Aphrodite I. Kalogianni

The objective of the present study is to evaluate the effects of lactation stage, age, somatic cell count (SCC), and daily milk yield on plasmin–plasminogen (PL–PG) system activity and physicochemical milk traits in intensively reared Chios and Frizarta ewes. A total of 52 purebred ewes (26 ewes per breed and farm) were randomly selected and prospectively monitored during the 3rd, 5th, and 6th month post-lambing. Daily milk yield and body condition score (BCS) were recorded, and individual milk samples were collected for the assessment of PL–PG activities using enzymatic assays, SCC, electrical conductivity (EC), refractive index (RI), and pH. Correlation analysis and mixed linear regression models were used for the assessment of the effects. Lactation stage significantly affected PL–PG system traits in both breeds, but in opposite direction; plasmin and plasminogen plus plasmin declined toward late lactation in Chios ewes, whereas it increased in Frizarta ewes. Lower SCC was associated with reduced plasmin system activity in Chios ewes, whereas no effect was observed in Frizarta ewes. The plasminogen-to-plasmin ratio remained stable across lactation, breeds, and SCC classes, indicating coordinated regulation of the system. BCS was positively associated with plasmin activity during late lactation, suggesting a stage-dependent metabolic modulation. EC and pH were closely associated with SCC, while RI mainly reflected compositional variation. Our findings underline that, although the PL–PG system is primarily affected by lactation stage and mammary health status in sheep, there are breed-specific regulatory patterns which should be further investigated.

Although soybean meal (SBM) is generally used as the main protein source in livestock diets, canola meal (CM) appears as a sustainable alternative, since it lowers diet cost, especially when regionally produced, while still meeting animal nutritional needs. The objective of this study was therefore to assess the effects of dietary protein source (SBM vs. CM) on carcass traits and meat quality characteristics of feedlot-fattened dairy lambs. A total of 193 weaned lambs, approximately 3 months of age, from two indigenous Greek dairy breeds (75 Chios and 118 Serres), were used. Lambs were randomly assigned to one of two isocaloric and isonitrogenous dietary treatments: a control ration containing SBM as the primary protein source, and an alternative ration in which SBM was completely replaced by CM. After a fattening period of 13 weeks for Chios lambs and 15 weeks for Serres lambs, animals were slaughtered upon reaching a live weight of 35–40 kg, and hot and cold carcass weights were recorded. After 24 h of carcass storage at 4 °C, Longissimus lumborum muscle was sampled and used for the measurement of pH, colour attributes, cooking loss, shear force, and intramuscular fat content. Lipid oxidation was evaluated on days 1, 3, 6, and 9 of refrigerated storage at 4 °C. The substitution of SBM by CM as the main dietary protein source did not affect carcass traits in Serres lambs, whereas CM- treated Chios lambs showed an increased hot and cold carcass weight (p < 0.05). Meat quality characteristics were not affected by the dietary treatment in either Chios or Serres lambs, with the exception of meat oxidative stability that was deteriorated in CM compared to SBM Serres lambs (p < 0.001). In conclusion, the utilization of canola instead of soybean meal did not negatively influence carcass traits or meat quality characteristics in either Chios or Serres lambs, with the exception of lipid oxidation which was significantly higher in CM supplemented Serres lambs.

Precision livestock farming (PLF), by integrating multimodal sensor data, provides opportunities to enhance welfare monitoring and management in small ruminants. This study evaluated whether environmental, physiological, and behavioral measurements—including the temperature–humidity index (THI), carbon dioxide (CO₂) and ammonia (NH₃) concentrations measured at the barn level, body condition score (BCS), rectal and ocular temperatures, GPS-derived locomotion metrics, accelerometry data, and fixed animal traits—can serve as key predictors of welfare and productivity in dairy sheep. Data were collected from 90 ewes: all animals underwent the same repeated welfare assessments, while 30 of them were additionally equipped with GPS–accelerometer sensor collars; environmental conditions were continuously recorded for the entire flock, generating 773 complete multimodal records. All predictive models were developed using data from all 90 ewes; collar-derived behavioral variables were included only for individuals equipped with GPS–accelerometer collars. Nine regression methods (linear regression (LR), partial least square regression (PLSR), elastic net (EN), mixed-effects models, random forest (RF), extreme gradient boosting (XGBoost), support vector regression (SVR), neural networks (multilayer perceptron, MLP), and an ensemble of RF–XGBoost–EN were evaluated using a combination of nested cross-validation (CV) and leave-one-animal-out CV (LOAOCV) to ensure robustness and generalization at the individual animal level. Nonlinear models—particularly RF, XGBoost, SVR, and the ensemble—consistently delivered superior performance across traits. For behavioral (e.g., daily distance movement) and thermal indicators (e.g., medial canthus temperature), the highest predictive capacity (R² ≈ 0.60–0.70) was achieved, while moderate predictive capacity (R² ≈ 0.40–0.50 and ≈0.35–0.45), respectively, was observed for respiratory rate and milk yield, reflecting their multifactorial nature. Feature importance analyses underscored the relevance of THI, CO₂, NH₃, concentrations, and BCS across results. Overall, these findings demonstrate that multimodal sensor fusion can effectively support the prediction of welfare and productivity indicators in intensively reared dairy sheep and emphasize the need for larger and more diverse datasets to further enhance model generalizability and model transferability.

