WA Livestock Disease Outlook - for vets - April 2018

Calling a vet to investigate diseases protects 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, one-year-old cattle, seven died and six were affected with dyspnoea and abdominal breathing. The cattle appeared anaemic and were being fed a variety of vegetable scraps (including sweet potatoes), wheat stubble, hay and pellets.
Histopathology showed a severe, diffuse, subacute interstitial pneumonia with emphysema. A diagnosis was made of toxic interstitial pneumonia likely due to ingestion of mouldy sweet potatoes.
Sweet potatoes can be colonised by a fungus which causes production of the toxin 4-ipomeanol.
Differential diagnoses: Fog fever, bacterial pneumonia, bovine respiratory disease complex, bovine anaemia due to Theileria orientalis group (BATOG) where anaemia is present.
Waste vegetables may be a source of of animal matter as well as toxins. Animal matter-contaminated food constitutes restricted animal material and is illegal to feed to ruminants in Australia.

Firm, inflamed lung from cow affected by interstitial pneumonia.

Respiratory signs and sudden death in 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 cattle were 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.

In some cases of ARGT, you may see hepatic lipidosis.

Neurological signs such as paddling and change in eye position

Mature annual ryegrass

In autumn, watch for these livestock diseases:

Typical history and signs	Key samples
Gastrointestinal (GIT) worms in cattle Mild summer weather and some rain may have allowed survival of infective larval stages on pasture in the southwest. Recent cases of cattle showing signs including diarrhoea, lethargy and poor body condition have been submitted to DPIRD. Testing has found significant worm burdens and GIT damage despite drenching. This can lead to reduced immunity and poorer outcomes when cattle are affected by other conditions. In winter rainfall areas, the brown stomach worm (Ostertagia ostertagi) is a major parasite of cattle. Ensure drenches are effective against parasites in your region and administered correctly. See the DPIRD drenching beef cattle webpage for more information.	Ante-mortem: Faeces: 4g in cattle for worm egg count. Post-mortem: Alimentary sections: fresh and fixed GI contents (abomasal contents, SI contents) Faeces
Pregnancy toxaemia in ewes Consider pregnancy toxaemia if late pregnant/early lactating ewes present with depression, anorexia, weakness, recumbency, neurologic signs, and death. Signs may be worse following stress. Affected ewes may separate from the mob. Ewes carrying multiple lambs are at higher risk and if identified early at scanning can be separated and fed carefully. Pregnancy toxaemia can be avoided if producers provide adequate nutrition to the ewes and minimise stress (e.g. avoid herding and yarding of ewes in late pregnancy and early lactation). Differential diagnoses: Scrapie (exotic), cerebral abscess, acidosis, enterotoxaemia, hypocalcaemia, nutritional myopathy in primiparous ewes and meningitis. Early diagnosis and treatment with glucose and supplementary feeding of good quality hay and oats can halt deterioration. DPIRD’s pregnancy toxaemia webpage has information on prevention and treatment.	Ante-mortem: 10mL blood in lithium heparin tube Post-mortem: 2mL vitreous humour in plain tube (post-mortem) in addition to base tissue sample set. Adult sheep showing neurological signs should be tested for reportable diseases such as scrapie. Speak to your DPIRD vet about subsidised investigations.
Calf diarrhoea/scours Affects young calves in autumn and early winter. Newborn calves that received a good supply of colostrum from their dams will be better protected. Signs include depressed appearance, diarrhoea, dehydration, recumbency and death. Calf scours may be caused by single or multiple organisms. Some common organisms include coronavirus, rotavirus, E. coli, Salmonella and Cryptosporidium. Cows can be vaccinated against a number of these prior to calving. DPIRD’s calf scours webpage contains a number of strategies to prevent and treat an outbreak.	Ante-mortem: 10mL faecal sample (chilled) from 5 affected animals if possible

Typical history and signs

Key samples

Gastrointestinal (GIT) worms in cattle

Mild summer weather and some rain may have allowed survival of infective larval stages on pasture in the southwest.
Recent cases of cattle showing signs including diarrhoea, lethargy and poor body condition have been submitted to DPIRD. Testing has found significant worm burdens and GIT damage despite drenching. This can lead to reduced immunity and poorer outcomes when cattle are affected by other conditions.
In winter rainfall areas, the brown stomach worm (Ostertagia ostertagi) is a major parasite of cattle.
Ensure drenches are effective against parasites in your region and administered correctly. See the DPIRD drenching beef cattle webpage for more information.

