Dairy R&D in SA

Heat stress typically results when the heat load of the air temperature, the associated humidity, and the solar radiation at the time prevents the ability of the cow to effectively dissipate the heat generated from production and metabolism.

Some farmers with herds producing high milk yields extend the lactation cycle to more than 305 days. This is related to reproductive management, which then obviously results in long open days. One argument is that high producing first lactation cows will have higher lifetime milk yields with increasing milk yield per day of lifetime. The question is if this assumption is correct and therefore the authors cited aimed in their study to determine if the effect of duration of the first lactation period has a significant effect on lifetime performance.

Concentrate feeding on pasture- based systems has increased lately, often at a cost as intake of pasture may be partially replaced and therefore the increased milk yield with concentrate supplementation may not attain the intended level. Therefore, the approach should rather be maximizing intake from pasture with concentrate supplementation at a level which does not substitute pasture intake. This may be possible if concentrate supplementation can be partially replaced with a high-quality, fast-degradable pasture such as the forage herb plantain.

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.

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 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.

A pasture paddock of 3.3 ha was used for the study. It consisted of a mixture of one-year old perennial ryegrass, white clover, and red clover. A 2 × 2 factorial design, arranged as a randomised block with three blocks was adopted, viz. 12 experimental plots. Each plot was approximately 15 × 132 m in size and plots were separated by mobile electric fencing for grazing management. Two factors were studied, grazing period being the first. Winter and summer were chosen as grazing periods, and two grazing cycles per grazing period were examined.

Dairy cow welfare is recognized and promoted in the S A dairy industry through various organizations, which include the MPO, Milk SA and the DSA. According to the code of practice for milk producers by the DSA, animal welfare is dependent on both sensible and sensitive animal husbandry practices. As a result, most intensive dairy farm practices in the country ensure animal welfare primarily through their management systems, being supported by skilled and trained personnel. Also, many SA dairy farmers have followed world trends with application of balanced selection indices.

Claw trimming is used as a management tool to control claw lesions. In South Africa, claw data are limited to the use of private hoof trimmers, who record lesions on paper, and data is not necessarily captured in an electronic recording system. In the study cited, routine trimming data from five intensively managed dairy farms over a 6-year period (2014–2019) were analysed to investigate the prevalence and distribution of claw lesions in Holstein cattle in the central region of the country in order to facilitate more effective recording and management.