Mastitis

Question 1

Define mastitis

Answer 1

Inflammation of the mammary gland for any reason

Question 2

List causes of mastitis

Answer 2

• Bacterial
• Viruses
• Fungi
• Physical e.g. trauma
• Toxins
• Neoplasi

Question 3

Compare acute vs chronic disease

Answer 3

• Acute: sudden onset, often severe signs of disease

- Chronic: disease persists for a prolonged period of time, usually subclinical or mild signs of disease

Question 4

What are the 2 classifications of mastitis?

Answer 4

• Contagious

- Environmental

Question 5

Define contagious mastitis

Answer 5

Spread from cow to cow

Question 6

Define environmental mastitis

Answer 6

Pathogen lives in environment and causes infection from environment to cow

Question 7

What is the main method of transmission in contagious mastitis?

Answer 7

Milking process, infected cows are primary reservoir of infection

Question 8

What are the main bacteria that cause contagious mastitis?

Answer 8

• Staphylococcus aureas

- Streptococcus agalactiae and dysgalactiae

Question 9

Describe the clinical signs of contagious mastitis

Answer 9

• Mild-moderate in severity
• Often chronic infection
• Associated with high somatic cell counts
• Infected quarters intermittently shed large numbers of bacteria into milk often without clinical signs

Question 10

Describe Staphylococcus aureus in mastitis

Answer 10

• Gram +ve cocci
• Chronic, mild or subclinical mastitis
• High somatic cell counts
• Occasionally causes gangrenous mastitis

Question 11

Describe Streptococcus agalactiae in mastitis

Answer 11

• Gram +ve cocci
• Highly conagious
• Obligate udder pathogen living in gland
• Now rare, once removed from herd will not return (only found in udder)
• High somatic cel count

Question 12

Describe Streptococcus dysgalactiae in mastitis

Answer 12

• Gram +ve cocci

- Usually considered contagious but can survive in environment

Question 13

Outline transmission of pathogens causing mastitis during milking

Answer 13

• Infected cow in
• Contagious milk contaminates milker’s hand or equipment
• Infects sbsequent animals
• Milking most important point of control for contagious mamstitis

Question 14

List bacteria important in environmental mastitis

Answer 14

• E. coli
• Streptococcus uberis
• Streptococcus dysgalactiae

Question 15

Describe environmental mastitis

Answer 15

• Infection acquireed directly following contact with pathogens in environment
• Environment is primary reservoir
• Most cases milk-moderate, less likely to eastblich sub-clinical disease (except S. uberis)

Question 16

Describe E. coli in mastitis

Answer 16

• Gram -ve bacilli
• Minority of cases by E. coli are acute and severe often around calving
• chronic infection rare

Question 17

Describe Streptococcus uberis in mastitis

Answer 17

• Gram +ve coccus
• Most common cause of clinical mastitis in UK
• Cows on straw yards
• Chronic infection, high somatic cell count

Question 18

Outline how infection with environmental mastitis occurs

Answer 18

• Contamination before milking

- Pathogens into udder during milking when teats open

Question 19

Compare clinical vs sub-clinical disease

Answer 19

• Clinical: identified based on clinical signs
• Sub-clinical: disease present but no visual signs, additional tests required for diagnosis, presents greater transmission risk

Question 20

List clinical signs of mastitis

Answer 20

• Changes to milk
• Inflammation of the gland
• Systemic illness

Question 21

Describe some changes to milk that occur in mastitis

Answer 21

• Clots, lumps, strings present
• Changes in colour (off whites/yollows/reds)
• Changes in consistency
• Smell

Question 22

Describe the appearance of an inflamed mammary gland

Answer 22

• Swollen
• Hot
• Hard
• Painful
• Possibly necrosis of the qaurter

Question 23

Describe teh appearance of systemic illness with mastitis

Answer 23

• Varying severity
• Reduced milk yield
• Pyrexia
• Anorexia
• Recumbency
• Tachycardia
• Tachypnoea
• Collapse
• Death

Question 24

Describe a grade 1 mastitis

Answer 24

• Mild
• Changes to milk only
• Clots, change of colour, change of consistency

Question 25

Describe a grade 2 mastitis

Answer 25

- Moderate - changes to udder - Heat, pain, swelling

Question 26

Describe a grade 3 mastitis

Answer 26

- Changes to the cow (sick cow) | - Pyrexia, anorexia, tachycardia, tachypnoea plus others

Question 27

What are the points in the 5 point plan for mastitis control?

Answer 27

- Post0milking disinfection - Treat clinical cases promptly - Dry cow therapy for all animals - Cull chronically infected animals - Milking machine maintenance

Question 28

Describe the post-milking teat disinfection in the control of mastitis

Answer 28

- Anythign on teat from milking killed - Immediately after unit removal - Dips or sprays - Cover all sides on all teats - Many disinfections - For control of contagious mastitis

Question 29

Describe the treatment of clinical mastitis

Answer 29

- Identify and treat rapidly - Aseptic infusion of intra-mammary antibiotic tubes most common - Wide range of products - Injectable antibiotics also used

Question 30

Describe dry cow therapy in the control of mastitis

Answer 30

- Cures existing infections, prevents new infections in dry period - Cure existing: long acting antibiotic tubes infused at drying off - Prevent new: antibiotic dry cow tubes or internal teat sealant - Aim to use more non-antibiotic prevention

Question 31

Describe culling of chronically infected cows in the control of mastitis

Answer 31

- Represent major reservoir | - Culling from herd prevents contagious spread

Question 32

Describe milking machine maintenance in the control of mastitis

Answer 32

- Act as fomite for transmission of contagious - Vacuum instabilities can drive pathogens into quarter - Regular maintenance important

Question 33

How can mastitis in the herd be monitored?

Answer 33

- Maintain and complete accurate records - Sample proportion of cases for bacteriological analysis to identify pathogen causing most disease on farm - Different methods for clinical and subclinical

Question 34

Describe the monitoring of sub-clinical mastitis

Answer 34

- Usually contagious pathogens - Infection does lead to to elevated somatic cell count - Large number infected BMSCC wll rise for example

Question 35

Describe monitoring of sub-clinical mastitis using bulk milk somatic cell count

Answer 35

- Guide to levels of subclinical in herd | - To be legal in europe, 3 month geometric mean of BMSCC of a dairy herd must be before 400,000cells/ml

Question 36

Describe the monitoring of sub-clinical mastitis using indvidual cow somatic cell count

Answer 36

- Samples from individaul cows collected regularly usually montly) analysed - National milk records - Problem cows identified and managed appropriately

Question 37

Describe the California Milk test in the monitoring of subclinical mastitis

Answer 37

- Binds to somatic cells, not bacteria i.e. not a measure for infection - Simple, cheap, cow side indirect measure of SCC - Identify problem cows and infected quarters - Milk mixed with coloured detergent, reacts with cells present, degree of thickenign directly proportional to number fo cells present (i.e. thicker = more cells)

Question 38

Outline the control of environmental mastitis

Answer 38

- Ensure environment is clean | - Pre-milking disinfection

Question 39

Explain how pre-milking disinfection helps control environmental mastitis

Answer 39

- Rapid bacterial kill time - Applied, leave for 60s, dry with clean towel - Removes pathogens before milking so cannot get into udder when teats open for milking - If very dirty need to thoroughly clean - Cannot use post-dips as pre-dips

Question 40

What is another potential cause of alumpy udder in pigs?

Answer 40

Actinomyces (chronic mastitis, also causes lumpy jaw)