Machines and Mastitis Risk:Machines and Mastitis Risk:A Storm in a TeatcupA Storm in a Teatcup

Graeme MeinGraeme Mein, , AustraliaAustralia

Douglas ReinemannDouglas Reinemann, , UW-Madison, USAUW-Madison, USA

Norm SchuringNorm Schuring, , Westfalia-Surge, USAWestfalia-Surge, USA

Ian OhnstadIan Ohnstad, , ADAS, UKADAS, UK

2GAM mmch98

Herd & farm Herd & farm managementmanagement

CowCow

MilkingMilkingmanagementmanagement

MachineMachine

FeedingHerd healthCalving areasMuddy lanesClean udders

YieldTeat characteristicsImmune system

Relative Effects on MastitisRelative Effects on Mastitis

3GAM mmch98

Effects of milking Effects of milking on new infection rateon new infection rate

MilkingMilkingmanagementmanagement

MachineMachine

HygieneCalm cowsVisibly clean teatsTiming of cup attachment Cluster removal techniqueTeat disinfection

Contamination

Teat health / colonization

Bacterial penetration } Table 1 IDF,1987

Dispersing pathogens in udder

Frequency /degree of emptying udder

““What percentage of all infections are due What percentage of all infections are due

to milking machine factors?”to milking machine factors?”

(Eberhard, Montreal, 1987)(Eberhard, Montreal, 1987)

Range of responses:Range of responses:

““We don’t really know”We don’t really know”

“ “ Probably quite low”Probably quite low”

““Anywhere between 0% and 100%”Anywhere between 0% and 100%”

Machines and Mastitis Risk:Machines and Mastitis Risk:A Storm in a Teatcup?A Storm in a Teatcup?

5GAM mmch98

Most new infections are due to Most new infections are due to factors other than the machinefactors other than the machine

MilkingMilkingmanagementmanagement

MachineMachine

HygieneCalm cowsClean teatsTeat disinfectionCluster removalTiming of cups on

Contamination

Teat health, colonization

Liner slip, rough removal

RPGs, other effects???} 6-20%

6GAM mmch98

Infe

cted

Qu

arte

rs (

%)

Peak Milking Rate (kg/qtr/min)

Grindal & Hillerton, 1991

Extreme effects of Extreme effects of the first three mechanismsthe first three mechanisms

Teatcup liners are damp, drippy places and Teatcup liners are damp, drippy places and contamination of teat skin is commoncontamination of teat skin is common

Contamination of teat skin does not Contamination of teat skin does not necessarily lead to new infections:necessarily lead to new infections:

• NIRs remain low in control quarters of NIRs remain low in control quarters of most milking studies involving high most milking studies involving high bacterial challengebacterial challenge

• Two other instructive examples ...Two other instructive examples ...

1. Contamination:1. Contamination: A storm in a teatcup ?A storm in a teatcup ?

High cyclic plus high irregular vacuum High cyclic plus high irregular vacuum fluctuations failed to produce high NIRs in:fluctuations failed to produce high NIRs in:

• the first series of challenge experiments the first series of challenge experiments in the UK when teatcups were in the UK when teatcups were notnot joined joined by a common claw by a common claw (Thiel et al. 1973)(Thiel et al. 1973)

• the second series of challenge the second series of challenge experiments in Ireland when a stable liner experiments in Ireland when a stable liner was usedwas used (O’Shea & O’Callaghan, 1978)(O’Shea & O’Callaghan, 1978)

Examples of low NIR Examples of low NIR despite high bacterial challengedespite high bacterial challenge

1. Conclusions: contamination1. Conclusions: contaminationA storm in a teatcup ?A storm in a teatcup ?

Machine-induced IMIs are low in the absence Machine-induced IMIs are low in the absence

of teat damage of teat damage (which assists colonization (which assists colonization

in or near the teat canal)in or near the teat canal) or high local winds or high local winds

(that might impel pathogens into the canal)(that might impel pathogens into the canal)

Milking machine effects are low relative to Milking machine effects are low relative to

the effects of herd and milking managementthe effects of herd and milking management

2. Changing the resistance of the 2. Changing the resistance of the teat canal to bacterial invasionteat canal to bacterial invasion

““Milking machines influence the level of Milking machines influence the level of

exposure to pathogens by their direct effect exposure to pathogens by their direct effect

on the health of the teat duct or teat skin”on the health of the teat duct or teat skin”

(Dodd, 1987 & 2003)(Dodd, 1987 & 2003)

Teat canal integrityTeat canal integrity

Congestion or edemaCongestion or edema

Skin or orifice lesionsSkin or orifice lesions

11GAM mmch98

100:1

Infe

cted

Qu

arte

rs (

%)

Duration of C+D phases (sec)

Infe

cted

Qu

arte

rs (

%)

(from Reitsma et al. 1981)

Wide pulsator ratios Wide pulsator ratios increase the risk of mastitisincrease the risk of mastitis

100:1

75:25

70:3060:40 50:50

12GAM mmch98

Pulsation failure and mastitisPulsation failure and mastitis

No pulsationNo pulsation

Short C + D phase Short C + D phase

Short linersShort liners

Short liners + o/milkingShort liners + o/milking

No pulsationNo pulsation

x 5-20 x 5-20 (Bramley, 1978)(Bramley, 1978)

x 2x 2 (Reitsma, 1981)(Reitsma, 1981)

x 2x 2 (Mein et al. 83)(Mein et al. 83)

x 9x 9 (Mein et al. 86)(Mein et al. 86)

7 vs 07 vs 0 (Lacy-Hulbert, 98) (Lacy-Hulbert, 98)

13GAM mmch98

None

Tea

t-en

d c

on

dit

ion

Increasing “strength” of pulsation

Effect of pulsation Effect of pulsation on teat-end condition on teat-end condition

Gentle Aggressive Positive pressure

N

S

R

VR

14GAM mmch98

None

Tea

t-en

d c

on

dit

ion

Increasing “strength” of pulsation

Association with NIR ? Association with NIR ?

