Introduction

Where is the Victorian winter rainfall region?

This region generally has winter-dominant rainfall, mostly greater than 500 mm.

The area covers most of Victoria, except for the drier north-western area (Mallee and northern Wimmera) to the north or west of Kaniva, Warracknabeal, Charlton and Cohuna. This area is in the WormBoss Pastoral Region.

Those in the more uniform- and summer-dominant rainfall areas of East Gippsland may also find the WormBoss NSW non-seasonal rainfall a useful reference.

These boundaries are approximations only as seasonal temperature and rainfall variations affect worms. A map of the region is shown below.

What worms are covered in this program?

Roundworms

The most important roundworms in this region are:

• Scour worms
  • Black scour worm Trichostrongylus vitrinus / Trichostrongylus colubriformis
  • Small brown stomach worm Teladorsagia (Ostertagia) circumcincta
  • Thin-necked intestinal worm Nematodirus spp
• Barber’s pole worm Haemonchus contortus

Very wet years generally cause higher burdens of all worms. These can be fatal without scouring occurring.

Barber’s pole worm

In this region, barber’s pole worm is generally sporadic but very important in some areas particularly with summer rainfall, therefore the Barbervax^® vaccine may be cost-effective compared to 4–6 weekly monitoring of worm egg counts during high-risk periods and treatment with a short-acting drench or closantel.

If your farm has periods of high barber’s pole worm risk for several months each year (which may occur in coastal areas or on irrigated pastures) seek professional advice as to whether the Barbervax^® vaccine program should be considered.

Liver fluke

Liver fluke is an internal parasite that occurs in parts of this region depending on the distribution of the intermediate host snail. It can cause deaths from acute infections of immature fluke and Black disease from October to January, or anaemia and ill-thrift from chronic infections (generally January–June).

The life cycle differs from the simple lifecycle of roundworms, so control strategies are different.

This program relates to roundworms. To control liver fluke, see the ‘Liver Fluke Control’ section in Appendices: Further information on sheep worm control for Victorian Winter rainfall regions.

Other worms

Gastro-intestinal parasites of minor importance, such as stomach fluke and tapeworm, are not covered.