LSIRD WITZENHAUSEN WORKSHOP PROCEEDINGS

Organic grazing livestock production: possibilities and prospects

Susanne Padel


Introduction

Organic farming is best understood by referring to the concept of "farm as an organism" and not by the use of organic fertilisers. This refers to a self containing unit where the different parts of the farm are connected and which does not or only to a lesser extent rely on external inputs, such as nitrogen fertiliser. Organic livestock production is mostly land based, and frequently the animals, especially grazing livestock are seen as an essential part of the system. With the emergence of stockless organic rotations (by including a sufficient time period of growing legumes) this has to be questioned as an overall necessity but in many areas livestock based farming systems are certainly the most site appropriate form of agriculture.

The organic management in general differs from conventional agriculture because of its reliance on the management of internal farm derived resources as compared to external inputs. Grazing animals help to provide economic return for the forage legumes that are grown because of nitrogen fixation. However, in the past the main focus of research and development has been on organic cropping systems, the use of farm yard and other organic manure, techniques for mechanical weed control and biological control of pests and diseases. This reflected also the more rapid development of the markets for vegetables and cereals. Less attention had been paid to the management of the animals in the farming system and specialised livestock farmers were in a minority and had to find their own solutions.

Fortunately, the situation has changed and there is some indication from Germany, Denmark and Austria that recent growth of the organic sector is due to an increasing number of livestock producers (7.5% of all Suckler cows in Germany are now managed organically) and producers in the marginal areas converting to organic production (AGÖL, 1997; Schulze Pals, 1994). At the same time an increasing number of researchers have began to work with livestock systems for organic farms and the markets for milk and meat are developing.

Even though the same principle applies for all organic systems, the practical questions that arise on a specialised livestock farm are very different from mixed or cropping oriented farms. Changes during conversion are most likely to arise in the area of forage production, ration composition and diet, animal health, breeding. In the following paper I will briefly discuss each of these areas and highlight the most important changes that are likely to occur during conversion from conventional to organic agriculture, and highlight the strategies for marketing and the likely financial success of the system. In the end I will briefly summarise where research can further assist the development of organic livestock production as a truly sustainable alternative.

Converting to organic livestock production

Grassland productivity and stocking rates

The first important question that farmers with grazing livestock usually come up with once they consider conversion is: "what will happen to my stocking rate?". Forage production has to rely on nitrogen fixation of legumes, mainly clovers and the clover content is therefor one of the important factors in forage productivity on organic farms (Newton, 1995); other factors are soil type, soil nutrient content (P,K) and climatic conditions. The sward type has an influence on the yield, the productivity of short term leys (Red clover/Italian Ryegrass mixtures) for cutting is in most cases higher and the quality (energy and protein content) better than that of long term grazing fields either with permanent pastures or long term leys (Haggar and Padel, 1996).

Forage production during conversion to organic production will, apart from the above mentioned factors, depend on the intensity of the previous conventional management; the seasonal production pattern of the swards is also likely to change with a reduction in early spring growth. Despite the lack of clear experimental evidence of lower forage yields feed shortages are reported frequently during the process of conversion (Haggar and Padel, 1996; Rantzau et al., 1990; Schulze Pals, 1994). In established organic dairy systems stocking rates are on average at about 80% -90% of the conventional system (1.6 to 2.0 LU/ha). In Beef and Sheep systems the variation is even greater ranging from similar levels of production as conventional to reductions of up to 60% (Elliot and Keatinge, 1997; Lampkin, 1993; Medcalf et al., 1996; Younie, et al., 1990). Reduction in stocking rate appears to be more dramatic on poorer soils than on better soils (Schulze Pals, 1994) but depends also on the intensity of the conventional system. However, the stocking rate can be a very inaccurate measures for forage productivity, because changes in other farm inputs such as concentrate and purchased forage and improved grazing management can mask changes in the forage productivity of the farm.

Frequently farms diversify by including another species of grazing animals, such as beef into a purely sheep based system.

In summary it can be said that the grassland productivity (in terms of stocking rate) is likely to be lower on organic than conventional farms, the degree of reduction will depend on clover content, soil and climatic conditions and the intensity of the conventional system with which the organic system is compared.

