Dairy R&D in SA

1. A newly developed system of obtaining Dairy Cattle farm-recorded data from automated systems to be used for biological and economic benchmarking as well as future genetic merit predictions

     by DA Kruger, RR vd Westhuizen & D Victor, SA Stud Book, Bloemfontein, South Africa.

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.

The most popular dairy breed in South Africa is the Holstein. Being of European origin the Holstein is not well adapted to South African veld conditions. Consequently, its milk production on veld is very low, and the animals cannot subsist and produce without some form of supplementary feed. The Nguni breed is an African breed, and is used by communal farmers in KwaZulu-Natal for household milk supply.

Recent research shows that the contribution of methane (CH4) to the atmosphere by shale gas and other earth sources is much higher than accepted in IPCC calculations, which implies that much less is from ruminants (Howarth, 2019). Secondly, in carbon footprint calculations the CO2 capture by photosynthesis through the biogenic cycle in plant foods (say maize) (which apart from CO2 may also have resulted indirectly from atmospheric CH4) is not taken into account (Frankelius, 2020). This is actually a carbon sink.

Pseudomonas is a highly competitive bacterial genus that is generally found in the environment.  They also act as opportunistic pathogens of both animals and humans. In the dairy environment it can cause a damaging form of mastitis in dairy cows and is often resistant to a wide spectrum of antibiotics which makes it difficult to treat. Ps aeruginosa, is not a factor in causing spoilage of refrigerated milk due to its high optimum growth temperature.

The severe droughts in successive years in several parts of the country have suggested that more regular droughts and water shortages could become the norm in future farming. This, of course, is also predicted by climate change scientists and it implies that farmers will have to look at ways to make the most of the water they have. Soil management, rainwater harvesting and proper storage of water will determine how efficiently farmers make use of water resources.

The peripartum period comprises the last three weeks of gestation to three weeks after calving. During this period, many adaptations occur in preparation for calving and the onset of lactation. These are of endocrine, metabolic and immunological nature and include increases in circulating concentrations of oestrogen, non-esterified fatty acids and beta-hydroxybutyrate, and reduced serum concentrations of progesterone, calcium, glucose, insulin and insulin-like growth factor 1.

Coagulase negative Staphylococcus or non-aureus Staphylococcus (CNS/NAS) pathogens are relatively new isolates affecting udder health. The most common strains isolated from a study on 20 SA dairy herds were Staph. chromogenes, Staph. epidermidis and Staph. haemolyticus. The numbers of the CNS/NAS strains increased as lactation progressed.The results were also evaluated to identify a probable correlation between the CNS/NAS strains and somatic cell count (SCC) levels. Staph.

The response of pasture yields to nitrogen (N) fertilization is a long-standing topic of debate. In dairy-pasture systems, N application is often thought to be directly proportional to pasture yield. The question is: is it. This was evaluated using data from 153 pasture camps over five years. Fertilizer application rates were grouped into three treatments: <200, 200-350 and >350 kg N per hectare (ha) and the herbage yield response over the five years was recorded.

Age gelation is a process in which there is formation of a three-dimensional protein network within UHT milk which occurs during storage, and is marked by increasing viscosity before observable gelation. In South Africa, the dairy industry loses millions of Rands annually as a result of the condition in UHT milk. As such, there is a need to study and evaluate the possible correlation of variables that may contribute to the occurrence of age gelation in UHT milk.