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.

Heartwater is caused by the proteobacterium Ehrlichia ruminantium, which is transmitted by the tick Amblyomma hebraeum.

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.

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.   

Conception and re-conception rates of high-producing dairy cows remain of concern in dairy production systems, especially in the subtropics. Apart from the major effects of nutrition and specific nutrients on reproduction, other risk factors such as negative energy balance, inflammation and impairment of the immune response have been shown to affect re-conception rates. Dietary energy levels interact with blood urea nitrogen (BUN) and may influence the pregnancy rates of dairy cows.

Discipline: genetic evaluation;