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Making progress with mastitis

by
01 December 2016, at 12:00am

THE 2016 BRITISH MASTITIS CONFERENCE (BMC) took place last month prior to the European Mastitis Research Workers’ second meeting, and included speakers from France, Brazil and Denmark with posters from research groups linked with Brazil, Nigeria, Italy and the USA, as well as UK-based contributors. The opening paper by Cyril Crosson of Bioteck Lait in France described the application of an ELISA test for the biomarker Milk Amyloid A (MAA), combined with somatic cell count results, to advise farmers whether to infuse antibiotic with teat sealant or teat sealant alone at the end of lactation.

The advice is on a quarter, not cow, basis. Tridelta Development Ltd of Ireland has developed the test and assisted with the eld trials in France.

An algorithm has been developed utilising quarter cell counts, MAA and cow yield data. Bacterial identification is being recorded to support an ongoing programme for dairy farmers, and cows receiving teat sealant only had no cases of clinical mastitis in the previous four months.

The farmer takes the milk samples which are forwarded to the milk laboratory for MAA testing. Bioteck Lait applies the algorithm and advises the farmer by e-mail on which therapy to use. The cows were monitored for six weeks after calving and no cases of clinical or subclinical mastitis were recorded in the animals only receiving teat sealant. Antibiotic dry cow therapy was reduced by 29%.

Bacteriological culture indicated that 65.5% of quarters were infected at the end of lactation. A predictive value for the algorithm was over 90%, with intramammary infections at drying off in the range 40% to 60%.

The MAA indicates a high proportion of coagulase-negative staphylococci. It is assessed that fewer than 10% of infected quarters would receive teat sealant alone and less than 10% of uninfected quarters would receive antibiotic therapy. Application of the algorithm to advise farmers is expected to reduce the use of antibiotics and contribute to the French 2012-2017 reduction plan.

Selective therapy

Peter Orpin from the Park Veterinary Group in Leicester and Chris Gerard of Shorn Hill Farm described their experiences of selective dry cow therapy.

Historically, clients of the practice had administered teat sealant alone with disastrous results, resulting in severe mastitis and sudden death. This resulted in a lack of confidence in using teat sealant alone by both veterinary surgeons and farmers.

In 2015, the training programme supported by ARLA raised awareness of the need for a structured programme for herds. Utilising a strict methodology and approach has proved successful but the conclusion is that partial hygiene approaches result in failure. Nowadays, the practice does not advise dairy clients with ongoing issues of somatic cell count, clinical mastitis, hygiene and operator skill to change from blanket dry cow therapy to selective dry cow therapy.

Chris Gerard is the herdsman at Shorn Hill Farm, owned by Martin Beaumont, with a 275 all-year calving herd. Herd health is a priority with high standards of milk production. Utilising Interherd, cows are segregated into low and high risk groups as they approach drying off.

An increase in clinical mastitis during the first 60 days of lactation was experienced from 2014, which was due to a fundamental problem with the milking parlour. Correction of the parlour faults together with the adoption of selective dry cow therapy has resulted in a significant fall in mastitis cases.

An in-parlour video demonstrated the technique adopted by Chris to apply antibiotic therapy and teat sealant. The attention to detail with cleanliness, care and use of alcohol spray was clear to see.

The point was emphasised that a more precise technique is required for the administration of teat sealant alone than for antibiotic dry cow therapy. Referring to teat sealant or dry cow therapy or both as selective dry cow therapy is confusing, Mr Orpin said. There is a need to advise farmers on the risks and how to avoid them. The ARLA initiative was very successful, with 40% of their 1,750 farmers attending, but it appears important to find ways of overcoming the real doubts of the majority of dairy farmers if a reduction in the use of antibiotic at drying off is to be realised.

The practice is accelerating one-to-one discussions with dairy clients and increasing surveillance of Gram- positive pathogens. The vets are watchful that Staph. aureus does not colonise cows in herds that reduce antibiotic administration. 

More detailed information about the application and outcomes with teat sealant alone would be welcomed, Mr Orpin said, to add to the growing accuracy of knowledge (e-mail pete. orpin@parkvetgroup.com).

On-farm culture

Dr Peter Down of the University of Nottingham explained that a simulation of 5,000 cases of mastitis indicated that selecting treatment on the basis of on-farm culture may not be cost effective.

On-farm culture results in only Gram-positive and mixed culture cases being treated with Gram-negative cases left untreated. Treating all clinical cases with antibiotic resulted in a cost benefit 68% of the time; with on-farm culture-based selection economic for herds with predominately Gram-negative mastitis cases. There is concern that reducing antibiotic therapy for clinical mastitis in all herds could result in financial losses and poorer cow welfare.

Michael Farre of SEGES Dairy Research in Denmark has been working with farmers and veterinarians to develop accurate use of on-farm culture. Training programmes, utilising workshops and web-based materials, have shown that herds with a high management level, assisted by their veterinary surgeon, can operate the culture techniques successfully.

He explained that Danish farmers do not have easy access to fast, cost- efficient diagnostic services. Herd sizes are increasing and there is a rapid move away from the use of robots because of the cost. The aim is to reduce the use of antibiotics.

Automated parlours

John Baines of Fullwood Ltd apologised for utilising some of the same slides that he presented to the BMC before, in discussing developments in automated parlour technology to detect mastitis. There have been over 1,400 patent applications for sensors but development is very slow.

It is necessary, he said, to educate users to avoid mistrust of the system when no clinical signs are evident. An operator may not want to be burdened with mastitis alerts, where intervention may not be economically justified, but early warning can improve treatment success rates.

Combining sensor information provides better sensitivity and specificity. The cost of camera technology has fallen considerably and thermography is able to show the “hot quarter” or the “hot foot”. Conductivity findings that compare one quarter to another, rather than a single reading, improve the reliability of detection of a developing clinical mastitis case.

An assessment of the AHDB dairy mastitis control plan indicates that the benefit to farmers is over £11 million per year. Katharine Leach pointed out that over a three-year period implementation of the plan has resulted in a reduction in the rate of clinical mastitis of 20% and an improvement of 10% to 16% in udder health.

After costs, the benefits to the farmers have been £40 per cow per year. To date 1,366 plans have been registered involving 1,044 herds and 219,354 cows. Monitoring is recognised as the most important part for success of the plan. One million fewer antibiotic treatments in lactation have been recorded, with a 15% reduction in cows infected at drying off and 7.5% fewer cows receiving antibiotic at drying off.

Best poster

The best poster plaque was presented to Alison Bard of the University of Bristol for “It’s the dollar value ... isn’t it? Form, function and efficacy of veterinary advice for farmer behaviour change: A qualitative investigation.” Veterinary communication is believed to be at the heart of the issue of mastitis reduction but, although veterinarians recognise their influence, they struggle to be proactive communicators of advice.

Role-playing sessions involving an actress and veterinarians mimicked a vet-farmer consultation for an average of 11 minutes. Enhancing veterinary delivery, by being mindful of farmer motivation and utilising open questions, would stimulate changes in farmer behaviour and increase the uptake of a successful mastitis control programme, the poster revealed. 

  • Copies of the proceedings are available from Karen Hobbs: e-mail bmc@thedairygroup.co.uk. Previous proceedings and supporting information are available at www.britishmastitisconference.org.uk.