Ketosis is one of the most common metabolic disorders in high-yielding dairy cows in early lactation. It has a negative impact on milk yield, reproduction, and general health of the animals. The present review aims to systematize and critically analyze current scientific data on the monitoring, diagnosis, prevention, and treatment of subclinical and clinical ketosis, with the aim of developing an applicable protocol for good veterinary medical practices (GMP). Based on the comparative analysis method of data from the literature and clinical practice, β-hydroxybutyrate (BHBA) in blood is confirmed as the gold standard for diagnosis with specificity and sensitivity above 90%. Indicators such as fat/protein (F/P) > 1.4 and NEFA > 0.4 mmol/L, as well as reduced citrate content in milk, have been evaluated as useful screening tools, although with lower diagnostic value. Despite the advantages of some indirect methods (such as F/P), critical analysis shows that they are strongly influenced by physiological status, lactation stage, and diet and cannot replace direct blood tests. Preventive approaches emphasize the importance of stable nutrition in the pre- and post-calving period, restriction of ketogenic feeds, and use of oral glucose precursors. Literature analysis shows that propylene glycol is effective, but with prolonged use it can reduce appetite. Combined antiketotic products have also been introduced, providing not only energy support but also liver protection. Particular attention has been paid to monensin (applied in the commercial product “Kexxtone”)—a polyether antibiotic with sustained release, which reduces the incidence of ketosis by over 50% and increases milk yield in the first weeks after calving. However, its high cost, antibiotic nature, and need for veterinary supervision limit its universal use. The treatment protocol is differentiated according to the clinical type: glucose I. V. and propylene glycol in type I ketosis and avoidance of glucocorticoids in suspected type II (hepatic steatosis). In the critical analysis It is noted that improper use of glucocorticoids can lead to a worsening of the condition. A structured protocol for DVMP (Dairy Veterinary Medical Practice) is proposed, which includes targeted metabolic monitoring (NEFA, BHBA, F/P); proven preventive regimens (Kexxtone, propylene glycol, balanced rations), and staged prevention and treatment according to the form of ketosis. The adaptation of good practices to the scale of the farm and the level of knowledge and skills of the staff for their correct application remains a challenge. Providing training, a standardized control log, and access to field diagnostic tools is key to the success of any protocol.

Passive transfer of immunoglobulin G (IgG) through colostrum is essential for early immune protection in dairy calves. This systematic review synthesizes the most relevant evidence on colostrum quality, feeding practices, storage methods, and post-feeding assessment. High-quality colostrum (≥50 g/L IgG and low bacterial contamination) can be reliably assessed using Brix refractometry (≥22%) or radial immunodiffusion. Early administration is critical: feeding within 1–2 h after birth maximizes IgG absorption. Providing 8.5–10% of body weight (≈3–4 L) at first feeding, followed by a second feeding within 8–12 h, significantly reduces failure of passive transfer. Pasteurization at 60 °C for 60 min and controlled freezing maintain immunological integrity while reducing microbial load. Monitoring passive immunity using serum total protein (5.0–5.5 g/dL) or serum Brix (8.1–8.5%) offers practical field diagnostics aligned with the IgG ≥ 10 g/L threshold. Integrated colostrum management protocols—combining quality evaluation, timely feeding, hygienic handling, and trained personnel—are essential to improve passive immunity, health, and overall performance of dairy calves.

Background/Objectives: Hypocalcemia is a major transition-cow disorder in dairy cattle, with clinical and subclinical forms differing in detectability, severity, timing, and herd-level consequences. This systematic review integrates evidence on calcium (Ca) homeostasis, classification of clinical hypocalcemia (CHC) and subclinical hypocalcemia (SCH), diagnostic interpretation, risk factors, systemic effects, and preventive and therapeutic strategies in dairy cows. Methods: Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 statement, PubMed, ScienceDirect, SpringerLink, and CAB Abstracts were searched in February 2026 for 1994–2025 publications, and 23 reports were included in a qualitative synthesis; meta-analysis was not performed because of methodological and outcome heterogeneity. Results: The evidence indicates that hypocalcemia should be interpreted as a failure of homeorhetic adaptation to abrupt mammary Ca export rather than as a simple mineral deficiency. The parathyroid hormone–vitamin D axis, skeletal Ca mobilization, renal Ca conservation, intestinal Ca absorption, magnesium (Mg) status, dietary cation–anion difference (DCAD), dry matter intake, parity, and acid–base balance jointly determine whether blood Ca is maintained during early lactation. Total calcium (tCa) thresholds are useful decision aids for herd-level monitoring, but their interpretation depends on sampling time, parity, persistence pattern, clinical signs, and the relationship between tCa and ionized calcium (iCa). Subclinical hypocalcemia is most relevant when it is delayed, persistent, or occurs in high-risk cows because reduced Ca availability can impair smooth muscle function, feed intake, immune competence, uterine health, and metabolic resilience. Management should therefore combine prepartum ration control, Mg adequacy, DCAD and urine pH monitoring, selective Ca testing in high-risk cows, targeted oral Ca supplementation for standing cows, and intravenous Ca treatment for recumbent CHC cases. Conclusions: The evidence supports a risk-based, context-aware strategy rather than universal threshold-driven treatment.