The main problem in the management of permanent grassland and long term swards is weed control, especially the control of deep rooting species such as docks (Rumex sp.) and creeping and spear thistles (Cirsium arvense and vulgare). The farmers need to return to traditional husbandry methods, such as good grazing management to form a close competitive sward, mixed grazing and frequent topping for their control. However, weed control of deep rooting weeds in permanent pastures and long term leys is frequently mentioned as an unsolved problem after conversion (Haggar and Padel, 1996) even though the farmers vary in their perception of what consists a problem.

All standards allow some, usually slow releasing P and K fertilisers to be applied but the application should be based on nutrient budgets rather than blanket recommendations. The establishment of clovers in the sward has also frequently been reported as a problem during conversion, especially on soil conditions which are not the natural habitat of white clover.

There are a number of environmental benefits to be expected once grassland is under conversion to organic management. Firstly, the absence of any nitrogen fertiliser and exclusive reliance on legumes is likely to lead to more species diverse grassland even though some "modern" clovers have a vigorous growth and can be quite competitive in the sward. The absence of nitrogen fertiliser is also likely to reduce the risk of ground water pollution with nitrates which has increasingly been recognised by water companies (Hess et al., 1992; Redman, 1992). The lower stocking and the introduction of other species of grazing animals rates are likely to further increase bio-diversity in the sward, with positive implications for other wildlife. In some support schemes this has been considered by offering the possibility to combine organic management with other environmental or conservation objectives and/or to offer organic farming it as a "qualitative" method to fulfil the requirements of the scheme.

Feeding regime and diet

The conversion to organic management is likely to have some implications on the feeding regime, especially if the previous conventional system was to a large extent relying on external inputs. The aim in an organic grass based farming system usually is to maximise the production from home grown forage. However the standards do not exclude the use of ready mixed concentrates but place some restriction on the components and the proportion of conventional feed.

Dairy farms often reduce the amount of concentrate by up to 40%, reductions appear to be related to the levels of concentrate feeding before conversion; in cases of very low levels before conversion increased use of concentrate feeding has also been reported (Lampkin, 1993; Schulze Pals, 1994, Haggar and Padel, 1996). There is little research available about the concentrate use of other grazing livestock systems such as beef and sheep enterprise under organic management. Reduced concentrate feeding will lead to a higher demand in forage (in quantity as well as quality) so the planning of the forage supply of the farm needs some careful consideration.

Little is known about what types of concentrate are best suited to supplement the forage in order to maximise its utilisation. Currently the decision on what concentrate to feed is taken on grounds of availability and price. Not in all areas are companies supplying farmers with concentrate mixes that fulfil all requirements of the standards, so that some farmers might need to change the feeding regime and in some cases the farmers decide to grow cereals for feeding in order to reduced the reliance on externally produced inputs, even though this is not a requirement of the standards. There also is some uncertainty on what other protein sources can be used in concentrate mixes, either on the farm or by commercial suppliers, that fall within the standards. Most recently the introduction of genetically modified Soya has restricted the choice, because not all suppliers are in a position to source Soya that is not affected and the organic standards do not permit the use of GMO.

There is no clear evidence that the forage quality changes as a result of the conversion to organic farming (Kristensen et al., 1994; Veauthier and Krutzinna, 1992) even though it is likely that the higher proportion of legumes in the sward and the potentially later cutting date might have some effect. The high legume content in the diet is likely to be beneficial for forage intake, due to a more rapid microbial digestion in the rumen (Sheldrick et al., 1987), even though these effects have not always been confirmed in larger scale experiments and system studies (Bax and Brown, 1995). There is some evidence that the overall diet fed on organic farms is more diverse than on conventional farms, with a higher proportion of hay and root crops (Swedes and fodder beet) and a reduction in silage in addition to the reduction in concentrate (Ebbesvik and Loes, 1994; Krutzinna et al., 1995). The converting livestock farmers might than also be faced with the decision on what alternative crops can be grown on the farm to improve the diet and performance of the stock.

Animal health and breeding

Conversion to organic production implies a changes in animal health management, best characterised by a move away from therapeutical treatment to preventive management. This represents potentially the most difficult area for many farmers to comply with. On the other hand, problems with animal health, are apart from soil erosion one of the most frequently mentioned motivations for farmers to convert to organic methods (Fischer, 1982; Vogtmann et al., 1993; Wernick and Lockeretz, 1977). By improving the level of stockmanship within the organic herd or flock and improving the immunity of the animals to disease, many problems can either be prevented or detected in the early stages of development and effectively treated with alternative remedies without the need to routinely use conventional medicines. In many cases, the key issue during the conversion period is the confidence to stop routine medication, such as dry cow therapy or routine use of anti-helmintics, in favour of alternative approaches.