Gentle Aggressive Positive pressure

N

S

R

VR

New infection risk

NIR is increased by machine-induced NIR is increased by machine-induced

changes in teat-end condition:changes in teat-end condition:

Increased congestion or edemaIncreased congestion or edema

Increased hyperkeratosisIncreased hyperkeratosis

Slower removal & re-growth of keratin Slower removal & re-growth of keratin

Teat orifice more ‘open’ after milkingTeat orifice more ‘open’ after milking

2. Teat damage & colonization:2. Teat damage & colonization:A storm in a teatcup ?A storm in a teatcup ?

NIR is reduced if teat massage is effectiveNIR is reduced if teat massage is effective

(= compressive load or over-pressure) (= compressive load or over-pressure)

Compressive load depends on:Compressive load depends on:

Pulsator ratio, B & D phases, ratePulsator ratio, B & D phases, rate

Vacuum inside the liner barrelVacuum inside the liner barrel

Liner material, geometry and tension Liner material, geometry and tension

Teat size and shapeTeat size and shape

Teat health and “teat massage”Teat health and “teat massage”

‘‘Impacts’ due to acceleration and inertia of Impacts’ due to acceleration and inertia of

small milk droplets that hit the teat-end.small milk droplets that hit the teat-end.

‘ ‘Impacts’ may result in partial penetration Impacts’ may result in partial penetration

of the teat canal:of the teat canal:

• Liner slips, machine stripping, rough take-offLiner slips, machine stripping, rough take-off

• Effects confined within an individual clusterEffects confined within an individual cluster

• Higher infection risk late in milkingHigher infection risk late in milking

• Lower risk with free-draining claws and tubesLower risk with free-draining claws and tubes

3. Producing forces to impel pathogens 3. Producing forces to impel pathogens into or through the teat canalinto or through the teat canal

18GAM mmch98

Cluster removal technique and NIRCluster removal technique and NIR

Rough take-off 23 per 1000 qtrmilkings

Gentle take-off 6.5 per 1000 qtrmilkings

MM16, NIRD, unpub

Effect of sudden air Effect of sudden air admission into a teatcupadmission into a teatcup

Managing Milk Quality, Levesque, 1998

150 kPa/s (45 inHg/sec)

Effect of sudden air Effect of sudden air admission into a teatcupadmission into a teatcup

Vacuum changes in milkline affect claw Vacuum changes in milkline affect claw vacuum but rate of vacuum change is slow vacuum but rate of vacuum change is slow

Managing Milk Quality, Levesque, 1998

Vacuum changes in milkline affect claw Vacuum changes in milkline affect claw vacuum but rate of vacuum change is slowvacuum but rate of vacuum change is slow

15 kPa/s(4.5 inHg/sec)

3. Impacts and penetration:3. Impacts and penetration:A storm in a teatcup ?A storm in a teatcup ?

Teat duct penetrated by 6 m/s jet speed (20 ft/s) Teat duct penetrated by 6 m/s jet speed (20 ft/s)

but 2 m/s (6.5 ft/s) is too slowbut 2 m/s (6.5 ft/s) is too slow (Thiel et al. 1969)(Thiel et al. 1969)

Liners move much too slowly to generate high Liners move much too slowly to generate high

air speedsair speeds (Spencer, 2003)(Spencer, 2003)

Sudden air admission into a teatcup can Sudden air admission into a teatcup can

generate air speeds > 6 m/sgenerate air speeds > 6 m/s (Woolford et al. 1980)(Woolford et al. 1980)

Prime causes: liner slips, abrupt cluster Prime causes: liner slips, abrupt cluster

detachment, vigorous machine strippingdetachment, vigorous machine stripping

Likely conditions for ‘impacts’Likely conditions for ‘impacts’

6inHg

(from Levesque, 1998)

7.5inHg

12inHg

Vacuum changes in milklines or receiver are Vacuum changes in milklines or receiver are

too slow to generate air speeds > 2 m/s too slow to generate air speeds > 2 m/s

within a clusterwithin a cluster

Unstable milkline or receiver vacuum may be Unstable milkline or receiver vacuum may be

associated with higher NIR but this is associated with higher NIR but this is

unlikely to be a cause/effect relationshipunlikely to be a cause/effect relationship

Impacts and penetration:Impacts and penetration:A storm in a teatcup ?A storm in a teatcup ?

New Infection Risk is lower during lactation New Infection Risk is lower during lactation

than in the dry periodthan in the dry period

Regular milking has a positive effect !Regular milking has a positive effect !

- NIR reduced by regular flushing of canal - NIR reduced by regular flushing of canal

Complete milk-out seems important but Complete milk-out seems important but

may be less so with more frequent may be less so with more frequent

milking per daymilking per day

5. Frequency and degree of 5. Frequency and degree of udder evacuationudder evacuation

Reducing the riskReducing the riskReducing the riskReducing the risk

Reduce transient air inrush, Reduce transient air inrush,

especially late in milking:especially late in milking:Stable liners, cluster positioningStable liners, cluster positioning

Free draining SMTs, claw and hose Free draining SMTs, claw and hose

Calm cows (to reduce kick-offs)Calm cows (to reduce kick-offs)

Gentle removal, no strippingGentle removal, no stripping

Maintain effective teat massageMaintain effective teat massage

Maintain healthy teat-ends Maintain healthy teat-ends