FAC32: Mastitis Introduction

Question 1

What goes into the cost of a case of mastitis?

Answer 1

• Milk discarded after treatment
• Reduction in milk yield
• Reduction in milk quality (SCC and Bactoscan)
• Antibiotic treatment
• Farm labour costs
• Veterinary costs
• Culling rates and/or deaths

Question 2

What are the natural defences against mastitis?

Answer 2

Teat End Defences

• Teat skin
• Teat canal barrier
• Teat canal closure (takes up to 30 mins post-milking)
• Genetic factors

Intrinsic defence Mechanisms

• Lactoferrin (dry period)
• Lactoperoxidase

Inducible Defence Mechanisms

• Inflammatory Response

Influence of Management

Question 3

How do bacteria enter an udder?

Answer 3

Grown in - contagious pathogens

Forced/propelled in via milking machine, antibiotic tube, capillary action, surgical/cannula

Question 4

What are the contagious pathogens that cause mastitis?

Answer 4

Staph aureus

Strep agalactiae

STrep dysgalactiae

Mycoplasma

C. bovis

Question 5

What are the environmental pathogens that cause mastitis?

Answer 5

E. coli

Strep uberis

Pseudomonas aeruinosa

Bacillus cereus

Teasts and moulds

Question 6

Why is Staph aureus so difficult to treat successfully?

Answer 6

• Poor antibiotic penetration
• Production of B-lactamase
• Persistence of bacteria within the cell
• Bacteria insensitive to antibiotic therapy
• Insufficient duration of therapy

Question 7

When do most cows get mastitis from E. coli?

Answer 7

Infection during dry period

Question 8

Why is pathognomonic of mastitis caused by mycoplasma?

Answer 8

Hard udder with water/sandy/thick secretions

Question 9

What is mastitis from strep uberis associated with?

Answer 9

Straw yards and infection during the dry period

Question 10

How do you determine clinical mastitis? subclincial?

Answer 10

Clinical - milk, udder, cow

Subclinical - Somatic cell count and bacteria

Question 11

What are the effects of mastitis on milk constituents?

Answer 11

Decrease

• Protein (including casein)
• Lactose
• Butterfat
• Calcium, phosphorous
• Stability and keeping quality
• Taste deteriorates

Increase

• RBC
• WBC
• Bacteria
• Plasmin (degrades casein)
• Lipase (degrades fat)
• Sodium, chloride, pH (make bitter)

Question 12

How do you detect mastitis?

Answer 12

Clinical Mastitis:

1. Foremilking
2. Palpation of udder
3. Systemic illness in cow
4. In-line mastitis detectors
5. Milk sock/filter

Sub-clinical Mastitis:

1. SCC
2. Bactoscan
3. Increases in milk conductivity
4. Measurement of acute phase proteins in milk