The Research Column

Discipline: sensory; Key words: fluid milk, ultra-pasteurization, direct steam injection, flavour, consumer acceptance.

Discipline: economics; Key words: profitability, marginal response, supplementary feed, marginal economics. 

Discipline: management; Key words: sensor technology, dairy cow behaviour, ruminating. 

Discipline: mastitis; Key words: bovine clinical mastitis, fertility, economics, animal health management. 

Costs associated with clinical udder infection can be divided into treatment costs, costs of mortality through culling (replacement of culled animals) and indirect costs from production losses. Intervention for clinical cases usually consists of (mainly within udder) antibiotic treatment. However, in light of its connection with antimicrobial resistance, it may be prudent to search for alternative interventions. For instance, culling cows with clinical mastitis could be a viable alternative.

South Africa is 13th on the list of highest emitters of global greenhouse gases GHG). Despite this is Africa still the smallest contributor to GHG emissions among the continents, yet the most vulnerable to the impacts of climate change. The effects will not be limited to rising temperatures and changing rainfall patterns, but also to increased severity and frequency of droughts, heat stress and floods. Agriculture is not only impacted upon by climate change but also contributes to global warming.

Bacterial contamination of foods may lead to reduced shelf life due to outgrowth of spoilage organisms and, in the case of pathogens, to food borne illness upon consumption of contaminated products. To inactivate bacteria that may grow in finished products, many food products undergo heat treatment. Pasteurisation results in inactivation of vegetative cells. However, bacterial spores will survive such treatments, after which they may germinate and grow in finished liquid products.

Choline is a known essential nutrient as it is required for synthesis of essential membrane phospholipids, acts as a precursor for synthesis of acetylcholine, and in particular, has a role in lipid intermediary metabolism. In ruminants, however, almost all dietary choline is degraded by ruminal microbes and requires choline to be supplemented in a rumen-protected form. 

Successful management of an automatic milking system (AMS) requires effective functioning of the milking unit (MU). It is well established that an increased detachment level, i.e. earlier removal of the teat cups at the end of milking, can decrease milking time substantially with minimal to no milk yield loss. However, these studies were all conducted at cluster level, and some studies suggest an increase in residual milk or strip yield at increased cluster detachment levels, which indicates decreased udder emptying.

Trace minerals such as Cu, Zn, and Mn are essential to life, and their deficiencies in livestock result in health deterioration. In an effort to prevent such deficiencies, dairy cows are commonly supplemented with Cu, Zn, and Mn. Various sources of trace minerals are used for this purpose, with inorganic sources (oxides, chlorides, sulphates, and carbonates) being the most commonly supplemented to dairy cows. Alternative sources such as organically complexed trace mineral supplements (chelates) are specifically developed to provide greater nutritional bioavailability.