Informed decisions ensure the future of your flock

18 November 2016

Ovine Brucellosis (OB), a contagious bacterial infection caused by Brucella ovis, is hard to detect and can result in reduced fertility, extended lambing periods and lower marking rates. OB poses considerable flock health and financial risks and producers are urged to make biosecurity measures an integral part of their husbandry program.

MLA Project Manager Animal Health, Welfare and Biosecurity Dr Johann Schröder said on-farm biosecurity measures are not cost-prohibitive and have the potential to pay off through increased protection against all infectious diseases and marking percentages.

Dr Samantha Allan, Senior Veterinary Officer with the NSW Department of Primary Industries, North West, agreed, saying measures such as isolating new rams, securing fences and conducting pre-joining examinations of rams were best practice and affordable measures that all producers could employ.

“Leaving rams with ewes year-round is a high-risk strategy that places on-farm and neighbouring stock at greater risk of infection," she said.

What are the signs?

Animals may show no sign of infection and a producer may not realise a flock is infected until marking percentages are adversely affected, or ram wastage becomes abnormally high. Infected rams carry the disease for life and pass it on when mating. Infected ewes can pass the disease to rams at joining and to offspring through milk.

What can producers do?

Johann and Samantha said that every producer should adhere to the following biosecurity guidelines to reduce the incidence and spread of OB:

  • Buy rams from accredited breeders: buying from accredited studs ensures you do not introduce infected rams into your flock. Rams purchased from non-accredited sources should be quarantined until their status is established via blood tests.
  • Never buy rams from saleyards: rams offered in saleyards can have a high risk of disease or conformation faults.
  • Quarantine new ewes: introduced ewes should be separated from rams (and ram lambs) for one month prior to joining. Pregnant ewes should be lambed in isolation and not joined for four months.
  • Separate rams and ewes during lambing: rams can become infected from serving ewes that abort due to OB.
  • Maintain boundary fences: stray rams can spread the disease.
  • Check rams regularly: routine scrotal examinations for abnormalities in appearance or texture should be carried out on all rams. Watch this video to learn how. If more than 5% of the ram mob have abnormal testes the most likely cause is OB. This can be confirmed by a veterinarian using a blood test.
  • Maintain records: reduced conception rates, lower marking percentages, extended lambing periods and abortions are possible OB markers and should be monitored.
  • Keep younger and older rams separated: reduce ram-to-ram infection by separating older and younger rams, and running rams in smaller mobs. Rams should be run in securely fenced paddocks when they are not working to prevent straying.

Samantha said that all members of the NSW OB Accreditation Scheme are committed to the program. There are more than 850 studs participating, representing all of the major breeds.

“The scheme is successful with some studs maintaining continuous accreditation since it began in 1981; however buying accredited rams is only part of the solution," she said.

"Purchasers still require biosecurity best practice measures on their properties, and all sheep producers should monitor the OB status of their ram team annually, at least one month prior to joining."

Accreditation is carried out by an accredited private vet and includes an inspection of the property, oversight of a biosecurity plan, and blood testing and examination of rams. Producers can access details for accreditation schemes in the following states: NSW, QLD, WA, VIC, SA and TAS.

Go to Making More From Sheep for general information and Livestock Biosecurity Network[K2]  for further resources and guidelines.  

More information

Dr Johann Schröder E: jschroder@mla.com.au

Dr Samantha Allan E: sam.allan@dpi.nsw.gov.au

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