Farm animal 4 Flashcards
Outline the management of a possible complications of teat laceration repair in cattle
- Teat fistulas:if unsuccessful repair or left untreated
- perform surgery on granulated tissue at least 2-4 weeks after injury, and after daily cleaning and steps taken to prevent mastitis
- Fistulous tract dissected out all the way to teat cistern to expose healthy teat mucosa
- Close resulting hole with 3 layer closure
When is open teat surgery indicated?
For mid-teat obstructions or teat spiders
Outline open teat surgery in cattle
- Vertical incision on opposite side to lesion
- Do not enter teat sphincter or rosette of Furstenberg with incision
- Granulation tissue masses excised, correct mucosal deficits by undermining adjacent mucosa and sliding over defect
- If >30% mucosa affected, can use prosthetic implant
- Close in 3 layers
Discuss the value of open teat surgery in cattle
- Fresh, non-contaminated, usually elective: good success rate
- Use in place of other methods e.g. teat knives or spirals
Discuss possible complications and their management following open teat surgery
- Haemorrhage: locate and ligate
- Blood clots: may require surgical removal
- Incisional leakage following surgery: close incision again
- Failure to milk from affected quarter: no milk within 24 hours, place sterile teat cannula into teat, lavage with warmed sterile saline and drain teat using cannula until suitable for machine milking
Discuss the management of teat fistulas in cows
- Usually secondary to trauma
- If no effect on normal teat drainage allow to heal self
- can be trimmed and sutured if needed during dry period
What are the indications and contraindications for the use of teat prosthesis?
- Indications: defect in mucosa >30% of mucosa
- Contra: infection, remove if chronic or frequent mastitis cocurs
Outline the management of irreversible trauma and severe gangrenous mastitis in cows
- Teat amputation under local anaesthesia or lumbosacral epidural
- Allow milk to drain and give prophylactiv intramammary antibacterial therapy
- Place rubber tourniquet at base of teat, trim out milk sinus, close defect with 3 layers of sutures
- If necrotic or infected, trim/crush and remove devitalised tissue with burdizzo, then leave open to drain
- Leave tourniquet on for 24-48hours to prevent haemorrhage
Outline the management of supernumerary teats in cattle
- Ideally remove <4 weeks old
- If >3months old must be removed by vet
- Local anaesthetic always recommended
What are the possible complications resulting from supernumerary teats in cattle?
- Interference at milking
- Risk of mastitis
- Cosmetic appearance
Outline the management of conjoined teats in cattle
- Must be removed
- Surgical intervention
- Elliptical incision parallel to long axis of primary teat, dissect down to annular ring to isolate sinus of accessory teat, transect it, close wound in 3 layers
- Care not to enter teat cistern of primary teat
- Good prognosis but consider heritability
Outline the management of atresia of the teat in cows
- Often not seen until first lactation
- Treat as for obstructive lesions
- Consider cause: may be congenital, or as a result of trauma from suckling and infection from flies
List the risk factors for teat hyperkeratosis in cattle
- Long pointed teats
- Slow milking cows
- Higher producing cows
- Peak lactation
- Cluster on before milk let down
- Low threshold for ACRs (automatic cluster release)
- Over-milking
- high vacuum
Describe a teat scored as “N”
- No ring
- Teat end smooth, small even orifice
- Typical appearance for many teats soon after start of lactation
Describe a teat scored as “S”
- Smooth or slightly rough ring
- Raised ring encircles orifice
- No fronds of old keratin evident
Describe a teat scored as “R”
- Rough ring
- Raised, roughened ring with isolated fronds or mounds of old keratin extending 1-3mm from orifice
Describe a teat scored as “VR”
- Very rough ring
- Raised ring with rough fronds/mounds of old keratin extending 4mm or more from orifice
- Rim of ring is rough and cracked, often giving teat-end a flowered appearance
Briefly outline the steps in a clinical examination of a cow’s teats
- All 4 teats and glands
- Examine milk/secretion
- Look and palpate for signs of acute/chronic inflammation (heat, swelling), injury/trauma, coldness
What are cold teats indicative of?
