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MastitisSimon Kenyon

Udder anatomy

Udder anatomy

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Allometric Growth

Economic Impact

• 40% of morbidity on dairy farms• Most costly cattle disease in the US• Estimated cost to the industry greater

than 2 billion dollars/yr• Estimated to cost $200-300/cow• For herd-based worksheet:

– http://www.uwex.edu/milkquality/Economics/finimpmq.html

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Mastitis Classification

• Mastitis caused by a wide variety of microbial agents

• Classified as:– Clinical– Subclinical

• Also classified as:– Contagious– Environmental

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Subclinical mastitis

• No visible changes in the milk• Elevated somatic cell counts

– Normal milk has less than 200,000 SCC/ml• Most common form of mastitis• National Mastitis Council estimate:

– 15-40 cases of subclinical mastitis for every 1 case of clinical mastitis

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Economic Impact

• 70% of loss due to decreased production• Remaining losses due to:

– Lost premiums– Treatment costs– Discarded milk– Death/Culling– Veterinary expenses– Cost of violative antibiotic residues

Economic Impact

Contagious vs Environmental

• Contagious– Strep. agalactiae– Staph. aureus– Corynebacterium

bovis– Mycoplasma

• Environmental– Environmental Streps

• Strep uberis • Strep. dysgalactiae

– Coliforms• E.coli• Klebsiella

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Contagious vs Environmental

• Contagious– Transmitted during

milking

• Control– Parlor hygiene – Machine function– Post-dip– Dry cow Rx

• Environmental– Transmitted in the

environment or during milking

• Control– Cow environment– Udder prep.– Health of teat end– Dry cow Rx

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Pulsation System Graph

0.6 sec 0.4 sec

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Contagious Mastitis• Spread from cow to cow.• Bacteria must live in

udder tissue or on skin• Organisms are

transferred during the milking process

• Major impact is as cause of subclinical mastitis

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Environmental Mastitis

• Organisms spread from environment to cow

• Spread may occur between milkings or during milking

• Include some of the common causes of clinical mastitis as well as subclinical infections

Teat ends

• Vacuum level• Liner tension• Liner condition• Overmilking

Response to mechanical stress or irritation of the teat end is hyperkeratosis

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N S

R VR

Risk factors for hyperkeratosis

• Long pointed teats• Slow milking• High producing cows• Stage of lactation• Parity• Weather conditions• Chemical irritation• Cluster removal time

Mein et al. 2001

Recommendations• Particular attention to cleaning teat ends• D (massage) phase at least 250 ms• Cluster removal when milk flow reaches 1 lb/min• Teat skin in good condition• Follow recommendations:

– Vacuum levels– Liner bore– Liner length and tension– Liner replacement schedules

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Hyperkeratosis and Disinfection

Low Disinfected

Non-treated

126,000

178,000

NS

NS

Medium Disinfected

Non-treated

142,000

306,000

NS

P <.01

High Disinfected

Non-treated

157,000

412,000

NS

P <.01

HyperkeratosisScore Treatment Ave. SCC Significance

Gleeson et al. 2004

Risk of New Infections

Calving

Dry Milking

Str. uberisStr. dysgalactiae

Coliforms

Contagious mastitis

Environmental Streps

Dry cows

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Back Flush System

Mastitis Diagnosis

• Physical examination• DHIA reports/SCC reports• Strip Cup• CMT• Milk conductivity• Bacterial culture• On farm observation

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Clinical Mastitis

• M1 - Changes in the milk (Clots, flakes, clumps, or discoloration)

• M2 – Changes in the milk + udder swelling, heat or pain

• M3 – Changes in the milk + udder changes + systemic illness

Mastitis Treatment

• Treat clinicals during lactation• Treat subclinicals at dry off• Dry treat every quarter of every cow• Coliform infections – supportive therapy

+/- antibiotics• ALWAYS CORRECT THE

MANAGEMENT FLAW

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Antibiotic Choice

• Use proprietary intramammary products as primary treatment

• Systemic antibiotics may be used as adjunct treatment (ampicillin or penicillin)

