Ruminants Pathology Flashcards
1
Q
Field Sx prep considerations
A
- Hazard analysis - critical control points - how to minimise + back-up plan
- Sx procedure
- Handling + restraint facilities
- Environment - v contaminated
- Patient + assistants
- Location - sheltered, weather
- Flooring - non-slip, clean, bedding, rubber matting
- Restraint - temperament, compliance, halter, crush, tie small ruminants down
2
Q
Contaminated environment
A
- Transport to more appropriate environment
- Sx freq infected - pre-operatively + prep
- High likelihood of inadvertent, accidental contamination during Sx
- Freq need for perioperative AB
- Inc risk of post-operative infections
3
Q
Main pre-op considerations
A
- Local/regional anaesthetic techniques - infiltration/inverted L; proximal/distal paravertebral (T13 - L2 +/-3); epidural (L6 - S1 or C1 - C2)
- Speed of onset
- Licensed anaesthetic agents e.g. procaine + adrenaline
- Analgesia - ideally few hours before/IV at beginning to do Sx prep
- Pre-op antimicrobial therapy - not advised during Sx
- FT
- Sx prep
4
Q
Pre-op antimicrobial therapy considerations
A
- Infection status - non-contaminated (0 d min) e.g. LDA correction; contaminated (3 - 5 d min) e.g. C-section to remove dead calf; infected (5 - 7 d min) e.g. TRP
- Contamination risk - opening viscera; decompressing viscera; duration of Sx + environmental hygiene; patient compliance w/ procedure
- Likely bacteria present - G+ organisms in skin; G- organisms associated w/ GIT + repro tract; anaerobic organisms - GIT + established peritoneal/uterine infections - resistance + C&S
- IV/IM
- Licensed products
- Milk + meat withhold - therapeutic aspects e.g. spectrum considered first
5
Q
Opening viscera procedures
A
- Rumenotomy
- Typhlotomy - removal of fermenting contents in cattle with enlarged caeca due to hypocalcemia and poor motility and with caecal displacements and torsions
- C-section
6
Q
Decompressing viscera procedures
A
- Right-sided approach to LDA correction
7
Q
Pre-op FT considerations
A
- Pre-op assessment - hydration status, degree of shock
- Likelihood of electrolyte derangement
- Acid/base balance
- Route (IVFT/ORT) + timing with regards to Sx
- Condition - RVA (right displacement + volvulus of abomasum) produces marked systemic shock with severe electrolyte derangement (hypochloraemic, hypokalaemic metabolic alkalosis); grain overload results in systemic shock with a metabolic acidosis
8
Q
Pre-op Sx prep considerations
A
- LA first
- Wide clip area - for procedure, externalisation of viscera necessary
- Secure tail in cattle - tie to cow
- Sx scrub
- Sx gloves, gowns + drapes
9
Q
Laparotomy considerations
A
- Access - large abdo size; cranial extension of abdo cavity beneath rib cage - only some viscera can be exposes, others can only be visualised, some only alpated; short mesenteries + omenta limit visceral mobility, rumen obstructs left flank
- Location of path
- Technique + familiarity
- Compliance of patient
- Handling + restraint
10
Q
Exploratory laparotomy indications
A
- Severe or inc abdo pain, unresponsive to analgesics
- Unresponsive or deteriorating shock
- HR > 120 BPM, congested MM,
CRT > 3 s, weak peripheral pulses, cold extremities - Rectal exam findings - distended SI loops, tight mesenteric bands, palpable impaction
- Chronic rumenal indigestion/tympany
- Complete absence of faecal production
- Lab findings - clinical biochem - severe pre-renal azotaemia/and or ion sequestration; abdominocentesis suggesting gut necrosis/rupture
- To obtain Dx
- Most of time Right approach - access to more organs
- If have suspicion won’t have access on LHS e.g. TRP penetrated peritoneum - better access to peritoneum
- RHS impedes access to reticulum - liver
11
Q
Ruminal Sx disorders
A
- Traumatic reticulopericarditis (C)
- Ruminal tympany (bloat)(peracute/chronic) (C/S/G) disorders