Gangrene
List the methods that can be used for the detection of abnormal milk
- Clinical examination/fore milking
- Conductivity (electrical)
- Chemical tests e.g. acute phase proteins, NAGase
- California Milk test
- Individual cow somatic cell counts
Explain the importance of fore-milking
- Detect abnormal milk
- Legal requirement during milking
- Look for clots, watery consistency, colour change
- May use inline filters to detect clots in milk
Describe the use of conductivity for the detection of abnormal milk
- Charge passed through milk, affected by mastitic changes
- Need to compare over time and between quarters
- Often found in robotic milkers
Describe the california milk test for the detection of abnormal milk
- Detects elevation in SCC
- Crude but useful indicator of subclinical mastitis
- Test kit reagent or Fairy liquid, mix at 50/50 ratio
- High SCC leads to coagulation of solution (changes >400,000 cells/ml)
Describe the use of individual cow somatic cell counts for the detection of abnormal milk
- Useful for detecting sub-clinically affected cows
- Composite sample from all 4 quarters, send to lab for analysis
Explain the difference between clinical and subclinical mastitis
- Clinical: cases detected by farmer during milking e.g. clots, swelling, sick cow
- Subclinical: only detected by SCC >200,000 cells/ml
In a clinical mastitis, what might a low bulk milk cell count be indicative of?
Environmental organisms
In a severe clinical mastitis, organisms are likely to be implicated?
Coliforms
How is the causative pathogen of a clinical mastitis determined?
- Impossible to determine at clinical exam, need to collect sample and send to lab
- Cow side petrifilm available but rare in UK, possibly useful on farms with lots of G-ve infections
- Newer methods: mass spec aka Molditoff, strain typing, not commercially available
What are the steps required to collect a milk sample for bacteriology?
- Clean udder
- Disinfect teat
- Spirit swab teat end
- Collect sample
- Store (can be frozen)
Discuss the value of bacteriology in the investigation of mastitis
- Useful, but sensitivity limited value
- Good decisions can be made without
- Herd patterns often more valuable (timing of infection, SCC, prevalence of infection)
- Important to have bacteriology for Strep. agalactiae
What is lactation new infection rate defined as?
The proportion of cows acquiring new intramammary infections between milk recordings
Explain what is meant by the bulk milk somatic cell count
- Overview of herd
- Calculated from individual cow recordings
- But circumvents on-farm management of bulk tank by withholding cows
What rate of lactation new infections triggers intervention?
5%
Explain what is meant by, and the importance of, the proportion of herd infected and chronically infected
- Provides indication of cows currently infected, as well as those persistently infected
- Can allow insight into potential dynamics within the herd
What would be the most likely cause of mastitis if the proportion of herd infected, and proportion of chronically infected cows is both rising and converging?
Suggests cause is pathogens that are more likely to cause persistent infection, and less likely to be cured i.e. contagious pathogens
What would be the most likely cause of mastitis if the proportion of herd infected, and proportion of chronically infected cows are both rising but diverging?
Suggests cell counts are being driven by pathogens less likely to cause persistent infection and more likely to be cured i.e. environmental pathogens
Define dry period infection rate
The proportion of cows moving from below to above the SCC threshold between the end of one lactation and the beginning of the next (incl. heifers)
Define dry period cure rate
The proportion of cows moving from above to below the SCC threshold between end of one lactation and the beginning of the next i.e. indication of proportion of cows curing during dry period
Define the putative dry period origin mastitis rate and give the target
- The rate of clinical mastitis cases occurring in the first 30 days of lactation
- Only includes first index cases of each cow
- 1 in 12 cows
Define the putative lactating period origin mastitis rate and give the target
- The rate of clinical mastitis cases occurring after the first 30 days of lactation
- 2 in 12 cows