Health and welfare are fundamental to goat production; however, their impact on milk yield in goats reared under different farming systems remains insufficiently studied. The objective was to examine the frequency of various health issues in dairy goats reared under two different farming systems and to assess their effects on daily milk yield (DMY). A total of 286 Skopelos goats from an intensive (N_A = 153) and an extensive (N_B = 133) farm, all with the same genetic background, were prospectively monitored for two consecutive lactation periods. Each goat was clinically examined for animal-based health indicators every 50 days, while individual DMY was also recorded. Morbidity frequency measures (cumulative incidence, point, and period prevalence) were calculated for each one of the studied health issues, and mixed linear regression models were developed to assess the effect of each one of the studied health issues on DMY. The results indicated that overgrown hooves were more common in intensively reared goats, while anemia and nasal discharge prevailed in extensively reared goats. Udder asymmetry, udder fibrosis, body abscesses, poor hair coat quality, and swollen lymph nodes were common in both farms, albeit more prevalent in extensively reared goats, except for udder asymmetry. Among the studied health issues, lameness (18.5%, p < 0.05), mouth lesions (14.1%, p < 0.05), udder asymmetry (6.6%, p < 0.001), and udder fibrosis (9.5%, p < 0.001), were significantly associated with reductions in DMY. These findings provide valuable insights for optimizing herd health management practices in dairy goats based on evidence and farming system requirements.

The objective was to examine the frequency of various health issues in dairy goats reared under two different farming systems and to assess their effects on daily milk yield (DMY). A total of 286 Skopelos goats from an intensive (NA = 153) and an extensive (NB = 133) farm, all with the same genetic background, were prospectively monitored for two consecutive lactation periods. Each goat was clinically examined for animal-based health indicators every 50 days, while individual DMY was also recorded. Morbidity frequency measures (cumulative incidence, point and period prevalence) were calculated for each one of the studied health issues, and mixed linear regression models were developed to assess the effect of each one of the studied health issues on DMY. The results indicated that overgrown hooves were more common in intensively reared goats, while anaemia and nasal discharge prevailed in extensively reared goats. Udder asymmetry, udder fibrosis, body abscesses, poor hair coat quality, and swollen lymph nodes were common in both farms, albeit more prevalent in extensively reared goats, except for udder asymmetry. Among the studied health issues, lameness (18.5 %, p < 0.05), mouth lesions (14.1 %, p < 0.05), udder asymmetry (6.6 %, p < 0.001), and udder fibrosis (9.5 %, p < 0.001), were significantly associated with reductions in DMY. These findings provide valuable insights for optimizing herd health management practices in dairy goats based on evidence and farming system requirements.

The high genetic heterogeneity of small ruminant lentiviruses (SRLV) renders the genetic characterization of the circulating strains crucial for the epidemiological investigation and the designation of effective diagnostic tools. In Greece, research data regarding the genetic diversity of the circulating SRLV strains is scarce, hindering the implementation of efficient surveillance and control programs. The objective of the study was to genetically characterize SRLV strains isolated from intensive dairy sheep farms in Greece and evaluate the variability of the immunodominant regions of the capsid protein. For this reason, a total of 12 SRLV-infected animals from four intensive dairy sheep farms with purebred Chios and Lacaune ewes were used for the amplification and sequencing of an 800 bp gag-pol fragment. The phylogenetic analyses revealed a breed-related circulation of strains; Chios ewes were infected with strains belonging exclusively to a separate group of genotype A, whereas strains belonging to subtype B2 were isolated from Lacaune ewes. Immunodominant epitopes of capsid protein were quite conserved among the strains of the same genotype, except for the Major Homology Region which showed some unique mutations with potential effects on viral evolution. The present study contributes to the extension of the current knowledge regarding the genetic diversity of SRLV strains circulating in sheep in Greece. However, broader genetic characterization studies are warranted for the exploration of possible recombinant events and the more comprehensive classification of the circulating strains.