- Impaction (C/S/G)
12
Q
Abomasal Sx disorders
A
- Left displaced abomasum (C)
- Right abomasal dilatation, displacement and volvulus (C)
- Impaction (C/S/G)
- Ulceration (C/S/G)
13
Q
Intestinal Sx disorders (uncommon)
A
- Intestinal intussusception (C/S/G)
- Caecal dilatation and torsion (C)
- Rectal prolapse (C/S/G)
14
Q
Rumenotomy indications
A
- Suspected TRP - access to inside of rumen, traumatic reticulo-pericarditis
- Ruminal FB (esp if linear)
- Ruminal tympany (chronic/acute) - alternatively place ruminal trochar + red cannula (red devil), frothy/free gas
- Ruminal impaction
- Grain overload + acidosis
- Intoxication
15
Q
Ruminal trochar placement
A
- Peracute ruminal tympany unresponsive to decompression
- Management of chronic ruminal tympany = chronic intermittent bloat
16
Q
Abomasal disorders - considerations for Sx approach
A
- Effective return and stabilisation of the abomasum in a normal anatomical
position - Management of concurrent abdominal pathology
- Minimising additional risk
- Practicality in light of available handling facilities
- Economic cost-benefit
- Surgeon experience and familiarity with the chosen technique
17
Q
LDA
A
18
Q
Intra-op complications of LDA Sx
A
- Failure of decompression - obstruction of tubing; incorrect needle placement; inadequate reach/large abdo size; incorrect Dx
- Failure of relocation - adhesions; incomplete decompression; dorsal incision placement/deep abdomen (unable to reach ventrally to get abomasum); incorrect Dx
- Other - peritonitis (v poor Px); friable intra-abdo/omental fat
19
Q
LDA - open Sx adv
A
- Good visualisation
- Concurrent pathology addressed
- Suitable for most DAs
- Adhesions of body wall can be managed
- Low risk of recurrence
- Prognosis 80 -100%
20
Q
LDA - open Sx disadv
A
- More invasive
- Time consuming
- More expensive
- Risk of generalised peritonitis
- Reasonable surgeon arm length
- Right paramedian requires rolling
21
Q
LDA - closed Sx adv
A
- Less expensive
- Rapid
- Any surgeon arm length
- Relatively low risk of recurrence
- Prognosis 77 - 91%
- Inc visualisation + less invasive w/ laparoscopy
22
Q
LDA - closed Sx disadv
A
- Blind procedure - less visualisation of other viscera
- Concurrent pathology not addressed
- Risk of trauma to other viscera
- Requires rolling
- Careful case selection (large gas cap and absent adhesions)
- Risk of local peritonitis and abomasal fistula
- Laparoscopy - expensive equipment
23
Q
RDA - indications for Sx intervention
A
- Present or deteriorating hypovolaemic/endotoxic shock - torsion more common
- HR > 120 bpm; congested MM; CRT > 3 s; weak peripheral pulses; cold extremities
- Severe or inc pain unresponsive to analgesics
- Regurg on passing stomach tube
- No response to conservative management in 2 - 4 h
24
Q
Caesarean section indications
A
- Irreducible obstructive dystocia
- Absolute foetal oversize
- Uncorrected faulty posture / position / presentation
- Congenital monster - deformities
- Irreducible uterine torsion
- Prolonged duration of dystocia
- Delayed assistance
- Insufficient progress towards vaginal delivery
- Appropriate manual / mechanical traction is ineffective
- Foetal distress
- Elective caesarean section
25
Maternal dystocia - inadequate expulsive forces
- Primary uterine inertia - overstretching; incorrect E2 : P4 ratio; inadequate secretion of oxytocin + PGF2 section; failure of receptor regulation/development; Ca2+ and/or Mg2+ deficiency; fatty infiltration of myometrium; nervous voluntary inhibition; hysteria
- Secondary uterine inertia - myometrial 'exhaustion'
- Weak abdo straining - age, debility, pain, herniation of uterus
26
Maternal dystocia - inadequate size of birth canal (obstructive dystocia)
- Incomplete dilation/constriction of birth canal - uterus: torsion, displacement; cervix: ringwomb, (incomplete dilation), duplication; vagina: stricture, neoplasms, cystocele, prolapse, vestigial structures; vulva: stricture, incomplete relaxation
