Konstantina Dimoveli

Heat stress (HS) constrains livestock production under climate change, impairing health, welfare, productivity and survival. Because fixed resource use is then spread over less output, HS is also a systems-level sustainability problem. This narrative review, based on a targeted search of PubMed, Web of Science and Scopus (2013–2026), proposes a framework linking climate exposure, animal responses, resource flows, circular interventions and Life Cycle Assessment (LCA) across dairy cattle, pigs, poultry and small ruminants, and grades the evidence behind each link. A decomposition of meta-analytic data indicates that HS raises the impact per kg of milk by approximately 3–12% during heat-stress periods, mainly through non-feed burdens. Monte Carlo analysis shows that the direction of this effect is robust, whereas its magnitude depends mainly on the feed share of the total burden. A Heat-Stress Circularity Index (HSCI) is operationalized with explicit metrics, normalization bounds, a geometric aggregation rule and a minimum-welfare gate. A worked example shows that system rankings depend on the aggregation rule, and a pilot application to a commercial Mediterranean pig farm shows that heat-season piglet and weaner mortality triggers the welfare gate despite moderate productivity retention. Evidence is strong for physiological responses but absent for LCA under measured heat stress; five falsifiable hypotheses, with the corresponding validation designs and sample sizes, are therefore proposed.

Heat stress remains a significant issue in pig production, particularly in Mediterranean regions, due to the link between climate change and rising temperatures. This study evaluated the effects of heat stress on physiology, oxidative status, animal welfare, histopathological changes, and production in a commercial farrow-to-finish pig farm during the warm season of 2025. Environmental conditions, physiological parameters, welfare, and oxidative stress biomarkers were monitored throughout the study period, while continuous neck skin surface temperature monitoring in lactating sows was carried out using Bluetooth sensor technology. Heat stress was evident over an extended period, as indicated by increased temperature in lactating sows, compromised welfare, oxidative stress, reduced antioxidant capacity, poor reproductive and productive performance, decreased daily growth rate, and higher mortality-related indices. Histopathological examination also revealed multisystemic lesions, including fibrinous microthrombi in renal vessels, hepatocellular degeneration, perivascular oedema with vascular wall thickening in the skin, and lymphocyte depletion in splenic germinal centres. These findings are consistent with endothelial dysfunction, ischaemic tissue damage, and stress-induced immunomodulation. In conclusion, heat stress causes multi-dimensional biological and productive alterations in pigs under intensive farming systems, involving thermoregulatory, oxidative, welfare, reproductive, and histopathological impairments, which support the implementation of integrated precision livestock farming monitoring approaches.

In the Mediterranean principality of Thessaly, Greece, heat stress has become an environmental limitation on animal production and welfare. This study aims to quantify livestock heat stress using the temperature–humidity index (THI) and assess its spatial and temporal distribution across Thessaly during the warm seasons from 2020 to 2025, based on ERA5-Land reanalysis data. For selected livestock units, hourly air temperatures and dew point temperatures were used to generate and calculate maximum temperature fields and the THI under outdoor conditions, with no directly measured physiological responses in animals, but potential heat stress exposure was evaluated using THI derived from ERA5-Land data. The results reveal persistent thermal hotspots in the central and southeastern Thessalian plain, where maximum daily temperatures frequently exceeded 38–40 °C and locally surpassed 45 °C during August. THI values regularly exceeded 72, indicating productivity decline, and reached 82 during peak summer months, corresponding to high and severe stress categories. Mountainous regions were consistently 6–10 °C cooler and exhibited lower THI levels. Thermally stressful conditions extended from May through September, indicating sustained seasonal exposure rather than isolated heatwave events. The spatial coincidence between intensive livestock production and high-THI zones suggests structural vulnerability under current climate conditions. These findings offer a spatially explicit assessment of climate-driven thermal risk and support the development of targeted mitigation strategies and climate-resilient livestock management in Mediterranean agricultural regions. They also offer a data-driven foundation for integration into emerging Digital Twin frameworks for predictive livestock management.

