Čimbenici koji utječu na sadržaj kolesterola u mlijeku krava hranjenih konzerviranim krmivima TMR sustavom tijekom godine

The aim of this study was to evaluate changes in the cholesterol content in the milk of high yielding cows fed a uniform diet composed of conserved feeds over the whole year. The investigations were conducted on 124 Polish Holstein-Friesian cows, selected fromherd yielding 8457 kg milk with 4,58 % and 3,56 % of fat and protein content, respectively. The cows were maintained in a loose barn and fed ad libitum with TMR (total mixed ration) throughout the year. The diets consisted of corn silage and grass silage (at 50:50 ration on dry matter basis) and concentrates with mineral-vitamin mixture additives. Samples of milk were collected individually from each cow at monthly intervals during the whole year. The cholesterol content in milk (mg/dL) and in milk fat (mg/g) was related to the stage of lactation, season of the year, somatic cell count and fat content, but was not affected by the parity. The cholesterol content in daily milk yield (mg/cow/day) depended also on parity. Even though the cows were fed a uniform diet throughout the year according to the TMR system the cholesterol content in milk differed among seasons.Cilj ovog istraživanja bio je ispitati promjene udjela kolesterola u visokomliječnih krava hranjenih obrokom sastavljenim od konzerviranih krmiva tijekom cijele godine. Istraživanja su provedena na 124 holstein-frizijske krave, odabrane iz stada koje proizvode 8457 kg mlijeka s 4,58 % mliječne masti i 3,56 % proteina, respektivno. Krave su držane u otvorenom tipu staja i hranjene ad libitum s potpuno izmiješanim obrokom (TMR, total mixed ration) tijekom cijele godine. Obrok se sastojao od kukuruzne i travne silaže (50:50, na bazi suhe tvari) i koncentrata s mineralno-vitaminskim dodacima. Uzorci mlijeka prikupljani su pojedinačno od svake krave u mjesečnim intervalima tijekom cijele godine. Sadržaj kolesterola u mlijeku (mg/dL) i mliječnoj masti (mg/g) u vezi je sa stadijem laktacije, godišnjim dobom, brojem somatskih stanica i udjelom masti, ali nije bio pod utjecajem redoslijeda laktacije. Sadržaj kolesterola u dnevnoj količini mlijeka (mg/kravi/dan) ovisi također o redoslijedu laktacije. Unatoč hranidbi krava uniformnom prehranom tijekom cijele godine TMR sustavom, sadržaj kolesterola u mlijeku mijenjao se pod utjecajem sezone

Does Small Ruminant Lentivirus Infection in Goats Predispose to Bacterial Infection of the Mammary Gland? A Preliminary Study

The aim of this study was to determine whether asymptomatic small ruminant lentivirus seropositive (SRLV-SP) goats were more susceptible to bacterial infection of the udder when lactating by comparing the presence and species of pathogenic bacteria in their milk with the values for seronegative goats (SRLV-SN). Milk samples were collected during morning milking on days 20, 40, 60, 150, and 210 of lactation for three consecutive years and subjected to bacteriological examination. Staphylococcus caprae and S. xylosus were the most frequent strains identified in both SRLV-SP and SRLV-SN goats. The prevalence of pathogenic bacteria was the highest in the 1st lactation, regardless of SRLV status. Moreover, the prevalence of pathogenic bacteria was significantly higher in SRLV-SP goats, but only those in the 5th or further lactation (p = 0.010). This suggests a relationship between long-lasting SRLV infection and susceptibility to bacterial infections of the udder

Microproteomic-Based Analysis of the Goat Milk Protein Synthesis Network and Casein Production Evaluation

