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: body condition score; Keywords: body reserve status, fat, hormonal changes, pregnancy, metabolic disorders.

Research in this context was reviewed by J.R.Roche and coworkers in a paper published in the Journal of Dairy Science, Volume 92, pages 5769 to 5801. The title of the paper is: Body condition score and its association with dairy cow productivity, health, and welfare.

Discipline: mastitis; Keywords: dry cow therapy, Staphylococcus aureus, antibiotics, re-infection,teat sealant.

 In a large study this question was addressed in two papers: in the first paper the preventive effect of various dry cow measures on new infections were investigated and in the second paper the cure of existing infections. These studies are unique in the sense that a highly powerful statistical method, called meta-analysis, was used which enable scientists to pool research data from various studies conducted in different circumstances and synthesize a highly reliable result which for all practical purposes can be considered correct to implement. The titles of the respective papers published by T. Halasa and co-workers in the Journal of Dairy Science, Volume 92 of 2009, page 3134 to 3149 and page 3150 to 3157 are: Meta-analysis of dry cow management for dairy cattle. Part 1. Protection against new intramammary infections and Part 2. Cure of existing intramammary infections.

Discipline: lactation management; Keywords: reproduction, model, MDP, daily information, economic implications.

Discipline: dairy & health; Keywords: Calcium, nutraceuticals, osteoporosis, colon cancer, CLA

Discipline: antibiotics; Keywords: gram positive bacteria, altered fermentation, propionate, Streptomyces cinnamonensis, health concerns.

Discipline: economics; Keywords: pasture systems, TMR systems, net margin, cost of production, milk yield per cow,  labour cost, feed costs.

Discipline: dairy & health; Key words: non-alcoholic fatty liver disease, probiotic yogurt, metabolic factors.