Dairy R&D in SA

Amidst growing global concerns over sustainability, the imperative for sustainable agriculture has become increasingly important. This urgency is enhanced by an increasing awareness among consumers and policymakers, the demands of activists, and the questionable influence of dietary choices on environmental sustainability.

Feed efficiency (FE) has major implications for dairy production profitability and indirectly for environmental sustainability. It thus has become a priority for monitoring the economic viability of milk production and the environmental footprint.

Feed efficiency traits such as dry matter intake (DMI) and gross feed efficiency (GFE) are imperative in the improvement of herd performance, profitability and sustainability. These traits are however normally not included in selection indices, because of the difficulty to measure DMI.

Cow fertility has recently received much more attention world-wide in breeding programmes than previously, because of its economic implications. Age at first calving (AFC) and calving interval (CI) are typically the parameters of choice in South Africa, but the success thereof is affected by the farmer’s management choices. As alternative, service records could be used to derive fertility traits such as services per conception (SPC), calving to first service (CFS) and days open (DO).

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.