FA mastitis

• How can it be graded? Inflammation of the mammary gland, can be clinical or subclinical.

  
  

  Subclinical = infection is present but there are no visible CS (only changes in SCC and milk yield).

  
  

  Infection: viable pathogen on teat end > bypass sphincter and streak canal > spread into the udder.

  
  

  Grade 1 > mild changes to the milk

  Grade 2A > acute changes to the milk with a hot painful udder

  Grade 2C > chronic changes in the milk, with hard and lumpy udder

  Grade 3 > changes in the milk, udder and the cow is systemically sick.

  Teat immune defence to mastitis:

  What are the different types?
• What are the barriers faced by invading pathogens? TYPES OF IMMUNE SYSTEM:

  Innate immune system > first line defence (teat skin and canal, resident leucocytes- can be impacted by ABs in the milk).

  Acquired immune system > humoral and cellular memory

  
  

  Teat skin > present to prevent the colonisation of teat skin with bacteria = stratified squamous epithelium + bacteriostatic FAs.

  Can be compromised by bruising, chapping, trauma, lesions and problems with the milking machine. This can allow colonisation with ubiquitous skin bacteria.

  Therefore best to treat lesions promptly and use post-milking teat dip emollients.

  
  

  Teat canal > bacteria can enter when the canal is open after milking, teat sphincter muscle acts as a barrier- but takes 30 mins to close.
• What are the components of the innate IS in the udder? Inside the udder there macrophages, neutrophils and T lymphocytes = phagocytose the invading pathogen + release pro-inflammatory mediators & antigen presentation.

  When there is an infection, a high increase in these will be noticed= high SCC.

  
  

  Also release:

  - Lactoferrin > Iron binding protein produced by epithelial cells + leucocytes. High concs found in dry periods and prevents the growth of pathogens which require iron = E.coli

  
  

  - Lactoperoxidase > bacteriostatic agent

  
  

  - Lysozyme > bactericidal protein

  
  

  - Complement > activates and attracts phagocytes
• What are the components of the acquired IS in the udder? - Neutrophils

  
  

  - B lymphocytes > present in the lymph fluid and produce IgM, IgG1 and IgG2 (on repeated exposure) > circulate to enter the inflamed udder and help the neutrophils. Can be utilised for vaccines= only able to minimise the severity of mastitis infections.

  
  

  - T lymphocytes > T helper cells produce cytokines and stimulate IR. cytotoxic T cells are present to kill host cells invaded by pathogens.

  
  

  - Antibodies > IgG2 is the most important. Abs present pathogens + neutralise toxins + agglutinate bacteria.
• What are the factors influencing mammary gland immunity? 1. Genetics (immunity and conformation) > hard to select as low heritability, also problems with speed of milking and yield size.

  
  

  2. Stage of lactation > dry period is high risk for new infections and existing infections to persist (despite long term AB use).

  Highest risk at:

  - Early dry period > high levels of neutrophils but lots of fat and cellular debris.

  - Peri-parturient > colostrgogenesis can interfere with neutrophil capacity and recruitment + phagocytic ability is reduced. There are also hormone changes.

  
  

  3. Nutrition > NEB results in low leukocyte counts, also low Vit E and Selenium levels can interfere with leukocyte function.

  Hypocalcaemia = weakened teat sphincter mechanism + lying down in a contaminated environment.

  Also sub-acute rumen acidosis is at risk (reduced appetite> reduced DMI > NE > diarrhoea >poor hygiene and not eating enough > high risk of infection and NEB.

  
  

  4. Vaccination > only one, and against S.aureus and coagulase-negative staphylococci. Reduces incidence and severity of clinical mastitis. Takes a lot of effort = repeated every gestation.

  
  

  5. Stress

  
  

  ** Dry period management is key to udder health. Make sure they get correct ABs and clean up any infections.
• What to consider with teat injury? Teats are vulnerable to trauma (being trodden on), damage > allows bacterial colonisation > mastitis.

  
  

  Often lesions are painful and will prevent calves from suckling.

  
  

  **Can be a sign of systemic disease= FMD, MCF, photosensitisation, milking machine error.

  
  

  Ensure good breeding genetics, loafing time post milking, teat sealants at drying off and a good quality milking machine. Care as loafing time can exacerbate lameness problems
• General teat disorders, approach and treatment? General approach > check age / how many animals are affected / painful or not?

  
  

  General treatment > use teat cannula to allow milk to drain during milking + IM ABs / emollients / antiseptics. Consider milking order.
• Teat end hyperkeratosis: Can be due to excessive milking vacuums or faulty pulsations or liner type or teat shape.