• Avoid aminoglycosides e.g gentamycin (meat withdrawal 6 –18 months)

• Mycotil milk withdrawal is 15 – 21 days• Naxcel/Excenel systemically does not

reach therapeutic levels in the udder

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Lactating Cow Intramammary Antibiotic Preparations

• Amoxicillin trihydrate (Amoximast)• Sodium cloxacillin (Dariclox)• Hetacillin potassium (Hetacin-K)• Penicillin and Novobiocin (Albacillin)• Cephaprin sodium (Today, Cefalak)+

• Ceftiofur hydrochloride(*Spectramast LC)

Common antibiotics for dry-off treatment

• Benzathine Cloxacillin (Dryclox, Orbenin Dry Cow)• Cephaprin benzathine (Tomorrow, Cefadry) +

• Penicillin and Novobiocin (Albadry Plus)• Penicillin and Streptomycin (*Quartermaster)• Ceftiofur hydrochloride (*Spectramast DC)

Herd Investigation

• Examine records• Individual cow somatic cell counts• Samples for bacteriology

– Individual cow samples– Quarter samples

• Evaluate parlor procedures• Milking machine evaluation• Look at the dry cows!

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Somatic Cell Counts

• No infection in quarter: 50 – 100,000 SCC• Infected quarters: SCC 250,000+• In small herds a few cows may be

responsible for high percent of BTSCC• Compare Linear Score and actual

BTSCCBTSCC LS

Few infected

600,000 3.1

Many infected

600,000 4.5

Milk loss vs linear score

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Average LS versus average SCC

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Bulk Tank Cell Counts

Cow # Linear Score SCC1 2.5 50,0002 2.5 50,0003 2.5 50,0004 2.5 50,0005 2.5 50,0006 2.5 50,0007 8.0 3,000,000

3.8 540,000

Individual cow SCCs for two herds with same herd average SCC

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Culturing

• Individual quarter samples• CMT positive quarter samples• 16 samples from 16 CMT positive cows• Sample as they come through the parlor• Do not specially select problem clinical

cases

Interpretation of Culture Results

• Strep. agalactiae – always significant• Staph. aureus – underestimates number

of infected cows• If 3 or more Staph. aureus - culture the

whole herd• Environmental Streps. – easy to grow,

often significant• Coliforms – occasional chronic cows

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Culture of CMT positive quarters

ANIMAL No. 1 3 4 19 27 30 31 39 40 52 53 55 57 64 74 78 91 93 104

Strep species X X x

Staph aureus X X X X X X X x

Coryne species

X x X

Staph species X X X

No growth X X

Troubleshooting contagious mastitis

• Liner squawks• Post-dip coverage• Dip NMC tested• Appropriate dry cow treatment• Identify individual Staph. aureus cows

Culture of CMT positive quarters

ANIMAL No. 71 55 50 315 72 12 79 47 316 77 57 82 36 83 62 172

QUARTER RR LF LR LF LR RR RR RF LR LR LF LR LR LR RF LF

Strep uberis X X X X X X X

Staph hyicus X X

Staph epi X X X

Staph aureus X

No growth X X X

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Troubleshooting environmentals

• Check environment• Visit the dry cow lot• Kill time for pre-dip• Teats and base of udder dry?• Time attachment delay• Time how long it takes to milk cows• Examine teat ends• Time the detachers

Farm monitoring

• No. of clinicals– 3 cases/100 cows per month

• Count mastitis tubes used– 20 cases/100 cows per year

• Bulk tank SCC reports• DHIA linear scores and hot sheet• Bulk tank cultures

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Bulk Tank Cultures

• Good for Strep. agalactiae• Mycoplasma surveillance• Not good for Staph. aureus

– all herds affected– Variable shedding– Does not distinguish high/low herds

• Environmental bacteria – origin?

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Udder edema