Mammary gland and mastitis Flashcards
What is the average and peak lactation for a Holstein milk cow?
Average 65-85 lbs/day
Peak lactation 100-140 lbs/day
What is the economic impact on mastitis in a dairy herd?
Economic impact of mastitis o 40% morbidity on dairy farms o most costly cattle disease in US o est to cost 2 billion/yr o est $200-300/cow
The function of the median suspensory ligament
o Most important structure
o Supports and separates the two lateral halves
“Sag Bags” occur when the median ligament gives out.
T/F: The front and back quarters of an udder are separated by a thin membrane
True
T/F: There is crossover in the duct system of the udder
False. Each quarter is a separet unit. however, abx fused into one quarter will quickly find their way to other quarters via the bloodstream
Which teats are longer?
The front
What are the 3 main barriers to protect against intra-mammary infections?
o Teat skin condition
o Teat end condition
o Keratin lining of streak canal
The function and appearance of the secretory parenchyma
Secretory parenchyma – grape-like clusters of myoepithelial tissue, express milk under influence of oxytocin
The function of the ducts
Ducts – lead from secretory tissue to cistern - lobes composed of alveoli release milk into ducts
The function of the cisterns
Cisterns – gland cistern and teat cistern
Milk available in the cisterns between milkings is 100-400 ml/quarter
Function of the streak canal. Name a management practice used to keep it clean.
Streak canal - lined with epithelium and keratin that lines teat and has a good protective feature that helps with sealing the teat end. Eat after they come out of the milking parlor so that the streak canal can close before they go lay down in the manure.
What happens to the sphincter muscle at the end of the teat when the milk is sucked out?
Sphincter muscle around the end of the teat - as milk is sucked out, sphincter expands until it can’t stretch anymore, leads to speeding up speed of milk and this can lead to removal of keratin
Where are the notable lymphnodes of the udder and why would they get enlarged?
2 big Lymph nodes in the back of the udder, lymphosarcoma is the reason why they get enlarged.
What does allometric growth mean in reference to udder development?
Mammary tissue develops at an accelerated rate between 3 months and puberty = allometric growth
What happens if the calf is fed too much during udder development?
Mammary tissue grows a lot faster than rest of calf - if fed at growth rates at over 2 lbs per day - the fat pad in the udder is grown at the expense of the rest of the udder.
Overfeeding in this period can lead to excess deposition of fat in the udder and reduce milk secretion capacity later in life
What is the consequence of underfeeding a calf during udder development?
impairs udder development
what is the predominant hormone governing synthesis of milk in cattle?
Growth hormone (it is prolactin in non-ruminants)
What is the physiology behind keeping cows from “drying up”?
Frequent removal of milk minimized the effects of feedback inhibition (mechanism used to “dry off” cows at end of lactation) - feedback inhibitor of lactation protein - if removed by milking cow, feedback inhibition is removed - so more often cow is milked, the more milk we get
How does oxytocin induce milk ejection?
Oxytocin is:
o Triggered by stimulation of the teats and other situational triggers (ex. entering the milk parlor)
o Travels from pituitary to mammary gland via bloodstream
Delay of 60-90 seconds = “milk let down time”
o Oxytocin causes myoepithelial cells to contract and eject milk into ducts - expresses the milk that Is already in the alveolus - has no effect on making more milk
How many seconds does it take for the milk to be “let down”?
60-90 seconds
What hormone antagonizes oxytocin release and how doe we prevent it?
Adrenalin is a powerful antidote to oxytocin release – hence milking parlor must be calm and quiet
What drives the dry matter intake of a dairy cow?
Dry matter intake is driven by milk product
What is the “main” barrier to infection of the teat?
The teat canal
What immune cells constitute the major response to bacterial pathogens in the udder?
PMNs (somatic cells) constitute major cellular response to bacterial infection – no immune memory
What vaccines are available to protect the immunity of the udder?
Vaccine against coliform mastitis is effective
No effective vaccines have been produced for strep agalactiae, staph aureus and mycoplasma bovis
What are the classifications of mastitis?
Clinical
Subclinical - have to count neutrophils and somatic
cell count to know
Also classified as:
o Contagious - obligate parasites of skin or
mammary tissue
o Environmetal - more important today
o NO viral causes of mastitis in cattle - but in small
ruminants there is OPP?
What are the TYPES of pathogens that can cause mastitis?