Organic standards contain detailed animal welfare provisions, which are an important component of successful organic management. Outside access and housing appropriate to behavioural needs are required. Depending upon the system on the farm, some changes to the housing conditions might therefore be inevitable; a change to loose housing for the dairy herd, even though not strictly prescribed, might be seen as beneficial by the individual farmer and implemented as part of the conversion process.

Detailed studies on the health situation of animals under organic management are rare and usually focus on dairy cows. There is some indication of lower incidence of ketosis, milk fever, mastitis and lameness in organic herds (Ebbesvik and Loes, 1994; Haggar and Padel, 1996; Offerhaus et al., 1993), even though the result in terms of mastitis are not conclusive. There appears to have been a slight improvement in fertility and age of the cow on the organic and in conversion holdings (Ebbesvik and Loes, 1994). The biggest health problems mentioned by dairy farmers are mastitis, hoof disorders (Baars and Buitink, 1995; Haggar and Padel, 1996) and infertility (Roderick et al., 1996). Poor nutrition (structure, energy and protein supply) often underlies health problems and it has therefore been suggested that a recommendation for regular forage analysis should become part of organic standards (Ebbesvik and Loes, 1994).

The situation is somewhat different on farms with sheep and beef enterprise, where parasites are likely to represent the biggest challenge. The control of internal parasites can be successfully achieved with management practices such as clean grazing systems, mixed stocking, rotational grazing and selection of resistant stock and breeds. A reduction in stocking rate will also have an effect in reducing the parasite burden of pastures. Drenching of particularly stressed and therefore more vulnerable animals such as ewes with twin lambs is considered to be acceptable. The situation is slightly more difficult with regard to the control of external parasites, where up until now management practises are not so well developed and farmers have to resort to using conventional treatment on a more regular basis, such as for the treatment of sheep scab, or to comply with legal requirements.

However, overall organic livestock farms appear not have major health problems, other than similar to conventional herds. The farmers use a combination of preventative management, good supervision for early detection and alternative treatment, especially the use of homeopathy and, in severe cases, the use of conventional veterinary treatment to maintain animal health.

In the area of breeding, emphasis is given to maintaining a closed herd, the rearing of the herd's own replacements and the feeding of whole milk to calves (Lampkin and Measures, 1995). Both in dairy and in other grazing livestock systems organic farmers frequently choose more robust or sometimes even rare breeds. There is very little research that addresses the suitability of breeds for the organic farming systems and there is no clear evidence that high intensity breeds can not be farmed successfully under organic management. However, the development of special breeding programmes for longevity (for other animals than diary cows in the German speaking countries) would be beneficial.

Animal productivity

The reported milk yield in organic systems varies widely with reductions of about 10% as compared to conventional yield (Lampkin, 1993), reductions up to 25% (Augstburger et al., 1988; Winckler and Steinback, 1991) as well as lower or no differences in yield between the two system (Haggar and Padel, 1996; Kristensen et al., 1994; Schulze Pals, 1994). The effect seems to be more marked on intensively managed systems with more intensive breeds, such as HF, and high levels of concentrate feeding. Yield reductions can be the result of a combination of all the different factors mentioned above, but the main influence is likely to come from reduced concentrate feeding and low forage supply (in quantity and/or quality, lack of continuity).

The animal productivity in other grazing livestock systems is more difficult to compare as the production patterns can vary widely and farms often combine a variety of different enterprises on one farm. In addition the variance between breeds can be considerable so that it is difficult to find a sample of farms for a comparative study. There is no clear evidence that, apart from a potentially lower stocking rate, the productivity of individual animals is lower under organic management. In contrary, in some cases a similar or even better daily live weight gain in a clover based system was found (Bax and Brown, 1995; Younie, 1991).

Marketing

After the conversion period of the land and the livestock the farmer can apply for certification and will be entitled to use registered trademark for organic production. Once the EU livestock regulation (Amendment to EU Reg. 2092/91) is in place this will be legally enforceable.