- Feto-maternal (pelvic) disproportion - inadequate pelvis - immature; Fx; breed deformity
27
Foetal dystocia - oversize, feto-maternal (pelvic) disproportion (obstructive dystocia)
- Relative + absolute - small litter; breed; prolonged gestation' IVM/IVF derived embryos
- Congenital monsters
- Foetal pathology - ascites; anasarca; emphysema
28
Foetal dystocia - fault disposition (obstructive dystocia)
- Presentation
- Position
- Posture
29
C-section - additional pre-op considerations
- Calf - size + weight, position + location, preparation for resuscitation, availability of Doxapram
- Cow - uterine contraction (clenbuterol); abdo contraction (epidural); recum vs standing; temperament + available safe restraint
- Equipment - calving ropes, Kruse caesarean knife; tie a long rope to contralateral HL
30
C-section - right-sided paralumbar fossa laparotomy indications
- Calf in the right horn (especially posterior presentations)
- Intractable uterine torsion
- History of previous surgery on the left flank
31
C-section - left ventrolateral laparotomy indications
- Useful dead emphysematous foetus
- Improved uterine exposure and reduced contamination of abdomen
- Requires right lateral recumbency and elevated right hind limb
- Closure is more involved and prolonged
32
C-section - common complications
- Infections - peritonitis,metritis, incisional infection + woun dehiscence
- RFM
- Abomasal disorders
- Adhesions
33
Episiotomy indications
(Cut between vagina and anus (perineum))
- Heifers
- Incomplete relaxation of posterior vagina/vulva (usually heifers)
- Prevent tearing of vaginal wall
34
Vaginal/cervial prolapse considerations
- Usually in mature cows/ewes - last trimester
- Elevation of intraabdominal pressure - Pregnant uterus; Fat; Rumen distention; Due to relaxation and softening of pelvic canal/perineum (oestrogens and relaxin)
- Severely damage to prolapse or unresponsive to treatment - elective caesarean might be indicated (premature neonates), +/- induction
35
Atresia ani
- Lambs
36
Elastrator bands - adv
- No training /expertise
- Farmers can use
- No open wound
- Quick + easy
- Can combine w/ tagging
37
Elastrator bands - disadv
- Cannot use in older animals - becomes one big necrotic tissue mass, poor age compliance
- Chronic pain + reduced growth rate
- No local anaesthetic - welfare, analgesia not always used
- Unilateral or failed castration due to testicular retraction
- Failure of elastrator ring
- Dehiscence + infection
38
Burdizzo - adv
- Good option for poor hygiene when don't want open wound
- Local given > 2 m/o by vet
- Performed by farmer up to 2 m/o
- No training/expertise
39
Burdizzo - disadv
- Testicles not removed - potential still left entire
- Failure to occlude blood vv / failure to occlude vas deferens
- Accidental crushing of urethra - if crush too high up = fatal
- Sloughing of scrotal skin - clamped too many blood vv
40
Surgical castration, twist + pull - adv
- Guaranteed both testicles
- Anaesthesia + analgesia used
- Quickest Sx castration
- Can remove inguinal testicles also
- Carry out on any age
41
Surgical castration, twist + pull - disadv
- H+
- Infection + abscessation
- Fly strike
- Tetanus
- Eventration
- Adhesions of remnant of spermatic cord to bowel (rare + operable_
- Herniation - tunic = extension of peritoneum
- Must be carried out by vet
- Open wound - risk if poor hygiene
42
Surgical castration, emasculator - adv
- Guaranteed both testicles
- Anaesthesia + analgesia used
- Can remove inguinal testicles also
- Carry out on any age
43
Surgical castration, emasculator - disadv
- Must be carried out by a vet
- Open wound - risk if hygiene
- Clamp must remain in place for 1 - 2 min
- Risk of bleeding / infection
44