Contagious, environmental, and minor pathogens
What are the contagious pathogens responsible for mastitis?
o Staph aureus - some strains cause a gangrenous mastitis and this quarter will slough off
o Strep agalactiae - very susceptible to antibacterials
o Mycoplasma bovis - only organism that MAY spread hematogenously; many occasionally have Mycoplasma bovis pneumonia or ear infections
o Corynebacterium bovis
What are the environmental pathogens responsible for mastitis?
o Strep uberis
o Strep dysgalactiae
o Coliforms – E. coli, Klebsiella - main event is toxemia from endotoxins of Ecoli
What are minor pathogens responsible for mastitis?
o Corynebacterium bovis
o Staph epidermis
o Staph hyicus
What are the differences between transmission and contraction of contagious and environmental mastitis?
Contagious mastitis is transmitted during the milking process as a result of contamination of milking equipment and teat-end impacts which result from fluctuations in teat-end vacuum
o Fluctuations are most often cause by liner slips and flooding the milk line
o Obligate parasites, do NOT live in cow’s environment
Environmental mastitis organisms may live in udder or free in environment
o Enter udder through the teat end during milking process or because of environmental challenge due to large #s of bacteria and teat damage
What used to be the most prominent mastitis causing organism (before the 5 point program)?
Strep agalactiae
What are the points of the 5 point program to control strep agalactiae?
- Maintain the milking machine
- Disinfect every teat after every milking and post-dip - post-dipping stops from carrying over from one milking to another
- Treat all quarters at dry off – cure rates are high d/t little abx resistance
- Treat clinical cases promptly
- Cull chronic cases
What is the effectiveness of the 5 point program? And why was there a resurgence of strep agalactiae?
Most farms were able to ERADICATE the infection completely
o Recently there has been a resurgence because of the movement of cattle into rapidly expanding herds (1980’s)
What is the pathology assoicated with strep agalatiae?
Doesn’t penetrate deeply into the mammary stroma (just causes fibrosis)
Why is strep agalactiae so easily spread?
Shed large #s of bacteria in milk and thus spread easily from cow to cow
Can antibiotics be used on strep agalactiae?
Are accessible to abx treatment
Abx resistance is uncommon
What classifications of mastitis does strep agalactiae cause?
clinical and subclinical
What is NOW the most important cause of contagious mastitis? (now that strep agalactiae is controlled)
Staph aureus
5 reasons that staph aureus is dificult to control
o Virulence factor is able to penetrate tissue forming micro-abscesses which the cow walls off
o Shedding of the bacteria is intermittent – milk cultures don’t always show infection - Need repeated cultures to detect
o Established infections are not readily accessible to abx – cow walls off
o Chronic infections are common and probably incurable
- Especially when farmers don’t use post-dipping
because it is too cold outside
- Longer a cow is in a herd, the more likely it is to
have staph
o Some strains are resistant to beta-lactams - so normal Abx used for mastitis often have no effect on Staph
What classifications of mastitis can staph aureus cause?
Clinical and subclinical
What organism can cause acute gangrenous mastitis?
some strains of staph aureus.
What is the sequelae to acute gangrenous mastisis?
Sloughing of the affected quarter
What vaccine can be used against acute gangrenous mastitis and what is it’s effectiveness?
Bacterin vaccine can be used to lessen severity but not to prevent
- Using an autogenous vaccine made from strain in the particular herd - Somatostaph or Lysogen - 3 doses to heifers before first calf and boost yearly appears to have less infections
What is the epidemialogic concern over Mycoplasma bovis as a mastitis causing agent?
There is growing concern – it is an emerging problem
How is mycoplasma bovis spread?
Once in herd, behaves as contagious organism and is spread during milking process or by contaminated bulk mastitis treatments
Common inhabitant of respiratory tract – can spread to udder and cause new infections
o Link between middle ear infections and
respiratory infections starting a mastitis problem
Only mastitis organism of cattle that spreads hematogenously
o History of respiratory disease or ear infection in
calves occasionally precedes outbreaks
Characteristics of a mycoplasma bovis mastitis?
o Multiple quarters affected
o Dramatic drop in milk production
o Cows appear healthy apart from severe mastitis
o Unresponsive to abx
o Milk has flakes in it, and is often watery
Control method used with Mycoplasma bovis mastitis?
Culling the affected cows
What must be requested when sending samples to the lab?
mycoplasma culture must specifically be requested
o Bulk tank cultures are effected in identifying – very sensitive (1:1000 cows), good for monitoring
What are the most common isolates from herds with high SCC where contagious mastitis is under control
Strep uberis and Strep dysgalactiae
environmental streps can cause a high rate of which classifications of mastitis?
