Search Results (64)

The objective of this study was to evaluate the effect of two limestone granulometries (0.568 and 1.943 mm) and different levels of vitamin D3 (12.5 g and 25 g) on the thermoregulatory and behavioral responses of replacement pullets. Lohman brown lineage pullets (270 birds), with an average weight of 639.60 g ± 6.05 and an initial age of eight weeks, were used in this study. The experimental design adopted was completely randomized in a 2 × 2 × 2 + 1 factorial arrangement (2 limestone granulometries × 2 levels of vitamin D3 × 2 shifts). The respiratory rate (RR), cloaca temperature (CT), feather surface temperature (FST) and featherless surface temperature (FLST) were higher in the afternoon (p < 0.05), while the thermal gradient (TG) was higher in the morning (p < 0.05). Birds supplemented with different limestone granulometries and different levels of vitamin D3 showed similar thermoregulatory and behavioral responses. The “eating” activity was more frequent in the morning, while in the afternoon, the birds remained seated for longer (p < 0.05). The dietary supplementation with different limestone granulometries and vitamin levels did not impair thermoregulation even at higher temperatures. Regardless of the level of vitamin D3, they showed a better expression of welfare-related behavioral activities in the morning in the semiarid region. Full article

Background: Heat stress challenges small ruminants in semi-arid regions, requiring integrative multi-modeling approaches to identify adaptive thermotolerance traits. This study aimed to identify phenotypic biomarkers and explore the relationships between thermoregulatory responses and hematological, behavioral, morphometric, carcass, and meat traits in lambs. Methods: Twenty 4-month-old non-castrated male lambs, with an average body weight of 19.0 ± 5.11 kg, were evaluated under natural heat stress. Results: Thermoregulatory variables were significantly associated with non-carcass components (p = 0.002), carcass performance (p = 0.027), commercial meat cuts (p = 0.032), and morphometric measures (p = 0.029), with a trend for behavioral responses (p = 0.078). The main phenotypic traits related to thermoregulation included idleness duration, cold carcass weight, blood, liver, spleen, shank, chest circumference, and body length. Exploratory factor analysis reduced the significant indicators to seven latent domains: carcass traits, commercial meat cuts, non-carcass components, idleness and feeding behavior, and morphometric and thermoregulatory responses. Bayesian network modeling revealed interdependencies, showing carcass traits influenced by morphometric and thermoregulatory responses and non-carcass traits linked to ingestive behavior. Thermoregulatory variables were not associated with meat quality or hematological traits. Conclusions: These findings highlight the complex biological relationships underlying heat adaptation and emphasize the potential of combining phenomic data with computational tools to support genomic selection for climate-resilient and welfare-oriented breeding programs. Full article

Floating aquatic vegetation and algal blooms are increasing with global warming, potentially reducing UVB exposure and, consequently, vitamin D (vit-D) synthesis in freshwater turtles. Vit-D mediates calcium metabolism and overall health, yet the effects of floating aquatic vegetation on vit-D levels remain unclear, as is whether turtles actively avoid habitats with abundant floating vegetation. Here, we address these questions by quantifying vit-D₃ levels in the blood of adult female painted turtles (Chrysemys picta) exposed to high-vegetation (darker/colder) or clear-water (lighter/warmer) treatments for one month outdoors and one month indoors at a single temperature during late summer and early fall. The observed circulating vit-D₃ levels resembled those reported for other freshwater turtles, declined over time in both treatments, and were marginally lower under high vegetation after 60 days compared to clear water. However, this difference disappeared after correcting for lymph contamination and multiple comparisons, suggesting that perhaps adult females are robust to the effect of floating vegetation, but whether they were buffered by vit-D₃ stores in lipids is unclear. Additionally, in subsequent years, females were exposed to habitat choice experiments and exhibited a strong preference for high floating vegetation over clear water, both as a group (outdoors) and individually (outdoors, and indoors at 21 °C and 26 °C), consistent with known benefits conferred by floating vegetation (food, predator avoidance). While no ill effects of high vegetation nor behavioral avoidance were detected here, longer experiments at different seasons on both sexes and varying ages are warranted before concluding whether painted turtles are truly resilient in their vit-D levels or if, instead, a tradeoff exists between the known benefits of floating vegetation and potential [yet unidentified] detrimental effects (lower dissolved oxygen or vit-D) when vegetation is overgrown for extended periods. Full article