Goat milk has been consumed by humans since ancient times and is highly nutritious. Its quality is mainly determined by its casein content. Milk protein synthesis is controlled by a complex network with many signal pathways. Therefore, the aim of our study is to clearly depict the signal pathways involved in milk protein synthesis in goat mammary epithelial cells (GMECs) using state-of-the-art microproteomic techniques and to identify the key genes involved in the signal pathway. The microproteomic analysis identified more than 2253 proteins, with 323 pathways annotated from the identified proteins. Knockdown of IRS1 expression significantly influenced goat casein composition (α, β, and κ); therefore, this study also examined the insulin receptor substrate 1 (IRS1) gene more closely. A total of 12 differential expression proteins (DEPs) were characterized as upregulated or downregulated in the IRS1-silenced sample compared to the negative control. The enrichment and signal pathways of these DEPs in GMECs were identified using GO annotation and KEGG, as well as KOG analysis. Our findings expand our understanding of the functional genes involved in milk protein synthesis in goats, paving the way for new approaches for modifying casein content for the dairy goat industry and milk product development

Impaired Expression of Cytokines as a Result of Viral Infections with an Emphasis on Small Ruminant Lentivirus Infection in Goats

Knowing about the genes involved in immunity, and being able to identify the factors influencing their expressions, helps in gaining awareness of the immune processes. The qPCR method is a useful gene expression analysis tool, but studies on immune system genes are still limited, especially on the caprine immune system. Caprine arthritis encephalitis, a disease caused by small ruminant lentivirus (SRLV), causes economic losses in goat breeding, and there is no therapy against SRLV. The results of studies on vaccines against other viruses are promising. Moreover, the Marker-Assisted Selection strategy against SRLV is possible, as has been shown in sheep breeding. However, there are still many gaps in our knowledge on the caprine immune response to infection. All types of cytokines play pivotal roles in immunity, and SRLV infection influences the expression of many cytokines in different types of cells. This information encouraged the authors to examine the results of studies conducted on SRLV and other viral infections, with an emphasis on the expression of cytokine genes. This review attempts to summarize the results of studies on the expression of cytokines in the context of the SRLV infection

Small ruminant lentivirus infection influences expression of acute phase proteins and cathelicidin genes in milk somatic cells and peripheral blood leukocytes of dairy goats

Abstract The aim of the study was to analyze acute phase protein and cathelicidin gene responses to small ruminant lentivirus (SRLV) infection in goats. In uninfected goats, we found higher Cp and lower Fbγ mRNA levels in blood leucocytes (BL) than in milk somatic cells (MSC), as well as lower SAA, Hp, and CRP and higher Cp and AGP concentrations in blood serum than in milk. In SRLV-infected goats, we found higher Fbγ and MAP28 and lower Cp expression in MSC than in BL, and higher SAA, Hp, Fb, and MAP28 and lower AGP concentrations in milk than in blood serum. Higher SAA and Hp expressions in BL and Hp expression in MSC were found in SRLV-infected goats. In SRLV-infected goats, we observed a higher concentration of SAA in blood serum, while in milk, lower SAA, Cp, and MAP28 and higher MAP34 concentrations were observed. The expression profiles of the studied genes differed between BL/serum and MSC/milk. The elevated SAA concentration in blood serum was accompanied by a decreased concentration of SAA and Cp in the milk of infected goats. No differences in the expression of the other studied genes may mean that the SRLV has the ability to evade the immune system, continuing to replicate. The elevated concentration of SAA in blood serum may promote viral multiplication. This higher concentration of SAA in blood serum and simultaneous reduced concentration of SAA and Cp in milk may be additive indicators of this infection

Acute Phase Protein Levels as An Auxiliary Tool in Diagnosing Viral Diseases in Ruminants—A Review

We examined acute phase protein (APP) concentrations in viral infections of dairy ruminants and assessed the potential role of characteristic patterns of APP changes in auxiliary diagnosing viral diseases. All viruses reviewed are common causes of farm animal diseases. APPs are among the first agents of immunity, and their concentrations could be diagnostically relevant. In the most common ruminant viral diseases, elevated serum amyloid A (SAA) and haptoglobin (Hp) levels in blood serum have been observed. However, since these proteins are the main APPs in many viral infections, it is impossible to use their levels for diagnosing particular infections. Decreased Cp and albumin expression could help differentiate the bluetongue virus infection from other diseases. Lastly, analysis of SAA levels in blood serum and milk could be helpful in diagnosing small ruminant lentivirus infection. While promising, APP levels can only be considered as an auxiliary tool in diagnosing viral diseases in ruminants