Western NSW landholders warned after toxic weeds kill sheep

Sheep Central, March 13, 2020

Sheep and lambs on a NSW flood plain. Image – Di Hall.

TOXIC weeds have killed significant numbers of ewes in western New South Wales recently, prompting a warning for landholders re-introducing sheep to recent regrowth.

Incidents of sheep deaths from nitrate poisoning, including one case involving 60 ewes, have prompted a warning from Western Local Land Services to landholders in the western region of the state to be vigilant.

One landholder lost more than a quarter of a mob within a day of unloading them onto green feed.

LLS said following decent rainfall over summer and into the start of autumn in parts of the western region, green feed has begun to emerge in a number of areas. While the rain has been happily received by all landholders, it does present some unwelcome risks, such as consumption of toxic weeds, as stock favour the emergence of anything green.

A common scenario is empty stock coming off trucks either into the paddock or into yards where weeds thrive due to uptake of nitrates from urine and faeces, LLS said.

Western Local Land Services district veterinarian, Charlotte Cavanagh, is urging caution from livestock owners, particularly if re-stocking.

If possible, landholders are being urged to feed some hay to fill stock up before releasing them onto the attractive green feed so they cannot gorge. Stock should be monitored closely and any unknown plants should be identified.

Toxic weed warning – Tribulus terrestris (caltrop, yellow vine, cathead) and Portulaca oleracea (pigweed). Image – LLS.jpg

“Livestock consuming nitrate containing plants such as Tribulus terrestris (caltrop/yellow vine/cathead) and Portulaca oleracea (pigweed) will show a variety of symptoms dependent on how much of the plant they consume and over what timeframe,” Dr Cavanagh said.

“In some cases, nitrates cause direct irritation to the lining of the gut causing diarrhoea, salivation and abdominal pain.

“Nitrate can also be converted to nitrite in the rumen, which then enters the bloodstream and decreases the animal’s ability to carry oxygen,” she said.

“The outcome is rapid breathing, staggers and in severe cases, death.”

Landholders with questions relating to nitrate poisoning or another animal health matter should contact their nearest Western Local Land Services District Veterinarian:

Contact your nearest Local Land Services office on 1300 795 299.

Source: LLS.


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  1. Jack Cleary, March 16, 2020

    A neighbour, livestock man for 56 years told me that it was nonsense sheep were affected by Patterson’s Curse…he’d never lost sheep to it and had extensive patches of it. I asked at what age he sold his sheep and on his reply said ‘so they probably die at the buyer’s property”. Weeds are the ultimate plant survivors. Placed under survival stress weeds burst into improved environment using all survival resources, ‘guns blazing’, reinforced by manures. Our livestock is feral and so are many of our worst weeds. Underused yards are a haven for plants which can survive in powerful doses of chemicals leached through manure.

    Over millions of years, and I don’t credit aboriginals with the outcome through fire, the plant life and Australian wildlife learned about each other. An harmonious balance seemed to take place. We disrupted that. When sheep were $3/head it may not have been a major issue, but at $100’s it is and requires an education in science and plant identification. The tragic report says ‘prepare your yards so that even ‘nibbles’ are not showing through. Another job on top of the others, but it’s a part of husbandry.

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