ShapeShapeauthorShapecrossShapeShapeShapeGrouphamburgerhomeGroupmagnifyShapeShapeShapeShape

The constant challenges of high cell counts and cases of clinical disease

by
01 July 2009, at 12:00am

PETER EDMONDSON summarises the latest developments in mastitis control

HERD cell counts continue to rise in the UK and throughout the world. A large part of this will be due to the increase in milk price and people building up herd size to maximise production. 

In New Zealand, for example, over the past five years the national herd has increased by 25% and the average age of the herd has increased by one year. Here are a variety of snippets which all relate to the constant challenge of high cell counts and problems with clinical mastitis. 

Teat end damage 

Just a reminder of importance about the teat canal. If you bathe a healthy teat in billions of Strep. uberis bacteria then only a few cows will get infected. However, if you infuse one hundred Strep. uberis bacteria through the teat canal into the udder, 90% of these cows will get infections. 

This shows that a healthy teat canal is critical to keeping infections out of the udder and an assessment of teat condition should always be part of a mastitis investigation. 

Don’t forget to teat score after the unit comes off and if you find there are significant problems with hyperkeratosis or congestion, then these can be referred back to the milking machine company as these are machine induced problems. 

Keeping cows standing for 30 minutes after milking

I remember carrying out a referral herd up in Herefordshire where the first cow to be milked in the morning or afternoon was kept standing for twoand-a-half hours before she was released back to feed and lie down. It used to be the case that everyone thought it was essential that cows were left standing for 30 minutes after milking to allow the teat canal to close thereby avoiding new cases of clinical mastitis.

We need to be practical. If cows exit from the parlour and are offered fresh feed then they will naturally go and eat. If you have a lame cow who really wants to go and lie down, then I think it is only fair that she should do so.

Too many cows spend too much time standing to achieve their 30 minutes for the teat canal to close at the expense of lameness and lack of resting time. 

Drying off individual quarters

If a high cell count cow has only one infected quarter, then one option is to dry off the individual quarter. The first thing we need to do is establish which is the infected quarter. We can do this by carrying out a CMT test or individual cow cell counts over a period of a few days to ensure it is the only quarter affected.

The best way to dry off a quarter is to give a course of intramammary therapy and then stop milking. Do not administer antibiotic dry cow therapy at this time otherwise you will have problems with residue failures. 

However, do administer antibiotic dry cow therapy into the quarter at the end of lactation along with the rest of the quarters of the cow. 

Many quarters return to normal production at the next lactation. Roger Blowey carried out a trial on 125 cows which had quarters dried off. Of these, 66% came back into full production at the following lactation. However, the success of treating a cow with intramammary therapy before the quarter was dried off increased the number of quarters returning to full production to 92%.

Benchmarking 

Often we rely on farmers to tell us if they have mastitis problems. We have been benchmarking our farmers according to milking cow tube sales per cow per year for some time. Farmers are put into green, amber or red bands.

We find it is a really helpful way to be able to target advice to problem farmers. Remember that most farmers don’t record all cases of clinical mastitis accurately, and if cases are not recorded then there isn’t a disease problem! 

Written treatment and milking protocols

I was recently on a farm of 150 cows which has five different milkers and five different ways of milking and treating mastitis!

Written treatment protocols will ensure that everyone follows the same guidelines, no matter who is milking. This will improve cure rates for clinical mastitis and help to minimise the number of repeat cases.

It is also important that cows are handled and teats prepared in the same way at every milking. I was very impressed when I was advising a farm in Portugal earlier this year that they had explained the milking routine to all their staff and every member had a written protocol on how to prepare and treat cows.

This is a really good training opportunity for vets to carry out milker schools with their farm clients.