However, even though research shows and increasing demand for organic milk and meat, many organic farmers in Europe are still not able to sell all their livestock produce with a premium. In many cases only a small proportion of milk or meat can be sold to an established organic outlet. Marketing is therefore a very important issue on livestock farms during conversion as access to premium has a significant beneficial effect on the financial performance. The farmers are exploring a variety of strategies.

Direct marketing of meat usually relies on good access to slaughter facilities and close co-operation with a local butcher. The farm might either sell fresh quarters for home freezing directly from the butcher, which usually requires no or little investment on the farm. If the farm wants to sell frozen meat parcels or selected cuts and/or a range of meat produce such as sausages, salamis or mince meet, a considerable amount of investment might be need to fulfil the high hygiene requirements, both in the case of meat and milk. Some farms in the UK that started initially with the processing of only their own products have grown substantially and are now processing for other farms as well, either under their own label or under contract. They seem to illustrate a dilemma, faced by many: in order to find technological solutions to fulfil the hygiene requirements a certain production volumes appears to be necessary. This implies that the on farm processing becomes a major enterprise and can dominate the farming activities (Revell et al., 1996).

It can therefor be concluded that the necessary investment to fulfil the hygiene requirements in the milk and meat sector are restricting the possibilities to develop on farm processing and direct marketing for the majority of many organic meat and milk producing farms.

An alternative strategy, which increasingly is becoming more popular is co-operation to develop a joint marketing initiative, either by investing in a shop or other outlet of their own or by organising continuous supply for larger byres. This approach has been successfully developed in the case of the organic milk producers in Denmark and with the organic milk and livestock marketing co-operatives in the UK.

In all these marketing initiatives the organic certification will be an advantage by setting a defined quality for which consumers are willing to pay a premium. But, and this applies equally to all the above mentioned different marketing strategies, the organic certification will not replace the need to produce high quality in all other terms of quality standards.

Financial performance

Apart from the realised premium in the market place the financial success of any organic livestock production will depend upon the above discussed parameters of production and variable and fixed costs. The most significant saving in the variable cost will be achieved through reduced spending for fertiliser. Savings because of reduced concentrate use will often be cancelled out by higher prices (or opportunity costs for those farms that produced their own concentrate) for organic cereals and higher costs for other components and mixtures as a result of a lack of economic scale.

Where no premiums for the produce can be achieved the livestock gross margins are likely to be lower than conventional (Huus, 1992; Weber, 1993) or can in the case of dairy herds be similar, when the savings in forage costs are high enough to balance losses in production (Lampkin, 1993; Padel and Lampkin, 1994). Even individual cases of dairy farms outperforming conventional comparisons without access to premium have been reported, where the overall management of the herd is very good (Winter, 1991) but are certainly not the average. Enterprise gross margins for beef and sheep enterprises are showing similar trends, with access to premiums higher gross margins than under conventional management can be achieved, without a specialist market there are likely to be equal or lower.

Decreases in stocking rate lead to almost uniformly lower gross margins per hectare on organic than on conventional farms, indicating the lower intensity of the organic system and may result in lower whole farm gross margins. During conversion the farmers will in addition face some learning costs and costs of the adjustment of the farm, which can be in the range of 10-30% of gross margin (Diers and Noell, 1993). During this period they are unlikely to have access to premium prices for livestock products. Depending on the standards in each country the conversion period for meat producing farms can be quite long, since on top of the conversion period for the land the livestock also has to undergo a conversion. Rapid conversion strategies, where all land is included in conversion in one or two year, will allow earlier access to premiums and can therefore be financially advantageous, even though the risk can not be spread and learning costs can potentially be higher (Medcalf et al., 1996). However, these reductions are not likely to exceed the current rate of payment for conversion to organic production that is available in all countries of the EU under the Agri-environement programme (Reg. 2078/92).

Summary and conclusions

Grazing livestock producers who want to convert to organic management have to adjust their farming system so that reliance on external inputs, namely fertiliser, concentrate and routine use of veterinary drugs is replaced through management and farm derived resources.

The forage production will depend on the successful establishment of legumes in the swards, mainly white clover for permanent pastures. The forage production in terms of stocking rate is likely to be reduced, depending on factors such as intensity of the previous conventional management, soil and climatic conditions.

High emphasis should be given to maximise the production from home grown forage so that concentrate inputs can be reduced, but do not need to be replaced completely. This might include some diversification in what forage crops can be produced on the farm, such as making of more hay instead of silage, growing of fodder crops.

