SHEEP producers have scored their first new worm drench in 15 years with today's release of Novartis Animal Health's Zolvix.

And a second new drench, Startect, developed by Pfizer, - not in the monepantel family - is going through the approval process with the Australian Pesticides and Veterinary Medicines Authority.

Zolvix, and the pending Startect release, defy reports during the past decade that manufacturers would be unable to afford the research and development for any new sheep drench.

Fort Dodge's Cydectin, containing moxidectin, was the last commercially released drench in 1995.

The drench, along with many others from the mectin family, is now encountering high levels of resistance.

Zolvix, developed at a cost of up to $440 million and containing the active ingredient monepantel, comes at a price - three to four times that of current drenches.

This week a major Victorian retailer was quoting a 10-litre pack of Zolvix at $2524.

At a dosage rate of 1ml/10kg liveweight, a lamb would cost 75 cents to drench while an adult would cost about $1.50.

But, as Novartis technical services veterinarian Dr Justin Bailey said, it was a waste of money using existing drenches if worms were already resistant to them.

Novartis is claiming a kill rate of at least 99.9 per cent regardless of whether worms were resistant to other drenches.

Zolvix was released 18 months ago in New Zealand at a similar price.

NZ South Island veterinarian John Smart said although the Zolvix was highly effective, many New Zealand sheep producers had baulked at the price, which had now been reduced by a third.

Dr Smart said drench resistance hadn't reached the same problematic levels in New Zealand as in Australia, hence many producers were still obtaining reasonable control with the lower cost "dual" and "triple" drenches.

He said New Zealand producers were looking forward to the release of Pfizer's Startect, which contained another new active ingredient, derquantel, and would used in combination with abamectin.

Dr Smart said Zolvix was an excellent "quarantine" drench for producers who bought-in stock.

Novartis is also proposing Australian producers use Zolvix as a quarantine and summer drench.

Dr Bailey said Novartis was training retailers as to recommendations and advice for producers.

Like most departmental veterinarians and livestock consultants, Mr Bailey said to obtain maximum benefits from Zolvix a drenching strategy should be integrated with a testing program for worm egg counts.

In conjunction with the Zolvix release, Novartis has also released a redesigned drenching gun.

The Optiline drencher is claimed to overcome handling and ergonomic problems associated with traditional drenching guns.