Diverse individual energy-budgeting tactics within wild populations provide resilience to natural fluctuations in food availability and expenditure costs. Although substantial heterogeneity in activity-related energy expenditure has been documented, few studies differentiate between responses to the environment and inter-individual differences stemming from life history, allometry, or somatic stores. Using tri-axial accelerometry, complemented by diet analysis, we investigated inter-individual within-season variation in overall dynamic body acceleration (ODBA; activity intensity measure) and “Activity” (above an ODBA threshold) in a high-density population of European badgers (Meles meles). Weather (including wind speed) affected ODBA and activity according to predictors of earthworm (food) availability and cooling potential. In spring, maximal ODBA expenditure at intermediate rainfall and temperature values suggested that badgers traded foraging success against thermoregulatory losses, where lower-condition badgers maintained higher spring ODBA irrespective of temperature while badgers in better body condition reduced ODBA at colder temperatures. Conversely, in summer, lower-condition badgers modulated ODBA according to temperature, likely in response to super-abundant food supply. Between 35% (spring, summer) and 57% (autumn) of residual total daily ODBA variance related to inter-individual differences unexplained by seasonal predictors, suggesting within-season tactical activity typologies. We propose that this heterogeneity among individual energy-expenditure profiles may contribute to population resilience under rapid environmental change. Full article

Ectotherms can elevate their body temperature in response to infection by seeking warmer environments, a phenomenon known as behavioral fever. This adaptive response, widely documented in fish, activates immune defenses and improves survival. To explore an eco-friendly approach for managing Vibrio-induced enteritis in lined seahorse (Hippocampus erectus) aquaculture, we investigated whether Vibrio harveyi infection triggers behavioral fever and enhances immune function. Seahorses were intraperitoneally injected with V. harveyi (1 × 10⁷ cfu/fish) and placed in a thermal gradient tank (19–31 °C), allowing free movement between chambers. Challenged seahorses exhibited a significant preference (p < 0.05, 1.31-fold) for warmer zones compared to unchallenged controls, whereas no such difference (p > 0.05) was observed in a constant temperature (25 °C) tank, confirming behavioral fever. Furthermore, fevered seahorses showed significantly elevated plasma cytokine levels (PGE2, IL-1β, IL-6, and TNF-α; p < 0.05), which normalized (p > 0.05) to baseline levels, except for TNF-α, compared to unfevered individuals. In kidney tissue, challenged seahorses expressing behavioral fever exhibited gene expression levels (tnf-α, il-6, ifn-g, and il-10) similar to unchallenged controls (p > 0.05) but significantly lower (p < 0.05) than those kept at constant temperature. These findings suggest that behavioral fever in H. erectus modulates core temperature to regulate cytokine release and immune-related gene expression. This study provides foundational insights for developing practical, non-invasive strategies to mitigate enteritis in seahorse aquaculture through thermal behavior manipulation. Full article

Fescue toxicosis (FT) is a mycotoxin-related disease caused by the ingestion of tall fescue, naturally infected with the ergot alkaloid (EA)-producing endophyte Epichloë coenophiala. Some grazing on endophyte-free (E−) or non-toxic (NT), commercial endophyte-infected pastures takes place in the US as well. Earlier, we found that grazing on toxic fescue with low levels of EAs during fall affects thermoregulation, behavior, and weight gain. Building on these findings, the current study aimed to investigate how the presence of low EA-producing E+ or NT endophytes can influence animal metabolome, microbiome, and, ultimately, overall animal health. Eighteen Angus steers were placed on NT, E+, and E− fescue pastures for 28 days. Urine, rumen fluid (RF), rumen solid (RS), and feces were collected pre-exposure, and on days 2, 7, 14, 21, and 28. An untargeted high-resolution metabolomics approach was used to analyze urine and RF, while 16S rRNA-based next-generation sequencing (NGS) was used to examine RF, RS, feces, and fescue plant microbiomes. While alpha- or beta-microbiota diversity across all analyzed matrices were unaffected, there were specific effects of E+ on the relative abundance of some taxa (i.e., Prevotellaceae). Additionally, E+ grazing impacted aromatic amino acid metabolism in the urine and the metabolism of lipids in both the RF and urine. In both matrices, trace amine-related metabolic features differed markedly between E+ and the other groups. Compared to the endophyte-free group, endophyte presence, whether novel or toxic, influenced amino acid and carbohydrate metabolism, as well as unsaturated fatty acid biosynthesis. These findings suggest that low-EA-producing and non-toxic endophytes in fescue have more prominent effects on the metabolome than the microbiome, and this metabolome perturbation might be associated with decreased performance and reported physiological signs of FT. Full article

