The Research Column

Reducing methane emissions in livestock production is one of the challenges of this century and researchers from different disciplines including nutrition, physiology, and genetics have made substantial efforts to develop tools that can help reduce methane emissions. Methane traits in dairy cattle have low to moderate heritability, from 0.11 to 0.33.

Lameness is the clinical condition of impaired locomotion and is caused by a range of foot and leg problems, the most common of which are hoof lesions caused by infectious agents or internal and external forces. It is a leading animal welfare concern in the dairy industry and also has substantive economic consequences, as productivity is decreased through reduced reproduction, milk production and increased culling. Various management practices for preventing lameness and treating lame cows have been developed. Despite this, lameness persists as an industry problem.

Ninety-nine farms were visited during the grazing period, and 85 farms were revisited during the housing period. At each visit, all lactating cows were scored for lameness (0 = good mobility, 1 = imperfect mobility, 2 = impaired mobility, 3 = severely impaired mobility), and potential herd-level risk factors were recorded through questionnaires and infrastructure measurements. Routine cow-level management data were also collected.

Discipline: reproduction; Keywords: reproductive performance, genetic progress, health, glucose manufacturing, hormonal interference, appetite control.

Sub-fertility in high-producing dairy cows is a known problem in most countries, also in South Africa. The question is do we understand the causes and can farmers limit the consequences? The status of current knowledge and understanding has been reviewed recently by L.M. Chagas and co-authors in a paper published in the Journal of Dairy Science (2007), Volume 90, pages 4022-4032; the title being: New perspectives on the roles of nutrition and metabolic priorities in the sub-fertility of high-producing dairy cows.

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: carbon footprint; Keywords: climate change, rumen fermentation, manure, beef cattle, dairy cattle, smallstock, pigs, poultry, game.

Discipline: technology adoption; Keywords: structural changes, labour, efficient operations, holding pen, udder washer, breeding technologies, coputerized milking systems.

Discipline: ethics; Keywords: ecosystems, biodiversity, waste accumulation, Code of Conduct, profitability, heritage responsibility.

Discipline: carbon footprint; Key words: enteric methane, methanogen, feed efficiency, lifetime productivity, mitigation. 

Antibiotic treatment of udder health and associated conditions is in the spotlight because of possible resistance by pathogens, but also because of the world-wide trend to move away from antibiotics. In South Africa the group of Prof Mark Laing at UKZN is evaluating bacteriophages and bacteriocins as alternatives to antibiotic treatment. Another method is through potent products that can be supplemented in the feed. In this context Dr F Hashemzadeh-Cigari and co-workers investigated a herbal mixture.