6.2.1: Severe mastitis in sheep and cattle Flashcards
Clinical signs of acute toxic mastitis (cow)
- Severely sick cow - down, ataxic, very dull
- Cardiovascular shock - dehydration, injected mucous membranes, tachycardia, tachypnoea, cold extremeties
- Temperature increases briefly, then is low
- Eating/ drinking/ milking = 0. May see yellow/ watery secretion in milk
What is the prognosis for a severe E. coli mastitis / toxic mastitis?
- Poor
- About 50% of cows will die despite treatment
- Treatment needs to be rapid and aggressive
Treatment of severe E. coli mastitis / toxic mastitis
- Strip all quarters - try to get all the milk (and endotoxin) out
- TLC - keep her comfortable and sheltered
- NSAIDs e.g. flunixin (probably most potent endotoxic properties), ketoprofen, carprofen
- Some people in practice give glucocorticoids
- Systemic antibiotics: practice choice from oxytetracycline/ penicillin + something else / TMPS -> must have good gram -ve coverage
- IV fluid therapy - 4.5 ml/kg hypertonic saline (about 3L per cow) given quickly; provide cow with water. Could give oral fluids. Sheer volumes make isotonic fluids cost-prohibitive.
True/false: there is a vaccine able to prevent E. coli mastitis
False
* The vaccine does not prevent E. coli mastitis very effectively but does decrease severity
* Is expensive but only have to save 2-3 cows from death to benefit
* Requires 3 doses during the dry period so a bit of hassle
Many cases of toxic mastitis in cows are acquired when?
In the dry period
Factors affecting treatment outcome in cows with toxic mastitis
- Concurrent disease
- Age of cow
- Prognosis is often poor regardless of what you do - warn the client of this
Impact of mastitis in sheep
- Loss of udder function in ewes, reduced milk yield and quality
- Welfare issue and sometimes death of ewes
- Leads to premature culling of ewes
- Reduce milk production leads to lower growth rates of suckling lambs and impacts on farm profitability
- Estimated to cost the UK sheep industry £120 million per year in direct and indirect costs, ranked as one of the most important diseases affecting ewes
Clinical signs of acute mastitis in sheep
- Red/discoloured, hot, swollen udder or half of udder
- Udder is painful to touch
- Behavioural changes due to pain: lameness, increased vocalisation, reduced activity, unwillingness to lie down, not allowing lambs to suckle
- Unusual discharge: watery milk, pus
- Manual expression of milk may be difficult or impossible
- Other systemic signs: increased temperature, anorexia, increase in SCC
- Severe cases: can turn gangrenous (black bag, blue bag) due to bacterial toxins, udder or half can slough off and ewe may appear well after this; ewe may die and risk of secondary infection is
Clinical signs of subclinical mastitis in sheep
- Ewes will have increased levels of somatic cells in the milk
- Other indicators: underperforming lambs due to reduction in ewe milk yield and quality; lambs take longer to achieve finishing rate
Clinical signs of chronic mastitis in sheep
- Masses in udder can be palpaed -> lumps of abnormal consistency when compared with rest of udder (these are abscesses that have formed as a result of infection; size does not correspond with severity)
- Abscesses can rupture, spreading infection around the udder, and can reform at a later date
Major mastitis pathogens in sheep
- Major causative bacterial species: Staph aureus, Mannheimia haemolytica, Strep spp., E.coli , coagulase-negative Staphylococci (CNS)
- Staph aureus = acute, subclinical and chronic disease
- Mannheimia haemolytica = thought to be most common cause of acute mastitis in parts of UK, can persist and cause chronic disease
- E. coli = acute, also causes gangrenous mastitis
- CNS pathogens have been linked to acute and subclinical disease - less significant than other pathogens
How is mastitis transmitted to sheep?
- May be from environment e.g. E. Coli
- Could be contagious from sheep to sheep e.g. Staph aureus
- Can be spread via milking equipment/staff in dairy sheep
- Can be spread through cross-suckling of lambs in flocks of meat sheep
- Actual transmission pathways yet to be established
Risk factors for mastitis in sheep
Many are anecdotal and not necessarily causal
* Nutrition
* Low BCS
* Hygiene esp poor hygiene at lambing time, high stocking densitites
* Intramammary masses (IMM) - as % in flock with IMM increases, so does the risk of IMM in lactation in individual ewes
* Teat lesions - create an entry point e.g. orf
* Teat position and udder conformation
* Cross-suckling
* Age - increased risk of all types of mastitis in ewes >4 yrs
* Maedi Visna - can causes mastitis, presented as lesions and hardening of the udder
* Indoor lambing - incidence of mastitis is higher when indoor compared with outdoor lambing
Prevention of mastitis in sheep
- Maintain ewe BCS at 3+ -> may need more energy + protein in pregnancy/ lactation
- Provide extra supplementation for thin and old ewes
- Provide extra nutrition for ewes with multiple lambs
- Consider culling older ewes/ ewes with poor udder conformation
- Separate ewes with mastitis from rest of flock and manage as a separate flock -> reduces transmission between healthy and disease animals
- Ensure there is adequate shelter for the flock in bad weather -> overcrowding = higher risk
- Vaccinate ewes against orf if present
- There are mastitis vaccines - may only be economically viable for smaller pedigree flocks
Treatment of mastitis in sheep
- Broad spectrum antibiotics IM (amoxicillin or oxytetracycline) given for 5-7 days
- NSAIDs
- Damage is often profound - aim is to save the ewe, not the udder!
- Be realistic about chance of success and recognise that these ewes will likely need to be culled even if they survive
