balancing antibiotic treatment with regard to mastitis

Treating mastitis: Balancing cure, money, welfare and resistance

Henk Hogeveen

With input from Wilma Steeneveld and Claudia Kamphuis

My paper gives latest results from literature

But ...session on analytics:

The modern dairy farm has at its fingertips an endless array of data. When managed properly, these data can be used to create a competitive advantage. This session will explore the potential of analytical approaches to managing mastitis through the use of on-farm records, decision support for mastitis treatment, and statistical processing of information.

My presentation will have an emphasis on analytics, not on results

My presentation

Balancing treatments

Analytics of lactational treatment

Example of published results

Analytics of dry-cow therapy (optimization)

New possibilities with automatic milking

Concluding remarks

Important in treatment decisions

Cure

Much knowledge available

Keywords “Cure rate” and “mastitis”

11 scientific papers in 2013

There is more than cure rates: Welfare

Clinical mastitis gives pain (e.g., Kemp et al. 2008 VetRec)

Behaviour is also affected (Medrano-Galarza et al., 2012 JDairySci)

So: Better cure is better welfare

Antibiotic resistance

Heavily in discussion

Resistance of mastitis pathogens

●Self-interest

●No increase seen (Hogan, IDF-factsheet)

Antibiotic resistance in humans

●Externality

●Dairy cattle has very minor contribution (Oliver et al., 2011)

●In the Netherlands (self) regulations

Economics

A farm is a business

Self interest

Costs of antibiotics vs benefits of higher cure rates or better prevention

Difficult task of herd manager

There is:

●Cure rate (welfare)

●Money

●Antibiotic resistance

Should be balanced

Not much knowledge on balancing

11 scientific papers in 2013

One with economics (related to transmission); Down et al., JDairySci

My presentation

Balancing treatments

Analytics of lactational treatment

Example of published results

Analytics of dry-cow therapy (optimization)

New possibilities with automatic milking

Concluding remarks

Lactational treatment

Much knowledge available on cure, e.g., reviews

● Barkema et al. 2006 JDairySci

● Roberson, 2012 VetClinFoodAnim

● Roy and Keefe, 2012 VetClinFoodAnim

● Suojala et al. 2013 JVetPharmTherap

Some papers on economics

● Steeneveld et al., 2011 JDairySci

● Halasa et al., 2012 JDairySci

● Down et al., 2013 JDairySci

These are averages

Make your own calculations

Straightforward spreadsheet

Two scenarios

Straightforward spreadsheet

Cure rates(input)

Straightforward spreadsheet

Calculation of proportion of cured cows

Straightforward spreadsheet

What if animals do not cure?

We have not really thought that out very

well

Farm specific

Role of advisor

Let’s add economics

Proportion of proportion

Let’s add economics

But we are missing input

Let’s add economics

That depends on cure and

lactation stage

Let’s add economics

Formula for the average nr of days

We are missing some price levels

Let’s add economics

Let’s make final

calculations

Let’s add economics

And finally, what are the costs?

What’s the point

Specific situation -> no papers available

Creation of a tool is not too difficult

Input needed

●Price levels – farmers know these

●Specific situation of the cow – farmers know these

●Cure rates – this is a problem

Cure rates might be available from farm records

●Large farms

●Available data

Evaluate previous assumptions

My presentation

Balancing treatments

Analytics of lactational treatment

Example of published results

Analytics of dry-cow therapy (optimization)

New possibilities with automatic milking

Concluding remarks

Treatment of clinical mastitis

Causal pathogen●Streptococci (40%), S. aureus (30%), E. coli (30%)

Parity Day in milk Calving interval Most recent SCC-value Repeated CM case yes/no Systematically ill yes/no 305-day milk production

●Wood curve to determine daily milk production at moment CM and remaining milk production during lactation

All stochastic

Steeneveld et al., 2011, JDairySci

Defined treatments

3-day intramammary antibiotic treatment (IMM3)

5-day intramammary antibiotic treatment (IMM5)

3-day intramammary antibiotic treatment + systemic antibiotic treatment (IMM3_S)

5-day intramammary antibiotic treatment

+ systemic antibiotic treatment (IMM5_S)

Immediately culling

Simulating follow-up of treatment

Treatment CM1

Bact. + clin. cure

Bact. + clin. cure

Dry-off quarter

Treatment CM2

No bact. cure,no clin. cure

No bact. cure,no clin. cure

No bact. cure,clin. cure

No bact. cure,clin. cure

End lactation

Dying

Culling

Culling

Culling

Extended treatment

End lactation

End lactation

End lactation

Culling

etc.

