Mastitis

Question 1

What are the three main defining factors of mastitis presentation?

Answer 1

Clinical or subclinical - Dry or lactating period - Contagious or environmental

Question 2

What is the average prevalence of mastitis in the UK?

Answer 2

35 cases/100 cows/year

Question 3

What loses does mastitis cause?

Answer 3

Loss of actual and potential milk - Possible residues in milk from treatment - High somatic cell count (SCC)

Question 4

What happens in a Grade 1 mastitis case?

Answer 4

Milk change only, decreased yield

Question 5

What happens in a Grade 2 mastitis case?

Answer 5

Acute - Milk changes, changes in udder, decreased yield

Chronic - Persistent changes same as above

Question 6

What happens in a Grade 3 mastitis case?

Answer 6

Same as grade 2 (milk and udder changes) but a systemically sick cow

Question 7

How do you detect a subclinical case of mastitis?

Answer 7

Increased SCC - positive in California Milk Test - Reduced yield

Question 8

Which bacteria are involved in chronic/subclinical mastitis?

Answer 8

Staph. aureus - Staph. uberis - Staph. agalactiae - Corynebacterium bovis

Question 9

Why should mastitis cases almost always have a bacterial culture test?

Answer 9

Never tell on clinical signs what causes it - Allows selection of right antibiotics

Question 10

Where do contagious mastitis causing bacteria tend to live? What sort of mastitis do they cause?

Answer 10

In the udder and teat skin - Cause subclinical infection

Question 11

What are the main contagious pathogens that cause mastitis?

Answer 11

Streptococcus agalactiae - Strep. dysgalacitae - Staph. aureus - Strep. uberis

Question 12

Where do environmental mastitis causing pathogens come from? Why?

Answer 12

Environment - Poor farm hygiene

Question 13

What sort of mastitis do environmental pathogens cause?

Answer 13

Very serious acute

Question 14

What are the environmental mastitis causing bacteria?

Answer 14

E coli - Strep. uberis - Klebsiella - Coliforms - Bacillus cereus

Question 15

What does bulk tank SCC indicate?

Answer 15

Prevalence of subclinical mastitis in a herd

Question 16

What is the target for Bulk Milk Somatic Cell Count (BMSCC)? When would intervention be needed? When would a farm be penalised? When can it not be sent for human consumption?

Answer 16

200,000 - >400,000

Question 17

Outline the 5 point plan for treating mastitis on a farm

Answer 17

1) Prompt detection and treatment of clinical cases
2) Post milking teat dip
3) Dry cow therapy
4) Cull persistent offenders
5) Regular servicing and maintenance of milking machine

Question 18

What is classes as a persistent offender of mastitis?

Answer 18

3 or more cases during one lactation

Question 19

What is the most common entry of organisms into the mammary glands? What are the other two sites of entry?

Answer 19

Galactogenic (via teat canal) - Haematogenous - Percutaneous

Question 20

What are the three barriers of the teat canal that prevent entry of infection?

Answer 20

Smooth muscle sphincter - Keratin from epithelium - Furstenburg’s Rosette

Question 21

How does Keratin from epithelium stop infection of teat canal?

Answer 21

Contains cationic proteins the lyse gram +ve bacteria (Streps and Staphs) - Contains fatty acids which act as bacteriostatic and bactericidal

Question 22

How does the Furstenberg’s Rosette stop infection of the teat canal?

Answer 22

Prevents physical entry - Fatty acids and cationic proteins - Subepithelial plasma cells which produce immunoglobulin

Question 23

What humoral factors resist infection of the mammary glands? How?

Answer 23

Lactoferin (binds iron making it unavailable for bacteria) - Defensins (antmicrobial peptides) - Immunoglobulins (IgG,IgM and IgA)

Question 24

What is the process of subclinical mastitis?

Answer 24

Initial flare up - fibrosis repair - further flare ups - prgressive fibrosis

Question 25

Why are neutrophils less efficient in milk?

Answer 25

Large amount of protein reduces phagocytosis and killing

Question 26

Describe what the Lancefield grouping of mastitis bacteria is

Answer 26

Group A -least pathogenic / Group B - moderately pathogenic / Group C - most pathogenic