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Mastitis Simon Kenyon.

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Presentation on theme: "Mastitis Simon Kenyon."— Presentation transcript:

1 Mastitis Simon Kenyon

2 Udder anatomy

3 Udder anatomy

4 Allometric Growth


6 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 $ /cow For herd-based worksheet:

7 Mastitis Classification
Mastitis caused by a wide variety of microbial agents Classified as: Clinical Subclinical Also classified as: Contagious Environmental





12 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

13 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

14 Economic Impact

15 Contagious vs Environmental
Strep. agalactiae Staph. aureus Corynebacterium bovis Mycoplasma Environmental Environmental Streps Strep uberis Strep. dysgalactiae Coliforms E.coli Klebsiella

16 Contagious vs Environmental
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





21 Pulsation System Graph
0.6 sec 0.4 sec


23 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


25 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

26 Teat ends Vacuum level Liner tension Liner condition Overmilking
Response to mechanical stress or irritation of the teat end is hyperkeratosis


28 S N R VR

29 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

30 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

31 Hyperkeratosis and Disinfection
Score Treatment Ave. SCC Significance Low Disinfected Non-treated 126,000 178,000 NS Medium 142,000 306,000 P <.01 High 157,000 412,000 Gleeson et al. 2004

32 Risk of New Infections Dry Milking Calving Environmental Streps
Contagious mastitis Coliforms Str. uberis Str. dysgalactiae Dry Milking Calving

33 Dry cows








41 Back Flush System

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

43 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


45 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






51 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

52 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!

53 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 BTSCC BTSCC LS Few infected 600,000 3.1 Many infected 4.5

54 Milk loss vs linear score

55 Average LS versus average SCC

56 Bulk Tank Cell Counts Cow # Linear Score SCC 1 2.5 50,000 2 3 4 5 6 7
8.0 3,000,000 3.8 540,000 If btscc was at 540,000 because all cows were at 540,000 then SCR would be 5.8

57 Individual cow SCCs for two herds with same herd average SCC






63 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

64 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

65 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 Staph aureus Coryne species Staph species No growth

66 Troubleshooting contagious mastitis
Liner squawks Post-dip coverage Dip NMC tested Appropriate dry cow treatment Identify individual Staph. aureus cows

67 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 RF Strep uberis X Staph hyicus Staph epi Staph aureus No growth

68 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


70 Farm monitoring No. of clinicals Bulk tank SCC reports
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 Surveys show wide range from 2/100 cows to over 100/100 cows/year


72 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?


74 Udder edema

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