Sheep + goat castration considerations
- Small ruminants - more sensitive to local anaesthetic, small amounts toxic to goats
- Large testicular to bodyweight ratio
- Large vasculature
- Higher likelihood of herniation
- GA/Sedation risk
- Pet animals
45
Vasectomy
- To produce teaser males
- Removing spermatic cord + leaving testes; removal of a segment of ductus deferens
- Mostly done in sheep, can do in cattle
46
Vasectomy - post-op care advice + complications
- Could be fertile for up to 6 weeks after procedure
- Some evidence to suggest they are infertile after 2 weeks - leave for 2 w until introduced to any fertile females
- Preserve sections in formalin
- Could semen test before use to confirm have the spermatic cord
- Infection
- Herniation
- Haemorrhage
- Recanalisation and misalliance
- Testicular atrophy
- Removal of wrong thing
47
Urolithiasis
- Small ruminants, can affect cattle
- Ca2+, Mg2+, NH3, PO4^3-
- Risk factors - early castration (prevent full urethra dilation, stones stuck), high BCS, high conc diet, inadequate water supply
- Obstruction to urethra +/- bladder rupture
- Calcium phosphate most common
48
Urolithiasis - Dx
- CS - discomfort/colic, dry prepuce, kicking at abdo, inappetence, pulsating urethra on rectal exam
- Dx - US examination of bladder-large/presence of uroliths
- Usually found at sigmoid flexure or vermiform appendage (urethral process)
49
Urolithiasis - pathogenesis
- 1). High conc, low roughage diet
- 2). Dec production of saliva
- 3). Reduced excretion of phosphorus through saliva + into faeces
- 4). Inc levels of phosphorus get secreted in urine
- 5). Formation of urinary calculi
50
Urolithiasis Sx - post-op complications
- Complication rate high
- Bladder rupture
- Infection - cystitis
- Urethritis
- Recurrent obstruction
- Urine scald
- Anaesthetic complications
51
Castration - general anaesthesia recommended
- Mature goats / sheep (> 6 - 8 )
- Due to large relative testicular size + associated vasculature
52
Cattle castration - haemostasis
- < 6 m = torsion + traction
- 6 - 12 m = torsion, emasculators
- > 12 m = emasculators
53
Sheep + goats castration - haemostasis
- < 2 m = torsion + traction
- > 2 m = emasculators
54
Other conditions of the penis + prepuce
- Penile haematoma -> adhesions/abscessation - rupture of tunica albuginea, conservative Tx or Sx to remove blood, clots + serum
- Penile deviations - spiral deviation -> ejaculation slips to side, Sx to anchor apical ligament to penis so cannot slip laterally
- Penile fibropapillloma - young bulls (1 - 2 y/o) -> makes intrommission impossible + H+ affects semen quality - Sx = resection
- Persistent frenulum - Sx = resection of fibrous band under local
55
Umbilical disorders
- Omphalitis ('Navel ill') - infection of umbilical stump
- Umbilical abscess - organised infection - superficial or intra-abdominal
- Umbilical hernia - simple or complicated w/ concurrent infection
- Umbilical remnant disorders - urachal abscess, infection/abscessation of umbilical vein/arteries, persistent urachus
56
Omphalitis (Navel ill/umbilical abscess)
- Infection of umbilical stum,p - poor hygiene + poor umbilical care of neonate
- Umbilical abscess = 2y to omphalitis - walled off infection persists in umbilical stump
- May be concurrent w/ umbilical hernia
57
Omphalitis (Navel ill/umbilical abscess) - Dx
- Firm, hot, painful, non-reducible mass (cannot put back into abdo)
- Pyrexia + systemic illness
- Draining + sinus tract/purulent discharge
- US - hyperechoic pus = 'starry sky'
(Hernia = ST + guts on US + will see perstalsis movement)
- Risk of hernia + abscess at same time
- Deep abdo palp -> palpable intra-abdo dorsal extension of umbilical mass + on US
58
Umbilical hernia
- Ventral midline body wall defect extending causally from umbilicus
- Contents: greater omentum/abomasal fundus/intestinal loops (rare) - short mesentery attachments + enclosure in mental sling so less moveable
