Dairy R&D in SA

by Heinz Meissner

Click on any of the publications below to read more about the specific topic:


Title Date Discipline Extract
IS NITROUS OXIDE NOW THE MAJOR GHG CONCERN IN AGRICULTURE?

Recent research shows that the contribution of methane (CH4) to the atmosphere by shale gas and other earth sources is much higher than accepted in IPCC calculations, which implies that much less is from ruminants (Howarth, 2019). Secondly, in carbon footprint calculations the CO2 capture by photosynthesis through the biogenic cycle in plant foods (say maize) (which apart from CO2 may also have resulted indirectly from atmospheric CH4) is not taken into account (Frankelius, 2020). This is actually a carbon sink.

CARBON EMISSIONS AND SEQUESTRATION ON DAIRY FARMS IN SA.

Dairy has been targeted as a source of greenhouse gas emissions (GHG). However, research has shown that grazing livestock on pasture-based dairy farms restore carbon to the soil, enhancing its biodiversity and countering climate change. This poses the question: If farms can have a positive impact, but are also a source of negative impact, what is the net effect? This is an important consideration when assessing the negative contribution that dairy farming makes to climate change.

PRIORITY RESEARCH STILL TO BE DONE ON MILK FLOCCULATION IN SA.

Priority 1: The literature shows that almost any factor which has an influence on phosphate metabolism will affect the stability of milk. In the cow heat stress can reduce the availability of phosphate in the udder by up to 50%. It is also well known that the addition of phosphate salts can improve the stability of milk. One of the questions which should be addressed is whether milk not passing the 72% alizarol test has less phosphate than milk passing the 80% alizarol test. If so, it can be expected that low availability of phosphate plays a role during milk synthesis.

CAN PRE-WEANED CALVES BE FED ONCE A DAY INSTEAD OF TWICE A DAY?

In most calf rearing systems milk is fed twice a day to dairy calves. However, at Outeniqua Research Farm calves have been reared successfully by feeding milk once a day. The advantage is that by feeding once a day labour requirements are reduced and it may positively affect growth, health and rumen development of calves, e.g. more rapid development of the digestive system. Effective calf rearing will reduce calf mortalities and rearing costs in both commercial and small holder operations.

The possible dilemma of feeding concentrates on pasture.

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.

KEY PERFORMANCE INDICATORS FOR JERSEY COWS ON TMR.

For dairy farms to be economically sustainable, herd managers should continuously monitor specific key performance indicators (KPIs). Indicators must be based on quantitative or performance goals which are specific, measurable, attainable and relevant. These may include the average daily milk yield of the cows, their daily feed costs and specific reproduction parameters. These to a large extent are farm specific as each farm is unique in terms of natural resources, infrastructure and management style which will affect milk yield, production costs and breakeven milk yield.

POSITIVE CARBON BALANCE RESULTS REPORTED BY TRACE AND SAVE.

This is a summary of results reported by Dr Craig Galloway (see reference below) of farms where there have been improvements in the carbon balance and other parameters as indicated by data collected between 2013 and 2019. Some of the farms have data for all the years, whereas others only have data for two of the years. All improvements indicated are the most recent data relative to the baseline, which is the first time the assessments were done. The farms are pasture-based dairy farms in the Eastern Cape (Tsitsikamma, Oyster Bay, Humansdorp, Cookhouse, Cradock and Alexandria).

EVALUATION OF CLAW HEALTH IN DIRT LOT VS FREE STALL HOUSING.

Claw health is an important factor in animal welfare and its evaluation is an early indicator of lameness in dairy cattle. However, claw disorders on many farms are not routinely evaluated and the information not included in genetic evaluations as they are not always considered in terms of productivity. The aim of the study by the authors cited below was to evaluate claw health of dairy cattle housed in dirt lot vs free stall under the TMR systems.

BEHAVIOUR OF NGUNI X HOLSTEIN CROSSBRED COWS ON VELD

The most popular dairy breed in South Africa is the Holstein. Being of European origin the Holstein is not well adapted to South African veld conditions. Consequently, its milk production on veld is very low, and the animals cannot subsist and produce without some form of supplementary feed. The Nguni breed is an African breed, and is used by communal farmers in KwaZulu-Natal for household milk supply.

INBREEDING IN SA DAIRY BREEDS AS MEASURED BY GENOMIC PARAMETERS.

Small effective population sizes and inbreeding are major challenges faced by dairy cattle populations worldwide. Estimates of pedigree-based inbreeding (FPED) are unreliable due to a lack of pedigree data and pedigree errors and that may lead to an underestimation of inbreeding rates. Thus, inbreeding based on runs of homozygosity (FROH) has become the preferred method of estimating inbreeding as it is able to accurately predict the amount of autozygosity within the genome.