Ante-mortem:

Faeces: 4g in cattle for worm egg count.

Post-mortem:

Alimentary sections: fresh and fixed
GI contents (abomasal contents, SI contents)
Faeces

Pregnancy toxaemia in ewes

Consider pregnancy toxaemia if late pregnant/early lactating ewes present with depression, anorexia, weakness, recumbency, neurologic signs, and death. Signs may be worse following stress. Affected ewes may separate from the mob.
Ewes carrying multiple lambs are at higher risk and if identified early at scanning can be separated and fed carefully.
Pregnancy toxaemia can be avoided if producers provide adequate nutrition to the ewes and minimise stress (e.g. avoid herding and yarding of ewes in late pregnancy and early lactation).
Differential diagnoses: Scrapie (exotic), cerebral abscess, acidosis, enterotoxaemia, hypocalcaemia, nutritional myopathy in primiparous ewes and meningitis.
Early diagnosis and treatment with glucose and supplementary feeding of good quality hay and oats can halt deterioration.
DPIRD’s pregnancy toxaemia webpage has information on prevention and treatment.

Ante-mortem:

10mL blood in lithium heparin tube

Post-mortem:

2mL vitreous humour in plain tube (post-mortem) in addition to base tissue sample set.
Adult sheep showing neurological signs should be tested for reportable diseases such as scrapie. Speak to your DPIRD vet about subsidised investigations.

Calf diarrhoea/scours

Affects young calves in autumn and early winter. Newborn calves that received a good supply of colostrum from their dams will be better protected.
Signs include depressed appearance, diarrhoea, dehydration, recumbency and death.
Calf scours may be caused by single or multiple organisms. Some common organisms include coronavirus, rotavirus, E. coli, Salmonella and Cryptosporidium. Cows can be vaccinated against a number of these prior to calving.
DPIRD’s calf scours webpage contains a number of strategies to prevent and treat an outbreak.

Ante-mortem:

10mL faecal sample (chilled) from 5 affected animals if possible

Note: Include base samples and any clinical or gross lesions in submissions. For sample submission advice, contact your DPIRD field vet or the duty pathologist on +61 (0)8 9368 3351.

Register now for the next livestock disease investigation workshop!

Want to hear some great speakers and brush up on your post-mortem skills? There are two highly recommended workshops for livestock disease investigation coming soon:

Livestock disease investigation weekend workshop at Pagoda Resort, Como, on 23–24 June 2018 (Keynote speakers: Dr Tristan Jubb and Dr Kim Halpin, Australian Animal Health Laboratory)
Practical post-mortem workshop with Dr Tristan Jubb at DPIRD, South Perth, on 25 June 2018 (limited places).

Participation is free to rural practitioners, including meals and accommodation during the workshop.

For details and to register, see the Documents link on this page or contact your local DPIRD vet or Dr Gill Scroxton +61 (0)8 9956 8505 or 0418 943 064, email gill.scroxton@dpird.wa.gov.au.

DPIRD is pleased to facilitate this event, supported by funding from the Agricultural competitiveness white paper through the Department of Agriculture and Water Resources.

Feedback and subscriptions

We welcome feedback. To provide comments on the monthly email newsletter, email waldo@dpird.wa.gov.au. To subscribe or to see previous issues, see our WA Livestock Disease Outlook archive page.

In this issue

Download versions

See Also

Regions

Seasons

You are here

Newsletters

WA Livestock Disease Outlook - for vets

Recent livestock disease cases in WA

Deaths in cattle fed vegetable scraps

Respiratory signs and sudden death in cattle in the Midwest

In autumn, watch for these livestock diseases:

Gastrointestinal (GIT) worms in cattle

Pregnancy toxaemia in ewes

Calf diarrhoea/scours

Register now for the next livestock disease investigation workshop!

Feedback and subscriptions