Winter Meeting 2009 Strep uberis Staph aureus Coag neg staphs - - PowerPoint PPT Presentation

Winter Meeting 2009

Strep uberis

Staph aureus

Coag neg staphs

Subclinical mastitis

 What is it?  What is the cost of subclinical mastitis?  How do we control it? New strategy to control it.

Current trend in cell counts in New Zealand

 This year Fonterra rolling average was 200-300,000!  Increasing-why? 1.

Lack of banding incentives

2.

Effect of poor repro and growing dairy nos

What is subclinical mastitis

 Somatic cell count  Individual and bulk  Cows response to infection-types of infection

Golden Bay 2007-9. n=847. Subclinical only

5 10 15 20 25 30 35 40 CNS Staph aureus Strep uberis No Growth SU/CNS E.coli Series1

Cost of high cell counts and mastitis

 Estimates 2% production per 100,000  $20-30/cow moving from 212000 to 150000-achievable  Components of saving: 1.

Mainly cost saving through production

2.

Approx $200 clinical case

3.

Culling

Cost Benefit analysis-production

No Cows Prod/cow kg Payout $/kg Total $ Value of 2% 300 320 4.55 436800

$8736

Targets

 Subclinical targets- how to measure  BMSCC –what is achievable on your farm?  Individual cell counts –thresholds  Herd tests data 4 needed-limitations of less

Targets for Mastitis

CLINICAL Clinical cases over dry period < 2% Clinical cases over calving and first 6 weeks of lactation < 6% Clinical cases per month for rest of lactation < 2% Total percentage of clinical cases over whole lactation < 10%

SUB-CLINICAL Percentage of pickups above 250,000 for the whole season < 2% Individual S.C.C. above 150,000 at any herd test < 15% Average B.S.C.C. for season 200,000 Maximum B.S.C.C. in early lactation 250,000 Maximum B.S.C.C. before dry off 250,000

Change in nos of cows in cell count groups-herd test data

Date: Cell count ranges 4th last 3rd last 2nd last latest 0-149 84% 73% 57% 57% 150-249 4% 11% 18% 17% 250-499 5% 9% 11% 14% 500+ 7% 8% 14% 12% Total cows 424 422 415 355 Est Bulk Tank 177 209 331 258

Change in nos of cows in cell count groups- herd test data

Strategy to control subclinical infection

 Five point plan;  Targeted culling  Prompt treatment and detection  Teat disinfection  Milking machine maintenance and milking

management

 Dry cow therapy

Targeted Culling and treatment

 Use bacteriology of high cell count cows to improve in

this area;

 RMT positive at day 5/6  Herd test data

Results

 New research has shown value of treating different

infections in different circumstances

 Strep uberis  CNS  Staph aureus

Treatment action relates to prevalence and type of pathogen identified.

Prevalence and rate of new infection

 Aim of bacty investigation is to reduce the prevalence

and rate of spread of subclinical infection

 Rate of spread can be alarming

Group 1 4 times over 500000 Dry off 76 <1 week post calving 35 mean calving + 5mths21/01/2007 82 mean calving + 7 mths17/03/2007 82 Group 2 4 times under 200000 Dry off <1 week post calving 12 mean calving + 5mths21/01/2007 35 mean calving + 7 mths17/03/2007 47

Cumulative Prevalence (%) of cows yielding Staph aureus .Demonstrates how prevalence can alter strategy by influencing new infection rate.

Other management options

 Dry off  Separate herds

Again following bacteriology