Thermal heterogeneity of rivers is essential to support freshwater biodiversity. Salmon behaviorally thermoregulate by moving from patches of warm water to cold water. When implementing river restoration projects, it is essential to monitor changes in temperature and thermal heterogeneity through time to assess the impacts to a river’s thermal regime. Lightweight sensors that record both thermal infrared (TIR) and multispectral data carried via unoccupied aircraft systems (UASs) present an opportunity to monitor temperature variations at high spatial (<0.5 m) and temporal resolution, facilitating the detection of the small patches of varying temperatures salmon require. Here, we present methods to classify and filter visible wetted area, including a novel procedure to measure canopy cover, and extract and correct radiant surface water temperature to evaluate changes in the variability of stream temperature pre- and post-restoration followed by a high-intensity fire in a section of the river corridor of the South Fork McKenzie River, Oregon. We used a simple linear model to correct the TIR data by imaging a water bath where the temperature increased from 9.5 to 33.4 °C. The resulting model reduced the mean absolute error from 1.62 to 0.35 °C. We applied this correction to TIR-measured temperatures of wetted cells classified using NDWI imagery acquired in the field. We found warmer conditions (+2.6 °C) after restoration (p < 0.001) and median absolute deviation for pre-restoration (0.30) to be less than both that of post-restoration (0.85) and post-fire (0.79) orthomosaics. In addition, there was statistically significant evidence to support the hypothesis of shifts in temperature distributions pre- and post-restoration (KS test 2009 vs. 2019, p < 0.001, D = 0.99; KS test 2019 vs. 2021, p < 0.001, D = 0.10). Moreover, we used a Generalized Additive Model (GAM) that included spatial and environmental predictors (i.e., canopy cover calculated from multispectral NDVI and photogrammetrically derived digital elevation model) to model TIR temperature from a transect along the main river channel. This model explained 89% of the deviance, and the predictor variables showed statistical significance. Collectively, our study underscored the potential of a multispectral/TIR sensor to assess thermal heterogeneity in large and complex river systems. Full article

Heat stress in animals affects productivity, health, and reproduction, with particularly pronounced effects in dairy cows. Identifying heat stress requires understanding both physiological and environmental indicators, such as increased heart rate, respiratory rate, and rectal temperature, which reflect the animal’s thermal condition within its environment. Thermoregulation in cows involves behavioral and physiological adjustments to maintain homeothermy, aiming to stabilize their internal thermal state. To assess the thermal condition of animals, machine learning models have been developed, leveraging both environmental and physiological indicators for more accurate stress detection. Among the various indices of thermal environment, the Temperature and Humidity Index (THI) is the most widely used. Cooling strategies for animals and their environments are essential to mitigate the effects of heat stress. One effective approach involves the use of evaporative adiabatic cooling combined with forced ventilation systems in feeding alleys and pre-milking holding areas. This method enhances evaporative exchanges and facilitates heat dissipation between the animal and its surroundings, thereby alleviating heat stress and improving both the welfare and productivity of dairy cows. Full article

The use of escape protein, which is absorbed in the small intestine, can improve the production of ruminant animals because it meets their protein requirements better. This study hypothesized that wax lipid matrices are effective encapsulants for escape lysine in ruminants and tested tannin extract as an adjuvant. Forty intact male Santa Ines × Dorper sheep (~4 months old, BW 23 ± 1.2 kg) were allocated, in a randomized block design, to four treatments: control group (no lysine addition), supplementation with free lysine, escape lysine, and escape lysine + tannin extract. The ether extract intake was higher in the sheep fed escape lysine + tannin compared to the control and free lysine group. The sheep fed escape lysine presented higher DM and aNDF eating efficiency (p ≤ 0.05) compared to the free lysine and control groups. Escape lysine with and without tannin presented greater TDN compared to free lysine and control. The NFCs were lower in the free lysine diet, and the crude protein digestibility was higher in the sheep fed lysine + tannin and the control group compared to the escape and free lysine groups. The lysine treatments did not affect (p > 0.05) the performance, ingestive behavior, and blood parameters. The rectal temperature was higher in the sheep fed lysine escape compared to those fed free lysine. The sheep fed escape lysine + tannin exhibited reduced (p ≤ 0.05) large particles and improved peNDF 12 h after feeding. The escape lysine diet, regardless of the addition of tannin, improved the total digestible nutrients and eating efficiency, without affecting the performance, feed conversion, and blood variables of the sheep. Full article