A two-year longitudinal cohort study was conducted on a total of 407 purebred Chios and Lacaune ewes from four intensive dairy sheep farms to assess potential risk factors for small ruminant lentiviruses (SRLVs) seropositivity. Ewes were serologically tested semiannually at pre-mating and pre-lambing, and their age, breed, and body condition score (BCS) were recorded. Εwes were categorized as constantly seronegative, constantly seropositive, seroconverted, seroreverted, or animals with an intermittent presence of antibodies. Mixed binary logistic regression models were used to estimate the adjusted relative risks of the studied risk factors for (i) the individual ewes’ seropositivity, (ii) the manifestation of specific serological patterns, and (iii) the occurrence of seroconversion and seroreversion incidents. Increased age was associated with seropositivity and constantly seropositive status (p < 0.001 in both cases). On the other hand, age was negatively associated with constantly seronegative pattern, seroconversion incident, and the intermittent presence of antibodies (p < 0.05 in all cases). Moreover, breed was recognized as a risk factor: Lacaune ewes demonstrated increased seropositivity, whereas Chios ewes were more likely to demonstrate an intermittent presence of antibodies (p < 0.01 in both cases). Seropositive status (p < 0.001), seropositivity in animals with an intermittent presence of antibodies (p = 0.001), and seroconversion incidents (p < 0.001) were significantly increased at pre-lambing compared to pre-mating. The risk factors recognized in our study contribute to a better understanding of SRLVs epidemiology and the evidence-based designation of SRLVs’ control programs in intensive dairy sheep farms in Greece.

The objective of this study is to prospectively evaluate the seroepidemiology of maedi-visna (MV) infections in intensively reared dairy sheep. A total of 407 purebred Chios and Lacaune ewes from four farms were surveyed for two consecutive years and were serologically tested semiannually with an indirect ELISA at pre-mating and pre-lambing. The farms’ structure and management practices were similar and animal traits (age, breed, and production stage) were recorded. Based on the serological status, morbidity frequency measures were estimated, and ewes were categorized as constantly seronegative, constantly seropositive, seroconverted, seroreverted, or as animals with an intermittent presence of antibodies. During the study, period seroprevalence, incidence rate, and cumulative incidence were 84.8%, 33.6 new cases per 100 sheep-semesters, and 64.2%. Point-seroprevalence ranged from 48.5% to 96.0% among the studied farms and sampling occasions, and they increased by age. Increased morbidity frequency measures indicate the significance of horizontal transmission in intensive dairy sheep farms. A remarkable percentage of infected animals seroreverted (8.1%) or presented an intermittent presence of antibodies (10.3%) during the study, confirming the risk of misdiagnosis in cross-sectional studies and in the currently implemented testing and elimination programs. The serological patterns observed in our study need to be considered when studying MV epidemiology and for the designing of efficient MV elimination programs.

The replacement of soybean meal (SBM) from intensively reared dairy sheep diets has emerged as a significant challenge for sustainable production. However, the effects of this replacement on milk production have not been sufficiently elucidated. The objective of this study was to prospectively assess the effects of replacing SBM with a mixture of alternative protein sources on the milk yield (MY) and the milk quality traits (MQT) in intensively reared dairy sheep. A total of 112 multiparous, purebred milking ewes of the Chios and Frizarta breeds, from two intensive dairy sheep farms, were involved in the study, postweaning, and were assigned to either the control (CR) or the experimental ration (ER) group. In the ER, 3/4 of the SBM was replaced by a mixture of rapeseed meal, cottonseed cake, and fava beans, producing a ration of a similar nutritional value. MY, MQT, and body condition scores were recorded for each individual ewe monthly for a period of 4 months during lactation. The experimental ration was associated with beneficial effects on daily and 100-day fat yields and on the electrical conductivity of milk as an improved udder health status indicator, with no adverse effects on any of the rest of the studied milk production traits.

The objectives of this study were to investigate temperature distribution at the sheep hoof and evaluate the reliability and diagnostic performance of infrared thermography (IRT) for the detection of footrot and white line disease (WLD) lesions in intensively reared dairy sheep. Hoof lesions were clinically assessed, and IRT was used to measure temperature distribution on hoof superficial tissue in 600 multiparous ewes. Binary regression models were developed and validated, and receiver operating characteristic curves were estimated to assess the predictive value and diagnostic performance of IRT for the detection of hoof lesions. The most sensitive prediction model for the detection of IFR was based on the difference between ambient and hoof heel temperature (sensitivity: 83.3%, specificity: 47.8%, and threshold value: 6.5 °C), whereas the most specific prediction model was based on the difference between ambient and coronary band temperature (sensitivity: 51.9%, specificity: 79.7%, and threshold value: 11.3 °C). In the case of WLD, the diagnostic performance of IRT had limited predictive value. IRT could be a useful tool for hoof health screening in dairy sheep. However, it must be cautiously adapted in cases where environmental, operating, and operator variables are not effectively controlled.