholds for Dry Cows in a Subtropical Climate

2021 ◽  
Vol 2 ◽  
Author(s):  
Véronique Ouellet ◽  
Izabella M. Toledo ◽  
Bethany Dado-Senn ◽  
Geoffrey E. Dahl ◽  
Jimena Laporta
Keyword(s):  
Heat Stress ◽  
Respiration Rate ◽  
Rectal Temperature ◽  
Dry Matter ◽  
Dry Matter Intake ◽  
Subtropical Climate ◽  
Dry Period ◽  
Environmental Indices ◽  
Temperature Humidity Index ◽  
Humidity Index

The effects of heat stress on dry cows are profound and significantly contribute to lower overall welfare, productivity, and profitability of the dairy sector. Although dry cows are more thermotolerant than lactating cows due to their non-lactating state, similar environmental thresholds are currently used to estimate the degree of heat strain and cooling requirements. Records of dry cow studies conducted over 5 years in Gainesville, Florida, USA were pooled and analyzed to determine environmental thresholds at which dry cows exhibit signs of heat stress in a subtropical climate. Dry-pregnant multiparous dams were actively cooled (CL; shade of a freestall barn, fans and water soakers, n = 107) or not (HT; shade only, n = 111) during the last 7 weeks of gestation, concurrent with the entire dry period. Heat stress environmental indices, including ambient temperature, relative humidity, and temperature-humidity index (THI), and animal-based indices, including respiration rate, rectal temperature and daily dry matter intake were recorded in all studies. Simple correlations were performed between temperature-humidity index and each animal-based indicator. Differences in respiration rate, rectal temperature and dry matter intake between treatments were analyzed by multiple regression. Using segmented regression, temperature-humidity thresholds for significant changes in animal-based indicators of heat stress were estimated. Stronger significant correlations were found between the temperature-humidity index and all animal-based indices measured in HT dry cows (−0.22 ≤ r ≤ 0.35) relative to CL dry cows (−0.13 ≤ r ≤ 0.19). Although exposed to similar temperature-humidity index, rectal temperature (+0.3°C; P < 0.001) and respiration rate (+23 breaths/min; P < 0.001) were elevated in HT dry cows compared with CL cows whereas dry matter intake (−0.4 kg of dry matter/d; P = 0.003) was reduced. Temperature-humidity index thresholds at which respiration rate and rectal temperature began to change were both determined at a THI of 77 in HT dry cows. No significant temperature-humidity threshold was detected for dry matter intake. At a practical level, our results demonstrate that dry cow respiration rate and rectal temperature increased abruptly at a THI of 77 when provided only shade and managed in a subtropical climate. Therefore, in the absence of active cooling, dry cows should be closely monitored when or before THI reaches 77 to avoid further heat-stress related impairments during the dry period and the subsequent lactation and to mitigate potential carry-over effects on the offspring.

scholarly journals EFFECT OF HEAT STRESS ON PHYSIOLOGICAL AND SOME BLOOD PARAMETERS OF THREE LOCAL CHICKEN AND A BROILER GENOTYPES REASED IN HUMID SUBTROPICAL CLIMATE OF COTE DIVOIRE.

2019 ◽  
Vol 7 (1) ◽  
pp. 233-240
Author(s):  
Ndri AyaLydie ◽  
◽  
Assie AssieFabrice ◽  
Silue GahapieUrbainandSoroDofara ◽  
◽  
...  
Keyword(s):  
Heat Stress ◽  
Blood Parameters ◽  
Subtropical Climate ◽  
Local Chicken

Ascorbic acid: a limiting nutrient affecting performance and physiological response of broiler chicks under heat stress

1992 ◽  
Vol 1992 ◽  
pp. 82-82
Author(s):  
H.R. Kutlu ◽  
J.M. Forbes
Keyword(s):  
Ascorbic Acid ◽  
Heat Stress ◽  
Body Temperature ◽  
Physiological Response ◽  
Broiler Chicks ◽  
Blood Components ◽  
Optimum Performance ◽  
Limiting Nutrient

Birds are normally able to synthesize adequate amounts of ascorbic acid (AA). However, there are many indications that under stress they cannot produce enough AA for their metabolic needs. In particular, heat stress has been implicated in increasing birds’ demand for AA (Scott, 1975; Sykes, 1978; Coates, 1984). These reports suggest that conditions may exist in which endogenous AA synthesis of birds is not adequate to meet the physiological needs for optimum performance and that during such conditions exogenous supplementation with AA could be beneficial. This study was conducted to determine if dietary supplemental AA would alleviate heat-induced deterioration in performance and metabolism of broiler chicks and also to characterize the changes in body temperature, thyroid weight and blood components as affected by supplemental AA and/or heating.