Background/Objectives: Transient Receptor Potential Melastatin 8 (TRPM8) is a non-selective, Ca²⁺-permeable cation channel involved in thermoregulation and other physiological processes, such as basal tear secretion, cell differentiation, and insulin homeostasis. The activation and deactivation of TRPM8 occur through genetic modifications, channel interactions, and signaling cascades. Recent evidence suggests a significant role of TRPM8 in the hypothalamus and amygdala related to pain sensation and sexual behavior. Notably, TRPM8 has been implicated in neuropathic pain, migraines, and neurodegenerative diseases such as Parkinson’s disease. Our laboratory has identified testosterone as a high-affinity ligand of TRPM8. TRPM8 deficiency appears to influence behavioral traits in mice, like increased aggression and deficits in sexual satiety. Here, we aim to explore the pathways altered in brain tissues of TRPM8-deficient mice using the expression and methylation profiles of messenger RNA (mRNA) and long non-coding RNA (lncRNA). Specifically, we focused on brain regions integral to behavioral and hormonal control, including the olfactory bulb, hypothalamus, amygdala, and insula. Methods: RNA was isolated and purified for microarray analysis collected from male wild-type and TRPM8 knockout mice. Results: We identified various differentially expressed genes tied to multiple signaling pathways. Among them, the androgen–estrogen receptor (AR-ER) pathway, steroidogenesis pathway, sexual reward pathway, and cocaine reward pathway are particularly worth noting. Conclusions: These results should bridge the existing gaps in the knowledge regarding TRPM8 and inform potential targets for future studies to elucidate its role in the behavior changes and pathology of the diseases associated with TRPM8 activity. Full article

Reptiles are unable to generate metabolic heat and regulate body temperature behaviorally depending on environmental conditions. The thermal quality of their habitat is therefore of pivotal importance for their survival. Lizards render themselves as ideal ectothermic models, and their thermal biology has been extensively studied. In this work, we focused on the thermoregulatory performance of the endemic Milos wall lizard (Podarcis milensis) (Milos Archipelago, Aegean Sea, Greece). Applying the same standard methodology, we estimated the effectiveness of thermoregulation (E) taking into account the three main thermal parameters: body (T_b, the temperature of active animals in the field), environmental (T_e, the temperature that animals would achieve in the field if passively conform to the environment) and preferred temperatures (T_pref, the temperatures an animal achieves in a laboratory thermal gradient). Here, we compare the thermoregulatory profile of two remote rocky islet populations, Falconera and Velopoula, with the Milos Island population. We collected T_b values from active lizards as well as T_e from specially designed copper models, which were appropriately placed in the field so as to cover all possible microhabitats. Lizards were then transported to the laboratory where we assessed their T_prefs. Falconera and Velopoula populations showed the same high thermoregulatory effectiveness as that of Milos Island (E_Falconera = 0.97, E_Velopoula = 0.95, E_Milos = 0.89). However, when we used an alternative evaluation of the thermoregulatory strategy, the E values outlined a much more effective thermoregulation for the islets: de-db_Falconera = 6.97, de-db_Velopoula = 11.54, de-db_Milos = 4.27. The adverse conditions on the islets outline a demanding habitat of low thermal quality that dictates effective thermoregulation. However, the trend of increasing temperatures depicts an even harsher environment for the years to come. Could lizards that have already achieved the highest thermoregulatory effectiveness and cannot escape from the isolated islets they dwell cope with these new conditions? This is the kind of questions to which conservation biology will be called upon to respond. Full article

Body temperature is an important physiological parameter that influences the performance of working dogs. The main cooling mechanism in dogs is panting to support evaporative cooling, which reduces the dog’s ability to detect scents. In this study, we investigated the general body condition of four detection dogs searching for cheetah scats in a hot environment in northern Kenya. We evaluated the effect on the dog’s body temperature post-work in the short term (within hours) and long term (12–24 h). The fecal consistency and mean body temperature of the investigated dogs differed significantly between individuals but not between locations (moderate Nairobi and hot Samburu). On the morning after fieldwork, the dogs showed a significantly increased body temperature (37.9 ± 0.8 °C) compared to resting days (37.5 ± 2.2 °C). In the short term, on the first day of fieldwork, the dog’s body temperature (n = 2) decreased after 10 min of rest. On the second consecutive day of fieldwork, the 10-min recovery period was too short, and the body temperature did not decrease significantly. Our data showed that the use of detection dogs in hot conditions is possible and useful but requires increased attention to prevent heat-related illness. Full article

