Dairy R&D in SA

 Discipline: dairy research; Keywords: mastitis, AMR, liver fluke, milk flocculation, genetic and performance analysis.

 Author: Heinz Meissner, Milk SA Program Manager R & D, November 2018.   

1. Mastitis Program:

1.1. PRJ-0210 Antimicrobial resistance on dairy farms - Screening mastitis causing coliforms for the production of extended spectrum Beta-lactamases and Colistin resistance. Dr Inge-Marie Petzer.

Discipline: forages/grazing; Keywords: pasture management, water requirements, irrigation guidelines, subtropical pastures, grass/legume mixtures.

Discipline: mastitis; Key words: diversity, management practices, antibiotics, pre-dip, strip, bulk milk somatic cell count, AMR. 

The South African dairy industry shows immense diversity when it comes to mastitis management practices. However, if consistently executed, which should improve udder health and milk flow, it could be satisfactory, but supporting the diversity by extension is a challenge. As is the case globally, the dairy industry is aware of and actively addressing antimicrobial resistance (AMR). To that effect, a survey was funded by Milk SA to record what practices are followed and a project: ‘Resistance to Available Antibiotics in Lactating Cows with Mastitis’, was initiated in 2015. The results of the survey were published by the authors cited below. 

Discipline: mastitis; Key words: SSC, summer rise in SCC, mastitis, transitional category, season, temperature humidity index, heat stress.

Dairy farms often experience a summer through autumn rise in somatic cell count (SCC) with some farms affected more than others.  The extent to which climatic factors contribute to this summer rise in SCC in South Africa is unknown although weather is blamed anecdotally. Consequently, the value of heat abatement or other preventative intervention cannot be established. The relative effect of season and/or heat stress on milk production and SCC is likely to be unique to South African conditions and therefore this formed the basis of the study cited below.

Discipline: mastitis; Key words: Staphylococcus aureus, subclinical mastitis, antibiotis resistance, producer attitude.

The dairy industry is a major consumer of antibiotics globally and mastitis is the most treated disease of dairy cows. In South Africa, producers have unrestricted access to 12 of 22 registered within-udder antibiotic products without prescription, whereas the remaining 10 registered products are restricted for veterinary use. It is conceivable that the antibiotics available without prescription may be used incorrectly and may contribute to the emergence and/or persistence of antibiotic-resistant strains. 

Discipline: grazing/forages; Key words: kikuyu-ryegrass pasture, minimum tillage, nitrogen fertilization. 

The sustainability of current nitrogen (N) fertilization regimes for minimum tillage kikuyu-ryegrass (Pennisetum clandestinum, Lolium multiflorum) pastures in the southern Cape is questioned. The guidelines, originally, were developed for conventional tillage and non-grazing systems. It may well be that these guidelines may not apply any more. In fact, there is the possibility that the N levels applied are too high with implications to both economics and leaching of unutilised N. Thus, the aim of the investigation of the researchers referenced below was to study the effects of low to high N fertilization rates on soil and pasture characteristics.            

Discipline: grazing/forages; Key words: forage herds, chicory, plantain, dry matter yield, herb-grass mixture.

The forage herbs chicory (Cichorium intybus) and plantain (Plantago lanceolata) have become regular components of south-eastern seaboard dairy pastures. They are mostly planted in a mixture with grasses and often clover species are added as a minor component. How they do and what benefits they bring to the pasture mix and the cow have not been well researched in these areas. This was then the purpose of the trials cited below. 

Discipline: environment; Key words: greenhouse gas emissions, global baseline, milk yield, target, non-cow associated factors. 

Discipline: grazing/pastures; Key words: cultivated pastures, fertilisation, nutrient cycling, phosphorus, soil fertility

Discipline: mastitis; Key words: bovine mastitis, ethnoveterinary medicine, antibacterial activity,  cytotoxicity.