Dairy R&D in SA

The Dairy Standard Agency and Milk SA regularly engage with authorities to include dairy safety standards into legislation. The SA dairy regulations (R.1555 of 21 November 1997) are under revision with considerations for internationalisation, which amongst others, include focusing on only Enterobacteriaceae instead of Escherichia coli (E. coli) and coliforms. Since these indicator organisms are vital for dairy product safety and hygiene, this potential regulatory change could impact the South African dairy industry's monitoring practices. In the study cited, the relevance of E. coli, coliforms and Enterobacteriaceae as hygiene and food safety indicators in milk in South Africa, along with species identification, was therefore assessed.

During the transition period, dry matter intake (DMI) does not generally satisfy the increasing nutrient demand of dairy cows, mainly because of a decrease in feed intake and appetite. As a result, dairy cows go into a state of negative energy balance (NEB) and thus mobilize body reserves as a physiological mechanism to adapt to the energy deficiency from late gestation to early lactation. NEB starts a few days before calving, reaching a NEB low two to four weeks post-calving, with the energy balance (EB) becoming positive again by 10 to 12 weeks after calving. During the NEB period, non-esterified fatty acids (NEFA) are released intensively from adipose tissues and recycled as energy fuels.

During the transition period, pre-calving cows mobilize their stored body reserves in an attempt to meet the increased demands for pregnancy and growth before calving and milk production after calving. This results because of the immediate post-calving decline in dry matter intake (DMI), which creates a shortage in required nutrients and a state of negative energy balance (NEB). NEB, as evidenced by live weight (LW) loss after calving, is a physiological adaptation that occurs during the immediate post-calving period.

This report in particular pays attention to environmental integrity as it pertains to greenhouse gas (GHG) emissions, soil health and nutrient supply, waste management, water quality and quantity, and biodiversity.

Irrigated ryegrass and white clover pastures form a major part of pasture-based dairy operations in the Western and Eastern Cape provinces. Nitrogen fixation of legumes such as white clover, serves as an important component in increasing yield. However, the importance of fertilisation remains as, despite producing N for pasture grass species, only about 70% of potential herbage yield can be achieved using legumes without any N fertilisation. A possible alternative to standard fertilisation for increased N availability in pasture systems is the use of biostimulants, such as fulvic acid and bioflavonoids.

Genetic advancements have resulted in improved dairy production over many decades, due to the focus of breeding objectives on production as the driving force for genetic progress and overall farm profitability. Major advancements were made in the easy-to-measure traits with moderate to high heritability, which resulted in unintended consequences on herd fertility, health, and welfare of cows. In addition, climate change and animal welfare concerns demanded balanced breeding objectives and selection approaches for sustainable production—including health and longevity. The challenge for improvement of cow welfare often lies within implementation of sensitive and measurable parameters.

Claw lesions are the primary cause of lameness in dairy cattle, with serious implications for animal welfare due to the distress and discomfort experienced by the cows. Claw lesions are classified as either infectious lesions such as digital dermatitis, interdigital dermatitis, heel erosion, and interdigital phlegmon, or non-infectious lesions (including white line disease, sole ulcer, and sole haemorrhage). The majority of studies have reported digital dermatitis, sole haemorrhage, sole ulcer, and white line disease as the primary causes of dairy cattle lameness. There are several risk factors that influence the prevalence of claw lesions in dairy cattle, including environmental factors, design of housing facilities, and hygiene and management practices.

The study cited involves reviewing determination of the impact of Good Agricultural Practices (GAP) and Management Systems on dairy production, dairy processing, and end-product quality. This is a Milk SA funded project, the progress being reported here.

There is a decline in small-scale dairy farming in rural areas of the developing world, also in South Africa. Reasons provided in the literature include shrinking fringes, access to cattle feed, limited interest of future generations, increased cost of cattle, feed and fertilizer, poor cattle health, knowledge and management, poor understanding of livestock diseases, uncertain weather conditions, power failures and high cost of electricity, lack of machinery and equipment, stock theft, quality and safety of the product, poor packaging, and lack of government support, amongst others. The study cited explored the challenges of small-scale dairy farmers in the Bojanala Platinum District of the North West Province.

Selection in dairy cattle primarily emphasizes increasing milk yield and solids. This however may be negative to overall fitness, particularly fertility because of the antagonistic association between fertility and milk yield. Thus, although benefiting from yield, profitability may not improve because of deteriorating reproductive parameters such as increased inter-calf period, more AI services per conception, more days open and increased veterinary costs.