  
  

  Rough or very rough teats have an increased risk of mastitis.
• Bovine papillomatosis: Bovine papilloma virus, seen in young animals. Flies may be involved in transmission- so introduce fly control.

  
  

  The papillomas can harbour bacteria > mastitis > constant infection.

  
  

  Also poor liner attachment to the teat end will make milking difficult + painful.

  
  

  Most self cure given time, but can try ligation / surgery.
• Pseudocowpox: Parapox virus causing circular / horseshoe shaped scabs.

  
  

  Not painful but can spread through the herd and recur months later.

  
  

  Treated by thorough PMTD (post milking teat disinfection).
• Bovine herpes mammillitis: Very painful vesicle / ulcer which can cover the whole teat- starts as a blister which bursts.

  
  

  Infection from BHV-2.

  
  

  The ulcers are slow healing (weeks) but cows do develop life long immunity.

  
  

  Milk the affected cows last to reduce the spread.

  
  

  Potential to use antivirals- Acyclovir?
• Cowpox: Transmitted by cats, not present in the UK.

  
  

  Painful vesicles, ulcers, and scabs which take weeks to heal.
• Black spot: Damage to teat end (eg. teat end eversion from excess vacuum + secondary infections with Fusobacterium necrophorum).

  
  

  Treat with topical ABs + teat cannula. Also should check the milking machine.
• Udder / teat impetigo: Pustular lesions on the teat and udder skin. Usually S. aureus and can spread to the milkers. Control with PMTD + antiseptic udder creams.
• Photosensitisation: Can occur as part of generalised skin photosensitisation disorder in which non-pigmented skin is affected = underlying hepatic injury.

  
  

  Treat with general supportive care (keep in shade, NSAIDs, sunblocks).
• Chapped teats: Painful, due to worn teat liners / poor teat skin care.

  
  

  Can also impact calf suckling.

  
  

  Use emollients + teat cannula + rest.
• Teat pea: Pedunculated granuloma attached to the wall of the teat canal = blocks the flow of milk.

  
  

  Remove with Hudsons spiral > inserted by rotating up the teat canal and then jerk upwards to tear the granuloma off > can then be milked out. OR mosquito forceps up canal to tear granuloma off. OR treat like surgical lump removal.

  
  

  Can distort the canal + allow bacterial growth.

  
  

  Give prophylactic ABs to prevent mastitis + sedate, cannulate, open teat wall and suture.
• Teat stenosis: Often secondary to trauma.

  
  

  Treat with LA + sedation to insert a small teat knife and rotate.

  
  

  Rest with a teat cannula and IM ABs for 5d.

  
  

  Prognosis is guarded as scar tissue may reform.

  
  

  Blind teats- heifers with no milk in teat. If there is milk > treat as above.
• Supernumerary teats: Often inherited, ideally removed in heifers at time of disbudding.

  
  

  Can be removed without anaesthetic using sharp scissors in animals under 2mo.

  
  

  Older animals need LA + scissors or emasculators > use a crush to lift the leg to prevent kicks.

  How should you approach teat surgery?
• When would you need to do surergy? Can do surgery to remove teats- supernumerary or damaged.

  
  

  Need to sedate the cow in the crush with low dose xylazine and lift HL as for hoof trimming (to prevent kicks).

  Clean thoroughly.

  Can use ring / nerve block around teat.

  Can suture wounds or use tape or glue (best for superficial wounds).

  Suture with simple interrupted with swaged on needle OR staple OR glue.

  Prognosis is guarded & cow will always need prophylactic ABs.

  Also good to use teat cannula to allow the milk to drain during milking.

  Milking machine damage to teats:

  What would you see?
• What do you need to remember? Damage to teat skin > bacteria allowed to colonise.

  
  

  Blue, oedematous petechians or chapped teats.

  Often due to hard / worn linters or inadequate rate phase in pulsators = poor circulation.

  Also can be due to excessive vacuum in milking cluster or inadequate emollient use in post milking teat dip.

  
  

  It is better to leave residual milk in the teats and not leave her completely dry as this can cause damage / increase risk of infection / reduce milk yield in future.
• Name some environmental mastitis pathogens? E.coli (mainly slurry), D.klebsiella (poorly managed / damp sawdust)
• Name some contagious mastitis pathogens? S.aureus (mainly skin- high SCC and intracellular), Strep. dysgalactiae and agalactiae.
• Which mastitis pathogen has environmental origin but can become cow adapted and contagious? Strep uberis

  Describe how the milking cluster works:

  Why is good hygiene needed?

