Bovine Udder Health 1

Question 1

1. Mastitis as a production-related disease.
2. Mastitis as an endemic disease.

Answer 1

1. Production related disease – have bred for production qualities for too long and have neglected udder functionality.
2. It is an endemic disease, seen on every farm – 40-70 cases / 100 cows / year.

Question 2

1. Mastitis as a welfare issue.
2. Mastitis as a public health issue.

Answer 2

1. Welfare issue – painful, prevention important, identification by stockmen / milkers important, adequate and appropriate treatment when necessary.
2. Public health issue w/ effect on milk shelf life / taste, affects farmers pay, zoonoses in raw milk, antimicrobial use/resistance may lead to transfer of resistance to consumer in area of blanket use. Needs to implement control plans to reduce treatments needed.

Question 3

Define mastitis.

Answer 3

Inflammation of the udder.
Intramammary infection (IMI).
– Pathogen infection of the udder with or without clinical signs.

Question 3

1. Mastitis as an economic issue.
2. Mastitis and food sustainability.

Answer 3

1. £200M cost in UK dairy industry.
   – loss of milk due to discard during treatment, acute and chronic reduction in production, across all quarters.
   – Treatment / vet.
   – Labour.
   – Culling.
2. • We need more food w/ reduced environmental impact.
     - Carbon footprint of dairy may be lower than alternatives.
     - Wastage.
     – 50% reduction in mastitis cases = milk for 50 small towns.
     – 50% reduction in cows culled for mastitis = 250 extra 200 cow dairy herds.

Question 4

1. Classification of mastitis by clinical presentation.
2. Classification of mastitis by epidemiological presentation.

Answer 4

1. • Clinical – inflammation w/ changes in udder / milk / systemically.
     - Subclinical – inflammation w/o changes in udder / milk.
2. • Where.
     – Contagious = cow to cow spread.
     – Environmental = environment to cow.
     - When.
     – Dry period origin.
     – Lactation origin.

Question 5

1. Name the main internal part of the teat.
2. Name the muscle that contracts around the opening to the exterior of the teat.
3. Name teat opening.
4. Anatomical features of the teat that are important in the protection of the teat from infection.
5. Cellular immunity of the teat.

Answer 5

1. Teat cistern.
2. Teat sphincter muscle.
3. Streak canal.
4. Rosette of Furstenberg and stratified squamous epithelium, teat sphincter and keratin plug.
5. Macrophages and neutrophils.
   Acquired immunity against specific pathogens: immunoglobulins and lymphocytes.

Question 6

What happens to the udder after lactation?
– how long is this phase?

Answer 6

Involution
- Decrease in secretion volume.
- Decrease in milk components.
- Increase in immunoglobulins and lactoferrin.
- Milk synthesis approaches 0 in 48hrs.
– 20-30 days.

Question 7

1. What is the low risk phase for mastitis?
2. What is the phase called just before calving?
   - What happens in this phase?
   – How long is this phase?
3. What are the 2 times where mastitis risk is increased the most?

Answer 7

1. Steady state after involution. Quiescent regeneration is happening.
2. Transition state.
   - Reverse of involution w/ increase in size, colostrogenesis, hormones and initiation of milk production.
   – 10-15 days.
3. Involution phase and transition state.

Question 8

1. What is sub-clinical mastitis?
2. Diagnosis of sub-clinical mastitis.

Answer 8

1. Intra-mammary infection w/o overt clinical signs.
2. By detection of immune response.
   - Marker of inflammation associated w/ intra-mammary infection. – somatic cells = leucocytes.

Question 9

Why do we care about subclinical mastitis?

Answer 9

Important to industry.
- Importance for overall product – shelf life, taste, cheese quality.
- SCC >400K = unsuitable for human consumption (in Europe).
- Payment premiums and limits for quality milk.
For every doubling of SCC over 100K a cow loses 5% of her production.

Question 10

How do we detect subclinical mastitis?

Answer 10

Detection of immune response.
- CMT can be done cow side.
- SCC is machine quantified.
– by assessment of bulk tank.

Question 11

1. How often is SCC of bulk tank assessed?
2. When are payment penalties implemented?
3. What is regulatory legal limit?
4. What BMSCC influenced by?

Answer 11

1. Every collection or weekly.
2. When BMSCC >200K.
3. > 400K.
4. • N cows w/ intramammary infection.
     - Pathogen – whether contagious (long lived effects) or environmental (short lived effects).

