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Useful information to apply over the winter

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01 December 2010, at 12:00am

reports on the proceedings at this year’s British Mastitis Conference

MORE than 100 delegates attended this year’s mastitis conference, held in the different venue of Worcester Rugby Club. The conference facilities overlooked the pitch which was receiving careful grooming throughout the day.

A third of the delegates were veterinary surgeons from practice and the presentations contained useful information that could be applied over this winter. The event was organised by The Dairy Group, Dairy Co. and the University of Nottingham, with an impressive list of sponsors representing consultancy, pharma, milking machinery interests and dairy hygiene. 

The poster competition is voted on by the delegates and won by a study of a 1,000 cow dairy herd in Somerset combining veterinary (Synergy Farm Health) and farm management assessments (Bakers of Haslebury Plucknett). The poster asked the question: “Large herd mastitis – how low can you go?”

This herd is milked through an 80- point rotary parlour with nine Polish milkers working in shifts of five people, two farm managers and three times a day milking. The milk goes for cheddar cheese production and no Orbeseal is permitted.

The rolling annual clinical mastitis incidence is eight cases per 100 cows and at a valuation of £200 per case, the cost of clinical mastitis in 2006 was £180,000, which fell to £18,600 in 2009. The dry cow new infection rate is 9% (target 10%) and the dry cow cure rate 92% (target 85%).

The conclusion is that “this study demonstrates that with good facilities, following standard operating procedures, the highest levels of stockmanship and attention to detail, udder health can be maintained to the highest level even under intensive conditions in the UK”. Further information from Jon Reader (office @synergyfarmhealth.com).

The opening conference presentation was given by John Sumner, who looked back over the past decades and reviewed the progress in mastitis control against the background of a dairy industry undergoing political and rapid structural change.

In 30 years the average herd size has doubled, cell count has more than halved but the incidence of clinical mastitis remains high at 47-65 cases per 100 cows per year. The question was raised as to whether the well-recognised control methods are being adequately implemented. It would appear that messages of best practice are not getting through. The challenge is to improve communication and “to go back to basics”.

Andrew Bradley (QMMS Ltd) provided an update of the DairyCo. Mastitis Control Plan since it was launched last year. The aim is to provide targeted mastitis control measures for the situation on individual dairy units, to assure cost-effective mastitis control.

Veterinary surgeons and consultants undertake a two-day training programme. Principles of the plan and electronic resources are covered on the first day and then the plan is implemented on at least one farm before the second day of training. A total of 132 vets and 31 consultants have taken part with 50 more vets and eight consultants due to attend further courses. To October 2010, 428 farms have been enrolled on the scheme.

Initial data indicate that only 23% of the farms are implementing two-thirds or more of the recommendations but despite this some 3,000 fewer cases of clinical mastitis have been recorded and the aim is to achieve a 20% reduction in disease.

It is too early to draw conclusions but the initial signs are positive and uptake is ahead of the targets originally planned. Wholehearted industry support is requested for the plan to have a long- lasting benefit.

Mike Kerby (Delaware Vet Group) has 10 herds on the scheme and finds that the structured approach to specific areas is well accepted but completing the data and reviewing the analysis can be daunting to some clients. There is flexibility within the plan and there is also room for clinical judgement, described as “the art of veterinary practice”.

Detailed awareness

Enthusiasm and willingness to try the plan is important initially and also to have success and improvements. It is not only the herds with high cell counts and a high incidence of clinical mastitis that can benefit from the detailed awareness.

Dan Norris (Delaware practice client) was unable to present his paper but the content is in the proceedings. This farm has a particular approach to therapy for high cell count cows and specific infections at the end of lactation.

One week prior to drying-off, a sample is assessed for bacteriology; dry cow therapy and teat seal are inserted at drying-off and an injection given at the same time for Strep. uberis infections by the farmer and for Staph. aureus later by the vet at the next visit. The use of combination therapy for problem cows is worthy of further understanding.

James Montgomery, a cheese producer with a Friesian and a Jersey herd, based his decisions on mastitis control according to effects on the quality of cheese. The plan has only been in place for a few months but environmental bacteria in the dry period are recognised as a problem source. Deep straw dry cow beds have been installed as part of a new dairy.

Assessment of performance is linked to aspects of the plan but practical advice is required, not old messages of losses against zero cell counts. The point was made that the bigger the plan, the lower the feelings of involvement by farm staff.

The most likley route for infection of the mammary gland by Strep. uberis was identified by Professor James Leigh (University of Nottingham) as from gut to environment to teat end.

Not all strains of Strep. uberis are able to cause mastitis after introduction into the mammary gland. Once within the gland the organism has to be able to grow in milk and dry cow secretions, survive host defences including phagocytic cells and be able to induce disease. By deleting or mutating genes, it is possible to determine how this alters function of the organism as an approach to control. 

It would be possible to produce an antibody that inhibits the function of Strep. uberis and thereby immunise the cow. In the past work has been carried out mainly on strains derived from the mammary gland but as a great deal of Strep. uberis comes out of the back end of the cow, these isolates are also worthy of attention.

The organism cycles from the gut, to the environment, to the gut, with occasional detours to the mammary gland. The question arises whether more strains of non mastitis-causing organism prevent the establishment of infective strains. It may be possible to utilise natural strains that are unable to infect the udder as probiotics. The professor concluded that the application of technology is getting closer to being able to control Strep. uberis.

The use of PCR technology to identify pathogens, as an alternative to bacterial culture, was promoted by Hannah Pearse (NMR). The range of organisms able to be identified from a sample is greater with antibiotic sensitivity results available at the same time.

The application of PCR is expected to improve the efficacy of therapy through a more informed approach to treatment. James Allcock identified from the National Mastitis Survey that a third of the farmers do not utilise bacteriology and that two-thirds use more treatments than advised by pharma.

Alison Clark (GEA Technologies) presented a detailed paper on the 12 active ingredients in teat disinfectants, which is available in the proceedings. Iodophor-based products are still the most popular on UK farms.

With reference to various calculations and common sense observations, Jamie Robertson (Livestock Management Systems Ltd), pointed out that ventilation of buildings can directly influence the survival rates of E. coli and Strep. uberis.

There is great potential to improve existing buildings by creating good airflow and recognising the role of temperature differences between the inside and the outside. Bacteria within aerosols, flowing over a straw bed or cubicle, can lose microbial activity with evaporation. Moisture management of bedding is assisted by ventilation.

It was emphasised that removal of heat and moisture from a cow area is more important for mastitis control than stocking rate. 

“The role of the milking machine in mastitis” was outlined by David Reid (BouMatic, Wisconsin). In considering change he advises, “Always do what is best for the cows.” Removing the milk gently, completely and quickly will reduce the new infection rate, combined with consistency of cow handling and udder preparation.

Citing examples of kinked hoses, liner squawks, vacuum stability, pulsator performance and peak milk flow claw vacuum, the point was made that it is important to complete the physical examination of the system before arriving at a diagnosis.

Some of the problems are solved by minor changes but it is sobering that his conclusion is that “most milking systems do not function correctly”.

  • Further information and a copy of the proceedings can be sourced through www.britishmastitisconference.org.uk.