Dairy R&D in SA

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.

Female fertility is a fundamental trait for a profitable dairy herd enterprise. Studies have shown a decline in fertility probably because of dedicated selection for increased milk production. Age at first calving (AFC) and calving interval (CI) are prominent indicator traits to improve fertility, but these traits are greatly affected by management decisions. Service data present additional selection criteria with minimum bias.

To maximise production, dairy cow diets are balanced for amino acids through the use of feed formulation programmes. A limitation of these programmes is that the bacterial amino acid profile used is considered constant and based on assumptions about the composition of mixed ruminal bacteria. However, research has shown that the amino acid composition differs between the fluid-associated bacteria (FAB) and the particle-associated bacteria (PAB) and also depends on factors such as diet composition, feed intake, protein source and thus potentially, feed additives.

Smallholder dairy production, which is mainly characterised by a low input–low output production system, currently makes an insignificant contribution to the South African dairy industry. Several reasons can, however, be advanced to motivate the development of this sector. In Sub-Saharan Africa, in general, the performance of smallholder dairy cows is poor, suggesting low herd profitability. In order to develop the smallholder dairy sector, it is therefore important to identify herd production models or management strategies that would improve herd profitability.

Dairy breeds originated in the United Kingdom and Western Europe. Both regions have a wet and cool to cold climate. As a result, the environmental comfort zone for dairy cows varies between -5 and 21 °C. Anatomical features that help cows withstand cold conditions include a thick skin, a dense hair coat, subcutaneous fat layers, large muscles and a digestive system that is based on fermentation processes in the rumen which creates internal heat.

Research in the past 50 years has shown that the general health of dairy cows can be improved by higher post-ruminal delivery and absorption of poly-unsaturated fatty acids (PUFA), especially omega-3 (n-3) acid. Since flaxseed contains a high concentration of n-3, the objective of the authors cited below was to evaluate the effects of feeding the flaxseed-based supplement LinPro on the production and health of mid-to-late lactation multi-lactation Holstein cows.

There is not much information on the effect of dietary nitrate addition as a method to mitigate methane in grazing dairy cows. Therefore, the authors cited below did a study aiming to investigate the effect of nitrate addition on daily enteric methane emissions, production performance and rumen fermentation of multi-lactation Jersey cows grazing perennial ryegrass pasture, which contained about 7.3 g nitrate per kg dry matter (DM).

Vitamins, mostly A, C and E, and minerals, such as selenium, copper and zinc, have been used to mitigate oxidative stress. However, in confined systems, the risk of over- or undersupplying micro elements is high, hence the overproduction of pro-oxides is common. Additionally, in semi-intensive feeding systems, trace elements, particularly antioxidant supplementation, are limited owing to restricted or lack of supplementation. Therefore, research focus has shifted to exploration of the potential of natural antioxidants in improving animal production and health.

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).

Fasciolosis, or liver fluke infection, results in reduced production and economic losses in dairy cattle and other livestock species. The lifecycle of the fluke, Fasciola hepatica, involves lymnaied snails as the intermediate host and depends on the development and survival of larval stages both in the snail and in the environment. This implies that the infection risk will depend on pasture and other areas harbouring the snails, as well as climatic and other environmental influences.