Ovine brucellosis has no cure, but it is preventable.
That was the message Dr Emily Stearman wished to impart during the 2018 Graham Centre Livestock Forum held in Wagga Wagga.
The Riverina Local Land Services (LLS) district veterinarian has been working in animal health and biosecurity since she joined the LLS in 2015 having graduated from Charles Sturt University in 2010 among the first intake of veterinary science students.
The cost of Ovine brucellosis to a sheep business can be enormous, but it is preventable with sound bio-security and regular monitoring, according to Dr Stearman.
There are a lot of different aspects to this disease, and during her address she focused upon how that cost can be prevented going forward.
“It is spread from ram to ram through sexual activity, although the ewe can be infected but she will typically be clear after one heat cycle,” she said.
“The rate at which it can spread depends on a variety of conditions, but the key factors include the size of the ram flock, the age structure and the breed.”
Dr Stearman said the disease tends to spread a bit quicker through the meat breeds, as they tend to be more sexually active away from the ewes: and the smaller the flock, typically the easier it is to infect the sheep.
“In many cases the disease can be eradicated from the flock by following a specific testing protocol, and culling those rams tested positive,” she said.
Dr Stearman advised sheep producers, routine monitoring and awareness of following sound biosecurity principles will protect their flocks against an economically significant disease.
“Poor semen quality and reduced ejaculate volumes which will obviously reduce the pregnancy-scanning percentages,” she said.
“No one knows they have got the disease, but testical palpation is a good place to start, and blood testing is one-hundred-percent accurate.”
The options of control vary, but Dr Stearman recommends identifying those rams which are infected, and because the disease is not treatable the only way of eliminating it is to cull any animal which is infected.
“It is not just one test … and you are clear,” Dr Stearman reminded producers.
“It is a matter of continual testing until everything is clear.”
Obviously prevention is better, and there are ways in which the introduction of Ovine brucellosis to a flock can be restricted.
Rams should always be purchased from Brucellosis accredited studs, effective boundary fences properly maintained and critically, rams are kept in an internal paddock, preferably close to the properties work centre where they can be regularly monitored.
Especially if a stray ram should enter the property.