Antagonism in the carbon footprint between beef and dairy production systems

Mm Scholtz,J Du Toit,Fwc Neser

doi:10.4314/sajas.v44i5.4

Abstract

Primary beef cattle farming in South Africa is largely extensive, whereas dairy farming is based on both total mixed ration and pasture production systems. Under natural rangeland conditions, decomposition of manure is aerobic, which produces carbon dioxide (CO2), part of which is absorbed by the regrowth of vegetation rather than released into the atmosphere, and water (H2O) as end products. Thus the cow releases methane (CH4) and the manure CO2. This is in contrast to intensive cow-calf systems in large parts of Europe and North America, where large quantities of manure are stockpiled and undergo anaerobic decomposition and produce CH4. Thus both the cow and the manure release CH4, which result in a higher carbon footprint than the extensive cow-calf systems. In dairy farming, increasing cow efficiency through intensive feeding (same kg milk output by fewer animals) can reduce farm CH4 production by up to 15%. In addition, when differences in productivity are accounted for, pasture systems require more resources (land, feed, water, etc.) per unit of milk produced and the carbon footprint is greater than that of intensive systems. This raises the question as to why the carbon footprint of intensive dairy cow production systems is less, but the carbon footprint of intensive beef cow-calf production systems is higher. The explanation lies in the differences in production levels. In the case of beef cows the weight of the intensive cows will be ± 30% higher than that of the extensive cows, and the weaning weight of their calves will also differ by ± 30%. In the case of dairy cows the weight of the intensive cows will be ± 20% higher, but their milk production will be ± 60% higher. The higher increase in production (milk) of intensive dairy cows, compared to the increase in production (calf weight) of intensive beef cows, explains the antagonism in the carbon footprint between different beef and dairy production systems. Unfortunately, carbon sequestration estimates have been neglected and thus the quantitative effects of these differences are not known.Keywords: Cow-calf production, methane, pasture production, production levels, total mixed ration

Highlights

In South Africa, the cow-calf production cycle is mostly extensive, since large parts of the country are not suitable for crop cultivation, with approximately only 13% that can be cultivated
It is important to note that part of the CO2 from the manure is most likely absorbed by the regrowth of the surrounding vegetation rather than released into the atmosphere. This is in sharp contrast to the intensive systems in large parts of Europe and North America, where large quantities of manure are stockpiled and undergo anaerobic decomposition
The conclusion from these results is that intensive cattle production systems will have a lower carbon footprint than extensive production systems, if the production period can be shortened or the production per unit can be significantly increased

Summary

Introduction

In South Africa, the cow-calf production cycle is mostly extensive, since large parts of the country are not suitable for crop cultivation, with approximately only 13% that can be cultivated. The greater part of South Africa (71%) is only suitable for extensive livestock farming (RMRD SA, 2013) Under these natural rangeland conditions, decomposition of manure is aerobic, leading to the production of carbon dioxide (CO2) and water (H2O) as end products. It is important to note that part of the CO2 from the manure is most likely absorbed by the regrowth of the surrounding vegetation rather than released into the atmosphere. This is in sharp contrast to the intensive systems in large parts of Europe and North America, where large quantities of manure are stockpiled and undergo anaerobic decomposition. The anaerobic decomposition of manure in these intensive cow-calf systems, feedlots and intensive dairy systems produce CH4 as one of the major end products (Scholtz et al, 2013)

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