High rate of clinical and subclinical mastitis – esp. in hot weather
When do new infections of environmental strep mastitis occur commonly?
In the dry period
What is the most important virulence factor of environmental strep mastitis?
The ability to resist phagocytosis by PMNs
Where are the environmental strep organisms found?
- High levels are found in bedding – esp. straw - because of bedding pH - they can tolerate a higher pH
- Can also colonize gut and be isolated in high numbers from teats and underside of the cow
The best ways to treat environmental strep mastitis?
o Most can respond well to penicillin, cephalosporins
o Many spontaneously cure in 2-3 milkings with milking out and adjunct oxytocin treatment
The most common coliforms found to cause mastitis?
E. coli and Klebsiella
Opportunistic bacteria, ubiquitous in environment
In herds with very low SCC, most clinical mastitis is caused by what organisms?
Coliforms
Mechanism of action of Coliform bacteria in the mammary gland
Coliform bacteria grow to very large numbers in the mammary gland
o Die off and release endotoxin – responsible for
clinical manifestations of endotoxemia
o Rarely establish persistent infections – not
responsible for persistently elevated SCC
o New infections occur at dry off and calving
What environmental factor is associated with high levels of Klebsiella?
green and wet sawdust
Clinical signs of acute coliform mastitis
o Acute – swollen gland, watery milk w/small flakes, mild systemic disease
Clinical signs of peracute coliform mastitis
Peracute – rapid onset severe toxemia, fever, tachycardia, shock
May be recumbent
Gland may or may not be swollen
Milk is thin and serous w/very small flakes
Treatment of coliform mastitis
o Efficacy of abx is unknown – predominant pathology is toxemia not bacterial infection
o Frequent stripping of gland to remove toxins
o Fluids, electrolytes – hypertonic saline IV so cows rehydrate themselves
2 ways for control of coliform organisms
o Good sanitation
o J-5 vaccine in the dry period and early lactation – very effective
What are the minor organism involved with mastitis?
o Coagulase-negative staph – staph epidermis, staph hyicus
o Corynebacterium bovis
Why are minor organisms classified as minor?
Rarely cause clinical mastitis, yet generally behave as contagious pathogens
o Occasionally see flare-ups, but most are subclinical
What does the presence of Corynbecterium do for major mastitis causing pathogens?
Corynebacterium presence is thought to increase resistance to colonization by the major mastitis pathogens and thus exert a protect effect
How do we reduce the presence of Corynebacterium?
o Prevalence is low in herds using an effect teat dip, good milking hygiene, and dry cow therapy
What management practice might be deficient if staph epidermis and corynebacterium bovis are found?
In herd sampling, presence of staph epidermis and corynebacterium bovis suggests deficiencies in milking hygiene – esp. teat dipping
What are the 5 stages to examining an udder?
- Visual – symmetry, externally visible changes, lesions of the skin
- Palpation – 2 hands, compare side to side
a. Superficial palpation – inflammation (heat, pain, swelling)
b. Deep palpation – fibrosis and other changes in parenchyma - Strip cup to examine milk for consistency, flakes and clots
- California Mastitis Test (CMT) for subclinical cases
- Milk sample for bacteriological cultures and abx sensitivity
a. Request mycoplasma culture if wanted
What are the ranges of SCC determined by the California Mastitis Test?
o Normal/healthy < 200,000 SCC/ml
o Subclinical mastitis > 200,000 - elevated somatic cell counts
What is the most common classification of mastitis
subclinical
What visible changes occur to the milk in subclinical mastitis?
None –
What is the maximum SCC for milk to be sold as Grade A
750,000/ml milk
T/F: bacterial cure rates for mastitis organisms are high
False: Bacteriological cure rates for mastitis organisms is low – less than 60%
When is treatment of subclinical mastitis indicated?
Treatment is usually not an economical proposition unless the farm is going to lose its Grade A permit for having counts consistently above 750,000
o Can treat with cephalosporin or pirlimycin if identify cows with strep during the first 3 days of lactation – can recover the costs
In herds with SCC <100,000, most likely organism causing mastitis is?
