Cows as canaries: The effects of ambient air pollution exposure on milk production and somatic cell count in dairy cows

Air quality monitoring in dairy farms: Description of air quality dynamics in a tunnel-ventilated housing barn and milking parlor of a commercial dairy farm

This study aimed to describe air quality dynamics in a commercial dairy farm focusing on 2 locations: a tunnel-ventilated barn (TVB) and a milking parlor (MKP). Assessed air quality components included carbon monoxide (CO), carbon dioxide (CO2), methane (CH4), ammonia (NH3), particulate matter 2.5 µg/m3 (PM2.5), total volatile organic compounds (VOC), and temperature-humidity index (THI), which were continuously monitored from August 16 to December 22, 2023, using a multiple air quality sensor platform. Descriptive analysis revealed significant hourly variability in the air quality dynamics during the study period. Mixed-effects models revealed no significant differences in the overall CO and THI measurements between the barn and milking parlor. However, the location significantly influenced overall concentrations of other air components including CO2, CH4, PM2.5, VOC, and NH3. Overall comparisons between TVB and MKP showed that the TVB had a higher overall CO2 concentration mean during the observation period compared with the MKP (LSM ± SEM; 640 ± 9.02 vs. 612 ± 9.01 ppm), while the MKP recorded highest CH4 levels (11.03 ± 0.52 vs. 8.87 ± 0.52 ppm). In the TVB, the NH3 levels ranged from 0.401 to 44.9 ppm, whereas no NH3 was detected in the MKP. The MKP recorded higher overall PM2.5 compared with the TVB (5.51 ± 0.31vs. 3.21 ± 0.31µg/m3). The VOC levels exhibited higher overall means in the TVB compared with the MKP (153 ± 2.18 vs. 144 ± 2.16 ppm) but were characterized by substantial variability in both locations. Temporal trends suggested that the monitored air components might be influenced by farm activities such as feeding, cleaning, and milking as identifiable peaks we observed at specific hours of the day. We identified hourly pattern dynamics of CO, CO2, CH4, NH3, PM2.5, VOC, and THI within the TVB and the MKP. Understanding these dynamics provides the opportunity to develop mitigation strategies for enhancing air quality within dairy facilities.

The effects of ambient air pollution exposure on Thoroughbred racehorse performance

BACKGROUND

Limited research exists on impacts of air pollution on non-human mammals, particularly animal athletes such as Thoroughbred racehorses. Athletes have a greater risk of exposure as heightened exertion and increased airflow carry more pollutants deeper into the respiratory tract.

OBJECTIVES

To provide insights into the impact of ambient air pollution, particularly fine particulate matter (PM2.5), on race speed.

STUDY DESIGN

Retrospective observational study.

METHODS

Data were obtained from The Jockey Club Information Systems, covering 31 407 winning races by Thoroughbred horses in California spanning 10 years (2011-2020) and evaluated the association between air pollution and winning race speeds. For race days, we collected PM2.5 data from the nearest U.S. Environmental Protection Agency (EPA) monitoring site within 100 km of each racetrack (n = 12). We assessed the associations between daily average PM2.5 concentrations and speed of winning horses with linear mixed effects regression. We adjusted for horse characteristics, race-related covariates, temporal indicators (e.g., year), other air pollutants and temperature. We conducted sensitivity analyses by adjusting extreme air pollution days by reassigning values to the 95th percentile value and conducting linear mixed effects regression on series of datasets with incremental cutpoints of PM2.5.

RESULTS

In the cutpoint analysis, we found that for PM2.5 between 4 and 23.6 μg/m3, speed decreased 0.0008 m/s (95% CI: -0.0014562 to -0.00018) for every 1 μg/m3 increase of PM2.5.

MAIN LIMITATIONS

Limitations include the use of offsite monitors leading to imprecise exposure measurements, not using training practice data, and generalisability as the study focuses on California racetracks.

CONCLUSION

This study highlights the need to create advisories to safeguard the performance of horses during periods of poor air quality. Further research is recommended to explore additional factors influencing the relationship between air pollution and equine welfare.

Attenuation of PM2.5-Induced Lung Injury by 4-Phenylbutyric Acid: Maintenance of [Ca2+]i Stability between Endoplasmic Reticulum and Mitochondria

Fine particulate matter (PM2.5) is a significant cause of respiratory diseases and associated cellular damage. The mechanisms behind this damage have not been fully explained. This study investigated two types of cellular damage (inflammation and pyroptosis) induced by PM2.5, focusing on their relationship with two organelles (the endoplasmic reticulum and mitochondria). Animal models have demonstrated that PM2.5 induces excessive endoplasmic reticulum stress (ER stress), which is a significant cause of lung damage in rats. This was confirmed by pretreatment with an ER stress inhibitor (4-Phenylbutyric acid, 4-PBA). We found that, in vitro, the intracellular Ca2+ ([Ca2+]i) dysregulation induced by PM2.5 in rat alveolar macrophages was associated with ER stress. Changes in mitochondria-associated membranes (MAMs) result in abnormal mitochondrial function. This further induced the massive expression of NLRP3 and GSDMD-N, which was detrimental to cell survival. In conclusion, our findings provide valuable insights into the relationship between [Ca2+]i dysregulation, mitochondrial damage, inflammation and pyroptosis under PM2.5-induced ER stress conditions. Their interactions ultimately have an impact on respiratory health.

