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Brucellosis in rams

Brucellosis is a bacterial disease caused by members of the genus Brucella. It is an important zoonosis and is a significant cause of reproductive losses in animals.

The disease is most commonly thought of and identified in sheep flocks. The pathogen is Brucella ovis and is naturally transmitted from ram to ram and/or ewe to ram by sexual activity. It multiplies in blood and localises most commonly in the testicle which results in inflammed/blocked tubules and as a consequence low sperm counts, no sperm or abnormal sperm.  As such the ram becomes permanently infected.

Over the years we have had to deal with numerous outbreaks of Brucellosis, some of which have resulted in entire ram flocks being culled because of a very high infection rate. Others take longer to get under control because of a lower level of infection within the ram flock and a slower rate of spread. Such cases often require multiple blood tests several weeks apart before the disease can be eradicated from the ram flock.

Consequently, one of the keys to avoiding an outbreak is to have your rams checked prior to mating. Traditionally these checks have been carried out just prior to mating however the problem with this is that, if an issue is identified, there is often insufficient time to test and cull rams and ensure a Brucella ovis-free flock prior to mating. The disease can then spread like wildfire during tupping, which can have dramatic effects on scanning percentages.

Your rams can be checked at any time and any infection that spreads during the previous mating season should by then be detectable. Outside the breeding season, when rams are sexually inactive, it can be much easier to eradicate the disease with minimal blood tests.

 The important things to remember are:

  • Always purchase rams from a Brucella ovis-free source (rams purchased should at least have been palpated).
  • Avoid sharing or borrowing rams.
  • A community approach works best for preventing spread of disease within an area – talk to your neighbours and have a plan.
  • The disease is not carried from season to season in the ewe flock.
  • There is no treatment