Dairy R&D in SA

Banga, Cuthbert and others - ARC-Irene.

1. Projects:

Competitiveness is a function of efficiency, market access (broadening of the market of dairy products is a primary goal) and sustainability. In addition to volatility, structural and consumer needs of markets which with up-to-date information can be addressed only partially, sustainability is progressively also influenced by issues which can be categorized within the three P concepts: Productivity (economic focus), People (sociological focus) and Planet (environmental stewardship focus).

Small effective population sizes and inbreeding are major challenges faced by dairy cattle populations worldwide. Estimates of pedigree-based inbreeding (FPED) are unreliable due to a lack of pedigree data and pedigree errors and that may lead to an underestimation of inbreeding rates. Thus, inbreeding based on runs of homozygosity (FROH) has become the preferred method of estimating inbreeding as it is able to accurately predict the amount of autozygosity within the genome.

Dairy has been targeted as a source of greenhouse gas emissions (GHG). However, research has shown that grazing livestock on pasture-based dairy farms restore carbon to the soil, enhancing its biodiversity and countering climate change. This poses the question: If farms can have a positive impact, but are also a source of negative impact, what is the net effect? This is an important consideration when assessing the negative contribution that dairy farming makes to climate change.

Among the problems experienced by pasture-based dairy farmers in the southern Cape are required high stocking rates, poor persistence of pastures, an increase in weed ingression in no-till pastures, and increasing input costs associated with irrigation and fertilisation. Research should thus focus on strategies that can improve the resilience and efficiency of pasture systems.

It is fundamental to identify and understand the complexity of the dairy production system and to account for all the different variables that contribute to such an integrated system.

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.

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.

Kikuyu-ryegrass may no longer be optimum in the south-eastern Cape because of a number of reasons:
•    Extended periods of lower than expected rainfall
•    Poor persistence of ryegrass, with a decline of as much as 44% reported in even the most productive ryegrass cultivars from year one to year two

Discipline: genetic evaluation;