  How do you maintain good hygiene?
• What happens when the milking machine goes wrong? For milk release = apply vacuum to whole cluster > end of cow teat > liner closes on the teat to draw milk out..

  
  

  Not continuous as can do damage and limit BS = pulsator linter which opens and closes intermittently.

  
  

  Vacuum on to off is 2:1, and the claw piece collects milk > long tube > bulk tank.

  
  

  Need good hygiene to prevent introduction and spread of infection. Also to ensure no damage to teats and teat ends, and des not act as a vector for spread of infection.

  
  

  Milking parlours hold risk of spready mastitis pathogens from cow to cow.

  - Contagious pathogens from cow to cow in milk (esp. S aureus)

  - Environmental pathogens on the teat ends / cluster

  
  

  Best to flush clusters between each cow and keep parlour as clean as possible at all times.

  
  

  Essential hygiene: gloves, pre-milking teat preparation (kills coliforms), post milking teat dipping, loafing time, parlour management of those clinically / subclinically infected.

  
  

  Assess milking order and cluster disinfection, also observe the parlour wash up routine.

  
  

  
  

  Dysfunction:

  - Contamination of liners > transfer of pathogens on teat skin

  - Wet milking > milk flushed up into the teat canal + pathogens > due to inadequate vacuums, fluctuating vacuums or a blocked air bleed.
• What are some common problems with milking clusters? 1. Vacuum > can be too high (incorrect setting or the regulator is not working), or fluctuating / inadequate (poor pump, holes in tubing, liner slip with clusters flailing off, inadequate vacuum reserve)

  
  

  2. Blocked air bleed on cluster unit with flooding into the claw piece > milk will not drain away properly

  
  

  3. Faulty pulsation > set too fast can result in poor circulation with inadequate rest phase + holes in tubing.

  
  

  Can develop teat end sphincter hyperkeratosis = increased risk of mastitis, due to XS vacuum or overmilking or faulty liners or poor pre-milking teat preparation.
• How to assess milking machine? Examine cluster > blocked air bleeds, cleanliness of liners, wear of liners, holes in tubing.

  - Liner slipping = hear shhh sound

  - Note vacuum gauge in parlour and watch while milking to observe for fluctuations

  - Look at teats > those that are a bit blue or swollen = dodgy vacuum

  - Look at cows > kicking, over milking at the end, hard liners, excess vacuum

  - Teat score

  - Assess the wash up routine and look at service invoice.

  
  

  Milking parlour machinery needs a check up at least once a year, better to do it more often. Also need to replace rubber / silicone liners after a couple of months (depends on number of cows).

  
  

  Can also do milk filter analysis / bacteriology.

  Why is pre-millking important?
• Which refelex is involved? It is a legal requirement.

  Done to detect early mastitis and stimulate milk let down reflex > for more rapid milking overall.

  
  

  Can then clean / disinfect the teats depending on how clean the environment is.

  
  

  Aim is to decrease environmental bacterial contamination to improve public health and reduce mastitis cases- esp. the environmental pathogens= E.coli and Strep uberis.

  
  

  If the teat is being washed it must be dried before milking. Also can use cup with disinfectant / foaming products.

  
  

  Milk ejection reflex > teat stimulation results in stimulation of the hypothalamus > oxytocin is released from the posterior pituitary > results in contraction of myoepithelial cells in mammary gland.

  The stimulation to secretion delay determines milking routine.

  Faster milk = less teat end hyperkeratosis.
• What prevents the exchange of milk between quarters? Claw piece has valves and liner has an air vent.
• What is the purpose of post-milking teat dipping? Post milking teat dipping = aim is to remove bacteria transferred to the teats during milking.

  
  

  Is key for the prevention of infection with contagious pathogens > Staphylococcus aureus, Streptococcus dysgalactiae and Streptococcus agalactiae.

  
  

  Pre milking teat dipping is highly encouraged, but only post milking teat dipping is essential.

  Pre VS post teat dipping
• What disinfectants can be used? Pre-milking teat dipping is done to remove organisms from the teat skin which may enter the udder via teat during milking = environmental mastitis pathogens

  
  

  Post-milking is done to kill bacteria on the teat after milking and protect the teat from new infection from environment = contagious mastitis pathogens and teat skin pathogens.

  
  

  Can also condition teat skin to withstand disinfectants and milking machine.

