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VARIATION IN HERD SIZE AND MILK PRODUCTION ON SOUTH AFRICAN FARMS IN RELATION TO BENCHMARK INDICATORS.

The profitability and sustainability of dairy farming are often at risk. Some factors are external and not controllable by the farmer. Other factors can be managed and their effects minimized or where these factors can improve the outcome, the farmer should maximise their influence. Also, from a national (industry) level one is concerned about how these factors are dealt with and whether the industry moves in the direction of continuous improvement. As a first approach in this context, one needs to have a baseline and considers the variation between farms, their numbers, production levels and how this probably relates to profitability and sustainability. Obviously, in the space of this contribution it is not possible to deal with all factors, but some status quo data and calculations will provide directives. The references consulted are below.

South Africa currently (2014) has 1834 dairy farmers. The average herd size is 353 cows in milk, with a variation of less than 15, which accounts for about 42% of herds, to several hundreds and even thousands; the latter accounting for only about 2% of herds. The number of cows in milk is then calculated as 1834 x 353 = 647 402, and if one accepts that a herd consists of about 47% animals (mature cows and first-lactation heifers) in milk, the national dairy herd is about 647 402/ 0.47 = 1.38 million animals, which corresponds with estimates of other sources. Thus, these estimates appear to be fairly accurate.

All milk produced by farmers is not entering the commercial market, but some are used at household level or sold in the immediate vicinity. This would apply to the majority of cows producing less than 10 litres per day and with herd sizes less than 15 cows. If one takes that into account milk entering the market comes from only about 1250 herds which equates to 440 000 cows in milk. Raw milk sales in 2014 were on average 250 000 000 litres per month, which means that the average yield per cow per day was 250 000 000 litres/440 000 cows/30 days = 18.9 litres. The estimate in LACTODATA is 20.4 litres per cow per day for 2014. In comparison milk recording data from the Logiχ system for 2012-2015 shows averages of 22.4 litre per cow per day for Ayrshires, 19.3 for Jerseys and 29.0 for Holsteins, and if the ratio of these breeds in the national herd is taken into account, the average for milk recorded data from the Logiχ data base would be about 26 litre. One expects that cows in milk recording and stud animals which are the majority on the Logiχ system would produce more than the national average, and therefore the estimate of 20 litres per cow per day appears fairly accurate.

The concern from the point of view of moving the national herd forward is the variation in milk production. By far the majority of herds producing for the market have yields of less than 20 litres per cow per day, whereas probably less than 40 herds (calculated from the assumptions above) have yields of more than 35 litres per cow per day. Why is this important; because milk yield is highly correlated with efficiency. In a study where cows with an efficiency of 1.83 kg milk per kg dry matter intake was compared with cows with an efficiency of 1.03 kg milk per kg dry matter intake, it was found that the more efficient cows produced 98% more milk, but consumed only 21% more feed than the less efficient cows. Whereas we know there will be differences between production systems (TMR, pasture-based, low input, high input etc), these results suggest that in all systems, accepting that the biological optimum has not yet been attained, higher input will reap benefits, even with the increased feed costs. A further argument is that direct selection for efficiency will also be beneficial, since whereas milk yield as mentioned is highly correlated with efficiency, the variation between cows can be in excess of 20 %, meaning that cows with the same yield may be up to 20 % different in efficiency. Thus there is a large genetic base for improvement through selection. Thus, it is imperative that more emphasis should be put on improving milk yield per cow and efficiency where possible. Imagine the enormous influence on competitiveness and broadening of the market for milk and dairy products if the milk yield per cow over the shorter term can be increased to 25 litres and with a longer term target of 30 litres!

A spin off of increased yields and efficiency is less greenhouse gas emissions and water use per litre milk, which is the way these environmental issues are considered internationally. Calculations show that at 6000 litres over a 300-day lactation period (20 litres per day) the emissions on average range between 1.5 to 1.6 CO2 per kg milk, whereas at 9000 litres (30 litres per day) emissions range between 1.2 to 1.3 CO2 per kg milk, a difference of 20%. Between farms though, differences at the same production level can be more than a 100%, which suggests that management of environmental issues is largely an on-farm issue.

Another contributing factor to sustainability and profitability is herd size. The trend is for increasing herds because of capital and overhead cost. It is worth noting that the small number of herds that produce more than 35 litres per cow per day are large herds, often in excess of 1000 cows in milk. It is not surprising that they currently may produce 15 to 20% of the milk. Herd increase, although inevitable in today’s cost squeeze, is a function of farm conditions as it is determined by management skills, labour, equipment, infrastructure etc. Thus, there will be an optimum herd size per farm which should be investigated.

References:

MPOist, undated. Herd composition: Dairy Farmers, plus communication with J. Wasserman.

Logiχ Milk Recording Data, May 2015. B. Mostert, Studbook.

 H.H. Meissner et al., 2013. Sustainability of the South African Livestock Sector towards 2050 Part 2: Challenges, changes and required implementations. S. Afr J Anim. Sci. 43. 298-319.

 C.J.L. du Toit et al., 2013. Direct methane and nitrous oxide emissions of South African dairy and beef cattle. S Afr. J. Anim. Sci. 43, 320-339.

 C. Arndt et al., 2015. Feed conversion efficiency in dairy cows: Repeatability, variation in digestion and metabolism of energy and nitrogen, and ruminal methanogens. J. Dairy Sci. 98, 3938-3950.