The dairy industry contributes significantly to anthropogenic methane emissions, which have an impact on global warming. This study aimed to investigate the effects of a dietary inclusion of brown seaweed Ascophyllum nodosum on enteric methane emissions (EMEs), hematological and blood biochemical profiles, and milk composition in dairy cows. Eighteen Holstein cows were divided into three groups: CON (non-supplemented cows), BS₅₀ (50 mL of 10% A. nodosum), and BS₁₀₀ (100 mL of 10% A. nodosum). In each cow, measurements of EME, dry matter intake (DMI), and milk yield (MY), as well as blood and milk sampling with respective analyzes, were performed before supplementation (P1), after 15 (P2) days, and after 30 (P3) days of supplementation. A. nodosum reduced (p < 0.05) methane production, methane yield, and methane intensity in both BS₅₀ and BS₁₀₀, and raised DMI (p < 0.05) only in BS₅₀. Total bilirubin (p < 0.05) was higher in BS₅₀ compared to CON cows in P2, and triacylglycerols were lower (p < 0.05) in BS₅₀ than in CON cows in P3. Higher milk fat content was found in BS₅₀ than in CON cows in P3. C16:0 proportions were higher (p < 0.05) in BS₅₀ and BS₁₀₀ than in CON cows, while C18:3n-3 was higher (p < 0.05) in BS₁₀₀ than in BS₅₀ and CON cows in P3. Dietary treatment with A. nodosum reduced EMEs and showed the potential to increase DMI and to improve energy status as well as milk composition in peak-lactating dairy cows.

Cows in the peripartal period undergo changes in thyroid hormones and are susceptible to lipomobilization and/or oxidative stress. The addition of chestnut tannins as polyphenolic compounds in the diet may improve feed efficiency and prevent oxidative stress-related health disorders in transition cows. However, the relationship between chestnut tannin supplementation and thyroid function, which plays an important role in metabolic regulation, has not been investigated in dairy cows. This study was conducted to investigate the effects of chestnut tannin supplementation during the close-up period on thyroid status and to evaluate the interaction between thyroid hormones and oxidative stress biomarkers in prepartum dairy cows. Forty multiparous Holstein cows were fed either a diet containing chestnut tannins (CNTs, n = 20, 1.96 g chestnut tannins/kg feed, dry matter) or a non-supplemented diet (CON, n = 20) during the last 25 ± 2 days of gestation. Blood samples were collected on the first day of study (before chestnut tannin supplementation) and d 5 before parturition to measure hormonal and oxidative stress indices. Serum concentrations of T3 (p = 0.04) and T4 (p = 0.05) were higher in CNT cows than in the CON group on day 5 before parturition. Thyroid status of CNT cows was associated with higher serum total antioxidant capacity (T-AOC, p < 0.01), activities of superoxide dismutase (SOD, p = 0.03) and glutathione peroxidase (GPx, p = 0.01), and reduced glutathione concentration (GSH, p = 0.05). Serum thiobarbituric acid reactive substances (TBARS) were lower (p = 0.04) which was associated with lower aspartate aminotransferase (AST, p = 0.02), and lactate dehydrogenase (LDH, p = 0.01) activities in the CNT than in the CON group. Estradiol and progesterone did not differ between CNT and CON cows. Chestnut tannin supplementation improves antioxidant protection, prevents oxidation-reduction processes, reduces the degree of liver cell membrane damage, and protects thyroid tissue from damage, allowing higher T3 and T4 synthesis. Considering the importance of the thyroid hormone status before parturition, mechanisms of thyroid hormone regulation in CNT-supplemented dairy cows require more detailed investigations.