Coliform bacteria
T/F: Clinical mastitis may result as flare-up of subclinical or be new infection
True
What treatment is used for acute mastitis that arn’t systemically ill?
o If milk has clots or flakes or udder is inflamed (not systemically ill) – intramammary abx only
What treatment is used for acute mastitis that is systemically ill?
o Febrile or off feed (systemic involvement) – systemic abx, intramammary abx, NSAIDs
Summer mastitis: What organisms, signalment, clinical signs, and treatment
o Most often seen in heifers and dry cows at summer pasture
o Due to Arcanobacter pyogenes or Strep dysgalactiae
o Quarter is usually abscessed and lost
o Treatment is not effective
Which organisms are most intramammary abx aimed at?
Most intramammary abx are aimed at gram positives
Ceftiofur (spectramast LC) – will treat which bacterial organisms that cause mastitis?
coag-negative Staph, Strep dysgalactiae, and E. coli
T/F: Injectable antibiotics have been used as sole treatment or adjunctive therapy for mastitis
True
When should systemic antibiotic be used in a case of mastitis? Which should be used in this case?
o Systemic abx should not be used unless the cow is systemically sick
Procaine Penicillin G – 4 day milk withdrawal
Ampicillin (polyflex) – 48 hour milk withdrawal
Parenteral ceftiofur is NOT effective as a mastitis treatment
T/F: Homemade and bulk mastitis preps are ok to use.
False: Homemade and bulk mastitis preps are dangerous – common cause of yeast mastitis (Pseudomonas) and of transferring Mycoplasma from cow-to-cow
When does Naxel have no milk withdrawal period and what is the downside of this route?
Ceftiofur (naxcel) given systemically has no milk withdrawal but also does not have bactericidal activity in the udder
What antibiotic will not be effective in acute inflammation (mastitis) and why
Penicillin crosses the blood/milk barrier very inefficiently in the presence of acute inflammation
Which antibiotic should NEVER be used in cattle?
Gentamycin should NEVER be used in cattle – no defined withdrawal period for meat, may bind to kidney tissues
How is Tilmicosin (mycotil) used effectively extra-label? What is the withdrawal period in lactating dairy cattle in this instance?
Tilmicosin (mycotil) has been used extra-label to treat Staph aureus at dry off
If used in lactating dairy cattle, milk withdrawal is at least 15 days
What are the 8 steps of “dry cow treatment” (i.e. technique of udder infusion)?
- Confirm and segregate dry cows
- Prepare materials – gauze in 70% alcohol for cleaning teat ends
- Milk the quarters
- Sanitize teats – apply dip, allow to stand for at least 30 seconds
- Scrub teat ends – clean the teats furthest away from you first so that you do not re-contaminate teats by accidentally touching them
- Administer dry cow therapy – start with teats closest to you, use partial insertion method
- Re-dip teats immediately
- Clearly mark all animals as dry – use 2 methods on each cow (leg band and paint stick)
T/F: High SCC result in poor milk quality and economic loss to the producer
True
First thing that needs to be determined once a High SCC is found
Determine the type of bacteria responsible – lab investigation
How is a management strategy determined from a High SCC and what are the practices implemented?
Determine management strategy – depends on bacteria recovered in milk cultures
o Environmental bacteria – center in environment and cow comfort
o Contagious bacteria – aimed at improving milking hygiene
T/F: USA has rigid milk quality standards
False: The US milk quality standards are lax compared to other nation – competitive disadvantage worldwide
Why are good records vital when dealing with high SCC?
Increased SCC are first evident in processing plant tickets delivered to the farm
Must examine records for herd and individuals
What does the weighted (crude) average mean when dealing with High SCC?
Bulk tank SCC is important in letting producer know if the tank is of sufficient quality to attract a premium and provides crude average SCC of individual cows
o Small herds – one or two cows with high SCC can cause dramatic increase
What does the linear score mean when dealing with High SCC?
Linear scores – derived from individual cows, relate loss of production to SCC in a linear fashion
Small herds – one or two cows with high SCC: linear score may not increase b/c does not represent change in overall character of the herd
Changes in SCC along with changes in linear score indicate elevated SCC in a larger number of cows
How does the DHI 520 report contribute to High SCC investigation?
ranks cows by their contribution to the bulk tank
What is the benefit of bulk tank cultures?
Economical method of detecting the presence of new infectious agents in the herd and monitoring levels of infection within the herd
What is the effictiveness of the bulk tank cultures for monitoring Staph aureus, Strep agalactiae, or mycoplasma?
Factors affect efficiency to provide accurate information
o Limited value when monitoring for Staph aureus
o Effective monitoring of Strep agalactiae
o Diagnostic tool for mycoplasma – very sensitive
What is the main precaution that must be taken when collecting individual samples to investigate high SCC?