RGS2 attenuates alveolar macrophage damage by inhibiting the Gq/11-Ca2+ pathway during cowshed PM2.5 exposure, and aberrant RGS2 expression is associated with TLR2/4 activation

Staff and animals in livestock buildings are constantly exposed to fine particulate matter (PM2.5), which affects their respiratory health. However, its exact pathogenic mechanism remains unclear. Regulator of G-protein signaling 2 (RGS2) has been reported to play a regulatory role in pneumonia. The aim of this study was to explore the therapeutic potential of RGS2 in cowshed PM2.5-induced respiratory damage. PM2.5 was collected from a cattle farm, and the alveolar macrophages (NR8383) of the model animal rat were stimulated with different treatment conditions of cowshed PM2.5. The RGS2 overexpression vector was constructed and transfected it into cells. Compared with the control group, cowshed PM2.5 significantly induced a decrease in cell viability and increased the levels of apoptosis and proinflammatory factor expression. Overexpression of RGS2 ameliorated the above-mentioned cellular changes induced by cowshed PM2.5. In addition, PM2.5 has significantly induced intracellular Ca2+ dysregulation. Affinity inhibition of Gq/11 by RGS2 attenuated the cytosolic calcium signaling pathway mediated by PLCβ/IP3R. To further investigate the causes and mechanisms of action of differential RGS2 expression, the possible effects of oxidative stress and TLR2/4 activation were investigated. The results have shown that RGS2 expression was not only regulated by oxidative stress-induced nitric oxide during cowshed PM2.5 cells stimulation but the activation of TLR2/4 had also an important inhibitory effect on its protein expression. The present study demonstrates the intracellular Ca2+ regulatory role of RGS2 during cellular injury, which could be a potential target for the prevention and treatment of PM2.5-induced respiratory injury.

Data Linkages for Wildfire Exposures and Human Health Studies: A Scoping Review

Wildfires are increasing in frequency and intensity, with significant consequences that impact human health. A scoping review was conducted to: (a) understand wildfire-related health effects, (b) identify and describe environmental exposure and health outcome data sources used to research the impacts of wildfire exposures on health, and (c) identify gaps and opportunities to leverage exposure and health data to advance research. A literature search was conducted in PubMed and a sample of 83 articles met inclusion criteria. A majority of studies focused on respiratory and cardiovascular outcomes. Hospital administrative data was the most common health data source, followed by government data sources and health surveys. Wildfire smoke, specifically fine particulate matter (PM2.5), was the most common exposure measure and was predominantly estimated from monitoring networks and satellite data. Health data were not available in real-time, and they lacked spatial and temporal coverage to study health outcomes with longer latency periods. Exposure data were often available in real-time and provided better temporal and spatial coverage but did not capture the complex mixture of hazardous wildfire smoke pollutants nor exposures associated with non-air pathways such as soil, household dust, food, and water. This scoping review of the specific health and exposure data sources used to underpin these studies provides a framework for the research community to understand: (a) the use and value of various environmental and health data sources, and (b) the opportunities for improving data collection, integration, and accessibility to help inform our understanding of wildfires and other environmental exposures.

Data Gap: Air Quality Networks Miss Air Pollution from Concentrated Animal Feeding Operations

In the U.S., the agricultural sector is the largest controllable source of several air pollutants, including ammonia (NH3), which is a key precursor to PM2.5 formation. Livestock waste is the dominant contributor to ammonia emissions. In contrast to most controllable air pollutants, satellite records show ammonia mixing ratios are rising. The number of confined animal feeding operations (CAFOs) that generate considerable livestock waste is also increasing. Spatial and temporal trends in USDA-reported animal numbers normalized by county area at medium and large CAFOs provide plausible explanations for patterns in satellite-derived NH3 over the contiguous U.S. (CONUS). The correlation between summertime ammonia derived from the European Space Agency's (ESA) Infrared Atmospheric Sounding Interferometer (IASI) and CAFO animal unit density in 2017 is positive and significant (r = 0.642; p ≈ 0). The temporal changes from 2002 to 2017 in animal unit density and NH3 derived from NASA's Atmospheric Infrared Sounder (AIRS) are spatially similar. Trends and ambient concentrations of PM2.5 mass in agricultural regions are difficult to assess relative to those of urban population centers given the sparseness of rural monitors in regulatory surface networks. Results suggest that in agricultural areas where ammonia concentrations and animal density are highest, air quality improvement lags behind the national average.