Physiological response and miRNA-mRNA interaction analysis in the head kidney of rainbow trout exposed to acute heat stress

2019 ◽  
Vol 83 ◽  
pp. 134-141 ◽  
Author(s):  
Chang-Qing Zhou ◽  
Peng Zhou ◽  
Yan-Li Ren ◽  
Li-Hui Cao ◽  
Jian-Lin Wang
Keyword(s):  
Heat Stress ◽  
Rainbow Trout ◽  
Physiological Response ◽  
Interaction Analysis ◽  
Head Kidney ◽  
Acute Heat Stress

Physiological response to heat stress of tomato ‘Micro-Tom’ plants expressing high and low levels of mitochondrial sHSP23.6 protein

2013 ◽  
Vol 70 (2) ◽  
pp. 175-185 ◽  
Author(s):  
Cristina Moll Huther ◽  
Aline Ramm ◽  
Cesar Valmor Rombaldi ◽  
Marcos Antonio Bacarin
Keyword(s):  
Heat Stress ◽  
Physiological Response ◽  
Low Levels

scholarly journals Physiological response of glutamine and glutamic acid supplemented broiler chickens to heat stress

2015 ◽  
Author(s):  
J. Olubodun ◽  
I. Zulkifli ◽  
M. Hair-Bejo ◽  
A. Kasim ◽  
A.F. Soleimani
Keyword(s):  
Heat Stress ◽  
Glutamic Acid ◽  
Physiological Response ◽  
Broiler Chickens

Temperature regulation

2013 ◽  
Author(s):  
Bareket Falk ◽  
Raffy Dotan
Keyword(s):  
Heat Stress ◽  
Thermal Stress ◽  
Body Temperature ◽  
Physiological Response ◽  
Physiological Responses ◽  
Hydration Status ◽  
Physiological Changes ◽  
Thermoregulatory Response ◽  
Per Se ◽  
And Training

This chapter outlines the physical and physiological changes that occur during growth and maturation and the possible effects these changes can have on the nature and effectiveness of thermoregulation. The physiological responses to heat stress are discussed in terms of metabolic, circulatory, hormonal, and sweating responses, changes in body temperature, and in terms of heat tolerance. Also discussed is hydration status, which can affect thermoregulatory effectiveness in the heat. The physiological response to cold stress is considered in terms of the metabolic and circulatory responses and their possible influence on the effectiveness of thermoregulation. The discussion does not outline the thermoregulatory response per se, but rather emphasizes the differences in that response between children and adults. Finally, child–adult differences in the acclimatization- and training-induced adaptations to thermal stress are discussed.

Can a local weather station be used in place of on-site measurements for heat stress assessment in a sports setting?

2021 ◽  
Author(s):  
Olivia Cahill ◽  
Andrew Grundstein ◽  
Christian Walker ◽  
Earl Cooper
Keyword(s):  
Heat Stress ◽  
Research Question ◽  
Health And Safety ◽  
Subtropical Climate ◽  
Wet Bulb Globe Temperature ◽  
Playing Field ◽  
Weather Stations ◽  
Globe Temperature ◽  
Set Up ◽  
Local Weather

<p>Across the globe, exposure to environmental heat stress may impose increased health and safety hazards to active populations such as athletes and workers. Monitoring heat stress is a key component of a well-designed heat mitigation policy. Yet, the cost of several hand-held heat stress sensors may pose a financial barrier for use in many circumstances. Numerous areas, however, have existing networks of weather stations that could potentially be incorporated into monitoring heat stress. Currently, the Japanese Ministry of the Environment has set up a network of weather stations across the city to monitor environmental conditions in preparation of the 2021 Tokyo Olympic and Paralympic games. Our research question asks how representative are the values recorded at local weather stations (often located over a natural surface) to playing field conditions with various surfaces and microclimate conditions. In the U.S. the WeatherSTEM network has over 600 stations scattered across the country and measures a suite of variables relevant to heat stress including air temperature, humidity, wind speed, solar radiation and models the wet bulb globe temperature (WBGT) values. This study will compare measurements from a local WeatherSTEM station with on-site measurements taken over three different playing surfaces (grass, synthetic turf, and hardcourt tennis) in a humid subtropical climate in Athens, Georgia. U.S. It will also compare WBGT values computed using different models. Our results may provide insight not only for sports but also for the workplace which take place over various surface types and environments.</p>

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