Airborne microbial contamination in dairy cattle housing is strongly influenced by housing conditions and management practices. This study evaluated the influence of environmental and housing parameters on total bacterial, coliform, and mold levels across four dairy farms. Microclimatic variables, including temperature, relative humidity, wind speed, bedding moisture, air volume per cow, particulate matter (PM₁, PM_2.5, PM₁₀), and total volatile organic compounds (TVOCs), were measured. Comparative analyses showed that air volume per cow and bedding moisture were consistently associated with variability in total microbial and mold counts, while particulate matter and wind speed were linked to differences in airborne coliforms. Generalized linear mixed models indicated that most environmental variables did not have statistically significant effects, with the exception of farm type for coliforms and temperature for molds. The predominance of non-significant environmental effects, together with more consistent differences observed between farms, suggests that variability in airborne microbial levels is more strongly associated with farm-specific management and housing characteristics than with individual environmental parameters. Overall, the findings highlight the combined influence of housing design, management practices, and environmental conditions, emphasizing the importance of optimized ventilation and bedding management to improve air quality in dairy cattle housing.

The aim of the present study was to evaluate the association between seasonal variation, the temperature–humidity index (THI), and lipid indices related to human health in the milk of Simmental and Montbéliarde cows. The investigation was conducted on a dairy farm located in Central Southern Bulgaria over a 12-month period and included 100 lactating cows, with equal numbers from each breed, housed in semi-open free-stall barns and fed an unchanged total mixed ration. Monthly measurements of microclimatic parameters (temperature, relative humidity, THI, and air velocity) were conducted throughout the study, and composite milk samples were analyzed for fatty acid composition by gas chromatography. The atherogenic index (AI), thrombogenic index (TI), health-promoting index (HPI), hypo-/hypercholesterolemic index (h/H), desaturase indices (DI16 and DI18), and the UFA/SFA, PUFA/SFA, and MUFA/SFA ratios were calculated based on the fatty acid profile. The results indicate that season has a statistically significant effect on all studied lipid indices (p < 0.001). The Kruskal–Wallis H values ranged from 16.68 for AI to 27.82 for DI18, indicating that seasonal variations in microclimatic conditions significantly influence the lipid metabolism of the cows. The data for the studied lipid indices indicate that the most favorable fat profile for human health was observed in autumn, characterized by lower AI (2.24) and TI (1.26) values and higher HPI (0.45) and h/H (0.76) values. Seasonal variation also affected DI 16 and DI 18, with the most favorable values for humans observed in autumn (DI 16: 4.38; DI 18: 74.39). The ratios of unsaturated to saturated fatty acids (UFA/SFA, PUFA/SFA, and MUFA/SFA) indicate that the milk from the studied farm exhibits the most favorable functional properties in autumn.

The present study evaluated the effects of dietary supplementation with Bacillus coagulans DSM 32016 on growth performance, hematological and biochemical parameters, and nitrogen metabolism in weaned Danube White pigs reared under standard production conditions. While supplementation did not result in statistically significant changes in average daily gain (ADG), feed conversion ratio (FCR), hematological indices, or serum lipid profile, numerical trends indicated slightly higher ADG, improved FCR, and subtle stabilization of hematological parameters in the probiotic supplemented group. Notably, serum urea concentration was significantly reduced (3.78 vs. 3.21 mmol/L; p = 0.017; Cohen’s d = 1.01), suggesting a potential positive effect on nitrogen metabolism and protein utilization efficiency. These findings are consistent with previous reports that probiotics may exert beneficial physiological effects even in the absence of statistically significant systemic changes. The observed trends highlight the potential of Bacillus coagulans to support growth performance and metabolic efficiency in Danube White pigs, emphasizing the importance of breed and age-specific responses in probiotic supplementation.