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Signs of mastitis

  • Differences in size of two halves of the udder

  • Not eating, away from the mob, sick looking

  • Udder changed temperature or consistency.

  • How hard the udder is, how hot it is and milk output - are both sides producing the same sort of milk.

  • Swollen lymph nodes

The abundance of grass leading into the autumn has set many sheep producers up well for lambing, but it has also increased the risk of mastitis.

Vet Stuart Barber says elevated levels of mastitis comes hand in hand with the high milk production prompted by a good amount of grass.
Dr Barber is a lecturer and researcher at the University of Melbourne in veterinary and agricultural science, as well as coming from a Poll Dorset producing family.

“For the first few weeks after lambing in those areas that have had a good season it wouldn't be surprising to see high levels of mastitis,” he said.

“The first sign in a Poll Dorset ewe is they’ve stopped eating...that is a big sign in my books as it takes a lot to stop them feeding.
“Looking at those sheep as soon as you can identify them is critical - the biggest thing that makes a difference to successfully treating mastitis is early treatment - every day you leave it the less likely it is you will get the ewe back to full production.”

This means observation of lambing ewes is key, as is ensuring those who are monitoring lambing ewes have the skill set to identify mastitis.

For every ewe that has clinically obvious mastitis that you can see, there are likely another five to 10 in the flock that have sub-clinical symptoms that you can’t see, Dr Barber said.

“If you don’t get those nasty cases of black and blue mastitis within 36 hours you will probably only save them about 50 per cent of the time, even if you have really good treatment.

“Where feasible it is good to get those ewes and their lambs out of the flock, as the lamb will carry bacteria at the back of the throat and can cross-contaminate if they suckle other ewes, so moving them to the hospital zone will reduce transmission.

“In terms of keeping those ewes, presuming they have recovered 100 per cent there is no risk, but genetically speaking they are more likely to produce offspring that are more likely to get infection down the track - if they are not in the top for other traits I recommend culling those ewes.”

That said, culling for clinical mastitis will make little progress in limiting mastitis risk in your total flock, Dr Barber said.

“But if you select on sub-clinical mastitis (means collecting milk samples through lactation) you will make progress as it is a much bigger group - that is where genomics will come into play down the track, particularly around the ram flock in regards to being more or less likely to sire ewes that are more or less likely to get mastitis.”

While there is no commercially available medicinal prevention for mastitis in Australia as of yet, there are some management measures producers can adopt to lower the risk.

“The key thing to think about is anything that can cause damage to the end of the teat can increase mastitis risk, such as sharp stubble that might cut the end of the teat or wet and windy conditions can chaff the teat,” Dr Barber said.

“If you have paddocks where wind speed can be decreased by trees then put twin bearing ewes in there - you are more likely to have mastitis in multiples as there is more chance of bacteria getting in as they are getting suckled twice as much.

“And Poll Dorsets get up to peak production quite quickly, so managing this is crucial - if you have milk dripping from the teat canal it is a perfect avenue for bacteria to get up through the teat,” he said.

“We can see mastitis anytime pre-lambing through to lamb at foot and also post-weaning - if a ewe has a mastitis at weaning time, then when the lamb goes off the milk is being continually produced and there is opportunity for bacteria to take off then.”

contacting your local vet to discuss what mastitis investigation might look like on your property before lambing starts is good practice to ensure you can respond quickly.

If you are identifying cases of mastitis in your flock, taking milk samples to find out exactly what bacteria is causing the issue is the first step of treatment.

“Not every milk sample produces an answer, by sending three to five samples at once you will increase the chance of getting an answer - and the right answer - and the cost per sample will be less.”

Dr Barber said some Poll Dorset flocks can have mastitis outbreaks of up to five per cent of the flock, and at that level it was well worth establishing a solution.

“The longer term goal across the industry needs to be around prevention - we don’t have a registered vaccine, we need more research and funding of the genomics and genetics of mastitis and more research on not relying on antibiotics.”