Mastitis diagnosis and treatment in cattle Flashcards
Definition
- mostly caused by microorganisms
- rarely due to other cause
- inflammatory response
The infection
- mostly through the teat canal (ascending)
- mechanically through the skin of the udder
- Through blood and lymphatic spreading (viruses)
Economical impact of mastitis
a-Direct costs
• Discarded milk
• Medicine and Veterinary costs
b-Indirect costs
• Decreased milk price
• Milk production decrease in the remaining lactation due to elevated SCC
• Separation of the animals requires labour
• Cost of replacement heifers
• Culling
Classification of mammary gland infections based on pathological changes
- Galactophoritis:
gland cistern and teat cistern affection - Parenchyme mastitis:
minor cistern and ductus infection
3.Interstitial mastitis:
Inflammation in the alveoli and the interstitial tissue between the lobules
Clinical forms of mastitis
Clinical mastitis: 20%
Subclinical mastitis: 80%
Clinical forms of mastitis
Clinical mastitis
• Peracute
o Abnormal milk
o Abnormal mammary gland
o Sick cow (elevation in clinical baseline values, shock, exitus)
• Acute
o Abnormal milk
o Abnormal mammary gland manifest by inflammatory changes in the tissue such as redness, heat, pain, and swelling
• Subacute
o Abnormal milk only
Manifest by clots, flakes, and/or changes in the color and consistency of the milk secretion
• Chronic
o Chronic form with fibrosis, nodules and/or abscessation in the mammary gland
Clinical forms of mastitis
Subclinical mastitis:
• presence of inflammation with a normal appearing mammary gland and visibly normal
milk
Diagnosis of clinical and subclinical mastitis
clinical mastitis
Alterations in the milk + clinical signs of the animal
- After milking the first strips we perform test milking
- During this we observe the mammary gland
- In case of positivity separated milking + treatment
- E.Coli = Major cause of bovine clinical Mastitis
Diagnosis of clinical and subclinical mastitis
subclinical mastitis
• Somatic Cell Count (SCC)
o Uninfected→Neutrophils 1-11%, Macrophages 66-68 % (Surveillance) , Lymphocytes 1-2%, epithelial cells 2-5%
o Infected→Neutrophil 90% of total cells
o Leukocytes mean 80% of the somatic cells in uninfected quarters and 99% in uninfected quarters
→Str. agalactiae = Major cause of high SCC
• Milk lactose concentration decrease
o In damaged tissue, the secretory cells are unable to lactose biosynthesis
• Milk lactatate dehydrogenase concentration increase
o Due to cell damage LDH is released into the milk (secretory cells + leucocytes)
• Milk N-acetyl-b-D-glucosaminidase (NAGase) increase
o Due to epithelial cell damage exerts from cell lysosomes
• Acute phase proteins (haptoglobin, milk amyloid A)
o Due to increased permeability they cross the blood-milk barrier and occur in
milk
• Electrical conductivity (EC) of the milk increase
o Sodium Na and chloride Cl increases,
o Potassium K decreases
Diagnosis of clinical and subclinical mastitis
subclinical mastitis
somatic cell count determination
Milk with high SCC : Harmful to Hu + contains less casein + lower cheese yield
Direct
• Microscopic determination
• Automated electronic cell counters (flow citometry)
• Portable counters (DeLaval, Porta SCC)
o DeLaval Cell counter
▪ Propidium iodide→Stain nuclear DNA of somatic cells present in milk
▪ Measure with optical fluorescence readers→Proportional to SCC in milk
▪ Expensive
Indirect
• California Mastitest (CMT)
o Most reliable
o Detect viscosity change in milk
o Use of detergent + Bromocresol purple
o Importance in contagious pathogens mediated mastitis
Diagnosis of clinical and subclinical mastitis
subclinical mastitis
Evaluation of CMT
Negative
Evaulation: Fluid
SCC: < 250 000
±
Evaulation: Minor flakes
SCC: 300 000
\+
Evaulation: MAjor flakes
SCC: 900 000
\++
Evaulation: Increased density
SCC: 2 700 000
\+++
Evaulation: Jelly
SCC: 8 100 000Additional tools in the diagnostic of intramammary infections
- Bacteriological culture sampling
- PCR sampling
The sampling
• At the level of a quarter
• At the level of the cow
• At the level of the herd
Selection Criteria • Clinically affected animals before the therapy • At the time of drying off • After calving • animals with high SCC
Additional tools in the diagnostic of intramammary infections
Bacteriological culture sampling
• Easy culturing ( ! Mycoplasma spp.! )
1
1.A Bulk tank microbiology:
o raw milk quality testing
o IMI link: S aureus, Streptococcus agalactiae, and Mycoplasma spp.
