Dairy R&D in SA

Conjugated linoleic acid (CLA) has the ability to inhibit growth in a number of human cancer cell lines. It is also immune-modulating and growth-promoting and was shown to decrease fat mass without significantly affecting body weight. In terms of prevention of heart disease, CLA depressed total cholesterol and lowered the ratio of low-density lipoprotein (LDL) to high-density lipoprotein (HDL).

An elicitation exercise was conducted to collect and identify pressing questions concerning the study of helminths in livestock, to help guide research priorities. The authors cited below are the primary global experts who compiled the report. Whereas this presentation does not cover research results as usual, I consider it important to share their ideas with the reader as a main focus of our R & D is in control of parasites and because prominent researchers in the group are South African or South African of origin.

A RP of 1186 and a validation population of 128 was established, enabling the inclusion of genomic information in estimation of breeding values, based on the INTERBULL verified Logix Genetic Evaluations and a Single-Step approach, using Mix99, to present the industry with GEBVs. These GEBVs reflect the expression of genes in the SA environment, based on the genetic variation and gene frequencies of the SA Jersey population. 

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).

Claw health is an important factor in animal welfare and its evaluation is an early indicator of lameness in dairy cattle. However, claw disorders on many farms are not routinely evaluated and the information not included in genetic evaluations as they are not always considered in terms of productivity. The aim of the study by the authors cited below was to evaluate claw health of dairy cattle housed in dirt lot vs free stall under the TMR systems.

Stillbirth remains a problem in dairy herds in many countries and is increasingly included in national breeding objectives. In South Africa, however, we lack reliable information on the incidence of stillbirth that can be used to improve this trait genetically. Currently, there are no estimated breeding values (EBVs) for any measures of calving performance produced under the national genetic evaluation programmes.

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.