WA Livestock Disease Outlook - for producers

Calling a vet to investigate disease protects our markets

The WA Livestock Disease Outlook provides information about recent livestock disease cases in Western Australia and diseases likely to occur in the next month. Calling a vet to investigate diseases when they occur provides surveillance evidence to our markets that we are free of reportable and trade-sensitive diseases.

Recent livestock disease cases in WA

Deaths in cattle fed vegetable scraps

  • In a mob of 18 cattle, seven died and six had breathing difficulties.
  • The cattle had been fed vegetable scraps from a supermarket (including sweet potatoes), wheat stubble, hay and pellets.
  • Lab testing showed a severe pneumonia with emphysema. Toxic interstitial pneumonia was diagnosed, likely due to consumption of mouldy sweet potatoes.
  • Sweet potatoes can be colonised by a fungus which causes production of the toxin, 4-ipomeanol. The toxin results in severe respiratory problems when eaten by cattle and can cause sudden deaths.
  • Waste vegetables may be a source of contamination not only for toxins but also animal matter. Food that is contaminated with animal matter is restricted animal material and is illegal to feed to ruminants in Australia.

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Figure 1: Firm, inflamed lung from cow affected by interstitial pneumonia.

Respiratory signs and sudden death in Droughtmaster cattle in the Midwest

  • A total of 14 Droughtmaster cattle from a mob of 180 died suddenly within 7-10 days of being moved onto an oat stubble paddock with others showing respiratory and neurological signs.
  • Deaths stopped when cattle were moved to another paddock.
  • The cattle showed no further signs until fed hay cut from the oat stubble paddock. Several days later, 20 cattle died. Sheep fed the same hay were unaffected.
  • Testing of the hay samples showed moderate and high risk of annual ryegrass toxicity (ARGT). A faecal test from one of the dead cattle was also positive for ARGT.
  • Differential diagnoses: bovine spongiform encephalopathy (exotic) in animals showing neurological signs, thiamine deficiency, grass tetany. Discuss with your DPIRD vet subsidies available for testing where signs may be similar to exotic diseases such as transmissible spongiform encephalopathies.
  • Paddock management strategies to reduce the risk of ARGT in livestock include hay testing prior to feeding out, managing grazing of the paddock to remove seed-heads before they become toxic, controlling the ryegrass or sowing a safe ryegrass variety. Read more on these control strategies.

cattle liver
Figure 2: In some cases of ARGT, you may see a pale, fatty liver.

 

Cow showing altered eye position
Figure 3: Neurological signs such as paddling and change in eye position.

 

Annual ryegrass
Figure 4: Annual ryegrass.