Early-life heat stress exposure impacts dairy calf feeding and thermoregulatory behavior

Dairy calves exposed to late-gestation heat stress weigh less, have impaired immunity, produce less milk across multiple lactations, and have reduced productive life. However, less is known about the relationship between in utero heat stress and organ morphology and development. Herein, we characterized the consequences of late-gestation in utero heat stress on body and organ growth trajectories during early-life development. Holstein heifers were either in utero heat-stressed (IU-HT, n = 36, dams exposed to THI > 68) or cooled (IU-CL, n = 37, dams exposed to THI > 68 with access to active cooling) during late gestation (54 ± 5 d prepartum). All heifers were reared identically from birth to weaning. Upon birth, calves were weighed and fed 3.78 L of colostrum followed by 0.87 kg DM/d milk replacer (MR) over two feedings and ad libitum starter concentrate daily. Weaning began at 49 d and ended at 56 d of age. Feed intake was recorded daily, and body weight (BW) and other growth measures were recorded at 0, 28, 56, and 63 d. Blood was collected at d 1 then weekly. Subsets of heifers were selected for euthanasia at birth and 7 d after complete weaning (n = 8 per group each) to harvest and weigh major organs. Reduced BW and stature measures persisted in IU-HT heifers from 0 to 63 d of age with a 7% lower average daily gain and reduced starter consumption relative to IU-CL heifers. IU-HT heifers had lower hematocrit percentages and reduced apparent efficiency of absorption of IgG relative to IU-CL heifers. Additionally, IU-HT heifers had reduced gross thymus, spleen, thyroid gland, and heart weight at birth and larger adrenal glands and kidneys but smaller ovaries relative to BW at 63 d. The mammary gland of IU-HT heifers was smaller relative to IU-CL heifers at birth and 63 d adjusted for BW, suggesting mechanisms leading to impaired milk yield in mature IU-HT cows are initiated early in development. In summary, in utero heat stress reduces whole-body size and limits development of key organs with potential repercussions on dairy calf metabolic adaptation, immune function, and future productivity.

Download Full-text

Prior hormetic priming is costly under environmental mismatch

Biology Letters ◽

10.1098/rsbl.2013.1010 ◽

2014 ◽

Vol 10 (2) ◽

pp. 20131010 ◽

Cited By ~ 32

Author(s):

David Costantini ◽

Pat Monaghan ◽

Neil B. Metcalfe

Keyword(s):

Heat Stress ◽

Stress Response ◽

Stress Responses ◽

Life Stress ◽

Early Life ◽

Later Life ◽

Stress Exposure ◽

Mild Heat ◽

Response System ◽

Stress Response System

It is increasingly recognized that hormetic environmental priming of stress responses can improve resilience to later life stress exposure. However, such phenotypic adjustments may be costly, particularly if the subsequent environment does not match that to which the adjustment was made. Here, we show that hormetic priming to mild heat stress in early life increases survival only when heat stress is again experienced in adulthood; it reduces survival if the stressor is not encountered again. That such costs can occur explains both why the stress response system is not maintained in an upregulated state and why the hormetic adjustment of responses has evolved.

Download Full-text

Core body temperature does not cool down with skin surface temperature during recovery at room temperature after acute heat stress exposure

Livestock Science ◽

10.1016/j.livsci.2016.07.010 ◽

2016 ◽

Vol 191 ◽

pp. 143-147 ◽

Cited By ~ 3

Author(s):

A. Sapkota ◽

A. Herr ◽

J.S. Johnson ◽

D.C. Lay

Keyword(s):

Heat Stress ◽

Body Temperature ◽

Surface Temperature ◽

Room Temperature ◽

Core Body Temperature ◽

Skin Surface ◽

Skin Surface Temperature ◽

Stress Exposure ◽

Acute Heat Stress ◽

Core Body

Download Full-text

Long-Term Heat Stress Exposure Induced Poor Semen Parameters and Testicular Damage in Rats by Increasing Oxidative Stress, Sex Hormone Silencing, and Activation of Intrinsic Testicular Apoptosis [348]

Obstetrics and Gynecology ◽

10.1097/01.aog.0000463618.77648.44 ◽

2015 ◽

Vol 125 ◽

pp. 109S-110S

Author(s):

Mesfer Safar Al-Shahrani

Keyword(s):

Oxidative Stress ◽

Heat Stress ◽

Sex Hormone ◽

Semen Parameters ◽

Stress Exposure ◽

Testicular Damage

Download Full-text

235 Effects of rapamycin during an acute heat stress exposure in growing pigs

Journal of Animal Science ◽

10.1093/jas/skaa054.200 ◽

2020 ◽

Vol 98 (Supplement_3) ◽

pp. 117-117

Author(s):

Edith J Mayorga ◽

Erin A Horst ◽

Brady M Goetz ◽

Sonia Rodríguez-Jiménez ◽

Megan A Abeyta ◽

...

