Contents
    Summary
    Chapter One
    Chapter Two
    Chapter Three
    Chapter Four
    Chapter Five
    Chapter Six
    Chapter Eight
    Chapter Nine
    Chapter Ten
    Appendices
    Foot Notes
   

A project facilitated by the Research and Development Group of the Bio Dynamic Farming and Gardening Association

7 Case-Study of New Zealand Dairy Farms in Transition

Introduction

In the early 1990s a field research-project established by staff of the former Department of Soil Science at Massey University was amongst the first in New Zealand to gain first hand comparative information about the field performance between long established organic farms and their equally long established conventionally farmed counter parts. "Organic", here, refers to farms that were already certified according to internationally accepted organic standards of the day (i.e., BioGro or Demeter).

The results of the early 1990’s project, led by visiting academic researcher Dr John Reganold of Washington State University, USA, became the subject of a 1993 scientific report published in Science (Soil Quality and Financial Performance of Biodynamic and Conventional Farms in New Zealand). In New Zealand organic circles this publication is still popularly referred to as the Reganold report, as it presented data on measured differences in both soil quality and financial performance of seven matched pairs of farming activities in New Zealand, each matched farm-pair comprising a Demeter certified farm and its adjacent but conventional counterpart. The only significant difference between members of each matched farm-pair was their management and farming methodologies. Each Demeter farm involved in the study had been under organic management for a period of at least 10 years.

The abstract of the Reganold report, as published in Science, reads as follows:

For a new case study, the approach was to establish and compare important farming parameters of closely paired farms in which the organic farm of each pair, in contrast with the earlier 1993 study, was starting the transition stages of conversion from conventional to organic status, and was thus committed to organic management methodologies that could lead to full organic status and certification (Demeter, in this case). A compelling and practical reason for initiating a new study was to determine the sort of changes in farm performance (in the widest sense) a grower could reasonably expect to encounter that might likely influence on-going farming decisions during transition from an existing conventional state to organic status. Most farm organic conversions are believed to begin in this or a similar way

Present Case-Study

Background and funding

For this case study we chose to focus on commercial dairy-farm units as such farm-systems include not only soil, pasture, and milk production, but also animal-health and reproduction. Initially, farm-pairs at five potential North Island sites were evaluated for suitability and comparability. These potential sites were situated at Te Aroha, Newstead (near Hamilton), Maungatawhiri (southern edge of the Bombay Hills), Matarau (near Whangarei), and Te Kopuru (near Dargaville). As in the 1993 research, the process of matching farm-pairs was an integral part of the study and was based on similarities of soil pedology, slope of land and topographical aspect, pasture history, livestock and dairy herd composition, and fertilizer history along with soil tests.

While there were quite distinctive differences between the five geographic sites, we judged that the farm-pairs at only two sites had sufficiently comparable features to be included in the new study. These were matching farm-pairs at Te Kopuru and at Te Aroha, and we designed a sampling programme based on the physical aspects and stocking history of each farm-pair. Chief among the farms’ matching features were their pedological characteristics, as essential recognition that soil not only has potential for determining pasture growth but can also have a primary influence on livestock performance and therefore milk production. While conventionally managed farms would continue to use soluble fertilizers like urea and superphosphate, proprietary animal drenches and ectoparasite insecticides, and herbicides for weed control, transition farms would cease using such methods and adopt the organic methodology as proposed (in this case) by the Biodynamic Association.

The Pacific Development and Conservation Trust agreed to fund the project on a year-to-year basis over a rolling 3-year period. However, due to an exceptional call on Trust funds during the first year of the project, funding for years 2 and 3 was cancelled. This project, therefore, ultimately had funding to collect samples and obtain data for only the initial period of about a year.

What was Measured?

Five measurement categories involving the two paired dairy-farm sites selected for this study were chosen to achieve the project objectives:

• Milk production (based on monthly receipts from the respective dairy cooperatives)

• milk volume in litres; protein to milk fat ratio; milk-solids in kilograms; somatic cell counts.

These values were extracted from monthly farm dairy-receipts issued by the dairy factory processing the milk. In order to have more inclusive values for each farm, it was also necessary to add the volume of milk used in calf rearing over the 8-week period this feeding was done.

• Animal Health Data (as available)

• faecal-egg counts on calves; liver biopsy values for selenium, copper, and cobalt;
• live-weight data.

The veterinary parasitology laboratory at Massey University determined faecal-egg counts. Early and high egg-counts are often diagnostic of young dairy animals under stress. With calving almost a year-round activity on many organic dairy farms, sampling was more frequent (several times per year) than for conventional herds.

