Lamb's 'silent killer'

Lamb's 'silent killer'


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James Brady with Delta Agribusiness Wagga Wagga branch manager Matt Hardy.

James Brady with Delta Agribusiness Wagga Wagga branch manager Matt Hardy.

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ABORTION, still births and premature lambs – the campylobacter bacteria is responsible.

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ABORTION, still births and premature lambs – the campylobacter bacteria is responsible.

It is the silent killer that has farmers scratching their heads.

“Vanishing” lambs between scanning and marking can easily be overlooked, but ignoring the number can lead to losses of up to 40 per cent in some flocks.

More than halfway through gestation, from three months onward, abortion can occur in sheep that have been infected with the bacteria.

A low percentage loss can go unnoticed with ewes showing no consistent signs of ill health.

Coopers Animal Health’s Jane Morrison, Yass, said diagnosing an outbreak was difficult as foetuses were hard to come by.

“Farmers may be happy with the current marking percentage because they are unaware of the potential that was lost,” she said.

“They tend to notice when a huge disaster hits and lots of lambs are lost or marking percentages are dismal.”

The bacteria is transmitted through contaminated food or water and can be spread between flocks and properties by carrion-eating birds and scavengers.

Healthy sheep that are carriers excrete the bacteria in faeces, as well as aborted materials and uterine discharge.

The abortion occurs seven to 25 days after infection and the lack of symptoms is the main challenge, Mrs Morrison said.

“The issue is carrier sheep can’t be identified and removed from the flock,” she said.

“The only other sign of an abortion can be a bloodstained breech.”

Investigating lamb losses of more than 18pc between scanning and marking is recommended.

Weak lambs affected by the outbreak can also slip under the radar.

“Infected ewes with full-term lambs may also have a poor milk supply, so this is another problem that can cause further deaths from starvation and exposure,” Mrs Morrison said.

Any breed of sheep is susceptible to Campylobacteriosis and higher rainfall regions are at greater risk of the bacteria spreading.

High stocking rates and supplementary feeding can also favour contamination – and carrier sheep are carriers for life.

The vaccine Coopers Ovilis CampyVax is on shelves and Mrs Morrison said many farmers might not have realised a vaccine was available to aid in the control of the bacteria.

“It costs roughly $1 per shot and requires two shots in the first year, and an annual booster pre-joining,” she said.

Prime lamb producer Cam Hazlett, “Braeside”, Wallendbeen, finished his first round of vaccinations in mid-March.

He joins 3200 first-cross ewes each year and realised visually some ewes in his flock were aborting lambs well in to their pregnancy.

Mr Hazlett now vaccinates his maiden ewes after he suffered an estimated loss of 20pc last season.

“They were just planted all across the paddocks, it was quite scary,” he said.

“Every year we get a bit of that, I’ve always just thought it was common, but then last year we got hit pretty hard with it.”

Mr Hazlett attended a Sheep Matters Field Day in Cootamundra in February where he saw Mrs Morrison explain the vaccine.

He also realised a heavy fox population in the area have contributed to the problem.

The maiden flock will have their second shot at scanning on April 23.

“Hopefully each year if we keep vaccinating the maidens coming into the system, over time all of our ewes should be protected,” he said.

“All of our ewes are purchased ewes, and while we try to stick to the one line, we’re buying other people’s problems when we buy those sheep as well.”

Vaccination pays off at Eurongilly

LOSING 35 per cent of their scanned lambs three years ago rang alarm bells for the Brady family, “Bradford Park”, Eurongilly.

This year marks the fourth year they will vaccinate against campylobacter – a bacteria that can cause abortion after three months into the gestation period.

James Brady and his wife Bianca run the property with his parents James and Pip.

“We scanned 87pc in lamb but only two-thirds actually lambed,” he said.

After investigating the loss of lambs between scanning and marking the Bradys now vaccinate their ewe lambs.

Young ewes make up a quarter of their flock of almost 3000 ewes that are run on 1000 hectares.

They scan for singles and twins so keeping track of the number of expected foetuses to live lambs is easy.

Mr Brady said after four years signs of campylobacteriosis across the flock were now “very minimal”.

“It’s a cost but now it’s just part of the budget if you want to join lambs; it’s only about $2.20 to guarantee yourself a lamb,” he said.

“And it’s also got to do with stocking density.

“There’s going to be more potential for them to pick it up when you have more sheep on the ground.”

Delta Agribusiness Wagga Wagga branch manager Matt Hardy said this was the first year his store had sold the vaccine CampyVax.

“There’s a history in this area and a demand for it so we now stock it,” he said.

“It’s one of those things where they won’t know until they have a problem.”

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