Keyword(s):

Fatty Acids ◽

Heat Stress ◽

Rectal Temperature ◽

Blood Cells ◽

White Blood Cells ◽

Growing Pigs ◽

Stress Exposure ◽

Esterified Fatty Acids ◽

Acute Heat Stress ◽

Ad Libitum

Abstract Objectives were to determine the effects of rapamycin on biomarkers of metabolism and inflammation during acute heat stress (HS) in growing pigs. Crossbred barrows (n=32; 63.5±0.8 BW) where blocked by BW and randomly assigned to 1 of 4 therapeutic-environmental treatments: 1) thermoneutral (TN) control (n=8; TNCtl), 2) TN and rapamycin (n=8; TNRapa), 3) HS control (n=8; HSCtl), or 4) HS and rapamycin (n=8; HSRapa). The trial consisted of 2 experimental periods (P). During P1 (10d), pigs were fed ad libitum and housed in TN conditions (21.3±0.01°C). During P2 (24h), HSCtl and HSRapa pigs were exposed to constant HS (35.5±0.1°C); while TNCtl and TNRapa remained in TN conditions. Rapamycin (0.15 mg/kg BW) was orally administered twice daily (0700 and 1800 h) during P1 and P2. HS increased rectal temperature, skin temperature, and respiration rate compared to TN counterparts (1.28°C, 8.68°C, and 87 bpm, respectively; P< 0.01). Feed intake (FI) markedly decreased in HS relative to TN treatments (64%; P< 0.01). Additionally, pigs exposed to HS lost BW (4 kg; P< 0.01), while TN pigs gained BW (0.7 kg; P< 0.01). Overall, circulating white blood cells decreased in HS compared to TN pigs (19%; P=0.01). Circulating neutrophils did not differ across treatments; however, lymphocytes, monocytes, and basophils decreased in HS relative to TN pigs (23, 33, and 38%, respectively; P≤0.07). Despite marked changes in phenotypic parameters, circulating glucose and blood urea nitrogen did not differ among treatments (P >0.10). However, insulin:FI increased in HS relative to TN treatments (P=0.04). Plasma non-esterified fatty acids (NEFA) increased in HS relative to TN treatments; although this difference was driven by increased NEFA in HSCtl compared to TN and HSRapa pigs (P< 0.01). In summary, pigs exposed to HS had altered phenotypic, metabolic, and leukocyte responses; however, rapamycin administration had little to no effect on any of the variables measured.

Download Full-text

Deforestation and climate change are projected to increase heat stress risk in the Brazilian Amazon

Communications Earth & Environment ◽

10.1038/s43247-021-00275-8 ◽

2021 ◽

Vol 2 (1) ◽

Author(s):

Beatriz Fátima Alves de Oliveira ◽

Marcus J. Bottino ◽

Paulo Nobre ◽

Carlos A. Nobre

Keyword(s):

Climate Change ◽

Heat Stress ◽

Amazon Basin ◽

Stress Index ◽

Climate Change Scenarios ◽

Stress Exposure ◽

Extreme Risk ◽

High Emission ◽

Heat Stress Index ◽

The Impact

AbstractLand use change and deforestation can influence local temperature and climate. Here we use a coupled ocean-atmosphere model to assess the impact of savannization of the Amazon Basin on the wet-bulb globe temperature heat stress index under two climate change scenarios (RCP4.5 and RCP8.5). We find that heat stress exposure due to deforestation was comparable to the effect of climate change under RCP8.5. Our findings suggest that heat stress index could exceed the human adaptation limit by 2100 under the combined effects of Amazon savannization and climate change. Moreover, we find that risk of heat stress exposure was highest in Northern Brazil and among the most socially vulnerable. We suggest that by 2100, savannization of the Amazon will lead to more than 11 million people will be exposed heat stress that poses an extreme risk to human health under a high emission scenario.

Download Full-text

Numerical simulation of thermal effects of urban green enhancements in different urban environments in the city of Augsburg (Bavaria, SE Germany)

10.5194/egusphere-egu21-3562 ◽

2021 ◽

Author(s):

Christoph Beck ◽

Katharina Buse ◽

Marisa Fritsch ◽

Philipp Irber

Keyword(s):

Heat Stress ◽

Thermal Effects ◽

Horizontal Resolution ◽

Urban Environments ◽

Domain Model ◽

Future Climate Change ◽

Research Approach ◽

Stress Exposure ◽

Urban Green ◽

Adaptation Scenarios

The interdisciplinary research project Abc (Augsburg bleibt cool &#8211; Augsburg stays cool) &#8211; funded by the German Federal Ministry for Environment, Nature Conservation and Nuclear Safety &#8211; deals with different aspects of heat-stress exposure and adaptation to heat-stress in indoor and outdoor urban environments in the urban area of Augsburg (Bavaria, SE Germany).As one essential research approach this includes the estimation of the thermal effects of vegetation enhancements in different urban environments via numerical simulations performed with the ENVI-met V4 numerical model.For several model domains &#8211; each of them covering 300 m x 300 m with a 2 m x 2 m horizontal resolution - model runs have been performed utilizing observational data for a heat wave end of July 2019 as meteorological forcing, thus serving as a climate analogue for thermal conditions expected to appear more frequently under future climate change conditions. For each domain model runs for the current-state and several adaptation scenarios have been performed. Adaptation scenarios thereby comprise varying measures for enhancing urban green (street and facade greening) and blue infrastructure.In this contribution we present and discuss selected model settings and scenarios.Model results indicate the general capability of vegetation enhancements to counteract heat-stress exposure in urban environments. However, partly also contrary effects emerge pointing to the complex interdependencies within the urban climate system which have to be taken into account when projecting urban heat island adaptation strategies.

Download Full-text