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Mastitis Simon Kenyon. Udder anatomy Allometric Growth.

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Presentation on theme: "Mastitis Simon Kenyon. Udder anatomy Allometric Growth."— Presentation transcript:

1 Mastitis Simon Kenyon

2 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 $200-300/cow For herd-based worksheet: – inimpmq.html

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

16 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





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 N S RVR

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

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

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 BTSCCLS Few infected 600,0003.1 Many infected 600,0004.5

54 Milk loss vs linear score 54

55 Average LS versus average SCC

56 Bulk Tank Cell Counts Cow #Linear ScoreSCC 12.550,000 22.550,000 32.550,000 42.550,000 52.550,000 62.550,000 78.03,000,000 3.8540,000

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






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. 134192730313940525355576474789193104 Strep speciesXXx Staph aureusXXXXXXXx Coryne species XxX Staph speciesXXX No growthXX

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. 71555031572127947316775782368362172 QUARTER RRLFLRLFLRRR RFLR LFLR RFLF Strep uberisXXXXXXX Staph hyicusXX Staph epiXXX Staph aureusX No growthXXX

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 –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


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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