Adequate levels of selenium, copper and cobalt in dairy herds are considered to be a prerequisite for successful reproductive performance. Analyses were conducted on animals from the main dairy herd, and at irregular intervals of time. Samples of liver tissue were submitted to New Zealand accredited analytical laboratories for analysis.

• Pasture Production (monthly, depending on season).

• herbage dry-matter yields; major herbage components.

Pasture-cages were placed on pasture sites of each farm and herbage growth was trimmed to constant height, weighed fresh in the field (non-rainy days) and a grab-sample of the mixed herbage sent immediately by courier to Massey University for dry matter content and determination of the herbage-split (i.e. composition ) of the total herbage sample. Following grazing of each pasture site, the pasture-cages were re-sited to protect the development of new pasture growth.

Pasture herbage composition was conducted on each field sample in the laboratory, and for the Te Aroha site was expressed as percentage of rye grass, clovers (red and white), and other herbage (rather than weeds). At the Te Kopuru site, a fourth category , kikuyu grass, was required as this was a significant pasture herbage component in Northland pastures

• Soil Analyses ( initially and annually)

• total organic carbon, total soil nitrogen, total soil phosphorus, cation exchange capacity (CEC), exchangeable levels of potassium, calcium, magnesium, sodium, pH;
• biologically mineralisable nitrogen, soil respiration, and pasture earthworm count.

All these soil tests were made using well-established analytical methodologies of soil analysis by the Fertiliser and Lime Research laboratory at Massey University. At each farm-site a collection of 10 x 15 cm-soil cores was pooled from each of 5 field sampling sites under pasture. Soil sampling took place during late winter (August) of each year when it was believed analytical results would be at their most reproducible, particularly counts of pasture earthworms. The soil sampling protocol was similar to that used in the earlier Reganold report.

• Climate data.

We ensured that daily rainfall data and soil temperature data could be manually collected on one farm of each pair (normally the farm in organic transition) on a daily basis throughout the project. Rain gauges were provided and soil temperature was measured at a depth of 5 cm using thermocouple thermometers. Due to the close proximity of matching-farms to each other, rainfall and soil temperature data values were assumed to be identical at each of the two geographic sites.

Project Participants

It was originally planned that the research project would involve not only soil scientists and a veterinarian from Massey University, but also farming staff and managers as active collectors of field-data at both Te Aroha and Te Kopuru study farms. As both field-sites in the project were several hours driving-time away from Massey University, farm owners agreed to undertake regular monitoring of rainfall and soil temperature as well as pasture herbage sampling.

The farming staff on each organic unit undertook these regular tasks on their farm as well as on the matching conventional farm in addition to their regular chores. Before pasture-collection activities began, there was an orientation session to go over the purpose and details of sampling, and to seek and obtain agreement that farming staff would undertake to record all relevant observations and dates in a farm-diary kept on-farm so that apparently small and apparently trivial farm events could be reviewed as necessary at a later date. We considered this aspect of the field project to be of particular significance as it not only enabled the regular collection of on-farm data of considerable value to the project, but extended the responsibility and ownership of this data to the farm owners themselves and so promote understanding.

The Massey academic staff-members involved were established researchers with international reputations and were involved in organic programmes and workshops. The project emphasised and required expertise in soil genesis, soil-plant-animal relationships, experience in monitoring organic farming systems, and a successful rapport with farmers of organic livestock. Animal health issues related to animal parasite burdens, mastitis, and reproductive disorders linked to micronutrient deficiencies in animal diet were an important dimension of the project.

Collection of Data

As reported to the owner of each farm by the respective dairy company, the volume of milk actually collected by tanker was a primary measure of milk production from each herd over the month being reported. The volume of milk used for on-farm activities, such as calf feeding, was estimated from feeding procedures and added to tanker-collection volumes. On conventional farms, calves received 4 litres per day, while calves on biodynamic farms were fed at 6 litres per day and for a longer period.

Somatic cell counts were normally reported along with each month’s milk-production data from the respective dairy company for each farm.

Soil collection protocols and analytical services were similar to those used in the earlier Reganold project and results were reproducible to P <0.01.

Pasture production data were more variable. At each field-sampling, pasture herbage was sampled on each farm from 6 small cages (each approximately 0.4 square metre), the cut-herbage pooled and weighed fresh. After determining moisture content in the laboratory, the percentage dry-matter was calculated and expressed as kilograms on a per hectare basis per day over the specific growth period. Comparisons of monthly values were plotted to give visual comparison of pasture production within each farm pair.

