The Cost of Tb/Possum Control

The cost to the nation of the control of Tb/possums has steadily increased since 1970, as new areas of infection have been discovered and as larger numbers of cattle become at risk. Thus, while the NZFS and APDC together spent approximately $1.38 million in direct possum control up to March 1976 (Salisbury, MAF, pers. comm.), a further $1.3 million was requested for control in the 1977-78 financial year (from "Surveillance" 1977, No. 2, p. 13). These estimates do not include any of the substantial costs incurred by the replacement of diseased stock, herd testing, the loss of production, or the wages of NZFS staff employed in possum control.

The control activities of both the APDC and NZFS have been made possible by increased funding from central government, and made workable by close inter-organisational liaison. Finance for APDC control programmes has been derived from additional rates struck for possums, from the related increase in government subsidies, and from direct government grants. Grant monies for the control of disease-free populations increased steadily during the sixties to a high in 1967 (Fig. 3). This trend reversed in 1968 concurrent with the general economic recession of the time, but dramatically increased once again in 1976 and 1977 as the need for Tb/possum control in the North Island became apparent. Rate and subsidy monies available for Tb control have also been substantial - a total of $88,000 was spent in the 1976/77 year (P.L. Burston, APDC, pers. comm.). Thus for the period April 1976 to April 1977, the APDC spent a total of $408,000 directly on Tb/possum control, with by far the greater amount being spent in the North Island.

By contrast, control commitments of the NZFS have been greatest in the South Island, particularly in Buller and Westland. Complete costings of NZFS control operations are difficult to determine, as only the direct expenses of individual programmes are itemised. Nevertheless, approximate costings of two page 216

Fig. 3 Grant monies requested by the Agricultural Pests Destruction Council from central Government for the control of possums. Data from APDC and RDC reports.

page 217 typical Tb/possum control operations are presented below. The first (a) was carried out in 1974-76 in Westland by the NZFS, and the second (b) intended for the winter of 1977 in Canterbury by a local pest board.

Tb/possum control

It is apparent that control costs vary locally, regardless of whether they are expressed in terms of cost per unit area under control, or cost per unit of stock. Aerial control for possums has been costed out at $6–8/ha in the South Island and is suggested to be a little higher in the North Island (about $8.00/ha, P. Nelson, APDC). Further, the "kill" obtained is normally in the range of 50–80% and alone is usually considered inadequate for disease control. Ground control is often equally as expensive as aerial control, as it is rarely a "one-hit" operation and may continue for several years. It is also apparent that the economics of farming beef or dairy cattle in areas under Tb control are likely to be less than profitable. Any apparent profitability is eroded further by basic farm costs such as labour expenses and mortgage repayments which are not included in the profit margins quoted above, as well as by stock replacement.