Dairy R&D in SA

Definitions: Various definitions used by prominent world organizations provide pointers to answering this question. The World Organization for Animal Health defines Animal Welfare as “the physical and mental state of an animal in relation to the conditions in which it lives and dies”, whereas World Animal Protection defines it as “the quality of life experienced by an animal and encompasses how well the animal is coping with his or her current situation and surroundings“. So, animal care which is more encompassing comes into the picture.

Beef production from dairy herds is possible through culled cows while bull calves can be reared for veal or beef production. This potential is however often not exploited, probably because of its relatively small contribution to overall farm income. In South Africa beef contribution from dairy herds is estimated to be about 10% of the total beef production. One reason is the small national dairy vs. beef herd and secondly that large Jersey populations are popular in pasture-based areas. For Jersey farmers, little income is generated from rearing bull calves, because of low growth rate of culled cows and steers compared to other dairy or beef breeds. Beef production output of Jersey herds could be improved using beef or dual-purpose breed sires on part of the dairy herd.

Extended shelf life (ESL) milk is processed with the aim of obtaining a product encompassing the sensorial characteristics of fresh milk, but with a longer shelf life. To achieve these qualities, a sequence of processes is employed which may include pasteurisation, steam injection, bactofugation and ultra clean filling technologies. Although the technology for ESL milk production is designed to prevent post-pasteurisation contamination, recent studies have shown the occurrence of psychrotrophic spore formers in finished ESL milk products.

M. van Niekerk, a student from South Africa, reported genotype x environment interaction in SA Holstein dairy cattle, clear differences being seen in genetic parameters between herds using a total mixed ration (TMR) or pasture-based system. Specifically, genotype by environment interaction for persistency of production between the two production systems were indicated with genetic correlations for the first three lactations of below 0.64 throughout. This means that animals whose progeny perform well in TMR will not necessarily perform well under pasture conditions with regard to milk production traits.

Dairy farming is a water-intensive land use and one which can degrade water quality. Examples of potential impacts include:

1. Viability of Bifidobacterium species in probiotic yoghurt as influenced by reducing agents.

Automated BCS enables the owners to score their cows more often and more consistently compared to manual methods. A common approach to automated BCS scoring is using a regression-based model. This involves extracting features from the cows digitally and then fitting these features to the manually labelled BCS values through various regression techniques. These regression based models can then be used to predict the BCS of a never before seen cow. A newer approach to automated BCS is using Convolutional Neural Networks (CNN). The system uses a 3D scan of the cow’s back. A similar approach was used here, albeit with multiple 3D cameras.

Discipline: Milk quality Keywords: age gelation, UHT milk, Alizarol test, psychrotolerant bacteria, Pseudomonas, rapid tests. 

Discipline: Reproduction Keywords: MUN, urea, reproduction, season, subtropics

Discipline: pastures; Keywords: kikuyu-ryegrass pastures, stocking rates, weedy species, Plantain, clover, Lucerne, Tall Fescue, monoculture, mixed species.