01 / 08
Economic Losses from Heat Stress by US Livestock Industries
The Ohio State University · 2003
Quick overview
This 2003 Journal of Dairy Science review by St-Pierre, Cobanov, and Schnitkey estimates the economic toll of heat stress across US livestock industries. Combining USDA inventory data, 68–129 years of weather records from 257 stations, and Monte Carlo simulation, the authors modeled losses from reduced performance, higher mortality, and impaired reproduction. Without heat abatement, total annual losses averaged $2.4 billion, falling to $1.7 billion with optimal abatement. By industry, yearly losses averaged $897M (dairy), $369M (beef), $299M (swine), and $128M (poultry).
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02 / 08
Effects of Heat Stress on Postabsorptive Metabolism
Iowa State / Virginia State University · 2013
Quick overview
This 2013 Annual Review of Animal Biosciences review by Baumgard and Rhoads challenges the long-held assumption that heat stress lowers livestock productivity simply through reduced feed intake. Drawing on their own data, the authors argue that heat-stressed animals adopt distinct homeorhetic strategies that reprioritize metabolism and fuel use independently of nutrient intake or energy balance. Strikingly, despite an energetic deficit, animals show little adipose fat mobilization and blunted responses to lipolytic signals.
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03 / 08
Diurnal heat stress reduces pig intestinal integrity
Iowa State University / Biomin Research · 2018
Quick overview
This 2018 Translational Animal Science study (Mayorga, Reisinger et al.) examined how diurnal heat stress harms pig gut health. Forty-eight individually penned nursery-grower gilts were split between thermal-neutral conditions and three days of cycling heat (6 h at 38°C, 18 h at 32°C). Heat stress raised rectal temperatures and respiration rates and cut growth performance. Critically, it damaged the intestinal barrier: ileum transepithelial resistance fell while permeability rose, and circulating endotoxin climbed 150% versus controls.
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04 / 08
Heat Stress adaptation in pigs
Iowa State University · 2019
Quick overview
This 2019 Animal Frontiers review by Mayorga, Renaudeau, Ramirez, Ross, and Baumgard surveys how heat stress undermines pig production worldwide. The authors frame it as a global, welfare-relevant constraint that will worsen with climate change and the migration of pork production into hot, humid regions. In swine specifically, heat stress reduces growth and feed efficiency, degrades carcass quality, impairs sow and boar reproduction, and raises mortality—costing the US industry roughly $1 billion annually. They emphasize often-overlooked in-utero effects.
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05 / 08
Effect of Heat Stress on Feed Mgmt. on Growth Performance
PEGASE, INRAE, Institut Agro, Saint-Gilles, France · 2020
Quick overview
This 2020 Translational Animal Science study tested whether heat stress harms finishing pigs directly or merely through reduced feed intake, and whether feeding more frequently helps. Forty-eight pigs were kept at thermoneutral (22°C) or heat-stress (32°C) conditions for 20 days, fed either ad libitum or pair-fed in eight small daily meals. Heat-stressed pigs ate 19% less, gained 25% less, and finished 6.1 kg lighter, with higher internal fat and lower thyroid hormones. Splitting feed into more frequent meals did not improve the response.
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06 / 08
Effects of Hydration Level & Heat Stress on Thermoregulatory Response
Université des Antilles et de la Guyane, France · 2014
Quick overview
This 2014 PLOS ONE study (Waltz et al.) examined how growing pigs physiologically adapt to heat over their first week of exposure, and whether water restriction alters that response. Twelve Large White boars spent a week at 24°C then a week at 32°C, with physiological, hematological, and blood-rheology measures tracked. Water restriction had no effect. Heat initially raised skin and rectal temperature and respiration rate, which then declined—signaling successful acclimation, alongside substantial hematological and hemorheological changes.
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07 / 08
The Genetics of Thermoregulation in Pigs: A Review
Domaine Duclos Prise d'eau, Petit-Bourg, France · 2021
Quick overview
This 2021 Frontiers in Veterinary Science review (Gourdine et al.) tackles a problem every operation already knows costs money: pigs sweat poorly and struggle to dump heat, so summer hits performance, health, and welfare. The novel angle is genetic—the authors argue that selecting heat-tolerant genotypes is a viable long-term play alongside the cooling and management fixes you already run. They survey which thermoregulation phenotypes are worth measuring for breeding and document real breed differences in heat tolerance.
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08 / 08
Economic impact of losses attributable to PRRS in 2016–2020
Iowa State University / University of Minnesota · 2025
Quick overview
This 2025 Preventive Veterinary Medicine study (Osemeke, Holtkamp, et al.) updates the industry's benchmark PRRS cost figure using 2016–2020 data. Bottom line: PRRSV now costs roughly $1.2 billion a year in lost production, up ~80% from the $664M (2006–2010) estimate, split $381M breeding and $819M growing. Growing-pig herds now drive 68% of losses (up from 55%), which the authors tie to new variants and changes in sow immunization—reinforcing the case for tighter biosecurity.
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