The United States is predicted to experience an annual decline in milk production due to heat stress of 1.4 and 1.9 kg/day by the 2050s and 2080s, with economic losses of USD 1.7 billion and USD 2.2 billion, respectively, despite current cooling efforts implemented by the dairy industry. The ability of cattle to withstand heat (i.e., thermotolerance) can be influenced by physiological and behavioral factors, even though the factors contributing to thermoregulation are heritable, and cows vary in their behavioral repertoire. The current methods to gauge cow behaviors are lacking in precision and scalability. This paper presents an approach leveraging various machine learning (ML) (e.g., CNN and YOLOv8) and computer vision (e.g., Video Processing and Annotation) techniques aimed at quantifying key behavioral indicators, specifically drinking frequency and brush use- behaviors. These behaviors, while challenging to quantify using traditional methods, offer profound insights into the autonomic nervous system function and an individual cow’s coping mechanisms under heat stress. The developed approach provides an opportunity to quantify these difficult-to-measure drinking and brush use behaviors of dairy cows milked in a robotic milking system. This approach will open up a better opportunity for ranchers to make informed decisions that could mitigate the adverse effects of heat stress. It will also expedite data collection regarding dairy cow behavioral phenotypes. Finally, the developed system is evaluated using different performance metrics, including classification accuracy. It is found that the YoloV8 and CNN models achieved a classification accuracy of 93% and 96% for object detection and classification, respectively. Full article

(1) Background: Climate change is increasing the already frequent diverse extreme weather events (EWE) across geographic locations, directly and indirectly impacting human health. However, current ongoing research fails to address the magnitude of these indirect impacts, including healthcare access. Vulnerable populations such as persons with spinal cord injury (pSCI) face added physiologic burden such as thermoregulation or mobility challenges like closure of public transportation. Our exploratory research assessed commute and transport to healthcare facilities as well as the knowledge, attitudes and behaviors (KAB) of pSCI regarding EWE and climate change when compared to pSCI caregivers (CG) and the general public (GP). (2) Methods: A KAB survey was employed to conduct a cross-sectional assessment of pSCI, CG, and GP in Miami from October through November 2019 using snowball sampling. Descriptive and logistic regression statistical analyses were used. (3) Results: Of 65 eligible survey respondents, 27 (41.5%) were pSCI, 11 (17%) CG, and 27 (41.5%) GP. Overall, pSCI reported EWE, particularly flooding and heavy rain, affecting their daily activities including healthcare appointments, more frequently than CG or GP. The overall models for logistic regression looking at commute to and attendance of healthcare appointments were statistically significant. pSCI self-report being less vulnerable than others, and a large proportion of each group was not fully convinced climate change is happening. (4) Conclusions: This study provided insight to the KAB of 3 population subgroups in Miami, Florida. pSCI are significantly more vulnerable to the effects of regional weather events yet exhibit disproportionate self-perception of their vulnerability. Continued and more comprehensive research is needed to characterize the barriers that vulnerable populations face during weather events. Full article

Bergmann’s and Allen’s rules are two classic ecogeographic rules concerning the physiological mechanisms employed by endotherm vertebrates for heat conservation in cold environments, which correlate with adaptive morphological changes. Thus, larger body sizes (Bergmann’s rule) and shorter appendages and limbs (Allen’s rule) are expected in mammals inhabiting cold environments (higher latitudes). Both rules may also apply to elevational gradients, due to the decrease in external temperature as elevation increases. In this study, we evaluated whether these patterns were true in two coexisting sigmodontine rodents across an elevational gradient in central Chile. We analyzed whether the size of the skull, body, and appendages of Abrothrix olivacea (n = 70) and Phyllotis darwini (n = 58) correlated with elevation, as predicted by these rules in a range between 154 and 2560 m. Our data revealed weak support for the Bergmann and Allen predictions. Moreover, we observed opposite patterns when expectations of Bergmann’s rules were evaluated, whereas Allen’s rule just fitted for ear size in both rodent species. Our results suggest that morphological changes (cranial, body, and appendage sizes) may play a minor role in the thermoregulation of these two species at high elevations, although behavioral strategies could be more critical. Other ecological and environmental variables could explain the morphological trends observed in our study. These hypotheses should be assessed in future studies to consider the relative contribution of morphology, behavior, and physiological mechanisms to the thermal adaptation of these two rodent species at high elevations. Full article