WORK on a sheep mastitis trial - which has taken milk samples from more than 9000 ewes in the last five years - is due to conclude in the middle of next year.
Benalla veterinarian Stuart Barber, of Kennedy Creek stud, said he had taken milk samples from sheep throughout south-east Australia.
The Meat & Livestock Australia funded trial aimed to look at clinical and sub-clinical mastisis, in all sheep breeds.
Dr Barber said a specially designed "sheep milker" had been built, to make the job easier.
"The first 4500 we pulled over on the shearing boards, or did in races, the rest we have done in this, so it's a lot better," Dr Barber said.
"It's the 'bush tiger milker' - named after Bushy and Tiger, who made it."
Various modifications had been made to the machine, since it was first made, he said.
The milker had a height adjustment mechanism, to bring the sheep up to chest level, and swung around.
It also had a metal cover, to keep operators from the wind and rain.
Mastitis was caused by a bacterial infection of the udder
"Clinical mastitis cases you can see, but this is more looking at subclinical mastitis," Dr Barber said.
"The milk looks perfectly normal, but 15-20 per cent of sheep will have subclinical mastitis - I can't tell, and I have sampled 9000 of them.
"We don't know how much influence that has on lamb growth rates, that is part of this work."
Mastitis could reduce lamb growth rates by as much as 10pc, or even cause death.
"We already know five per cent of ewes might get clinical mastitis in a year, and often their lambs will die, so that is an obvious significant impact," Dr Barber said.
"It varies a lot, some will have none and some will have quite an outbreak."
Depending on the findings, a vaccine could be developed or sheep genetics modified, to reduce the impact of mastitis.
Analysis of the data should be completed by the middle of next year, he said.
