Dairy R&D in SA

Mastitis results in large economic loss to both farmer and processor. In addition it has welfare implications for the cow and antimicrobial resistance concerns. Therefore, describing and analysing the measures used to prevent the disease and to minimize the losses remain important. For example, somatic cell count (SCC) directly affects revenue from the sale of milk and in one of the investigations the revenue loss was studied.   

Cattle have been the focus of an intense debate between those concerned about, among other things, the possible negative effects on global warming, land degradation, food competition and human health, and those who are positive toward the possible role of cattle in maintaining global socio-economic and environmental sustainability. This paper reviews the pros and cons in view of a projected increase in demand for animal-based foods and therefore in cattle numbers. Analyses of cattle numbers and foods from various literature sources suggest gross overestimation towards 2050.

A web-based carbon footprint assessment tool was developed by the researchers cited below that will assist dairy farmers in understanding their GHG emissions and developing effective mitigation strategies and sustaining farmlands. The tool also provide a means with which to communicate and report back to stakeholders and key audiences, such as consumers, about the real impact of dairy farmers in South Africa on the environment.

In a survey among dairy farmers in 2017, it was found that routine evaluation of cows, groups and/or herds for SCC was relatively low at 67% for cows and groups and 53% for whole herd testing. The majority of high SCC cows are however treated. Only 1% of dairy farmers reported to clip or flame udders. Approximately 50% of dairy farms pre-dip, lower than in some other parts of the world and approximately a third of producers either do not strip or wipe and/ or do not use gloves.

What is A1 and A2 milk: The difference is associated with variation in the protein composition of cow’s milk. Both A1 and A2 variants are proteins in the casein group which makes up about 80 % of the proteins. The two variants are almost identical apart from differing in one amino acid at position 67 of the polypeptide (amino acid chain): A1 has histidine whereas A2 has proline.

Laboratory diagnosis of mastitis can be costly and time consuming, therefore cow-side tests such as the California Milk Cell Test (CMCT) and Milk Electrical Resistance (MER) need to be utilised to full potential. It has been estimated that financial benefit of correct diagnosis of mastitis per cow for the CMCT, MER and the tests done in parallel was R899, R519 and R1065 respectively. The CMCT was shown to be 11% more beneficial than the MER test, whilst using the tests in parallel was shown to be the most beneficial method for evaluating the mastitis-control programme.

Antimicrobial resistance (AMR): The results of an antibiotic susceptibility testing trial of Staph. aureus isolates showed that 75-80% isolates were multidrug resistant. The isolates were found to be 100% resistant to amoxicillin, ampicillin and penicillin G, 95% resistant to cephalexin, 82% resistant to streptomycin, 75% resistant to oxacillin, 64% resistant to erythromycin, 50% resistant to tobramycin, 46% resistant to tetracycline and 39% resistant to vancomycin. None of the Staph.

Coagulase negative Staphylococcus or non-aureus Staphylococcus (CNS/NAS) pathogens are relatively new isolates affecting udder health. The most common strains isolated from a study on 20 SA dairy herds were Staph. chromogenes, Staph. epidermidis and Staph. haemolyticus. The numbers of the CNS/NAS strains increased as lactation progressed.The results were also evaluated to identify a probable correlation between the CNS/NAS strains and somatic cell count (SCC) levels. Staph.

Fasciola species are liver flukes that infect cattle and reduce the productivity by 15-30%. The infection can affect general health and feed intake that leads amongst others to morbidity, reduction in milk production and weight gains.

Milk flocculation and gelation describe the phenomena relating to protein instability that could lead to the rejection of milk for processing or to defects in long-life milks such as UHT milk. The term flocculation which is the topic here, applies to the protein precipitate that is formed in the test tube when ethanol unstable milk is subjected to the Alizarol test.  The ethanol concentration in the test varies from 68% to 76% ethanol and milk that flocculates is then declared unfit for further heat processing and rejected.