Cow-specific cure

Probability of bacteriological cure (%) defined

●for heifers, SCC<200, <60 DIM, no CM before, not systematically ill

IMM3 IMM5 IMM3_S IMM5_S

StreptococciS. aureusE. coli

704080

806085

806085

907095

Defined effects of cow factors• Older cow: 10%• SCC 200-500: 10%• SCC >500: 20%

• >60 DIM:10%

• Repeated case: 20%

• Systematically ill:20%

Average costs ($US)

758

749

789

266

318

310

238

296

284

238

296

284

216

283

253

Causal pathogen

Streptococci

S. aureus

E. coli

766295275270245Overall

CullingIMM5_SIMM3_SIMM5IMM3

478

578

569

577

732

1,026

207

230

255

266

301

351

192

216

230

244

284

332

158

189

200

216

253

307

Daily milk production (kg)

<20

20-25

25-30

30-35

35-40

>40

174

206

223

238

279

326

Original calculations in €; € 1 = $US 1.37

Least cost frontiers

20

30

40

50

60

70

80

90

100

130 150 170 190 210 230 250 270 290

Total costs (€)

Prob

abili

ty o

f cur

e (%

)

IMM3

IMM5

IMM3_S

IMM3_N_SIMM5_S

High cure cowE. coli cow

Average cowS. aureus cowLow cure cow

My presentation

Balancing treatments

Analytics of lactational treatment

Example of published results

Analytics of dry-cow therapy (optimization)

New possibilities with automatic milking

Concluding remarks

The ongoing debate on dry-cow therapy

Dry-cow therapy has two uses

●Curative

●Preventive

“We” do not want preventive use of antibiotics (anymore)

Which cows to dry-off with antibiotics?

Let’s create another spreadsheet

●Basically the same as the previous one

Probabilities from: Scherpenzeel et al., 2014,

in preparation

Very basic input

Probabilities depend on risk group

Costs with and without

DCT

Average costs drying-off per cow

Costs per cow

We’re also interested in amount of AB

Daily doses

Totals

Let’s optimize (linear programming)

Minimize total costs of mastitis By the numbers

of treated cows

Under constraints:- Nr of cows equal- Less AB than threshold

The constraint

What’s the point

Literature never fits the individual farmer’s situation

Probabilities can be based on farmers on data

Quite straightforward economic modelling

Evaluate previous assumptions

My presentation

Balancing treatments

Analytics of lactational treatment

Example of published results

Analytics of dry-cow therapy (optimization)

New possibilities with automatic milking

Concluding remarks

Automatic milking

On-line mastitis monitoring (Electrical conductivity, colour, SCC)

Great possibilities for therapy evaluation

But ….. Sensitivity & specificity of mastitis detection

Farmer’s confirmation is needed

●Time consuming

●Mostly negative

●Not the nicest of work

3.5 % of alerts are checked

Study on farmer’s handing of alerts

7 farmers, student checked all alerts

●60 % of alerts false positive

●3.5 % of alerts is checked by farmers

●checked alerts are often clinical cases

●74 % of clinical cases is missed

How bad is this?

Options

1. Maintain the “old” paradigm of treating clinical mastitis cases hold in automatic milking

….. and educate our farmers better to check….. or have better sensors (less false positives)

2. Use the daily sensor measurements differently -> detect acute severe mastitis, for mild mastitis look at chronicity, use on-farm culturing before treatment

Lot’s of questions, no answers (yet)

My presentation

Balancing treatments

Analytics of lactational treatment

Example of published results

Analytics of dry-cow therapy (optimization)

New possibilities with automatic milking

Concluding remarks

I did not present all knowledge

There is more knowledge out there

Mostly economics

Welfare ≈ cure rate

On-farm culture systems

● Lago et al., 2011, JDairySci

● Cameron et al., 2013, PrevVetMed

● Pinzón-Sánchez et al., 2011 JDairySci (Economics)

Use of antibiotics only through dry cow therapy

On-farm analyses

Use straightforward calculation tools

Use farm-specific input

●Price levels

●Incidences

●Cure rates

Use those farm data!!!

Operational use should be automated

There is a future for tailor-made treatment decisions

PS Example models and ppt are available

Thank you for your attention

@henkhogeveen

animal-health-management.blogspot.com

On-line courses on Veterinary Economics on:

www.elevatehealth.eu