The biggest challenge during conversion is likely to be the move away from routine veterinary treatment to preventative management and the use of alternative treatment. Research indicates that the health status of diary animals is similar to conventional herds.

The animal productivity of dairy cows is likely to be somewhat reduced, but there is no clear evidence that the productivity of grazing animals for meat production is reduced, apart from a reduction in stocking rate.

The conversion to organic production offers the possibility to use registered trademark or organic production and, once the EU livestock regulation is in place, this will be legally protected across the EU.

The markets for organic livestock products have only recently developed and currently there is not guarantee that all milk and stock that is produced organically can be marketed as such. There are several successful examples where through co-operation with other producers a market could be established.

Livestock farmers during conversion are likely to face certain costs of conversion in terms of reduced output and learning and adjustment costs. This are likely to be partly offset by savings in variable costs, especially fertiliser and once certification has been achieved through premium prices. In all countries of the EU farmers are currently offered conversion aid programmes, which can in some cases be combined with other environmental or conservation schemes.


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Future research in the following areas would further assist the development of organic livestock management:

· Conversion of permanent pastures.

· Forage production under extensive conditions

· Weed control of deep rooting weeds, especially in permanent pastures.

· Animal health management, especially management techniques for the control of external parasites;

· Use of concentrate to maximise forage utilisation

· GMO free protein sources for concentrates;

· Setting up of farmer co-operatives for successful marketing of livestock products.

References

AGÖL (1997) Bodennutzung und Tierbestand der AGÖL Betriebe 1995 im Vergleich zur Gesamtlandwirtschaft in Deutschland. Ökologie und Landbau 25 (1),2.

Augstburger, F., J. Zemp and H. Heusser (1988) Vergleich der Fruchtbarkeit, Gesundheit und Leistung von Milchkuehen in biologisch und konventionel bewirtschafteten Betrieben. Landwirtschaft Schweiz. 1 427-431.

Baars, T. and I. Buitink (1995) Some practical aspects of preventing disease in organic husbandry, health promotion, natural behaviour enhancement. Luis Bolk Institut, Driebergen, NL.

Bax, J. and I. Brown (1995) The use of clover on dairy farms. MDC Milk development council, London. .

Diers, I. and C. Noell (1993) Anpassungs- und Lernkosten bei der Umstellung con konventioneller auf alternative Milchproduktion. Betriebswirtschaftliche Mitteilungen der Landwirtschaftskammer Schleswig-Holstein 459 (June 93),3-15.

Ebbesvik, M. and A. K. Loes (1994) Organic Dairy Production in Norway. Feeding, health, fodder production, nutrient balances and economy. Results from the "30 farm project", 1989-1992. Paper presented at the 'Nordiska jordbrugsforskares foerening seminar: Converting to organic agriculture', Mikkeli.

Elliot, J. and R. Keatinge (1997) Organic sheep and beef production in the Hills and Uplands. Unpublishe report of linked farms, MAFF funded project OFO 101, ADAS Redesdale.

Fischer, R. (1982) Der andere Landbau: Hundert Bio-Bauern und Gaertner berichten ueber ihre Beweggruende, Arbeitsweisen und Erfahrungen. Verlag Buchhandlung Madliger-Schwab; Zuerich.

Haggar, R. and S. Padel (ed.) (1996) Conversion to organic milk production. Technical Review No 4, IGER; Aberystwyth.

Hess, J., A. Piorr and K. Schmidtke (1992) Grundwasserschonende Landbewirtschaftung durch ökologischen Landbau? Eine Bewertung des Leguminosenanbaus und Wirtschaftsdüngereinsatzes im Anbausystem ökologischer Landbau. N. 45, Institut für Wasserforschung GmbH, Dortmund.

Huus, A. (1992) Oekoloegisk landbruk og oekonomi. 10, Norsk Insitut for Landbruksoekonomie, Oslo.

Kristensen, T., M. Vaarst and E. S. Kristensen (1994) Analysis of the production in danish organic and conventional dairy herds. Paper presented at the '10th IFOAM conference', Lincoln, New Zealand.

Krutzinna, C., H. Herrman, J. Woelfert and E. Boehncke (1995) Kennzahlen der Milchviehhaltung im oekologischen Landbau. Paper presented at the 'Wege zur dauerfaehigen, naturgerechten und sozialvertraeglichen Landwirtschaft' conference, CAU Kiel.

