Acute phase response in the primiparous dairy cows after repeated percutaneous liver biopsy during the transition period.

The aim of this study was to evaluate the acute phase response of dairy cows to repeated liver biopsy in order to estimate the safety of this procedure during the transition period. Liver biopsies (up to 1000 mg of liver tissue) were conducted twice a day, 7 days before expected parturition and 3 days after calving. The number of needle insertions for each biopsy was recorded and was dependent on the amount of obtained tissue.

Technical note: Selecting the best references in gene expression experiments in liver of cows receiving glucogenic supplements during the transition period.

Measuring gene expression is a commonly used method to monitor the reaction of cells and tissues to changing nutritional or physiological conditions. Selection of appropriate reference genes is a crucial point in gene expression experiments using real-time PCR techniques. Expression of the "ideal" reference gene should not be affected by the experimental treatments or physiological state of the tissue, organ, or the whole organism.

Why are dairy cows not able to cope with the subacute ruminal acidosis?

One of the largest challenges for the dairy industry is to provide cows with a diet which is highly energetic but does not negatively affect their rumens' functions. In highly productive dairy cows, feeding diets rich in readily fermentable carbohydrates provides energy precursors needed for maximum milk production, but simultaneously decreases ruminal pH, leading to a widespread prevalence of subacute ruminal acidosis. Maximizing milk production without triggering rumen acidosis still challenges dairy farmers, who try to prevent prolonged bouts of low ruminal pH mainly by proper nutrition and management practices.

Relationships between physiological indicators in blood, and their yield, as well as chemical composition of milk obtained from organic dairy cows.

Background: The occurrence of metabolic overload in cows maintained in organic herds is very likely, because organic production promotes feeding with high roughage diets and discourages supplementation with concentrates supplementation. It has the potential to negatively affect milk quality. The aim of this study was to determine the influence of physiological indicators in blood, reflecting the energy metabolism and liver status of dairy cows kept in organic herds, on the content of bioactive components in milk and the influence of lactation stage and feeding season on changes in milk components.

Differences in whey protein content between cow's milk collected in late pasture and early indoor feeding season from conventional and organic farms in Poland.

Background: The aim of the study was to investigate bioactive whey protein concentrations in cow's milk collected in late pasture (LP) and early indoor feeding (EIF) season from conventional and organic farms in Poland.

Results: Results showed that in the LP somatic cell count (SCC) was higher under organic farming conditions. However, percentages of protein and fat were higher under conventional farming conditions.