The aim of the survey was to compare the management practised on farms which were "affected" by the wet winters with those which were "unaffected" by the wet winters. Only the production up until December for each year was considered, as this i s the time period where winter and its management can influence milksolid production most strongly. The dry year of 1 993 was used as the "control" year, and production differences
were calculated from the total production up to December. The criteria for selection of the affected and u naffected farms were:
(i) Farms had to have milksolid production above 400 kgMS/ha.
(ii) The farm had to be continuing to supplying Tui Milk Products in 1 996. (iii) Sharemilkers had to be on the same farm in 1 996.
(iv) The total milksolid yield up to the end of December for the 1 993 dry year was used as the base production level for each individual farm. The total milksolid production up to the end of December for 1 994 and 1 995 wet years was compared to the production of 1 993 . The difference between 1993 & 1 994, and 1 993 & 1 995 were compared to the average for all 70 farms, with the loss in production having to be above the average losses for both wet years for a farm to be selected as an 'affected' farm.
(v) A simi lar criteria as (iv) was used for the selection of unaffected farms, except the milksolid production losses to the end of December were required to be below
average, with preference given to farms with no change to the total yield to the end of December for both the 1 994 and 1 995 wet years, compared to 1 993.
The reason for having (i) in the criteria, was that several farms had a total
mi lksolid yield of less than 400 kgMS/ha in the dry year of 1 993. This level of production is considered low, and when production in the wet years of 1 994 and 1 995 up to the end of December was simi lar to 1 993, it was considered to be the result of having an extensive management system, rather than intensive management initiatives to overcome the wet winter.
The initial selection of farms that met the criteria produced a bias in the soil groups with the farms on the Manawatu clays providing a majority of the affected farms. Therefore to eliminate a possible bias in the survey results due to the soil groups, the three worst and best farms for each of the three soil groups were selected to be surveyed. Selecting more than six farms for each soil group would have meant the selection of farms that did not fully meet the criteria of being affected or unaffected farms.
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3.2.2 The
The aim of the survey was to provide information about the w inter management used on farms affected and unaffected by the wet winters. All questions asked in the survey were about the wet winter of 1 995 . The reason for only questioning the farmers about the most recent year selected was that answers relating to 1 993 or 1 994 may have provided less accurate information, as well as the need for less specific questions. The questions asked in the survey were to i dentify management strategies used in 1 995, and to provi de differences in management between the affected and unaffected farms. The
questionnaire considered the period between the herd being dried off and the early part of the 1 995 lactation .
The areas of questioning were: - Herd breeding worth. - Reasons for drying off.
- Fertiliser applications over the winter period. - Supplementation during the winter.
- Off farm grazing. - On-off grazing. - Farm drainage.
- Management to prevent pasture damage.
- Cal ving targets in relation to pasture cover and cow condition. - Early lactation feeding.
The survey was conducted via the telephone. Reasons for this were the probable del ay i n waiting for the return of questionnaires if conducted via the post, and the need for a 1 00% return rate. Due to the small sample size and the surveyed farms being purposel y selected a 1 00% return rate was desi rable. A copy o f the survey (Appendix 1 ), with a coverin g letter was sent to all farmers before they were contacted by telephone. This
introduced farmers to the research and its aims, and also allowed the farmers time to think about the questions, which was important because the information sought rel ated to the winter one year ago.
3.2.3 Farm Visits:
A number of the farms selected in the survey were also visited after the survey w as completed. An attempt was made to visit as many of the farms surveyed as possible, but due to the unavailability of some farmers and time constraints, 1 4 of the 1 8 surveyed
farms were visited. Of the farms visited, 6 were affected farms, and 8 were unaffected farms. The purpose of the visit was firstly to confirm the information collected by telephone for each farm. Secondly, the farm visits were aimed at understanding the situation on each farm at the start of calving in 1 995, and to understand the farm management both before and after cal ving and the reasons behind the decisions made. The farm visits also provided an opportunity to ask further questions in relation to issues identified in the survey and the changes that have been made to the farms winter
management in particular for the 1 996 year. A I ist of question topics were taken on the
farm visits so as to provide similar questioning to all farmers. The information was
collected to supplement and add depth to the results of the survey, with the aim to provide better discussion on the factors identified in the survey.
3.2.4
The individual farm data for the farms selected were entered into a new Microsoft Excel spreadsheet. With e ach farm coded into the appropriate group, either affected or unaffected, the data variables were then tested for differences between the two groups by SAS for Windows 6. 1 1 .
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Non numerical responses from the survey were either coded into binary variables (e.g. no = 0 and yes = 1 ) or numerically coded (e.g. Fertiliser types applied: 1 = nitrogen, 2 = super and 3 = DAP). These variables were entered into a separate M icrosoft Excel spreadsheet. The data w as checked for data entry errors, before S AS w as used to derive cross tabulations to describe differences between the affected and unaffected groups. The open-ended questions, in relation to special management to prevent pasture damage, and changes m ade to management were not coded, with the responses discussed in chapter 5.