- Strangulation of intestines = emergency - lack of blood supply + necrosis, can deteriorate v quickly
- Due to failure of normal development + closure of umbilicus
- Dx - soft, non-painful, reducible lump, present shortly after birth
59
Umbilical hernia - pre-op considerations
- Case selection - small defects unlikely to become strangulating and can resolve themselves
- Large defects require surgical treatment
- Leaving/fattening the patient may result in entrapment and strangulation
- Age - old enough have strength for healing, holds fibrous ring suture / young - standing Sx, less rumen pressure on ventral abdo, perform from 8 - 12 w + reduced anaesthetic risk
- Anaesthesia - GA - ketamine + xylazine; high dose caudal epidural will immobilise back legs - consider aftercare of dragging back legs + ventral abdo; sedation + local infiltration
- Antibiotics
- Analgesia - NSAIDs
60
Umbilical hernia - complications and aftercare
- At surgery - intestine adhered to body wall within hernia -> end to end anastomosis
- Infection - wound dehiscence
- Haemorrhage
- Failure of sutures -> re-herniation
- Immediate post-operative complications: hypothermia, poor recovery, recovery injuries
- Clean bedding
- Close monitoring
61
Umbilical remnant disorders
- Urachal abscess - FNA only good Dx for abscess
- Infection/abscessation of umbilical vein/arteries
- Abscess + hernia at same time
- Patent urachus - ligate
62
Atresia ani/recti
- Failure of anal opening
- Congenital abnormality
- Surgical repair required
- 1). Colon/rectum still attached to anal sphincter but skin covering in place, Sx to keep tissues open + connect hole
- 2). Rectum still there but not attached to anal sphincter, no link w/ hole will just go straight into abdo
- CS - anorexia, dullness, abdo distension, discomfort, straining, no anus, no faeces
63
Horn Sx - what is preferred?
- Disbudding (over dehorning) -
- Less stressful + safer for calf + vet
- Improved local anaesthesia
- Reduced risk of horn regrowth
- 1 - 2 w/o (horn buds palpable)
- Or at castration, 4 - 6 w but double stress
- Polled breed (strains) = Hereford, Aberdeen Angus
64
Disbudding + dehorning - complications + after-care advice
- Inadequate anaesthesia
- Haemorrhage
- Infection: dehiscence or sinusitis
- Consider environment scratching on e.g. fence -> introduction of infection
- Fly strike
- Regrowth
65
Goat disbudding complications
- High risk
- Anaesthetic risks
- Ineffective anaesthesia
- Hypothermia - from injectable anaesthesia
- Brain damage - if leave hot iron on for too long can burn brain -> necrosis
- Skill Fx - thinner skull, inc risk
- REGROWTH - more common than in cattle
- Infection
- Fly strike
66
Umbilical remnant infection - urachus; urachal abscess
- Common
- +/- Purulent umbilical discharge
- +/- Pyrexia
- Poor growth/ill-thrift
- Pollakiuria = freq + small vols of urine passed
- Stranguria, pyuria + haematuria if concurrent cystitis
- Deep abdo palp -> palpable intra-abdo caudal extension of umbilical mass + on US
67
Umbilical remnant infection - urachus; persistent urachus
- Common
- Leaking urine from umbilicus
68
Umbilical remnant infection - umbilical vein; omphalophlebitis umbilical vein abscess
- Uncommon
- +/- Purulent umbilical discharge
- +/- Pyrexia
- Poor growth/ill-thrift
- Septicaemia + death
- Deep abdo palp -> palpable intra-abdo cranial extension of umbilical mass + on US
69
Umbilical remnant infection - umbilical arteries; ophaloarteritis
- Rare
- +/- Purulent umbilical discharge
- +/- Pyrexia
- Poor growth/ill-thrift
70
Umbilical repair Sx (herniorrhaphy)
- Umbilical hernias > 2 - 3 cm
- Complicated hernias where there is concurrent abscessation or presence of umbilical remnants
71
En-bloc resection
- Removal of entire tissues w/o violating capsule