Dietary tannin supplementation represents a potential strategy to modulate rumen fermentation and enhance lactation performance in dairy cows, though responses remain inconsistent. A 21-day feeding trial was conducted to evaluate the effect of chestnut tannin (CNT) extract on the enteric methane emissions (EME), blood metabolites, and milk production traits in mid-lactation dairy cows. Thirty-six Holstein cows were allocated to three homogeneous treatment groups: control (CNT₀, 0 g/d CNT), CNT₄₀ (40 g/d CNT), and CNT₈₀ (80 g/d CNT). Measurements of EME, dry matter intake (DMI), milk yield (MY), and blood and milk parameters were carried out pre- and post-21-day supplementation period. Compared with the no-additive group, the CNT extract reduced methane production, methane yield, and methane intensity in CNT₄₀ and CNT₈₀ (p < 0.001). CNT₄₀ and CNT₈₀ cows exhibited lower blood urea nitrogen (p = 0.019 and p = 0.002) and elevated serum insulin (p = 0.003 and p < 0.001) and growth hormone concentrations (p = 0.046 and p = 0.034), coinciding with reduced aspartate aminotransferase (p = 0.016 and p = 0.045), and lactate dehydrogenase (p = 0.011 and p = 0.008) activities compared to control. However, CNT₈₀ had higher circulating NEFA and BHBA than CNT₀ (p = 0.003 and p = 0.004) and CNT₄₀ (p = 0.035 and p = 0.019). The blood glucose, albumin, and total bilirubin concentrations were not affected. MY and fat- and protein-corrected milk (FPCM), MY/DMI, and FPCM/DMI were higher in both CNT₄₀ (p = 0.004, p = 0.003, p = 0.014, p = 0.010) and CNT₈₀ (p = 0.002, p = 0.003, p = 0.008, p = 0.013) cows compared with controls. Feeding CNT₈₀ resulted in higher protein content (p = 0.015) but lower fat percentage in milk (p = 0.004) compared to CNT₀. Milk urea nitrogen and somatic cell counts were significantly lower in both CNT₄₀ (p < 0.001, p = 0.009) and CNT₈₀ (p < 0.001 for both) compared to CNT₀, while milk lactose did not differ between treatments. These findings demonstrate that chestnut tannin extract effectively mitigates EME while enhancing lactation performance in mid-lactation dairy cows.

In recent years, there have been numerous research activities related to the use of different herbal agents, especially those originating from chestnuts and garlic, as alternatives to synthetic growth promoters like antibiotics. Garlic and its active ingredients have been studied for their potential benefits, such as improving feed intake, production performance, rumen fermentation, and udder health. The aim of our study was to investigate the influence of garlic polysulfides, including diallyl polysulfide and dipropyl polysulfide, on hematological and biochemical parameters in dairy cows, as well as their possible effect on subclinical mastitis therapy. Eighteen late lactation Holstein cows were divided into three numerically equal groups (n=6): CON (non-supplemented cows), ALL (supplemented with 1000 mg/day of diallyl polysulfide), and PRP (supplemented with 1000 mg/day of dipropyl polysulfide). Blood sampling for hematological and biochemical analyses as well as the California mastitis test (CMT) test were performed before and after the 15-day study. The results showed that garlic supplementation significantly increased blood leukocyte count and blood glucose concentration (p<0.05, respectively), and significantly decreased blood urea concentration (p<0.05) after the 15-day trial in both ALL and PRP groups compared with the day 0. In the supplemented groups, the CMT score was significantly lower (p<0.05, respectively) after the 15-day treatment compared with the CON group. The use of different mixtures of biologically active garlic polysulfides in the diet could improve immune and metabolic status, as well as support mastitis treatments in dairy cows.

Wild boars are important reservoirs of Aujeszky?s disease virus and African swine fever (ASF), making the animals a key factor in the spread of these diseases to domestic pig populations. One of the most common routes of virus transmission among wild boars is sexual contact, particularly during the close contact associated with mating, while migration and interactions with human activities further facilitate the spread of infections. The seroprevalence of Aujeszky?s disease varies across Europe, ranging from 0% to over 50%, depending on the region. In Serbia, the first case of ASF in domestic pigs was confirmed in 2019, and in wild boars in 2020 in border areas. The aim of this study was to determine the presence of Aujeszky?s disease virus and ASF in the wild boar population in central Serbia, specifically within the epizootiological units of Pomoravlje and Sumadija. The research was conducted using molecular and serological methods to detect the viruses and specific antibodies. Additionally, the spatial and temporal distributions of these diseases in the observed area were analyzed. For the purposes of this study, samples from wild boars of different sexes and ages were analyzed. The samples were collected during the hunting season from August to November 2023 in the territories of the Pomoravlje and Sumadija districts. A total of 90 samples were examined, with blood sera used for serological analysis and organs (spleen and kidney) from the same animals used for molecular analysis. Serological analysis of the examined samples revealed a high concentration of antibodies against Aujeszky?s disease virus in wild boars from both Pomoravlje and Sumadija. Regarding ASF virus, positive serological findings in the wild boars were recorded only in Pomoravlje, while all samples from Sumadija tested negative. Based on the total number of samples examined (n=90), the seroprevalence of Aujeszky?s disease was determined to be 26.7%, while that of ASF was 3.3%. Molecular analysis of wild boar organs did not confirm the presence of viral genetic material for either Aujeszky?s disease or ASF. Serological findings indicate ongoing circulation of these viruses in wild boars and a potential risk to domestic pigs. Continuous monitoring is, therefore, essential for early detection and effective disease prevention.