Lampkin, N. H. (1993) The Economic Implications of Conversion from Conventional to Organic Farming Systems.PhD, Department of Economics and Agricultural Economics, University of Wales, Aberystwyth.

Lampkin, N. H. and M. Measures (ed.) (1995) 1995/6 Organic farm management handbook. University of Wales Aberystwyth and Elm Farm Research Centre; Aberystwyth, Newbury.

Medcalf, R. A., P. Midmore, N. H. Lamkin and S. Padel (1996) Modelling the financial implications of strategies for converison to roganoc milk production. In: New Resaerch in Organic Agriculture, Proceedings of 11th IFOAM Conference. (N. H. Kristensen and H. H. Jensen). Ifoam'96; Copenhagen, 278-283. .

Newton (1995) Herbage production from organic farms. Journal of the RASE 156 24-34.

Offerhaus, E. J., T. Baars and F. J. Grommers (1993) Gezonheit en vruchtbaarheid van melkvee op biologische bedrijven. Unpublished, Luis-Bolk Institut, Driebergen, NL.

Padel, S. and N. H. Lampkin (1994) Conversion to organic farming: An overview (Chapter 17). In: The economics of organic farming: An internation perspective. (N. Lampkin and S. Padel). CAB-International; Wallingford, pp 295-313.

Rantzau, R., B. Freyer and H. Vogtmann (1990) Umstellung auf oekologischen Landbau. Angewandte Wissenschaft, 389. Landwirtschaftsverlag; Muenster-Hiltrup, FRG.

Redman, M. (1992) Organic Farming and the Countryside. British Organic Farmers, Bristol.

Revell, B., J. Dunn and S. Padel (1996) Hofeigene Verarbeitung von Milch und Fleisch auf konventionellen und ökologischen Betrieben in Grossbritannien. Paper presented at the '3 Witzenhäuser Direktvermarktertag 1996' conference, Witzenhausen.

Roderick, S., N. Short and M. Hovi (1996) Organic livestock production: Animal health and Welfare; Research priorities. VEERU, University of Reading.

Schulze Pals, L. (1994) Oekonomiche Analyse der Umstellung auf oekologischen Landbau. Schriftenreihe des BEMLF, Landwirtschaftsverlag; Muenster Hiltrup.

Sheldrick, R. D., D. J. Thomson and G. Newman (1987) Legumes for milk and meat. Chalcombe Publications; Marlow.

Veauthier, G. and C. Krutzinna (1992) Grundfutterqualitaet im oekologischen Landbau. Lebendige Erde (3),156-160.

Vogtmann, H., B. Freyer and R. Rantzau (1993) Conversion to low external input farming: a survey of 63 mixed farms in West Germany. Paper presented at the 'Agroecology and Conservation issues in temperate and tropical regions' conference, Padua.

Weber, S. (1993) Umtersuchungen zur Umstellung auf oekologische Milcherzeugung- Versuchsbeschreibung, Milchleistung, Kenngroessen der Energiebilanz, Milchqualitaet und betreibswirtschaftliche Auswertung. BM,Betriebswirtschaftliche Mitteilungen der Landwirtschaftskamer S.H. No 459 (June 1993),17-24.

Wernick, S. and W. Lockeretz (1977) Motivations and Practices of Organic Farmers. Compost Science 77 (6),20-24.

Winckler, C. and J. Steinbach (1991) Comparative studies of organic and conventional dairy farms in a hill region of Germany. Paper presented at the 'Alternatives in animal husbandry' conference, Witzenhausen.

Younie, D. (1991) Perfomance of fattening beef cattle fed clover-rich or conventionally produced silage: a six year study. In: Alternatives in Animal Husbandry. (E. Boehnke and E. Molkenthin). Proc. International Conference, July 1991, University of Kassel; Witzenhausen, pp 257-263.

Younie, D., C. Watson, G. Halliday, G. Armstrong, W. Slee and M. Daw (1990) Organic beef in practice. Scottish Agricultural College; Aberdeen.

Winter, R. (1991) Economic questions of dairy production in ecological agriculture in northern Germany. In: Alternatives in Animal Husbandry. (E. Boehncke and V. Molkenthin). Proc. International Conference, July 1991, University of Kassel; Witzenhausen, pp 329-334.