Smart grazing to control barber's pole worm in lambing ewes

WormBoss worm control program for goats

East coast

Smart grazing to control barber's pole worm in lambing ewes

‘Smart grazing’ is a system developed in Victoria by Dr Paul Niven to create low worm-risk autumn weaner paddocks in winter rainfall regions. This was adapted for the Northern Tablelands of NSW by Dr Justin Bailey, and is called ‘Smart Grazing—summer rainfall’. Both versions are based on very short periods of intensive grazing at increased stocking rates.

The Northern Tablelands version takes advantage of a four-month cold period in winter (May-August) combined with two bursts of intensive grazing in summer and autumn. This results in an eight-month period where contamination of the paddock with worm eggs is prevented and most of the existing eggs and larvae die.

The process uses a high stocking rate during the grazing period, about four times normal, in order to rapidly reduce the pasture mass, thus increasing exposure of worm larvae to the elements to increase death rate.

The success also relies on the sheep used for grazing being treated with a fully effective drench and that they only graze the paddocks within the protection period of that drench.

Steps for ‘Smart grazing—summer rainfall’

1. January/February: Graze the lambing paddock with sheep immediately after they have been treated with an effective short-acting drench and graze for no longer than three weeks after that drench. Stock at 3–4 times the normal stocking rate in order to reduce the herbage mass to about 1000 kg DM/ha (or about 3 cm in height).
2. March/April: Repeat step 1.
3. May, June, July and August:

• In cold, tableland districts, when the mean daily maximum temperatures are consistently below 18°C, these paddocks can be grazed by any stock as it is too cold for the eggs of the major worm parasites, barber’s pole and black scour worms, to hatch to infective larvae.
• In warmer areas adjacent to the tablelands, this cold period will be shorter and Step 3 (from above) may be restricted to June and July. Review your local climate history (see Find your ‘cold period’) to find when the temperatures over a week will have daily maximums below 18°C.
• In hotter areas, where the mean daily maximum temperatures are higher than 18°C, or below it for only days or a few weeks, step 1 can be repeated.