A Smart Approach to Mastitis Management

Kevin manages 550 cows at Ohakea, Manawatu.  The farm produces winter milk, and autumn and spring calvers are all run as one herd.  For several years he experienced seemingly intractable problems of clinical mastitis in the herd, and in the 2011/12 season there were 175 cases, 55 of which occurred between July and September.  In January 2012 half of the herd had had two or more high cell counts in a row, so there were a lot of infected cows.  Kevin was trying to treat and cull his way out of the problem and not really making any progress.  In 20 years of dairy farming he had never had a challenge like it and he says he felt almost like giving up dairying.

The farm owner asked Will Tulley, Senior Practising Veterinarian in Dairy Cattle Health at Massey University, to do a thorough examination and complete work-up on the problem.  Will analysed all the clinical cases that had been recorded on MINDA to identify the main causes of problems, and made several farm visits to look at milking routines and the farm environment.

“We looked at when mastitis cases were occurring, and the most significant time was the first month of lactation for the spring calving cows, so although there were also some things that Kevin could do around the cowshed we realised that the biggest gain would come from stopping cows becoming infected during the dry period and at calving,” says Will.

“So the main change was using dry cow therapy and teat sealant on the whole herd, which they hadn’t done before. We used teat sealant on the heifers as well because 15% of them had clinical mastitis in the month following calving.”

“We also looked at management of the colostrum cows as they came through into the milking herd to make sure we were controlling cell counts.  Kevin had already culled a number of cows and we established criteria for culling those that were not going to get better and that were an infectious risk to the rest of the herd.”

Teat spraying was also a fairly significant factor, and Kevin increased the volume and thoroughness of application and diluted the sanitiser to the manufacturer’s specifications.  There were also some small changes to shed hygiene – wearing gloves and treatment policies for clinical cases – but the main focus was on the big gains from dry cow therapy.

In the spring of 2012 wet weather meant that the area where the cows calved was muddy and that created problems, says Will.

“In a wet season putting the cows into a muddy area exposes them to infections like Streptococcus uberis, so ideally cows should be calved on dry, fresh areas and be removed from those areas as soon as possible after calving and milked out,” he says.

“For 2013 we had an alternative plan to calve down on neighbouring well drained areas but that proved unnecessary because the weather was very favourable.”

The “gold standard” approach of treating every cow including heifers with both dry cow antibiotics and teat sealant was effective in reducing the level of infection and the risk of infection transfer between cows, and controlling the environmental challenge.

“Mastitis levels are significantly lower – not perfect but with a split calving herd it is always a challenge because you can never completely break the cycle,” says Will.

“When we got involved in 2012 the average cell count was 275,000 and now we probably have an average of about 175,000. So far (to December 2013) there have been 9.5% clinicals whereas last year there were about 19% so that’s about halved and it’s what you can expect through using teat sealant.”

“For drying-off at the end of this season there is an argument for selective dry cow therapy but I would be happy if Kevin treated the whole herd again for one more year, and also the whole herd including heifers treated with teat sealant.”

Kevin says he is quite sold on that idea.

“I was quite sceptical about using teat sealant etc on the whole herd but this year has been much easier for me.  It was definitely a winner to take on board this new technology and use the advice I have been given,” he says.

“Even if you don’t use 100% of the plan, some plan is better than no plan.”

Dr Jane Lacy-Hulbert is a senior scientist with DairyNZ and the technical developer of the SmartSAMM mastitis management programme, available on the internet.“The approach Will and Kevin have taken is an excellent example of how successful mastitis control can be.  The SmartSAMM programme now recommends that you  consider protecting every cow at drying off.  This might mean antibiotic dry cow therapy, an internal teat sealant, or both,” says Jane.

“Farmers should work through this with their vet because antibiotics are prescription medicines and need to be used in the right way.  Also preparing for drying off is a good time to take stock and work out what has been happening over the whole season and look at some strategic changes.”

Jane recommends that farmers should work with their vet to decide which cows to cull from both reproduction and mastitis points of view, and then work out how to treat the rest of the herd.  Guidelines are available at SmartSAMM.co.nz.

“Decisions have to be made a month or so before drying-off so that treatment materials can be ordered and the plan set in place.  Ideally the high cell count cows and the skinny cows will be dried off first, and the timing for the bulk of the herd will depend on the weather, pasture and supplementary feed supplies and herd production levels,” says Jane.

“Generally we advocate that if cows are doing less than 10 L per day we don’t worry too much about changing the feed or doing anything pre-drying off and it comes down to how you manage the feeding levels after drying off.”

So it is a matter of:

• Identifying the cows to be culled/dried off
• Getting the treatments and materials needed for cleaning teats
• Ensuring that staff know which cows are being dried off
• Having staff trained – often a vet or a trained technician comes in on the day to make sure that everyone knows how to actually treat the cows properly, or maybe arrange a training session prior to that.
• Aseptic preparation of the teat.  The objective is to make sure there are no bacteria around the teat orifice so they won’t get pushed up into the teat canal when sealant or dry cow therapy is put in.  Many of the bugs on the end of teats are derived from faeces and dirt, so either alcohol medicated teat wipes are used or cotton wool soak in 70% alcohol.
• Applying long-acting antibiotic only if it’s required, and then teat sealant.

Treated cows are then kept separate from the main herd so that there is no danger of them rejoining the herd and being milked – they need to be well marked and their numbers recorded.

“The MrsT* approach used during lactation is also appropriate for the dry period, particularly when drying-off cows from the main herd (Marking the cow, Recording details, Separating her from the main herd, before Treating).  You will find more information about that it in Healthy Udder,” says Jane.  “Feed can be reduced to the amount that is normally given to dry cows and that helps reduce the drive to produce milk.  It takes 2 to 3 weeks for the cow to fully dry off so we suggest that the feed is pulled down for about a week to 10 days.”

“We encourage people to check cows in the paddock several times during that early dry period and if there’s anything suspicious then bring them into the dairy.  Look for visible signs of mastitis – swollen udders, cows that look sick and sore.”

“We also recommend bringing all the cows in at about day 14 to actually palpate the udders and feel for any heat and swelling.”

Teat sealant may need to be removed after calving.  The feeding calf will often strip the teat sealant out but Jane recommends that when cows come in for their first milking staff should check each teat and strip it 8 to 10 times to remove  the sealant. The sealant will look whiter than colostrums, she says, and is a different consistency.

“The emphasis is on working with the vet, taking advantage of training available through vets, and doing a careful and thorough job of teat preparation and treatment application,” says Jane.

“Drying off is such a strategic and critical time at which you can make huge impacts on herd health.”

Jane emphasises that in herds where mastitis levels are “normal” not every cow will need dry cow antibiotics, and for many the use of teat sealant will be sufficient to control mastitis.