Cattle health

Question 1

Cattle Salmonella - High prevalence linked to?

Answer 1

Large herd size

Use of flush alleys

Question 2

Salmonella - pathogen characteristics

Answer 2

Facultative anaerobe 
Facultative intracellular pathogen 
Survives pH range of 4.5-9 
Multiplies at temps 8-45
Survives in dust and feces for years

Question 3

Cattle salmonella - clinical signs

Answer 3

Anorexia
Fever
Diarrhea
Death

Question 4

Salmonella incubation time

Answer 4

Dependent on dose
Host Immunity
Pathogen virulence

Question 5

Salmonella diagnostic investigation

Answer 5

Salmonella cultures (fecal & tissue)

Electron microscopy - rule out other diseases (coronavirus)

Fecal flotation - Rule out other diseases

Gross & histopathology

Question 6

Salmonella - sources of pathogen exposure (cattle)

Answer 6

Purchased livestock 
Feed 
Water 
Environment 
Equipment 
People (vets) 
Wildlife 

Need to trace the source of infection back
e.g. contaminated feed which had been contaminated by irrigation water which had been contaminated by human effluent

Question 7

Salmonella Maternity Pen

Answer 7

Maintain clean & uncrowded maternity pen
Avoid adult to calf contact
Isolate heifers from lactating herd

Question 8

When is salmonella more likely to occur in cattle?

Answer 8

Calving season and summer

Question 9

Salmonella prevention in cattle

Answer 9

All in, all out system
Closed herd
Hygiene practices
No pong water access
Good nutrition
- Nutritional stress increases susceptibility
Passive transfer - colostrum - cow-calf management - need 100g of IgG

Question 10

Lactogenesis

Answer 10

Milk production

Hormonal control with neuronal inputs

Prolactin promotes milk production

Oxytocin facilitates milk ejection

Stressful stimuli interfere with oxytocin binding

Question 11

Peak lactation

Answer 11

4-8 weeks after parturition

Question 12

Cattle - typical lactation lasts?

Answer 12

305 days, followed by a 60 day rest or dry period

Question 13

Milk production in cows can be manipulated by?

Answer 13

Photoperiod

Bovine growth hormone

Question 14

Milk extraction

Answer 14

Clean milking equipment should be applied to clean, dry teats

Cows typically milk out in 5-7 minutes

Teat dip should be applied to all surfaces of the all teats

Question 15

Vacuum in milking machine

Answer 15

Vacuum is constant in the milk line

Vacuum fluctuates in the pulsator line

Milk flows when the vacuum is on in the pulsator line

When the vacuum is off in the pulsator line the teat is allowed to rest

The rest phase is important for the health of the teat end which is an important defence for the mammary gland

Question 16

Mastitis reflects…..

Answer 16

Compromised immune mechanisms or excessive challenge to teat

Compromised immune functions - teat injury

Excessive challenge - Environment, milking equipment or milking procedure

Question 17

Cow - mammary gland defences

Answer 17

The Teat (Streat) canal

• Tight & effective closure between milkings
• Adherence of bacteria to keratin lining of teat canal
• Shearing of keratin lining during milking
• Drying and re-sealing of the canal lumen after milking

Frequent milking

Phagocytes (somatic cells)

Antibodies

Lactoferrin

Question 18

Dairy cattle - teat lesions

Answer 18

Compromise the integrity of the teat sphincter and lead to bacterial colonization of the teat skin

Trauma

Milking Equipment – Excessive or insufficient teat end vacuum, poorly fitting liners

Teat dips – Chemical injury or excessive drying

Adverse Climatic Conditions – frostbite, photosensitization

Skin pathogens

Question 19

Contagious mastitis transmitted…

Answer 19

During milking

Question 20

Environmental mastitis transmitted…

Answer 20

Via the cows environment

Question 21

Mastitis - high risk periods

Answer 21

After dry off

Prior to and immediately after calving

Question 22

Mastitis prevention - Preparation prior to milking

Answer 22

Cows should be handled quietly so they are relaxed and let down milk normally

Minimise bacterial contamination on teats prior to milking (clean lanes and entry to dairy )

