Dairy R&D in SA

Discipline: reproduction; Key words:concentrate level, crossbreeding, days open, energy source, interval traits, genetic parameters, management-induced infertility. 

Because of high milk yield, some farmers of high producing TMR-based dairy herds  service cows later in the lactation period, i.e. after the live weight nadir point when live weight starts to increase because of a positive energy balance. Often maximum feed intake has been reached and milk yield is decreasing following peak milk yield. Some research has shown a positive response in conception when cows are inseminated at this stage of the lactation period.

 In recent years, there has been an increase in the prevalence of environmental pathogens as a cause of intra-udder infections (IUI) in dairy cattle. Increases in prevalence could potentially be ascribed to improved control methods for contagious pathogens, difficulties in controlling pathogens from an environmental reservoir and the ability of Streptococcus uberis and Escherichia coli to persist in the udder.

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.

Milk yield of dairy cows is influenced by genetic merit of the cow, its age, days in milk, daily feed intake, feed quality and body condition score. Milk yield in South Africa is much higher today than two decades ago since we produce 54% more with 24% less cows. As milk yield per se is highly correlated with profit, the push towards higher yields is also noticeable in pasture based systems.

Maize is the most important non-forage carbohydrate source in high yielding dairy cow diets. Both ruminal and total tract starch digestibility of dairy and other ruminant animals are significantly impaired by high vitreous maize, compared to moderate floury or dent maize. The genetic make-up, environmental conditions of cultivation and stage of maturity collectively affect the hardness of maize.

One of the key traits in profitable milk production is somatic cell count (SCC). It is used as a measure of udder health and management thereof in terms of cleanliness, cow health and selection is paramount. Over years, a substantial data base has accumulated from the milk recording and management system, allowing analyses from different perspectives to better understand factors influencing SCC. Some factors not normally thought of provide interesting results as shown by the author cited below. 

The claims and accusations in the campaign have been researched from various perspectives. The response by the author plus associated information is summarized below:

The Covid-19 pandemic has resulted both in shifts in South Africans’ demand for dairy products as well as changed purchasing habits according to BMi Research, cited below.

What is A1 and A2 milk: The difference is associated with variation in the protein composition of cow’s milk. Both A1 and A2 variants are proteins in the casein group which makes up about 80 % of the proteins. The two variants are almost identical apart from differing in one amino acid at position 67 of the polypeptide (amino acid chain): A1 has histidine whereas A2 has proline.