Pathways framework identifies wildfire impacts on agriculture

Wildfires are a growing concern to society and the environment in many parts of the world. Within the United States, the land area burned by wildfires has steadily increased over the past 40 years. Agricultural land management is widely understood as a force that alters fire regimes, but less is known about how wildfires, in turn, impact the agriculture sector. Based on an extensive literature review, we identify three pathways of impact-direct, downwind and downstream-through which wildfires influence agricultural resources (soil, water, air and photosynthetically active radiation), labour (agricultural workers) and products (crops and livestock). Through our pathways framework, we highlight the complexity of wildfire-agriculture interactions and the need for collaborative, systems-oriented research to better quantify the magnitude of wildfire impacts and inform the adaptation of agricultural systems to an increasingly fire-prone future.

The concentration of particulate matter in the barn air and its influence on the content of heavy metals in milk

Heavy metals are one of the components of smog, which is mainly the product of burning fossil fuels in residential buildings. These elements, introduced into the body of cattle by inhalation, may enter the milk. The goal of this study was to assess the impact of particulate pollution in the atmospheric air on the concentration of particulate matter in the air of a dairy cattle barn and on the content of selected heavy metals in milk from cows present in the building. Measurements were taken between November and April (148 measurement days). The calculations carried out showed a high correlation (RS = + 0.95) between the concentrations of particulates measured outside and inside the barn, which is indicative of a significant impact of the atmospheric air on the particulate pollution level of the livestock building. The number of days in excess of the daily standard for PM10 inside was 51. The conducted analysis of the chemical composition of the milk collected under high particulate pollution (February) showed that the permitted lead level had been exceeded-21.93 µg/kg (norm 20.00 µg/kg).

Effects of wildfire smoke exposure on innate immunity, metabolism, and milk production in lactating dairy cows

Wildfires are particularly prevalent in the Western United States, home to more than 2 million dairy cows that produce more than 25% of the nation's milk. Wildfires emit fine particulate matter (PM_2.5) in smoke, which is a known air toxin and is thought to contribute to morbidity in humans by inducing inflammation. The physiological responses of dairy cows to wildfire PM_2.5 are unknown. Herein we assessed the immune, metabolic, and production responses of lactating Holstein cows to wildfire PM_2.5 inhalation. Cows (primiparous, n = 7; multiparous, n = 6) were monitored across the wildfire season from July to September 2020. Cows were housed in freestall pens and thus were exposed to ambient air quality. Air temperature, relative humidity, and PM_2.5 were obtained from a monitoring station 5.7 km from the farm. Animals were considered to be exposed to wildfire PM_2.5 if daily average PM_2.5 exceeded 35 µg/m³ and wildfire and wind trajectory mapping showed that the PM_2.5 derived from active wildfires. Based on these conditions, cows were exposed to wildfire PM_2.5 for 7 consecutive days in mid-September. Milk yield was recorded daily and milk components analysis conducted before, during, and after exposure. Blood was taken from the jugular vein before, during, and after exposure and assayed for hematology, blood chemistry, and blood metabolites. Statistical analysis was conducted using mixed models including PM_2.5, temperature-humidity index (THI), parity (primiparous or multiparous), and their interactions as fixed effects and cow as a random effect. Separate models included lags up to 7 d to identify delayed and persistent effects from wildfire PM_2.5 exposure. Exposure to elevated PM_2.5 from wildfire smoke resulted in lower milk yield during exposure and for 7 d after last exposure and higher blood CO₂ concentration, which persisted for 1 d following exposure. We observed a positive PM_2.5 by THI interaction for eosinophil and basophil count and a negative PM_2.5 by THI interaction for red blood cell count and hemoglobin concentration after a 3-d lag. Neutrophil count was also lower with a combination of higher THI and PM_2.5. We found no discernable effect of PM_2.5 on haptoglobin concentration. Effects of PM_2.5 and THI on metabolism were contingent on day of exposure. On lag d 0, blood urea nitrogen (BUN) was reduced with higher combined THI and PM_2.5, but on subsequent lag days, THI and PM_2.5 had a positive interaction on BUN. Conversely, THI and PM_2.5 had a positive interacting effect on nonesterified fatty acids (NEFA) on lag d 0 but subsequently caused a reduction in circulating NEFA concentration. Our results suggest that exposure to high wildfire-derived PM_2.5, alone or in concert with elevated THI, alters systemic metabolism, milk production, and the innate immune system.