What did the Farm Measurements Tell Us?

To make an interpretation of any differences that might be detected between farm-pairs, there are several assumptions about each farm-pair that first need to be identified. For example, at the outset, it had to be assumed that the farms in each matched pair were at almost identical stages of development, pasture composition and age, and stocking rates, and that the dairy herds were of similar genetic potential and receiving equivalent treatment and care.

However, the dairy-farm sizes were not strictly identical, and it was further assumed that this would not have a significant effect on the measurements about to be made. For reasons of both insufficient planning-time and inadequate funding, we were not able to confirm any of these assumptions with actual pre-project evaluations. Both conventional dairy farms in the study used "run-off" properties as an integral part of their livestock management programme.

Measurements and determinations were made when management methods intended to lead ultimately to full organic status were first implemented, and then at regular times, as specified, throughout the following 12 months. Time related trends (e.g. estimations of pasture growth) were plotted throughout this period. Soil analyses were conducted only at the outset, and then 12-months later.

Size of Dairy Herds and Stocking Rates

Conventional dairy herds were numerically larger than those undergoing organic conversion, in one case only marginally (130 v 126), but significantly so in the other (220 v 150). Overall stocking rates were on average greater (2.2, 2.3 cows per hectare) on conventional farms, compared with 1.8, 1.5 cows per hectare on the transition farms.

Milk (Based on Factory-collection Data)

In terms of milk-solids produced per hectare, the estimated average for conventional milkers was 400–420 kg compared with 340–360 kg for transition milkers. When expressed on a per animal basis, conventional milkers generated on average 300 kg compared with 230 kg for transition milkers.

On a volume basis, milk production (litres per cow per month) on the conventional farm was up to 1.5 times greater than that on the transition farm over the July–October spring period. By December, milk production on both farms was similar for the rest of the season.

Pasture Herbage Production

From July to June of the project period, the estimated annual dry-matter production of herbage at the more northerly Te Kopuru sites were 21.5 tonnes per hectare on the conventional farm, compared with 16 tonnes per hectare for the transition farm. However, seasonal production (kg DM per ha per day) was not identical with a greatest daily production of 80 kg DM occurring during the September–October period on the transition farm pastures, compared with about half that daily rate on the conventional pasture. Pasture production on conventional pasture during the late-season April–May period gave a considerable boost to annual DM values.

There were no major surprises in the seasonal herbage composition of pasture. The percentage of clover herbage in pasture sampled during the February–May period tended to be greater on conventional pastures. Overall, both ryegrass and kikuyu components dominated pasture composition on both farms.

Pasture plants in the herbage identified as not being rye grass, kikuyu, or clover, were identified as "herbs", and were a measurable DM component of transition pasture herbage yields. At the Te Kopuru site, the "herb" component accounted for 10–15% of the DM production during the Spring period (July–September), and at the Te Aroha site, the "herb" component accounted for over 20% of the DM produced during the January–March period. As such, the "herb" component of pasture herbage was believed to be a significant dietary input for those animals.

Animal Health and Performance

An overview of the following are reported here: somatic cell count (SCC) in milk, faecal egg counts (FECs) for yearling heifers, levels of copper, selenium, cobalt (vit B12), and liveweight values of rising two-year-olds.

The Te Kopuru site milk-analyses gave a better data set for comparing SSCs throughout the season. Milk from the conventional herd starting in August had SCC-counts of 160–200 thousand and rose to 180–250 thousand by December, and later to 260–570 thousand in April. In contrast, milk from the dairyherd in organic transition started off at 140–200 thousand in August, rising to 250–290 thousand in December, and to 290–490 thousand by the last milking in April. There appeared to be no significant differences between the herds under the two different field managements.

Similarly there appeared to be no dietary deficiencies of selenium, cobalt, or copper that would have significance in reproductive performance of the cows in the organic transition herds, at least as based on liver biopsy analyses. Similar analyses on animals from the conventionally managed herd indicated a need for remedial action to counter lower than desirable levels of copper. Analyses were carried out at the Auckland Animal Health Laboratory of MAF.

With only one exception, there was no significant numerical difference in FECs between yearling stock under either management. Analyses were carried out by the Parasitology Laboratory at Massey University.