Mycotoxin contamination of cattle feed commonly results in chronic, subclinical exposure with adverse effects on liver function and oxidative status. This controlled field trial evaluated a multi-component mycotoxin detoxifier in fattening mixed Limousin calves fed naturally contaminated diets under commercial production conditions. Twenty-four clinically healthy calves were randomly allocated to a control group or to a treatment group receiving a detoxifying additive containing adsorbent clays, phytogenic extracts (silymarin and curcumin) and yeast-derived components for 60 days. Feed, blood, fecal and liver samples were analyzed to assess biochemical, oxidative and histopathological re-sponses throughout the experimental period. The diet contained aflatoxin B1, fumonisins and zearalenone at concentrations exceeding guidance limits, indicating chronic mul-ti-mycotoxin exposure. No clinical signs of overt mycotoxicosis were observed. All bio-chemical parameters remained within physiological ranges; however, γ-glutamyl trans-ferase activity and protein carbonyl levels were significantly lower in treated calves com-pared with controls (p < 0.05). Other oxidative stress markers did not differ between groups, and histopathology revealed only mild, non-specific liver changes. In conclusion, supplementation with the tested mycotoxin detoxifier was safe and associated with im-proved hepatic enzyme regulation and reduced protein oxidative damage under field conditions.

There is a scarcity of relevant information in the international literature regarding the welfare of dairy ewes during the milking process and the potential impact on the quality of the produced milk. Hence, there is a scope to further study potential interactions between the milking process and animal welfare in dairy sheep flocks. The specific objectives of this study were (i) the evaluation of the frequency of reactions potentially associated with the reduced welfare of dairy sheep during the milking process, (ii) the identification of predictors associated with the presence of these reactions, and (iii) the evaluation of associations with the quality of milk produced on a farm. The study was conducted in 52 dairy sheep farms in Greece. The farms were visited, and the milking process was observed and monitored, and the reactions of ewes during the milking process were recorded; samples from the bulk-tank milk were collected for somatic cell and total bacterial counting. Univariable and multivariable analyses were performed. The median duration of milking per row was 7.9 min, and the median duration of the milking process was 105 min. The reaction observed less often from ewes was vocalisation (in 9.6% of farms), and the one observed more frequently was ‘spot stepping’ (in 98.1% of farms). In total, eight different predictors were identified for the displaying of the various reactions observed and recorded; of these, two were related to the milking parlour and six were related to the milking process. Moreover, three different predictors were identified for the milk quality parameters; of these, one was related to the milking parlour and two were related to the milking process. Finally, a mild correlation was seen between the proportion of ewes that attempted to remove the milking cluster, and the somatic cell counts in the bulk-tank milk (p = 0.023). The results confirmed that incorrect practices during machine-milking can be stress factors for dairy sheep. In light of the present findings, procedures by milkers should be carefully carried out, which will contribute to minimising the nervousness and aggravation of ewes during milking. Stress factors can adversely affect the quality of milk produced on the farm. The findings underline that maintenance of animal welfare is linked to high product quality. This connection can further extend to consumer perceptions: the ethical treatment of dairy sheep is considered as an important facet of the overall food quality and sustainable production.

Mycotoxins are common feed contaminants that can affect the health, immune function, and productivity of ruminants by causing oxidative stress and organ dysfunction. In this field study, the effects of a phytogenic multicomponent mycotoxin detoxifier on oxidative status, liver function, udder health, and productive parameters were investigated in dairy ewes. One hundred clinically healthy ewes were randomly assigned to either a control group or a treatment group, with the latter receiving 1.5 kg/ton of the detoxifier over a 90-day period during lactation. The detoxifying agent contained adsorptive clays as well as phytogenic ingredients such as silymarin and curcumin, which are known for their hepatoprotective and antioxidant properties. Blood, milk, and colostrum samples were collected and analyzed for oxidative stress markers (TBARS and protein carbonyl (CARBS)), total antioxidant capacity (TAC), liver enzymes (ALT, AST, and ALP), and milk quality parameters (fat, protein, and solid content). Clinical assessments included mastitis scoring, udder inflammation, and fecal consistency. The treated ewes showed a statistically significant reduction in blood plasma and milk oxidative stress markers and liver enzyme levels while at the same time improving the fat and solid content of the milk. The incidence and severity of mastitis, udder reddening, and lactation abnormalities were lower in the treatment group. Brix refractometry indicated improved colostrum quality in the treated ewes. These results suggest that the detoxifier improved the oxidative balance, liver function, and overall health and productivity of dairy ewes under field conditions, supporting its use as a practical nutritional measure.