Question 12

1. Crude estimate of lost milk. #
2. SCC units.
3. Non infected quarters SCC.
4. Infected quarters SCC.

Answer 12

1. For every 100K above 150K, 1.5% of total milk is lost.
2. N cells / ml of milk.
3. 5-200K.
4. 200K-5M.

Question 13

Why do farms do milk recording?

Answer 13

• Data on individual cow yields.
• Identify cows contributing most to BMSCC.
• Identify cows to milk separately / last / with separate equipment.
• Identify new cases of subclinical mastitis.
• Identify chronic cases of subclinical mastitis.
• Identify cows that need treatment.
• Identify cows that need culling.
• Which cows to sample for bacterial culture to find causal organisms of mastitis.
• Disease monitoring – individual cow sampling for — neospora / Johnes etc.
• Pregnancy diagnosis.

Question 14

How are milk recording results used by the vet?

Answer 14

Identify cows for farm to investigate further.
- Do they have clinical mastitis / need treatment?
- To sample for bacterial culture.
Analysis of trends.
- Over time.
- % new infections / calving in w/ a high SCC.
- Chronic high SCC.
- Dry period cure rate.

Question 15

What factor affect SCC?

Answer 15

Infection is the largest single factor.
- Number of quarters infected.
- Type of pathogen.
- Severity of infection (and immune response).
Age (older).
- More likely to be infected.
- Have residual damage from previous infections.
- Have greater cellular immune response.
Stage of lactation.
- Rise in late lactation, esp. <10kg/d.
- Increased exposure during duration of milking.
- Residual damage from previous milkings.
- Fresh cows: cell counts unreliable for first 5-14 days.
Day-to-day variation.
- Lowest at milking (specifically mid-milking).
- Highest in strippings – before and after.
- Use either (stripped) foremilk or representative sample.
- Important to consider when organising milk recordings.

Question 16

1. Define clinical mastitis.
2. Grading system of clinical mastitis.

Answer 16

1. Intramammary infection w/ overt clinical signs.
2. • G1 (mild) – Changes to milk only (colour/consistency).
     - G2 – (moderate) Changes to udder (heat, swelling, pain).
     - G3 – (severe) Changes to the cow (sick cow) and/or gangrenous sloughing of the teat.
     - Toxic – Signs of toxicity – recumbent cow, raised HR, red MMs.

Question 17

Diagnosis of clinical mastitis.

Answer 17

Detected and treated by farmer.
- Milk changes.
- Udder changes.
- Sick cow with milk/udder changes.
Veterinary involvement.
- Sick cows.
- Toxic cows.
- Non response to treatment.
Take sample of infected quarter.
- Sterile milk sampling procedure.
- Can be frozen.
On farm culture / PCR ?
- Becoming more common in large herds.
- 24hrs for a result.
- Practice lab – 24hr for result.
- Won’t know pathogen at time of treatment.

Question 18

Why do we want to know the pathogen causing mastitis?

Answer 18

• Helps to know type of problem.
  – contagious.
  – environmental.
• Hence prevention and control.
• Only occasionally influences what treatment to use.

Question 19

Clinical mastitis treatment.

Answer 19

Broad spectrum intramammary ABX tube.
/ Multiproduct.
Systemic ABX for more severe cases.
Pain relief – NSAID.
Need vet prescription for ABX tubes.
On farm protocols.
- Detailed in herd health plan.
- Laminates up in office / parlour i.e. most cases treated w/o vet involvement in that case.
Record which cow has been treated.
- Statutory recording.
- Analysis of incidence and patterns in case numbers.

Question 20

Veterinary involvement in mastitis.

Answer 20

Phone advice of how to treat a case.
- Intramammary tube.
- Injectable ABX.
Drawing up protocols for what to treat with.
- In herd health plan.
- For decision making on farm.
Visits for sick cows, toxic cows, non-response cases.
- CE.
- Diagnostic testing.
- Antimicrobial sensitivity.
Monitoring and prevention.
- What data has been recorded?
– Milk recording services — cell count data e.g. NMR, CIS, QMMS.
– Parlour recording software —conductivity of milk.
– Treatment records — required by law.
— Data recording software.
— Sales records –> intramammary tubes = POM.
- Assessing incidence / prevalence.
– Data analysis programs e.g. TotalVet.
– Pattern recognition.
- Identification of risk factors.
- Recommendations on management changes.
- Motivating change.