Mastitis

Question 1

Methods for diagnosis of sub-clinical mastitis

Answer 1

Conductivity (comparison over time and between quarters)
California milk test (detects SCC elevation, crude)
Individual cow somatic cell count

Question 2

Cut off value for clinical/sub-clinical mastitis?

Answer 2

200,000cells/ml

Question 3

Two key aims in mastitis control

Answer 3

Cure of current infections during dry period
Prevention of new intra-mammary infections

Question 4

Is fore-milking a legal requirement during milking?

Answer 4

Yes

Question 5

Appearance of milk in mastitis

Answer 5

Clots
Watery consistency
Colour change (grey/yellow/red)

Question 6

Common environmental pathogens in mastitis

Answer 6

Streptococcus uberis
Staphylococcus species (except S. aureus)
E. coli

Klebsiella
Pseudomonas
Proteus
Serratia
Gram +ve bacilli
Yeast
Protetheca

Question 7

Common contagious mastitis pathogens

Answer 7

Staphylococcus aureus
Streptococcus agalactiae
Streptococcus dysgalactiae
Mycoplasma spp.

Question 8

Features of contagious mastitis pathogens

Answer 8

Adaption to mammary gland
Can cause persistent infection
Spread between cows at milking

Question 9

Features of grade 1 (mild) mastitis

Answer 9

Milk changes only

Question 10

Features of grade 2 (moderate) mastitis

Answer 10

Milk changes
Inflammatory signs in quarter

Question 11

Features of grade 3 (severe) mastitis

Answer 11

Milk changes
Inflammatory signs in quarter
Systemic signs

Question 12

Challenges with mastitis treatment

Answer 12

Pathogen unknown at time of treatment
Vast majority of cases not treated by a vet
Cow and farm factors, not just antibiotic choice, affect chance of cure

Question 13

Principles of lactating cow therapy

Answer 13

Identify bacterial pathogen
Select suitable antibiotic
Treat for suitable length of time

Question 14

Ideal route of antibiotics in mastitis

Answer 14

Intramammary tubes

Question 15

Is sensitivity testing usually required for mastitis? Why/why not?

Answer 15

No, resistance is not usually a feature of mastitis infections
(85% of S. aureus isolates are sensitive to penicillin)

Question 16

Ideal duration of treatment with intramammary tubes in mastitis

Answer 16

5-8 days (extended = best chance of cure)

Question 17

Are intra-mammary tubes narrow or broad spectrum?

Answer 17

Narrow (penicillin only) or broad

Question 18

Which pathogens is dry cow therapy aimed at?

Answer 18

Gram positive, contagious

Question 19

Aim of dry cow therapy

Answer 19

Treat existing infections at end of lactation

Question 20

Factors to consider when deciding which cows to administer dry cow therapy to

Answer 20

Individual cow somatic cell count

High/low cell count herd?
Clinical mastitis history?
Bacteriology?

Question 21

When administering dry cow therapy, are internal teat sealants used in uninfected or infected cows, or both?

Answer 21

Both

Question 22

What is considered an ‘uninfected cow’ in dry cow therapy decision making?

Answer 22

<200,000cells/ml for last 3 recordings
No clinical mastitis in last 3 months

Question 23

Dry cow therapy for uninfected cows

Answer 23

Internal teat sealant only
No antibiotic

Question 24

Dry cow therapy for infected cows

Answer 24

Antibiotic with Gram +ve efficacy
Internal teat sealant

Question 25

What is considered an 'infected cow' in dry cow therapy decision making?

Answer 25

>200,000cells/ml in 1+ of last 3 recordings And/or Clinical mastitis in last 3 months

Question 26

What can internal teat sealants be mistake for at calving?

Answer 26

Mastitis (the residual seal)

Question 27

What is 'summer mastitis'?

Answer 27

Disease of dry cows and heifers, can occur in winter

Question 28

What transmits summer mastitis?

Answer 28

Hydrotea irritans (sheep head fly), many other things involved though

Question 29

Clinical signs of summer mastitis

Answer 29

Hot, hard, swollen, painful quarter Characteristic foul smell Cow often lame Often leads to abortion

Question 30

Prognosis of summer mastitis

Answer 30

Poor, quarter often lost

Question 31

Treatment of summer mastitis

Answer 31

Systemic penicillin Regular stripping May remove teat/cut vertically for drainage (Intramammary antibiotics useless)

Question 32

Control of summer mastitis

Answer 32

Fly avoidance/control Dry cow therapy Teat sealants (internal and external e.g. Stockholm tar/tape)

Question 33

Clinical signs of acute toxic mastitis

Answer 33

Down cow Cardiovascular shock signs (injected membranes, dehydrated, tachycardia, tachypnoea, cold extremities) Temperature increase then decrease to subnormal Not eating, drinking or milking Mammary changes (hot, swollen, watery secretion; cow may get sick before udder pathology is seen)

Question 34

Differentials for a down cow

Answer 34

Hypocalcaemia Dystocia Trauma (nerve injury) Metritis (Neurological/toxins)

Question 35

Treatment and prognosis for severe (grade 3) E. coli mastitis

Answer 35

Strip quarters Nursing (lifting if down) Systemic antibiotics NSAIDs Poor prognosis (~50% will die)

Question 36

Toxic mastitis/toxic shock syndrome treatment

Answer 36

Strip quarters Nursing (lifting if down) Systemic antibiotics NSAIDs IV fluid therapy Oral fluids (Aggers pump into rumen, circulation poor)

Question 37

What causes blue bag/black bag in ewes?

Answer 37

Severe mastitis (gangrenous) Due to toxins secreted by bacteria

Question 38

Symptoms of subclinical mastitis in the ewe

Answer 38

Increased somatic cell count Underperforming lambs (reduced milk yield)

Question 39

Indirect costs of mastitis in ewes

Answer 39

Reduced milk yield and quality (--> reduced lamb growth rates)

Question 40

Major causative bacteria for mastitis in the ewe

Answer 40

Staphylococcus aureus (contagious) Mannheimia haemolytica Escherichia coli (environment)

Question 41

Risk factors for mastitis in the ewe

Answer 41

Nutrition not meeting energy requirements Low BCS Poor hygiene at lambing time (dirty bedding, high stocking densities) Intramammary masses Teat lesions Udder conformation/teat positions Cross suckling Older ewes (>4 years) Maedi Visna Indoor lambing

Question 42

Treatment for mastitis in the ewe

Answer 42

Broad spectrum injectable antibiotics (Amoxicillin or oxytetracycline) for 5-7 days (Aim to save ewe, not udder)

Question 43

Two most important environmental mastitis pathogens

Answer 43

Streptococcus uberis E. coli

Question 44

Two most important contagious mastitis pathogens

Answer 44

Staphylococcus aureus Mycoplasma

Question 45

Which type of mastitis (environmental or contagious) is more common in the UK and why?

Answer 45

Environmental because the 5 point plan has been very effective at preventing contagious mastitis