Mastitis: Intro and Immunity Flashcards
- What is mastitis?
- What are is the difference between clinical and subclinical?
- What do grade 1-3/A/C mean?
- Mastitis is inflammation of the mammary gland
- Clinical- visible changes in milk, udder and cow. Subclin- infection but no visivle or clinical signs, change in SCC, quality/yield
- Grade 1- mild changes in milk
Grade 2A- acute, changes in milk, udder hot, painful
Grade 2C- chronic, changes in milk, udder hard and lumpy
Grade 3- Changes in milk, udder, cow sick
What assists with infection of mastitis?
- Viable pathogens on teat end- transfered, skin integrity
- Bypass sphincter and streak canal- damaged, vaccum assisted
- Spread into udder- damaged defences, vaccum assisted
What are the differetn environmental and contagious mastitis pathogens?
Environmental-
E.coli, Strep uberis, Klebsiella
Contagious-
Strep uberis, Strep agalactiae, strep dysgalactiae, staph aureus, Coagulase neg staphs, mycoplasma
What are the consequences of mastitis infection?
- Clear the infection
- Not clear the infection:
Chronic infection- spread
Permanent damage- reduce milk yield
Death- toxaemia
How does SCC affect milk?
Rancid off flavour occurs a lot faster
What are the different innate immmunites of the mammary gland?
- Teat skin
- Teat canal
- Resident leucocytes
- Antimicrobial substances in milk
- What features of teat skin help immunnity of mammary gland?
- What are the problems?
- How can the problems be resolved?
- Prevent colonisation of teat skin with bacteria- stratified squamous epithelium plus bacteriostatic fatty acids
- Some bacteria ubiquitous, comprimised by trauma, bruising, teat lesions, deals with milking machines
- Post milking dips, treat teat lesions, good milking machine function
- When can bacteria enter the teat canal?
- What in the teat canal can trap bacteria?
- What forms a seal when dried off?
- What can cause teat canal damage?
- 20-30 minutes after milking whilst the teat sphincter is relaxed
- Keratin lining traps bacteria and is continuously sloughing
- Keratin plug forms seal over teat end when cow is dried off
- Milking machines, external trauma, teat lesions, teat cannulas
What does this image show?
What causes this?
Teat end hyperkeratosis
Top- rough ring
Bottom- very rough ring
Causes:
* Excessive milking vaccums
* Faulty pulsations
* Liner types
* Teat shape
Protection- genetics, machine function, loafing, teat sealants
What are the resident leucocytes of the mammary gland?
Mainly macrophages, neutrophils, T lymphocytes
Phagocytosis
Trigger the acquired immune with pro-inflammatory mediators and antigen presentation
What are the different antimicrobial substances in milk?
- Lactoferrin iron chelating protein produced by epithelial cells/leucocytes- inhibits growth of pathogens requiring iron (E.coli)- highest in dry period
- Lactoperoxidase- bacteriostatic agent
- Lysozyme- bacteriocidal protein
- Free complement- aid in opsonisation of bacteria
What cells and proteins are involved in the acquired immune system of the mammary gland?
- Invasion of circulating neutrophils and IgG2 antibodies
- B and T lymphocytes
- Inflammatory cytokines
What are the different functions of neutrophils?
- Margination
- Migration
- Phagocytosis
- Respiratory burst
- Degranulation
What are the functions of B lymphocytes?
- Circulate through lymphatic system
- Exposed to antigens in tissue fluids
- Initial response produce IgM, IgG1
- Repeated exposure produce IgG2 antibodies
- IgG2 circulate and enter inflammed udder aiding opsonisation by neutrophils
- Present antigen to T lymphocytes
What are the two functions of T lymphocytes?
- T helper cells- production of cytokines following antigen recognition stimulates immune response
- T cytotoxic cells- eliminate host cells invaded by pathogens