The Research Column

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

Discipline: reproduction; Keywords: fertility traits, selection indices, breeding values.

Discipline: acidosis; Keywords: lactic acid, rumen pH, level of production, feed energy, SARA.

Discipline: lactation management; Keywords: metabolic diseases, correct feeding strategies, moderate energy, lactation length.

These questions were addressed in a study by Dr Silva-del-Rio and colleagues in a study published in 2010 in the Journal of Animal Science, Volume 88, pages 1048 to 1060. The title of the paper appropriately was Effects of twin pregnancy and dry period feeding strategy on milk production, energy balance, and metabolic profiles in dairy cows.

Discipline: milk powder; Keywords: oxidation, rancidity, off-flavours, light exposure, package atmosphere.

The objective of the study was to establish whether nitrogen flushing and colder than normal storage temperature will be favourable to flavour and shelf life of whole milk powder. This research by Dr M.A. Lloyd and colleagues was published in The Journal of Dairy Science, Volume 92 of 2009, pages 2409 to 2422. The title of the paper is: Effect of nitrogen flushing and storage temperature on flavour and shelf-life of whole milk powder.

Discipline: sensory; Keywords: texture, aroma, flavour, taste, scorecard judging, analytical sensory tests, descriptive analysis.

Is sensory analysis a valuable tool to the dairy product manufacturer? M.A. Drake was invited by the American Dairy Science Association to review the work done on sensory appraisal. The title of his Review which was published in the Journal of Dairy Science, Volume 90 of 2007, page 4925 to 4937, was appropriately: Sensory Analysis of Dairy Foods.

Discipline: calf rearing; Keywords: individual housing, starter intake, group housing, automatic feeding system, target weight, respiratory problems.

The question addressed is when pre-weaning calves housed individually can be grouped successfully without increasing stress and the incidence of disease. This research by Drs Bach in colleagues was published in The Journal of Dairy Science, Volume 93 of 2010, pages 413 to 419. The title of the paper is: Optimizing weaning strategies of dairy replacement calves.

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: 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: birth weight; keywords: mortality, stillbirths, reproductive performance, calf-cow size index.

It is known that heavier calves tend to be more prone to stillbirths, dystocia and lower calf survivability than lighter, smaller calves, but it is not known whether calf birth weight is also associated with other factors affecting the economic efficiency of the dairy herd. A number of such factors were included in the study of T.C. Linden and co-workers reported here; the title being: Calf birth weight and its association with calf and cow survivability, disease incidence, reproductive performance, and milk production. The paper was published in the Journal of Dairy Science, Volume 92 of 2009, page 2580 to 2588.