Important to collect excellent quality, uncontaminated milk samples in order to have high probability of understanding which bacteria are the important contributors to the SCC
Growth of contaminating bacteria from the teat skin or environment complicates interpretation of results
What are 4 considerations when selecting individual cows to test in the face of high SCC?
- Do NOT select chronic problem cows that haven’t responded to treatment – not representative of the cause
- Check cows in the order in which they enter the milking parlor using the CMT
- Any cow with positive CMT is selected for sampling but only one CMT positive quarter is selected from each cow
- Do NOT select animals just based on very high SCC
Why would you check cows with the CMT in the order in which they enter the milking parlor?
o Least disruption to milking
o Allows us to collect samples in early part of milking
o Allows us to watch milking process – look at time take-offs and teat ends
Why is only one CMT positive quarter selected from a CMT positive cow when testing for High SCC?
o Culturing 16 CMT positive quarters generally gives us enough positive cultures to determine type of bacteria responsible
o Strep agalactiae is easy to culture – get high #s of positive samples
o Staph aureus is intermittent shedder – get 2-3 positive samples = significant problem
o Environmental streps are easy to grow
6-8 steps to collecting a milk sample from a teat
Pre-dip and forestrip all four quarters to observe any clumps/flakes in the milk
Dry teats well with individual towel
Carry out CMT on all 4 quarters and select a CMT positive quarter to sample
Swab the end of the teat with alcohol soaked cotton
Use sterile screw top tube
First squirt of milk goes onto parlor deck and the second squirt into the tube
Growth of Strep agalactiae is ALWAYS significant – can only have come from an udder infection
Request both abx sensitivity and culture of samples
What is the most common and second most common environmental strep?
Strep uberis is the most frequent environmental strep, then Strep dysgalactiae
How does an environmental organism (S. uberis) create/find an environment to thrive?
High levels of Strep uberis – colonize gut and large #s are ejected into environment
Thrive in warm, wet environment – problem in poorly ventilated freestall barns in summer
What is a solution to prevent for environmental strep mastitis?
Solution = provide dry, comfortable freestalls with adequate ventilation
o Opening of barn walls to provide air flow at the level of freestalls
o Adequate ridge opening
What could potentially happen if the liner slips and there are pathogenic organisms on the teat? How do you prevent this?
When liner slip occurs, the bacteria that are on the outside of the teat are sucked into the milking cluster vacuum and propelled into the teat end of one of the other teats
o Excellent sanitation of teat before attachment is essential
o Insist on dip tested in National Mastitis Protocols
What are the important aspects of teat dipping?
Teat dipping
o 20-30 seconds required to kill bacteria on teat skin
o Fore stripping increased effectiveness of dip
Why should water be avoided to clean when milking? What can be done to minimize the negative effects if water must be used?
Avoid use of water in udder preparation
o Water carries large #s of bacteria
o Teats and base of udder must be dried with single use paper or cloth towel if water is used to rinse off caked on dirt
What is the most important defense mechanism in the udder?
Most important defense mechanism in the udder is the integrity of the teat canal at the end of the teat
o Streak canal is lined with an extension of the skin surface which secretes keratin
o Milk flowing through the streak canal acts as a lubricant which minimized the loss of keratin - If milking continues after milk flow has stopped excessive loss of keratin
o Hyperkeratosis occurs with overmilking or incorrectly adjusted pulsation ratios – looks like donut ring around the teat end
o Damaged teat ends are less likely to seal after the cow leaves the milking parlor increased levels of environmental mastitis
5 common causes of overmilking
o Insufficient udder stimulation
o Insufficient time for milk letdown to occur
o Discomfort
o Fear
o Poorly adjusted automatic detachers – should be detached when milk flow falls below 1 lb/min
What can be done to keep cows from lying down after milking?
Provision of water in the exit ally and fresh feed in feed bunk will tend to keep comes occupied after the come out of the parlor and gives teat ends time to seal before they lie down
o If cows have been held for an excessive period of time in the holding pen before milking – more likely to bypass food/water and lie down immediately
What can “barrier dips” be useful for?
Use of barrier dips is also recommended as an aid to controlling high SCC caused by environmental mastitis
o Pre-dip to prevent infection from being sucked in
T/F: It is uneconomic to treat individual cows with high SCC during lactation
True
o Dry cow treatment with effective abx is method of choice for terminating existing infections
o Absence of dry cow treatment many new infections with environmental streps during first 2 weeks of dry period
Where do Strep agalactiae and Staph aureus reside?