Only one animal liveweight measurement was made of one year-old (12–14 months) Friesian calves for one matched farm-pair (Te Kopuru site). In September, 63 conventionally managed animals averaged 269 kilograms, while 30 organic-transition animals averaged 249 kilograms (CV~10%).

Soil Analyses

Based on comparisons of eight different analyses carried out initially and 12-months later on soil sampled from both farm-sites, there would appear to be no statistically significant changes in the levels of most plant-available soil nutrients and certain biological activities after one year of transition organic management.

There were two exceptions. Levels of soil sulphate and Olsen-P for conventionally managed farms remained between two to three-times greater than for transition organic farms. A simple explanation to account for this is that pasture applications of superphosphate continued as part of regular conventional farm management, while it had ceased for organic farm management.

There was some evidence, based on laboratory respiration studies, that soil from the transition farms had marginally increased its level of soil microbial activity over that of soil from conventional farm sites. This is entirely consistent with the findings of the earlier Reganold Report.

Climate Data

As the overall enterprise of each closely matched farm-pair was almost identical in operation as well as geographic site, temperature and rainfall data collected at only one farm of each pair was considered to be necessary. It had originally been anticipated that the field project would run over 3 years, so in order to help interpret likely seasonal differences over the 3-year period, a regular log of both daily soil temperature at 5 cm and rainfall was recorded by the farm managers. In this way it would be possible to see both the intensity and duration of rainy periods in any month of dairy production. As already pointed out, the project was reduced to a single year study due to funding restrictions and seasonal comparisons could therefore not be made.

At the more northerly site at Te Kopuru, just inland from the western coastline, soil temperatures at 5 cm remained above 10C throughout the year. They exceeded 20C during January and February. While monthly rainfall was fairly evenly distributed throughout the year (1300 mm), daily rainfall was restricted to just a few days in the months of February to May.

At the Te Aroha site, on the western flanks of the Kaimai Range, monthly soil temperatures dropped below 10C in July and August, but also exceeded 20C in January and February. Monthly and daily rainfall values were more evenly spread throughout the year (1400 mm).

Discussion and Conclusions

The project restricted to a one-year study fell far short of providing adequate information that would have been useful in constructing a more useful picture of the nature of the differences in those parameters chosen for measurement between dairy farms remaining under conventional management and those being deliberately managed towards achieving organic certification. There remains to the present day a scarcity of comprehensive information about the effects of the process of organic conversion on dairy farms, the transition effects on livestock production and dairy performance, and soil-plant interrelationships in grazed pastures in New Zealand.

In this preliminary case-study some interesting differences came to light, some of which were actually observed in pasture growth, for example, the proportion of "herbs" to normal pasture species and the implications this could have for ruminant animal nutrition. Some were not recorded as a part of regular data collection, but became a part of the growing flow of anecdotal information provided by the farm managers themselves. For instance, veterinary costs on transition farms were said to be reduced even, in the first year of operation, up to 90% as claimed by one farmer. However this was offset by the time required to learn about herbal and other remedies used in organic livestock management.

There was no convincing evidence that taking a conventional dairy farm and placing it under organic management methodologies would inevitably result in a dramatic decline in the farmability of land so often prophesised in the past. On the contrary, even in the first year of conversion, there were signs of physical and biological improvements to farmland under conversion, as well as repeated farmer observations that cases of bloat were being halved, even though the farms now in transition had a prior history of significant cases of bloat under conventional management.

It is strongly suggested that for future case studies, consideration be given to using established methodologies that enable evaluation to be made of the dietary and health effects of organic management on livestock performance. It is further recommended that the externalities of the environmental and sociological consequences of such comparisons be integral features of such research.

All farms in the study were commercial units and have remained so.

Acknowledgements

Dr Alan S Palmer, Institute of Natural Resources, Massey University, for his crucial involvement as a pedologist in helping to survey and select the matched farm-pairs used in the study.

Assoc. Prof. Kevin Stafford of the Institute of Veterinary and Biolgical Sciences, Massey University for his continuing advice on animal welfare issues and dairy animal issues.

Mr Gareth Bodle, Biodynamic Association, for his essential role as coordinator and advisor for the Biodynamic Association of New Zealand.

Special acknowledgements to both Barbara and Roger Gillat, "Tasman View", Te Kopuru, and to Alayne and Ross Campbell, Gordon Road, Te Aroha, for their cooperation and commitment in using their dairy farms, and for data-collecting from their neighbouring conventional farm owners.

The Pacific Development and Conservation Trust.

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© 2002 Bio Dynamic Farming and Gardening Association in NZ Inc.