The objectives of the present work were as follows: (i) the detection of cathelicidin biomolecules in the milk of individual goats during the early stages of mastitis and their potential use for the diagnosis of mastitis at its early stage and (ii) the evaluation of the presence of cathelicidin proteins in the bulk-tank milk from goat and sheep farms. In an experimental study, after inoculation of Staphylococcus simulans into a mammary gland of goats, bacteriological and cytological examinations of milk samples, as well as proteomics examinations [two-dimensional gel electrophoresis analysis (2-DE) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometer (MALDI-TOF MS) analysis] were performed sequentially, from 4 to 48 h post-challenge. Cathelicidin-1 and cathelicidin-2 were detected consistently in milk samples obtained throughout the study, and spot optical densities obtained from PDQuest v.8.0 were recorded. Associations were calculated between the presence of mastitis in a mammary gland at a given timepoint and the detection of cathelicidin proteins in the respective milk sample. All inoculated mammary glands developed mastitis, confirmed by the consistent bacterial isolation from milk samples and the increased somatic cell content therein. Spot optical density of cathelicidin proteins was higher than in samples from contralateral mammary glands. There was a significant association between the presence of mastitis in a mammary gland and the detection of cathelicidin biomolecules in the respective milk sample; the overall accuracy was 81.8% (95% confidence interval: 70.4–90.2%). In a field investigation, the presence of cathelicidin proteins was evaluated in the bulk-tank milk of 32 dairy goat and 57 dairy sheep farms. In this part of the work, no cathelicidin proteins were detected in any bulk-tank milk sample of goat, 0.0% (95% confidence interval: 0.0–10.7%), or sheep, 0.0% (95% confidence interval: 0.0–6.3%), farms.

This study examines the use of analgesic medications among sheep farmers, highlighting both their benefits and the significant gaps in their adoption. Our findings indicate that 26.7% of sheep farmers did not utilize any analgesics, a figure that contrasts sharply with high usage rates among swine (over 80%) and cattle (over 85%) farmers. The low utilization of NSAIDs and corticosteroids in sheep farming may be attributed to inadequate education and the lack of approved indications for these medications in Greece. Additionally, we found a positive correlation between farm size and the use of NSAIDs, with larger farms using more NSAIDs, especially flunixin. Furthermore, farms with higher NSAID use—typically the larger ones—tended to have higher milk yields, suggesting that enhanced management practices may contribute to improved outcomes. The results underscore the need for targeted educational initiatives to improve the use of analgesics in sheep farming and address welfare concerns. Overall, this research highlights the importance of addressing gaps in pain management practices in the sheep farming sector to promote better animal welfare. However, further studies with larger sample sizes are needed to expand our understanding of analgesic use and its implications for sheep welfare.

This study examines the use of analgesic medications among sheep farmers, highlighting both their benefits and significant gaps in their adoption. Our findings indicate that 26.7% of sheep farmers did not utilize any analgesics, a figure that contrasts sharply with high usage rates exceeding among farmers in swine and cattle sectors. Low utilization of NSAIDs and corticosteroids in sheep farming may be attributed to inadequate education and the absence of approved indications for these medications in Greece. Additionally, we found a positive correlation between farm size and the use of NSAIDs, with larger farms using more NSAIDs, especially flunixin. Furthermore, farms using more NSAIDs/larger farms tended to have higher milk yields, suggesting that enhanced management practices are associated with better outcomes. The results underscore the need for targeted educa-tional initiatives to improve the use of analgesics in sheep farming and address welfare concerns. Overall, this research highlights the importance of addressing gaps in pain management practices within the sheep farming sector to promote better animal welfare. However, further studies with larger sample sizes are recommended to expand our un-derstanding of analgesic use and its implications for sheep welfare.

An outbreak of acute mastitis was investigated in a dairy sheep farm in Central Greece with a prevalence of 8.2%. Two animals were examined with symptoms of hyperacute inflammation in one of the two mammary glands. Affected glands presented swollen to grossly enlarged, warm and painful. In both animals, haematological examination revealed mild anaemia, increased leucocyte counts with mature neutropaenia and left shift, and marked thrombocytosis. Bacteriological examinations of mammary gland secretion yielded heavy growth of Streptococcus dysgalactiae and Escherichia coli from each of the two animals, respectively. Serological examination revealed a high percentage of positive samples for small ruminant lentivirus infection in both animals. The somatic cell count in the bulk-tank milk was 0.65 × 10⁶ cells/mL. The housing conditions were inadequate with high levels of ammonia, intense stocking and muddy bedding. This pathological condition in nulliparous ewes was attributed to the extensive oedema of mammary gland and teat, the relaxation of immunity during the peri-parturient period and the heavily contaminated environment. These findings are in general agreement with corresponding incidents in heifers. Following our instructions for improving housing conditions, no other similar incidents were recorded.