The Research Column

The gastrointestinal tract is highly sensitive to a large number of internal variables in the lifecycle of dairy cows. The hindgut is susceptible to acidosis, much like the rumen, but due to a variety of physiological and structural differences, it is less capable of tolerating acidosis than the rumen, resulting in increased permeability to antagonistic compounds and repartitioning of energy to support an immune response. By improving gut integrity and function, less energy is repartitioned, thereby saving energy for productive purposes.

In last month’s column, I touched on the use of Saccharomyces cerevisiae fermentation products (SCFP) during the transient phase; the emphasis being on on performance, blood biomarkers, rumen fermentation, and ruminal bacteria population.

Four multi-lactation dairy cows in early lactation and subsequently in late lactation were fed two diets for 28 days in a changeover design that provided, within the same stage of lactation, similar amounts of rumen fermentable feed with either high (HS) or low starch (LS). All diets had similar dietary crude protein and rumen-undegradable protein content. Amino acid profiles were similar to that of casein.

Discipline: dairy & health; Keywords: inflammatory diseases, CLA, fishy flavors, rumen-inert calcium salts, sensory panel.

This topic was addressed by K.A.S. Nelson and S. Martini in a paper called: Increasing omega fatty acid in cow's milk through diet manipulation: Effect on milk flavor. The paper was published in the Journal of Dairy Science, Volume 92, pages 1378-1386.

Discipline: disease; Keywords: pathogen, faecal culture, blood serum tests, economic losses, culling.

How does infection with Johne's disease affect milk production in dairy herds? Smith and co-workers studied the status of the disease in three herds in the US and tried to predict the impact on milk production when the condition is latent or when the cows are actually shedding cells. The study was published in the Journal of Dairy Science, Volume 92 of 2009, pages 2653 to 2661, with the title: A longitudinal study on the impact of Johne's disease status on milk production in individual cows.

Discipline: animal welfare; Keywords: pain levels, behaviour, stress levels, serum cholesterol, wound healing.

Discipline: ethics; Keywords: animal welfare, improving efficiency, traditional systems, organic production, carbon footprint.

Discipline: technology adoption; Keywords: technological advances, activists, consumers, recombinant bovine somatotropin, safety and health implications.

Discipline: food safety; Keywords: background microbial population, salt, potassium chloride, food contact surfaces, salt-to-moisture ratio, pH.