  
  

  
  

  DISINFECTANTS= iodine, chlorhexidine, lactic acid, chloride dioxide, ammonium compounds.

  Can also use emollients (lanolin, glycerine) for skin conditions= keeps skin supple and moisturised.

  Can also use dye to then see when the dip has been applied and striking agents to make more gloopy= doesn't run straight off the skin.
• Ideal milking order: Milking orders can be used to reduce spread of contagious pathogens through the herd + STILL NEED CLUSTER DISINFECTION.

  
  

  1. Heifers

  2. Fresh calvers (care as may have unknown status)

  3. High yielders

  4. Low yielders

  5. High SCC

  6. Mastitis cows

  
  

  Also can utilise tape to ID the cows which need to be separated with milk into separate milk tank / proper milk cluster disinfection.
• How to clean the parlour? 1. Clean milk out and remove any bacteria deposited in clusters

  2. Cold rinse

  3. Hot wash

  4. Rinse with hypochlorite

  5. Acid and alkali washes

  
  

  Can have problems with this, especially when water at incorrect temps (needs to be 90; and at least 10L).
• Basic housing needs for cows: - Lying area > loose on straw or cubicles

  - Loafing area > natural interactions and oestrus behaviour, 120% of cubicle area must be loafing

  - Feeding space > 60cm per milking cow and 90cm per dry cow (at a minimum, RSPCA says a metre)

  - Safe flooring > reduce injury risk, encourage mounting, also good is uphill and into light.

  - Water > 10cm per cow, and allow 10% of the herd to drink simultaneously. Have diurnal pattern (sunset and peak drinking post milking)

  - Slurry > increase health by minimising slurry contact
• What is bactoscan? Used to measure the actual number of individual bacteria in the milk.

  
  

  This is often more accurate than colonies as cultures are affected by the tendency of bacteria to clump together in the milk.
• Loose housing with straw VS cubical bedding: LOOSE HOUSING: mostly dry cows / calving area. Comfortable so can be good in lameness cases.

  Hygiene can be limited = warm, wet straw can encourage bacterial growth > increased environmental mastitis risk.

  70:30 of bed:loafing, needs good drainage layer under bed, and store the dry bedding under cover.

  Scrape out daily and totally clean out at least every 2 weeks.

  Have clearly divided sections with bedding kept back by sleepers.

  
  

  CUBICAL BEDDING: each cubical needs concrete base with protective mattress. Also division + brisket barrier board + head rail to aid cow position.

  Good practice is 5% more cubicles than cows.

  Aims of cubicle design > comfortable when both lying / standing, 2% slope upwards, dung passed over the kerb with minimum deposited on cubicle rear. Whilst also minimising pathogen growth.

  Dimensions are recommended based on BW.

  Can assess CCQ (cow comfort quotient= <50% is poor, >80% is okay), SUI (stall use index) and SSI (stall standing index)
• What to consider with water supply in dairy herds? Assess daily requirements on the AHDB website.

  
  

  Decreased water supply > immediate affect on milk yield.

  
  

  Average cows need ad lib water, can drink 20L / min.

  
  

  Water trough needs to not be in a dead end, and ideally not over the bedding (so no spillage). Need large trough area with clean water.
• Evidence of poor cubicle design? - Increased disease incidence (lameness, mastitis, lesions- neck, hock, stifles)

  
  

  - Behaviour

  
  

  - Make adjustments and repeat observation of behaviour

  
  

  
  

  LESIONS:

  - Hock lesions > inadequate substrate / bedding

  - Neck > hair loss due to low feed barrier

  - Solar ulceration and / or slurry heel

  
  

  
  

  BEHAVIOURAL OBSERVATIONS:

  - Reversed in cubicle > too high kerb (dislike reversing down steep step)

  - Standing with HL in passage > head rail is too near to the kerb

  - Lying diagonally > cubicle is too wide

  May also be... too far forward, overhanging the kerb, half in-half out, dog sitting, lying in passageway.
• Can green bedding be used in cubicles? Yes it can be used in cubicles, but is not allowed in big straw yards.

  
  

  It is recycled manure solids > slurry pressed to remove any water and then is treated to be reused as bedding.

  Used fresh and not composted.
• What should the lighting be like when housing dairy cattle? Need 16-18h per day > maximise feed intake and milk production.

  
  

  Can increase milk yield by 2L compared to natural photoperiod.

  
  

  Still need to alternate with dark periods. The cows need enough light / dark to move around and exhibit normal behaviour.