Milking machine should be applied to clean dry teats (pre-milking wash and dry may be necessary under adverse environmental conditions)

Question 23

Mastitis prevention - milking procedure

Answer 23

Pre dip (reduce the risk of environmental mastitis)

Fore strip each quarter (to identify mastitis quarters)

Wipe teats dry with a single service towel
- Contact time 20-30 seconds, pre dip removed to avoid contamination of the milk

Attach milking machine

Post dip (prevents contagious mastitis)

Question 24

Clinical manifestation of mastitis

Answer 24

Abnormal Secretion

Abnormal Gland:

• Swelling
• Redness
• Pain
• Temperature

Abnormal Cow:

• Mentation
• Gait

Question 25

Detection of subclinical mastitis

Answer 25

Rapid mastitis test

Question 26

Contagious mastitis pathogens

Answer 26

Streptococcus agalactiae Staphylococcus aureus Mycoplasma spp. Streptococcus dysgalactiae

Question 27

Transmission of contagious mastitis pathogens

Answer 27

Transmission generally occurs at milking time - Milking machine - Hands - Teat washing materials - Treatment procedures Poor teat health Nutrition – macro and micro-nutrient deficiencies increase risk Milking – fluctuations in vacuum causing teat impacts

Question 28

Contagious Mastitis Control Strategies

Answer 28

Segregate infected cows Prepare teats properly prior to milking Use adequately sized, properly functioning milking equipment and appropriate milking technique Post milking teat disinfection (dip) Backflush or disinfect contaminated equipment Lactating cow treatment Dry cow therapy Consider culling chronically infected cows Maintain a closed herd Avoid feeding heifer herd replacements mastitis milk

Question 29

Environmental Mastitis Pathogens

Answer 29

Coliforms Coagulase negative Staphylococcus spp. Strep. Uberis, Strep. Bovis and other environmental streptococci Actinomyces pyogenes Yeast Corynebacterium bovis Prototheca spp.

Question 30

Controlling environmental Mastitis

Answer 30

Environmental Management Post milking teat dip (Environmental streptococci but not coliforms) Dry cow therapy (Environmental streptococci but not coliforms) Lactating Cow Therapy- Cure rates 50 – 60% for the environmental streptococci. Less against coliforms Milking machine function (teat health important) Udder preparation Pre-dipping Diet – Vitamins A, E, beta carotene and the trace minerals

Question 31

Mastitis risks in the milking parlour

Answer 31

Environmental pathogens: - Dirty equipment - Wet cows - Poorly fitting equipment - Vacuum fluctuations Contagious Pathogens: - Contaminated milk - Milkers hands - Milking equipment - Vacuum fluctuations - Teat dip is the single most effective way to prevent!

Question 32

Prevention of mastitis

Answer 32

Provide a clean and comfortable environment Maintain milking machine function Maintain teat health Maintain good milking procedures Detect and treat clinical mastitis Assess performance through monitoring the rate of new infections

Question 33

Teat dips (mastitis)

Answer 33

Maintain healthy skin Reduce the bacterial population at the teat orifice and on the areas of teat skin that have come into contact with the teatcup liner during milking.

Question 34

Dry cow therapy

Answer 34

The use of intra-mammary antibiotic therapy immediately after the last milking of lactation Dry cow therapy has the following advantages over lactation therapy: - Higher dose of antibiotic - Retention time of antibiotic longer - Reduced incidence of new infections in the dry period - Reduced risk of drug residues - It is important to clean and sanitize teats carefully before infusing antibiotic into a quarter

Question 35

Costs of mastitis

Answer 35

Reduced milk price Reduced milk production Premature culling Cow mortality