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The down cow (Modified clinical exam (ideally in lateral recumbency)…

- - - - movement of head of femur in the obturator foramen may be detected in cattle with caudoventral hip dislocation
  - - - often these infections are precipitated by the recumbency, esp. if udder engorged and remains unmilked.
- - - - indicated for use in cattle to control pyrexia associated with bovine respiratory disease and endotoxaemia, and to control inflammation in endotoxaemia
      - 2.2mg/kg BW, IV, SID for 5 days
      - withdrawal time
        
        meat 5 days
        
        milk 1 day
    - - fever, pain and inflammation, particularly during mastitis due to no withdrawal time.
      - 3mg/kg BW IM/IV/SC, SID 3-5 days.
      - No withdrawal period for milk, meat 4 days via IM route and 1 day via IV route.
    - - reduces pain, inflammation and pyrexia due to infectious disease, trauma, surgery and colic
      - IM: 1ml per 20kg bw to be repeated every 48h
      - IV: 1ml per 20kg bw to be repeated every 24h
      - No milk withdrawal period, 12 days for meat.
    - - treatment of muscle pain, rheumatism, febrile diseases, colic etc.
      - Cattle: 10 ml/100 kg body weight by IM or IV injection
      - Withdrawal time: Cattle: 9 days after IV inj., 28 days after IM injection
    - - 1 day withdrawal period in meat and milk
      - Ruminants: 100 mg/kg, twice daily, PO
  - - - hip lifter which is attached over both tuber coxae
      - assess if cow is trying to use legs (good for diagnosis)
      - leave to stand for period with hoist still attached
      - often causes superficial traumatic injuries
    - - fits around cow and can be used to lift
      - more comfortable than bashaw hoist, less pressure points
      - more staff and skill dependent
    - - gold standard option
      - Lift cow into full tank of warm water using a sling or hoist
      - slide cow into tank, slow door, fill tankard let cow float whilst tank is being filled up, ensure cow does not drown. For longer periods of time, drain the tank with standing cow.
    - - roll cow on inflatable bag
      - inflate bag and prevent cow from rolling off.
- - - - give IV Ca, but may be continued loss so ensure adequate Ca in feed and can give subcutaneous Ca, which is longer lasting.
        
        calcium gluconate salt often used
        
        calcium is cardiotoxic so must administer slowly (10-20min), while cardiac auscultation is performed
        
        if severe dysrhythmias or bradycardia develop, administration should stop until rhythm returned to normal. Endotoxic animals esp prone to dysrhythmias.
        
        administration of oral calcium avoids risks of cardiotoxic effects (useful if mild, but not recommended as sole approach for clinical milk fever cases).
        
        Note that cows with hypocalcaemia often have poor swallowing and gag reflexes, care to avoid aspiration pneumonia.
        
        animals not responding by 4-8 hr should be re-evaluated and re-treated if necessary.
      - commonly at or soon after parturition. Esp. high-producing dairy cows entering their 3rd or later lactations.
      - changes in mentation, generalised paresis, circulatory collapse
        
        parturient paresis (usually within 72 hours of parturition) can contribute to dystocia, uterine prolapse, retained fatal membranes, metritis, abomasal displacement and mastitis
        
        often retain foetal membranes, due to decrease Ca for contractions
      - sudden decrease in serum calcium levels causes hyper excitability of the nervous system and reduced strength of muscle contractions, resulting in both tetany and paresis
      - Prevention
        
        feed low Ca diets during the dry period
        
        -ve ca balance results in decline in blood ca conc. This stimulates PTH secretion, which in turn stimulates bone resorption and renal production of 1,25 dihydroxyvitamin D. This increases bone calcium release and increases efficiency of intestinal calcium absorption.
        
        difficult to formulate diets low enough in calcium (<20g absorbed calcium/cow/day).
        
        dietary straw and calcium binding agents such as zeolite or vegetable oil may make this approach more useful.
        
        delayed or incomplete milking after calving, which maintains pressure in udder and decreases milk production, but this may aggravate latent mammary infections and increase incidence of mastitis
        
        Dietary cation-anion difference
        
        decreases the blood pH of cows during the late prepartum and early postpartum period
        
        Most dairy cows are in a state of metabolic alkalosis due to high potassium diets. This combined with increased blood pH predisposes cows to hypocalcaemia by altering the conformation of the PTH receptor, resulting in tissues less sensitive to PTH/
        
        Reduce potassium content of diet
        
        include corn silage as large proportion (low K)
        
        Alfalfa
        
        Avoid use of K fertilisers on fields used to grow dry cow forage.
        
        Add readily absorbable anions to diet (more H+ -> lower pH of blood)
        
        Add anionic salts
        
        Calcium chloride
        
        Magnesium chloride
        
        magnesium sulfate
        
        calcium sulfate
        
        ammonium sulfate
        
        ammonium chloride
        
        Poor palatability
        
        mix with moist palatable ration e.g. molasses
        
        Mean urine pH ranges from approx. 6-6.5 are optimal. Urine should be measured >24hr after addition of an anionic diet in pre-fresh cows.
      - Clinical signs
        
        Subclinical (blood calcium 1.8-2.3mmol/l)
        
        able to stand
        
        hypersensitivity
        
        excitable
        
        Tremors
        
        ear twitching
        
        ataxia
        
        bloat/gas in gut (decreased gut motility)
        
