WA Livestock Disease Outlook - for producers

Changes to Johne’s disease in cattle regulation in WA

Following confirmation of Johne’s disease (JD) (cattle strain) in southern Western Australia, there will be some changes to JD in cattle regulation in WA. For more information about these changes, and JD prevention and management, see the following webpages:

• JD in cattle: management in WA
• JD in cattle: regulatory controls
• JD in cattle: frequently asked questions

DPIRD will be updating these pages with additional resources such as videos.

Recent livestock disease investigations 

Slender iceplant poisoning causes death in hoggets

• 5 out of 550 Merino ewe hoggets were found dead in a paddock they had been grazing for a week.
• The producer contacted their local DPIRD field vet, who attended the property and performed a post-mortem to determine the cause of the deaths.
• Always ask your veterinarian to investigate sudden death, high death rates, or unusual disease or behavioural signs in your livestock. Some reportable diseases have similar signs, and testing to exclude them helps to demonstrate to our trading partners that we are free from such diseases. 
• The paddock was inspected for possible causes of death. The fodder available to the sheep was mostly blue bush and clover, but there was also a significant amount of slender iceplant available in the paddock.
• Samples were submitted to the DPIRD laboratory and the pathologist diagnosed slender iceplant poisoning.
• Poisoning from slender iceplant normally occurs from October to April, as the plant has high levels of salt while drying out which attracts sheep. Toxicity may also occur at other times of the year, usually when stock have not had access to slender iceplant before or when they are introduced to the plant while hungry.
• Read more about slender iceplant poisoning in sheep. 

Slender iceplant

Liver fluke excluded from an abattoir

• 250 of 285 lambs from a line at an abattoir were detected with evidence of parasite infection in the livers. The liver lesions were detected through routine meat inspection.
• The livers from the affected lambs were condemned and did not enter the food chain.
• No clinical signs were observed in the live animals.
• The on plant vet suspected that the lesions were due to Cycsticercus tenuicollis (bladder worm), which is the larval stage of the dog tapeworm Taenia hydatigena.  
• The on plant vet collected samples from the condemned livers and submitted them to the DPIRD laboratory for analysis.
• The pathologist found evidence that parasites had been in the liver.
• Liver fluke is a reportable disease in WA that can cause similar lesions in the liver.
• A DPIRD field vet and biosecurity officer attended the property to collect follow-up faecal samples from animals to test for liver fluke. DPIRD lab testing ruled out liver fluke.
• Interstate control measures are in place to prevent entry of liver fluke into WA.
• The negative result in this case helped to demonstrate that WA is free from this disease.
• The final diagnosis was bladder worm, as suspected by the submitting veterinarian.
• Bladder worm is caused by the ingestion of eggs from the dog tapeworm Taenia hydatigena. It has little effect on sheep health or production and is of no concern for human health, however it causes economic losses due to condemnation of livers and trimming of cysts in the abdominal cavity of carcases at the abattoir.
• Pet and working dogs should be wormed regularly with a tapeworm treatment, and dogs should be prevented from accessing sheep carcases.
• Wild dogs and foxes can also carry the tapeworm that causes bladder worm in sheep. 
• Read more about bladder worm.
• Sheep measles (Taenia ovis) is another tapeworm parasite which can cause significant economic loss due to rejection or trimming of sheep carcases. The parasite is carried by dogs, however the larval stage in sheep muscle results in an unsightly cyst which is not acceptable for human consumption, although it poses no concern for human health. Control involves preventing transmission of the tapeworm from dogs to sheep.
• Read more about sheep measles.

Liver of sheep affected by bladder worm

Abortion in beef cattle 

• 3 second calvers from a group of 100 cows aborted their calves over a 3 week period.
• The cows all appeared healthy with no clinical signs.
• The producer contacted their private vet, who attended the property and collected samples from one cow and submitted them to the DPIRD lab.
• A sample of placenta was tested for a range of infectious causes of abortion in cattle, including the exotic and reportable disease Brucella abortus. The negative result protects market access by proving that Australia is free from such diseases.
• The cow also had mild inflammation of the placenta but this was not suspected to be the cause of the abortion.
• Testing of the blood from the affected cow was positive for the parasite Theileria orientalis.
• The cow also had anaemia, which is consistent with Theileria orientalis.
• Bovine anaemia due to Theileria orientalis group (BATOG) can cause abortion, anaemia, jaundice and sometimes deaths in cattle.
• WA's BATOG surveillance program encourages producers to have their private vet investigate the causes of anaemia, jaundice and abortion in their cattle.
• Read more about infertility and abortion in cows.

In late spring, be on the lookout for:

Barber’s pole worm

• Usually seen in late spring/early summer in coastal areas of agricultural regions of WA.
• Weaners with inadequate immunity commonly affected at this time of the year.
• Signs include sudden death, anaemia, weakness, bottle-jaw.
• Weaned lambs have reduced immunity to worms and depend on an effective drenching program. Weaned lambs that have not received their weaning drench (ideally 14 weeks after the start of lambing and no later than 18 weeks) and then their first summer drench (about 4 weeks after pasture senescence or no later than early December) are at risk of having significant worm burdens. 
• Read more on Barber's pole worm, and contact your vet for more information.

Selenium deficiency in lambs and calves

• Occurs mostly in young animals as they have an increased demand for the essential trace element during growth and have not accumulated the reserves of adult animals.
• Animals are typically grazing lush, rapidly growing pasture or legume-dominant pasture in the higher rainfall areas of the southwest coastal regions.
• Paddocks heavily fertilised with superphosphate applications may also predispose animals to deficiency.
• Signs of selenium deficiency include poor growth, stiff gait, arched back, apparent lameness, reluctance to move and sudden death. Selenium deficiency can also cause low fertility in breeding animals.
• Read more about selenium deficiency in sheep and cattle.