Worm management programs highlight summer as a prime time to control numbers

If done right, they can set up the program for the rest of the year.

This was the message from veterinarian Dr David Hucker as guest speaker on a Paraboss webinar in early spring, during which he told producers this summer could be a tricky season given the previous consecutive wet years.

Professor Bruce Hallworth, School of Agricutlural, Enviromental and Veterinary Sciences at Charles Sturt Univertsity, Wagga Wagga, said areas such as Holbrook and Tumbarumba were examples of potential hot spots and producers in those regions should be especially vigilant.

Prof Hallworth said the recent string of wet years had led to a higher than normal load of infective worms this season, particularly with barbers pole worms.

"The fact that there's still a fair few worms around means the young sheep in particular, the blue tag and potentially the red tag sheep, are still most at risk at the moment," he said.

"A low level exposure to worms is actually quite healthy, (but) an overwhelming amount of worms is not. So you're not trying to get rid of worms completely, you're just trying to keep them under control."

As well as keeping a check on the potential for problems to arise through summer, Dr Hucker, of Para-Tech Veterinary, Wickliffe, Vic, said good summer management helped to set up the operation for the rest of the year.

"A lot of people come to us with worm problems in winter and spring and they want an immediate fix for that, but the reality is they haven't got the worm numbers low in summer when they could have managed things a bit better," Dr Hucker said.

"The basis of managing the worm numbers is to attack the worms when they are most vulnerable to reduce numbers.

"This is generally in summer, when it's dry and we have a fair bit of sunshine compared to winter and spring and we get an effective kill for the worms just with the climatic conditions."

He said it was important to carry out worm counts and to only treat if it was greater than 100 eggs per gram of faeces in the summer.

"We generally talk about a first summer drench which is November, December and then second summer drench January or February," he said.

Along with a summer drenching program, Dr Hucker said producers should think about selecting a paddock that has had only dry sheep on it for the past few months, or a crop stubble.

He said this was usually the safest option for weaners on after the autumn break.

"That way it works is, the stock are paddocked with adult sheep at two to three times the normal stocking rate at the time of the first summer drench and you remove the sheep after 28 days," Dr Hucker said.

"Then leave the paddock unstocked until the time of the second drench (6-8 weeks later) and then do the same thing again.

"So after the removal of the sheep after 28 days grazing there, leave the paddock unstocked until the autumn break which might be 6 or 8 weeks later.

"Then we stock the paddock with the weaner sheep, so the theory here is to get the egg numbers right down by using the adult sheep to ingest a large number of the larvae and get the number down and then have very few larvae available for the weaners when they go onto that paddock."

The worm egg concentration was also significantly influenced by the faecal output of a sheep, he said. As the duration in the yards or shed increased, the more concentrated the worm eggs became, because there was less food passing through the sheep to dilute the eggs.

Livestock manager of Walleroobie Farming, Russell Bending, Walleroobie near Ardlethan, said he aimed to minimise his use of drenches.

Worm egg counts, used throughout the year, was an important tool in this, allowing him to safely only drench when necessary.

"I'll do a faecal egg count and that will determine whether or not I drench and it will give me an idea on what problems I'm having and what I need to drench for," Mr Bending said.

"It keeps the cost down a bit and we're not drenching if we don't need to.

"I like to drench them a month or so before lambing and that's when I'll do the ewes and then ideally do another one before weaning, so that we can see whether we need to drench the lambs at weaning."

The operation consists of a cropping rotation and 4500 Merino ewes joined to Poll Dorset rams.