        Clinical-moderate (blood calcium 1.2-1.8mmol/l)
        
        sternal recumbency (skeletal muscles, as well as smooth muscles start to be affected)
        
        depressed
        
        dry muzzle
        
        cold extremities
        
        bloat/gas in gut
        
        No defecation
        
        delayed/absent pupil responses
        
        severe (blood calcium <1.2mmol/l)
        
        decreased consciousness
        
        lateral recumbency
        
        unresponsive
        
        muscle flaccidity
        
        decreased cardiac output
        
        increased bloat -> death
      - Treatment
        
        I/V slowly- 20% CaBorogluconate 400ml (use 1 or 2 bottles) or 40% CaBorogluconate 400ml (1 bottle)
        
        Monitor HR, 1 bottle of 20% often enough- overdosingcow yo-yoing between hypoCa & hyperCa
        • Give S/C deposit to prevent recurrence (slow release)
        • Low Volume treatments Maxacal100ml
        • Also some mixed with Mg, P, Glucose
        • Proof of recovery: Passes dung, eructates, help cow to sit up if req.
    - - Staggers/Grass tetany, mainly in postpartum cows.
      - Little homeostatic regulation of Mg in ruminants (supply+demand)
      - deficiency (<0.5mmol/l) arises when high demand is combined with decreased intake
      - clinical signs (range from per acute to sub clinical)
        
        Hyperaesthesia
        
        excessive physical sensitivity and sensitive to sound/hand clap
        
        Ears twitching, champing of jaws, tachycardia, staggering and collapse (can lead to sudden death).
        
        In sub acute cases: slow onset over 3-4 days, typically quite subtle. Spasmodic urination + defecation, subtle muscle tremors and staggering gait.
        
        can usually spot and treat this.
        
        in chronic cases: few signs, poor appetite and decreased milk yield (not specific).
      - Causes
        
        Low Mg levels in diet (fresh grass - minerals diluted)
        
        Poor feed intakes (rain)
        
        Poor absorption of Mg
        
        Mg normally crosses the luminal wall quite passively and is absorbed, but...
        
        High potassium or nitrogen in ration and so in the blood = +ve ions, so prevent absorption of Mg (DCAB)
        
        Increase passage rate (lush grass) reduces the absorption rate of Mg
      - Treatment
        
        Beware the hyperaesthesia makes cows more likely to kick
        
        Bottle Ca borogluconate with Mg hypo phosphate IV slowly
        
        magnesium sulphate 25% s/c only
      - Prevention
        
        MgO in concentrates, mix with molasses. Not ideal for beef cows as often do not get fed concentrates, but Magnesium alone is not very palatable.
        
        Mg bolus oral
        
        Mg tablets/flakes added to drinking water, not ideal for beef as get most of their water from grass
        
        Avoid using potassium fertiliser or pig manure on pasture when hypomag is a known issue
    - - 'Happy' downer cows, alert and normal demeanour
      - Possibly if no response to Ca/Mg tx
      - Tx= Foston IV
  - - - Fractured long bones (especially in animals with subclinical hypocalcaemia)
      - Sub/dislocated joints (hip/knee)
      - Nerve damage
      - Muscle rupture (e.g. from cow doing splits)
        
        often see haemorrhage and rupture of adductor muscles
      - Peripheral nerve damage
        
        often caused 2ry to the cow being down
        
        e.g. peroneal/tibeal nerve damage causing hyeprflexion of the fetlock (knuckled), will recover in 2-3 month period.
    - - ischaemic necrosis of muscle esp. hindlimb
      - Compression -> anorexia -> cell damage -> inflammation -> further swelling -> poor tissue perfusion -> repeat
      - cows can recover from this, need to get cows up and supported so muscles can re-perfuse
      - Occurs 2ry to being down (primary cause e.g. Ca, Mg, P may be resolved already).
      - Lymphatic and venous drainage to muscle is decreased due to sustained pressure with no decrease in arterial blood flow
        
        causes an increase in interstitial fluid volume and pressure within muscle, because the fascia around each muscle cannot expand sufficiently to accommodate the increase in interstitial volume
        
        The increase in intramuscular pressure may be visible as a firm swelling of the muscle.
      - Complications
        
        damage to and functional loss of the sciatic nerve and its peroneal branch
        
        acute mastitis
        
        decubital ulcers
        
        decubital injuries to the lateral aspect of the stifle can be associated with damage to the perineal nerve.
        
        traumatic injuries to limbs e.g. laceration and rupture of muscle fibres in thigh from struggling and efforts to rise
    - - nerve damage during parturition
      - Obturator nerve damage/muscle rupture
        
        calving paralysis syndrome is damage to the L6 lumbar roots of sciatic and obturator nerves
  - - - manage by hobbling the cow
      - sciatic nerve may be damaged by direct compression against the caudal femur, secondary swelling of the surrounding muscles or both
        
        hyeprflexion of the fetlock indicates perineal nerve paralysis
      - Damage to the perineal branch of the sciatic nerve results from direct pressure on the nerve as it crosses over the lateral condyle of the femur
- - - - Indicates extensive muscle damage and euthanasia is necessary
      - AST best prognostic indicator in recumbent cattle. This is because although increased serum CK activity is a specific indicator of muscle damage, CK activity peaks shortly after the start of muscle damage and declines noticeably within 4hr.
      - In cattle with severe muscle damage, the urine may contain myoglobin as well as higher than normal concentrations of protein.