Johne's disease - Part Two: The Disease in Goats and Sheep

goatfaceHave any goats on your farm died after losing weight steadily?  Did they develop severe diarrhoea?  Did their condition worsen over a period of weeks or months? 

Have any sheep died after showing steady weight loss for weeks or months?

Did treatments such as anthelmintics, antibiotics, tonics and improved feeding prove to be useless?

If you answered ‘yes’ to these questions, you may well have Johne’s disease on your farm.  You may have experienced first hand the distressing and even heart-breaking effects of this awful disease.

  • Johne’s disease can affect all ruminants, and it can be a problem in deer and cattle as well as in sheep and goats. 
  • Goats and deer are particularly susceptible to Johne’s disease.
  • The disease is relatively common.

Sheep and goats have one big advantage over cattle and deer.  There is a Johne’s vaccine called Gudair that can help protect them, and the vaccine is not available for use in cattle and deer.  (The reason for this is that it can cause false positive reactions to the Tb skin test.)  

What are the signs of Johne’s disease?
  • Progressive weight loss.
  • Scouring in goats and sometimes in sheep.
  • The signs persist until the animal is emaciated and dies or is euthanased.
At what age do goats and sheep develop the disease?
  • Goats can develop the disease at any age after about 1 year old.
  • In sheep the disease is most common in 6-tooths (2 to 4 years old).
Is the disease infectious?
  • Yes, Johne’s disease is caused by a bacterium and it is very infectious, but fortunately there is an age-resistance to infection.
  • Older goats and sheep are less likely to become infected than young animals, and it is likely that most infections are picked up in the first few weeks or months of life. 
Do any treatments help?
  • No.  Some kaolin preparations given by mouth and some anthelmintics may cause a very temporary drying up of the diarrhoea but it soon returns. 
How do I confirm or rule out Johne’s disease as the cause of scouring and weight loss?
  • You will have to consult your vet, who will take blood and faecal samples or post-mortem samples for laboratory testing.
What can I do if I have goats and sheep with the disease?
  • Cull animals that show relentless weight loss and or scouring.  Get your vet to rule out other common causes of these problems first though – and definitely check for worms. 
  • If you have had the disease on your farm, it would be wise to vaccinate all sheep and goats and all new young animals before they are 2 months old.
  • If bringing in new stock, don’t buy in any unvaccinated sheep or goats. 
  • If you are serious about reducing the impact of the disease on your farm you may need to blood test all your stock before vaccinating, and cull all test positive animals.
  • Consider subdividing your farm.  If you have an area where there have been no animals with signs of the disease you might be able to use this as ‘safe’ area.  In the ‘infected’ area graze only older vaccinated animals.
What should I do to prevent Johne’s disease being brought onto my farm?
  • If you are bringing ruminants onto your farm, introduce only those from farms where no stock have shown signs of Johne’s disease in the last few years and/or buy in only vaccinated stock.
Are other species affected?
  • Johne’s disease is a disease of ruminants, so horses can safely graze pasture where there have been goats and sheep with Johne’s disease.
How long do the bacteria survive on the ground?
  • The Mycobacterium paratuberculosis bacteria that cause the disease can remain infective in the environment for 2 to 6 months, and in some sheltered places they may survive for over 12 months. 

The first part of this series “Johne’s disease:  Part one:  An overview” gives more detail about the signs of the disease and how it spreads. 

In next month’s article, the focus will be on Johne’s disease in cattle and deer.

 

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