Strep agalactiae and Staph aureus live on the udder tissue/skin – will NOT pick up in environment
How are Strep agalactiae and Staph aureus transmitted?
o Transmission from quarter to quarter or cow to cow occurs during milking process
What test can be performed if Strep agalactia and Staph aureus are suspected of causing a herd problem?
o Can perform Pro-Staph ab test
What is the most important method by which quarters acquire new infections with contagious bacteria
Liner slips (squawks) Milk particles impact the end of one of the other teats – blow back of milk particles can carry bacteria
T/F: Occurrence of liner slips should be monitored
True
o If frequent – cause needs to be determined
o Common causes – poor positioning of the inflation under the udder and low vacuum
T/F: Liner slips are not an emergency
False
Parlor emergency – inflation needs to be repositioned as soon as possible
o Dealing with it should override all other tasks
this management technique shows the greatest reduction in the number of new infections
Post-milking teat dipping
The purpose of teat dipping
To kill the bacteria that are on the surface of the teat when the inflation is removed and that are capable of being drawn into the milking machine at next milking
What is the recommended method for cleaning the teats (with dipping solution)
Dipping with a dip cup with a non-return reservoir is the ONLY method recommended
o Sprayers are only adequate for PRE-dipping
After teat dipping, this is the SECOND MOST IMPORTANT technique for the control of contagious mastitis
Dry cow treatment
What is the effective antibiotic regiment that follows the Dry cow treatment?
All quarters should be treated with an effective intramammary abx – cephalosporins, penicillins
o Some strains of Staph aureus are resistant to
penicillin – use another abx
Very invasive
Walls itself off in micro-abscesses
Abx cure rates are low
o Some resistance is developing in Strep agalactiae
– but will still provide good control
In which mastitis is culling a necessary means of control?
Staph aureus infected cows that have NOT been cleared by treatment during the dry period are difficult to cure and should be culled
o Longer they stay in herd, the greater the risk of
becoming infected
o Best cows that have been in the herd the longest
are most likely to become infected
What is a short term solution (until culling is appropriate) for dealing with Staph aureus infected cows?
Creating a group of Staph aureus cows that can be milked as the last group through the milking parlor is a successful short-term strategy
o Removes cows from main herd and allows them to be culled after they pass peak milk production
Other than short term segregation for staph aureus infected cows, at what time in the production cycle is is best to segregate cows
Cows have weakened immune system at time of calving are very susceptible to coliform mastitis
o Segregate into a fresh cow group – house and milk separately
What is the purpose of giving a vaccination for staph aureus?
Commercial vaccines for Staph aureus do not eliminate infection – may reduce rate of new infections if vaccinate heifers before they enter the herd
T/F: Effective and practical management techniques are available to control elevated SCC caused by contagious, but not environmental mastitis
False. The techniques are available for both
Once the bacterial cause of high SCC is established through testing, a SCC reduction plan should be put in place –> team approach is essential – who’s on the team?
o Producer o Vet o Milking equipment technician o Dairy company field person o Extension agent o Nutritionist
How do we make sure a SCC reduction plan is followed? When should it be reviewed?
- Essential that the milking crew understands what needs to be accomplished and why
- Effective monitoring must be installed
- Management review after 2-3 months will help fine tune the program
During how much of the milking cycle should the liner be open?
30%
Two types of pulsators
Most common pulsation - electrically activated
Pneumatic pulsator is an alternative - not as many advantages
How much of the total milk to rear vs front quarters produce?
Rear quarters give 60% of total milk production, front 40%
Ratio are set so that rear quarters work more
What are some issues that vacuum fluctuations in the milking system can cause?
Vacuum fluctuations cause the most problem in milking parlor - that is why there are alternative pulsations - one quarter than another to make sure there is little vacuum as needed - so a key part of milking is to avoid vaccumm
o Flooding milk line
o Letting air in - “liner squawks”
o Lead to milk back up
T/F: All four vacuum liners should be open at the same time
False: Need plenty of vacuum reserve - shouldn’t have all 4 liners open at same time
What is the process from dipping to applying milking machine?
Dip, strip, spray down milk machine, apply machine after dipping and stripping and wiping away iodine
How much milk should be left in the udder after milking?
Want some residual milk left in udder (200mL spread between 4 quarters) - don’t milk until dry
