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Published: 2003-07-21 00:00:00

The number of Waikato cattle herds infected with bovine Tb has dropped again from 34 last June to 25 this year, showing significant progress towards a Tb-free Region, this week’s Environment Waikato Biosecurity Committee heard.

The areas free of carriers had 0.03 percent infected cattle herds and no infected deer herds, while those areas with carrier risk had 0.47 percent infected cattle herds and 3.57 percent infected deer herds.

Following control operations, the residual trap catch for all operations – used to determine the number of possums and other feral carriers – was 1.38 percent, when the target was usually 3 percent, indicating very good results.

Some first monitoring results had failed due to increasingly stringent performance targets and more rigorous monitoring criteria.

As a result of several cattle herds showing reactors in May and June a number of surveys had been initiated to post mortem all feral animals caught to confirm whether feral animals were the source of Tb infection.

Environment Waikato staff had developed a computer application in-house for possum eradication monitoring. The semi-automated system located monitor start points using GIS applications with the latest aerial photography.

A trial of a deer repellent on 1080 baits attracted a small protest at Taupo, the Committee heard. Five different treatments were trialled over four different ground and aerial treatment plots each, one including a deer repellent. The tests covered costs, efficiency and effects of each type.

The area chosen was one of the highest use hunting areas in the country. Considerable time was spent explaining the trial with New Zealand Deer Stalkers, Forest and Game Foundation, Hunters and Habitats and Sika New Zealand.

Those organisations were totally in favour of the trial but some outside the organisations were still unhappy with the area being used.

More than 60 people intensively searched 250 hectares of the aerial blocks for effects on deer populations and four yearling and one hind deer carcasses were found. Mock carcasses in the form of paper rubbish sacks were used to validate the search process. The results indicated the repellent bait, which was used for the first time on Sika deer, would affect about 20 percent of deer. Three tomtits and two blackbirds were also found dead.

The results were considered good, and it was disappointing that the protest was given such a high media profile, Committee Chair Helen Lane said.