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MILK SA FUNDED PROJECTS: MILESTONES AND ACHIEVEMENTS SINCE 2015

Date
  1. Faciolosis (liver fluke): Since the liver fluke is developing resistance to all available anthelmintics, including the preferred triclabendazole, farmers need to manage the snail co-host of the fluke which is required for the fluke to complete its life cycle.                                                                                                                                                                                                        The research results showed control of the snail can be effective if dairy farmers fence-off wet patches and wetlands, prevent cows from grazing in open water and clean troughs regularly.
  2. Mastitis: Despite widespread global focus on udder infection and mastitis curing and prevention, mastitis control arguably remains the single most- costly input in dairy herds, also in South Africa. Thus, as elsewhere, Milk SA has embarked on a comprehensive R & D programme in assistance to dairy farmers.                                                                                                Some prominent results are: 1) The use of bacteriophages (natural viruses of mastitis pathogens) is promising as a teat dip. 2) Although antimicrobial resistance to the major mastitis pathogens is becoming problematic, results have shown that certain antibiotics are still effective against particular pathogens, and should therefore be targeted. 3) Milking equipment, in particular machine take-off time, can be a source of udder infection and should be applied correctly. The research results have provided guidelines. 4) In 2017 the cost of mastitis was calculated as R1980 per cow per year. Results have shown that this is mostly due to inadequate management which can be easily rectified. Guidelines have been provided. 5) Bulk tank SCC increases in summer due to immunity challenges, particularly due to ‘chronic’ mastitis cases. However, results showed that less heat stressed cows can be identified which can limit this increase. 6) Results demonstrated the use of routine bulk tank milk testing for the monitoring of bacterial counts in bulk milk combined with differential cultures and counts to identify the source of high bacterial counts, implying that bulk tank testing was useful as a further method to detect inadequacies in dairy herd management and possible mastitis causing pathogens.    7) Concerning is the finding of biofilm formation and zoonosis of some pathogens
  3. Sporidesmin toxicity: Sporidesmin is a toxin released by the fungus Pseudopithomyces chartarum, which infests grass pastures, in particular ryegrass. It results in photosensitivity in sheep and cattle, commonly known as Facial Eczema. Outbreaks in the Eastern Cape caused significant economic losses to dairy farmers in the area and highlighted the importance of this condition.                                                                                                                                                                                                                                                                                         Results of liver tissue showed clear evidence of typical periductular fibrosis, a lesion which characterizes sporidesmin toxicity. Also, the liver enzyme GGT was increased in cattle with affected skin originating from farms with high spore counts. In characterising the fungus, it does appear that the sporidesmin-producing species predominates in the Eastern-Cape, which is not the case in other countries. Other tests indicate that the fungus is not seed-borne. The results obtained enable a spore-counting service as early warning to farmers.
  4. Milk flocculation/gelation: These terms describe the phenomena relating to protein stability that could lead to the rejection of milk for processing or to defects in long-life milks, which is a major problem and therefore the focus of intense research.                                                                                                                                                                                                  Results showed that the major cause of flocculation is the survival of psychrotrophic bacteria because of inadequate cooling and hygienic practices on farms, and therefore a rapid test method for routine analyses of psychrotrophs has been developed. In addition to the surviving proteolytic enzymes of these bacteria, the activity of plasmin in the milk contributes to gelation. Milk flocculation may also result because of pasture fertilization and feeding of the cow as it affects P uptake and metabolism. Therefore, the recommendation is to carefully control and monitor the K level in the soil and the Ca:P ratio in the feed, as low P in the milk is conducive to protein instability.
  5. Pastures: The possible supply of nutrients is sometimes unclear as it depends on soil health, pasture type and seasonal influences, and therefore e.g. N application and mineral availability under specific conditions remain in question.                                                                                                                                                                                Conclusions from several studies in the south-eastern Cape pasture-based dairy areas were that fertilizer N applied at a level of 220 kg N/ha/year in addition to the animal excreta N, is sufficient to ensure adequate pasture yields of about 20 ton DM/ha/year to achieve a pasture milk yield of about 17 ton ECM/ha and a low carbon footprint. With respect to micro minerals, despite seasonal variation in supply from pastures and heat stress conditions, there was no indication that additional supply is warranted.
  6. Environment: Environmental protection is paramount to the sustainability of the enterprise and beyond its borders. Thus, the responsibility also implies to protect wetlands and river systems which may pass to neighbouring communities. In addition, dairy farms as others, have the obligation to limit their carbon footprint.                                                             A comprehensive study on buffer zones culminated in a guideline document for better management by dairy farmers for improved wetland and river management. In association, a feasibility analysis study of dairy waste water and slurry treatment options, showed that specific micro-algae consortia can substantially lower solids, fats, sulphates, oils and nutrients such as ammonia phosphates, which are harmful to the receiving environment. With respect to carbon footprint, an elaborate systems dynamic model (known as DESTiny) to estimate all on-farm carbon emissions and sequestrations/storages and their economic consequences, has been developed. Similarly, a model (known as DiEET) to compare the relative environmental footprint of milk and imitation plant beverages has been developed. The outcomes showed that milk was inferior to the plant beverages in LCA when compared per litre product, but superior when compared per nutrient index and also in relation to country-specific poverty levels and cost of production.
  7. Animal welfare: Lameness and other conditions and diseases are humane treatment concerns, but also highly impacting on sustainability of the dairy farm. Thus, much attention is given to animal welfare in research and extension.                                                                                                                                                                                                   One goal is to advance the genetics of cow welfare traits through genomics and other means, including claw quality and udder health, by 1) estimation of genetic parameters for claw quality  in dairy cattle, and 2) characterization of the genetic basis of mastitis susceptibility based on SCC as an indicator trait. Associated is to detect, record and monitor health and welfare traits using tools such as 2D and 3D imaging and machine learning technologies to enable automated detection and tracking (monitoring) of body condition, claw health and lameness.  The outcomes of this technology have been promising. Thirdly, animal welfare elements are part of a comprehensive study on the advantages of good agricultural practices on the sustainability of dairy farms.
  8. Food safety: The safety and quality of milk and dairy products are not negotiable, and therefore Milk SA through the DSA created an impressive structure and human resources for testing and advising dairy-related and commercial institutions in the quest to ensure safety and quality.                                                                                                                                      1) As yogurt is an excellent medium for probiotics, an objective was to isolate and select probiotic species/strains which can help protect against listeriosis, candiasis and diarrhoea. Isolation and selection were done by subjecting isolates to oxygen, pH, texture and temperature stress. Although a number of species/strains proved useful, B. animalis subspp animalis and L. rhamnosus GG became the choice as they effectively colonised the medium and inhibited the relevant organisms in vitro. 2) The safety of milk at retail depends on the levels of particular organisms, i.e. Enterobacteriaceae, coliforms and Escherichia coli. The Department of Health is in the process of updating regulations regarding these organisms. IDF associated countries decided that compliance to specifications for Enterobacteriaceae is sufficient, but our results disagreed, resulting in the recommendation that in the new regulation, compliance to specifications for all groups should be maintained.
Source
H.H. Meissner, 2025. Milk SA funded projects: Milestones and achievements since 2015. Milk SA, Pretoria. www.milksa.co.za. https://milksa.co.za/node/add/dairy_r_and_d_in_sa