▪ other pathogens: not only from the cow
o Standard Plate Count – SPC (Bactoscan, flow citometria)
1.B On-farm culturing method 1.C Classical laboratory culturing
Additional tools in the diagnostic of intramammary infections
Bacteriological culture sampling
Target numbers of bulk tank microbiology
Parameter / Goal [cfu/mL]
SSC – Somatic Cell count: < 150 000 SPC – Standard Plate Count: < 5 000 Thermoduric number (after cleaning the milking machine): < 175 Coliform: < 20 Pseudomonas: < 500 Streptococcus uberis: < 200 total Staphy. count: < 200 Staphylococcus aureus: < 50
Additional tools in the diagnostic of intramammary infections
Bacteriological culture sampling
Sampling guide for microbiological culture sampling
- Clean hand or glove
- Cleaning and drying of the teat
- Predipping and towel cleaning
- Milking first 4-6 strings
- Cleaning the teat end with an alcohol impregnated towel
- keeping the tube in 45o one string is milked into the tube
- identification of the tube
- 4 C° max. 72 h, freezer (coliform !!)
- Cooling bag, lab transport
! Staph. aureus !: at the end of the milking !!!!
Additional tools in the diagnostic of intramammary infections
- PCR – Polimerase Chain Reaction
• Advantage: within 4 hours
• Multiplex PCR and ‘real-time’ PCR assays
o Not able to distinguish between dead and alive organisms
Culture result [Cases %] (Mild / Moder. / Severe)
Streptococcus uberis [18,2 %] (62,3 / 33,8 / 3,9)
Escherichia coli [15,5 %] (45,8 / 36,6 / 17,6)
Staphylococcus aureus [7,3 %] (64,5 / 30,6 / 4,8)
Streptococcus dysgalactiae [7,2 %] (63,9 / 34,4 / 1,6)
Non-aureus staphylococci [5 %] (64,3 / 26,2 / 9,5)
Corynebacterium bovis Y [3 %] (72 / 28. / 0)
Yeast [2 %] (58,8 / 23,5 / 17,6)
No growth [19,9 %] (65,5 / 29,2 / 5,4)
Pharmacological therapy of mastitis
First step : Determination of severity of clinical mastitis ( mild / moderate / severe )
• Milk change only→Mild
• Abnormality in milk + udder parenchyma→Moderate
• Clinical mastitis + systemic involvement→Severe ( ++ coliform organisms assoc.)
o But also due to Streptococci, Arcanobacterium, pyogenes, yeasts…
Pharmacological therapy of mastitis
Cases occuring in early lactation
- The immunity of the cow is impaired
- There are less circulating neutrophils, harder to get into the udder
- Bacteria easier causing a septicaemia
Pharmacological therapy of mastitis
Answer of the immune system /1
- Release of immature neutrophils from bone marrow
- Less effective phagocytosis
- Extra-cellular release of ROS (Reactive Oxygen Species)
- Much more tissue damage
- Endotoxins are free in tissue to cause more inflammation
- Maybe toxic shock
Pharmacological therapy of mastitis
Answer of the immune system /2
Normal cow: • Phagocytosis • Internal killing by ROS • Endotoxins protected Peri-parturient cow • No successful phagocytosis • External killing by ROS • Endotoxins are free in tissue
Because all of these in the periparturient period toxic mastitis is more common
MASTITIS ACUTA GRAVIS (= Acute Mastitis) →Mastitis phlegmonosa
→Mastitis necroticans →Mastitis gangrenosa
Pharmacological therapy of mastitis
Antibiotic treatment
• First steps when choosing antibiotics:
o Lactating cow vs. Dry cow
o How many administrations ?
o Further medical therapy
o Initiation of treatment as early as EC change
• Empirical therapy
• Culture and Susceptibility Test ( CST )
o Identifies the infecting pathogens + provides specific data regarding drug efficacity
• Faster and more complete recurrence than self cure
• Decrease the chance of remission
• Decrease milk yield drop
Pharmacological therapy of mastitis
Antibiotic treatment / How to choose antibiotics?
- Sensitivity
- Bactericidal or bacteriostatic
- Withdrawal period
- Price
• The conus is partially inserted into the teat canal
• Close the end of the teat and massage up to the direction of the udder
• Post dip all four teats
• Record treatment
• Local treatment ( IMM )
• Parenteral treatment (IM)
• combination ( IMM + IM)
• “Aggressive” treatment: longer duration + higher dose
For parenteral treatment only those antibiotics, which reach sufficient concentration in the alveoli
Pharmacological therapy of mastitis
Antibiotic treatment / How to choose antibiotics?
If at day 4 still no progression towards cure :
- Change antibiotic
- Preferably on the basis of bacteriology and sensitivity
- Never treat longer than 7 days
- High likelihood of a yeast: check for it
- Cull or dry off quarter
Pharmacological therapy of mastitis
Antibiotic treatment / How to choose antibiotics?
Effectiveness of treatment:
- Bacteriological elimination → < 400,000 SSC ↓
- Up to 4-6 weeks
- No cure: subclinical mastitis (SCC remains high)