- Chronic, intractable omphalitis
- Umbilical abscess complicated by herniation
- Umbilical remnant infection
- Provide pre-op systemic AB min 3 days prior to Sx to reduce contamination of surrounding tissues
- Initial drainage + lavage may be appropriate in some cases
72
Fx management considerations
- FX site - distal > proximal, humeral/femoral - require euth, near impossible to stabilise
- Fx type closed > open; simple > comminuted; mid-diaphyseal > joint
- Animal size + weight younger = lighter, grow v quickly, need casting q 2 - 3 w, will heal by 6 q
73
Deep digital sepsis (DDS) -> digital amputation
- Septic pedal arthritis/osteitis
- +/- Navicular bone arthritis/osteitis
- Retroarticular abscess
- Synovitis + tenosynovitis
- If DDFT gets infected, infection travels up tendon
- Solar ulcer/white line disease - infection gets into foot structure -> septic joints -> DDS
74
Digital amputation
- Mainly cattle - dairy, beef = 2y to injury
- Deep digital sepsis (DDS)
- Toe necrosis
- Intractable claw horn laemness - DDS, toe necrosis, non-healing WLD
- Trauma (uncommon) - degloving/disarticulation
- Sheep + goats do well as less weight
- Most common = lateral hind limb claw amputation
- Infection + non-healing, big wound left to heal by second intention, rely on granulation tissue for healing
75
Digital amputation - considerations
- Salvage procedure - if no other Tx successful
- Px, palliative care, culling
- Area of deep digital sepsis (DDS)
- Other lameness in other limbs
- Imperfect contralateral claw
- Farm environment
- Nursing care available/post-op care
76
Digital amputation - complications
- H+
- Infection - dehiscence, osteomyelitis or ascending tenosynovitis
- Ischaemia + sloughing of sound claw due to tourniquet/thrombus formation
- Premature culling
- Px = guarded - dependent on case selection + post-op care
77
Teat Sx
- Supernumerary teats
- Teat lacerations
- Teat amputation
- Streak canal obstructions
- Fistulas
78
Supernumerary teat removal
- Obstruction at milking
- Greater risk of liner slip
- Cosmetic - show animals
- Performed in young calves at disbudding
- > 3 m/o anaesthetic required + by vet
79
Teat lacerations
- Common - standing on teat
80
Teat lacerations - pre-op considerations
- Full vs partial thickness - don't want to be deep in lumen, partial thickness through skin or will affect canal patency
- Consider amputation
- Age of wound
- Canal patency - teat cannula can be kept in for patency
- Interruption to blood supply
- Vertical vs horizontal laceration
81
Teat amputation
- Teat injury
- Chronic mastitis - when one quarter turns into one big abscess, remove teat -> allows drainage + heals
- Three quarters
82
Teat amputation - complications/after care
- H+
- Infection
- AB
- Flushing depending on cause
83
Entropion
- In-turned eyelid
- Hereditary problems in sheep (carried by the Ram)
- Secondary corneal ulceration
- Treatment varies on severity
84
Enucleation
- Often 2y to entropion
- Neoplasia - Squamous cell carcinoma of
third eyelid, white faced cattle e.g.
Hereford, causes ulceration from rubbing on eye
- Infection - intractable uveitis, severe ulceration: New forest eye, Silage eye, -> deep ulcer through layers of eye about to rupture -> rupture of eye globe, need removing
- Injury - globe rupture, penetrating injury
85
Enucleation - complications
- Complications
- Infection
- Haemorrhage
- Wound breakdown
86
Tail amputation
- Traumatic injury
- Ischaemic injury - tail tape, faecal build-up
- Paralysis - to prevent injury
87
Tail amputation - complications
- Swelling
- H+
- Infection
- Wound breakdown
- Osteomyelitis
88
Digital amputation - contraindications
- Imperfect contralateral claw on same limb
- Severe, ascending tenosynovitis
- Lameness affecting another limb
89
Teat canal obstruction
- Blind/blocked teats in maiden heifers
- Trauma and scarring
