Top 20 Bovine Conditions Part 4

For my own personal use only:
cow
  • This four-part series on the top 20 bovine conditions will set you up for boards success.
  1. Listeria monocytogenes
    image
    Unilateral facial nerve paralysis (here, right-sided ear and eyelid droop) is often seen in listeriosis
    • Classic case: Weaned-to-adult silage-fed cow
      • Acute onset pyrexia, depression, anorexia
      • Unilateral neurological signs:
        • Propulsive circling
        • Proprioceptive deficits
        • Unilateral tongue weakness, facial nerve paralysis, ear droop
        • Head tilt, nystagmus, strabismus
        • Drooling
      • Can cause placentitis, late-term abortion, and stillbirth
    • Dx: clinical signs confirmed by:
      • CSF: increased mononuclear cells, high protein
      • Culture: L. monocytogenes in brain or aborted fetal tissues
    • Tx:
      • IV oxytetracycline
      • Supportive care
        • Tube feeding, oral rehydration for inappetant animals
        • Electrolyte supplementation (potassium and bicarbonate lost in saliva)
    • Pearls:
      • Prognosis: fair to good if patient ambulatory at onset of Tx; poor if patient is recumbent at onset
      • L. monocytogenes grows in spoiled silage that is often at an elevated pH
      • Ascends nerves to brainstem, animal also becomes bacteremic
      • Often occurs in winter due to ability of pathogen to grow in cold temps
      • Contaminates milk; ZOONOTIC!

  2. Retained fetal membranes (RFM), metritis, pyometra
    image
    An expelled placenta
    • Classic case:
      • RFM: if not passed by 24 h post-partum
        • May see decomposing placenta hanging from vulva with foul smell
        • Delayed return to estrus
      • Metritis: 3 d to 2 wks post-partum
        • Large, fluid-filled uterus palpable per rectum
        • Red-brown, purulent, malodorous discharge from vulva and matted on tail
        • Shortened estrous cycles
      • Pyometra: similar to metritis
        • Purulent or mucopurulent exudate but NO odor
        • Corpus luteum (CL) on the ovary
    • Dx:
      • RFM: apparent visible signs
      • Metritis: etiologies usually nonspecific infection, but also:
        • Brucellosis
        • Leptospirosis
        • Campylobacter spp.
        • Trichomoniasis
      • Palpation per rectum for metritis/pyometra:
        • Enlarged, fluid-filled uterus
        • Retained CL with pyometra
    • Tx:
      • Retained placenta:
        • Manual removal potentially harmful, not recommended
        • Trim excess tissue for hygiene
        • Cows expel the membranes in 2-11 d without Tx
        • Intrauterine antimicrobials NOT usually beneficial and would be extralabel drug use
      • Metritis: prostaglandins
        • If cow septic: systemic antibiotics, NSAIDs, IV fluids
      • Pyometra: prostaglandins
    • Pearls:
      • Prognosis: good to excellent for all three conditions with appropriate Tx
      • Metritis and pyometra negatively impact reproductive efficiency by delaying return to normal estrous cycle postpartum
      • Good dry cow management is essential to prevent RFMs and metritis

  3. Uterine prolapse
    image
    Uterine prolapse, note the visible caruncles
    • Classic case:
      • Multiparous dairy cattle OR first-calf beef heifers
      • Within hours of calving, at most
      • One or both uterine horns everted from vagina and vulva
      • Caruncles (and often RFM) are visible
      • +/- Concurrent milk fever
      • Severe cases: hypotensive, hemorrhagic shock, often from rupture of the uterine artery
    • Dx: evident on physical exam
      • Labwork for IV fluid plan: assess serum ionized Ca+, K+, phosphorus, Mg+, PCV, and total protein
      • Tx in the field is usually presumptive based on clinical signs
    • Tx: physically difficult!
      • Address shock
      • Cleanse uterus and give epidural
      • Push uterine tip up and in, working between bouts of straining, using a closed fist to prevent laceration of the uterus
      • Once replaced, fill uterus with clean warm water, and then siphon it out OR fully evert tips using disinfected bottle to ensure complete reversion
      • Real-life tip: use caution administering IV calcium prior to everting uterus as it can increase straining against you as you work!
    • Pearls:
      • Prognosis good to excellent assuming minimal complications such as hemorrhage or uterine laceration
      • If properly replaced they do not recur, or only infrequently
      • Prevent uterine prolapses by minimizing incidence of milk fever

  4. Frothy bloat
    image
    Abdominal distention typical of bloat (arrows)
    • Classic case:
      • Acute abdominal distention: mainly on left side
      • Tachycardia
      • Open-mouthed breathing
      • STABLE frothy green rumen ingesta
        • Foam bubbles do not pop
        • Cow cannot eructate and blow off rumen gas
      • May be found acutely dead, bloated on left
    • Who gets bloat?
      • Pasture cows, recently put on legume pasture (past 2 wks)
      • Feedlot cows, cause unclear, but main theory:
        • Slime-producing rumen bacteria colonize rumen when fed high-concentrate, fine particulate diet
      • Remember that free gas bloat also occurs (many causes):
        • Generally due to obstruction of normal free gas eructation or decreased rumen contractions
    • Dx: visually see bloat, but to Dx frothy vs. free gas bloat:
      • Pass tube into the rumen
        • Frothy: frothy green rumen ingesta oozes out and not much relief of bloat
        • Free gas: high volume of gas blows off and bloat resolves
    • Tx:
      • Mild/early frothy bloat:
        • Antifoaming agents: help froth/foam bubbles pop, i.e.:
          • Vegetable or mineral oil, 250-500 mL
          • Dioctyl sodium sulfosuccinate (DSS, a veterinary surfactant): commonly combined w/ oils
          • Poloxalene for legume bloat, but not feedlot bloat
      • Severe, life-threatening case:
        • Emergency rumenotomy
        • Short of surgery, try a large-bore (2.5 cm) rumen trocar or cannula
        • Give antifoaming agents through it, allow gas to blow off (takes hours)
      • Free gas bloat:
        • Determine cause of physical or functional obstruction of eructation to prevent recurrence
    • Pearls:
      • Prognosis good for mild, early cases
      • Prevention, frothy pasture bloat:
        • Ionophores (monensin, lasalocid)
        • Gradually introduce cows to lush legume pastures
        • Feed hay prior to pasture access so they do not gorge themselves
      • Prevention, frothy feedlot bloat:
        • Add 10-15% coarse-chopped roughage to feed
        • Ionophore supplement like lasalocid

  5. Displaced abomasum (DA)
    image
    Location of LDA ping:
    yellow line between L elbow
    and L tuber coxae
    • Classic case: Multiparous dairy cow within 30 d of calving
      • Partial anorexia and decreased milk production
      • Scant stool with different consistency from herdmates
      • "Popped" or "sprung" rib cage: ribs pulled outward
      • High-pitched tympanic or musical "ping" over ribs
        • Ping on line between L elbow and L tuber coxae (hip) along ribs 9-13 for left DA (LDA)
        • Ping on R for right DA (RDA) +/- abomasal volvulus along ribs 10-13
      • If RDA with volvulus: tachycardia, “papple” shape (i.e., pear on L, apple on R), complete anorexia, colic, dehydration
    • Dx:
      • Ping on exam is usually diagnostic
      • Rectal palpation: may palpate convex muscular organ in right abdominal quadrant for RDA/abomasal volvulus (DDx: cecal dilatation)
      • Expect hypochloremic metabolic alkalosis: twisted abomasum sequesters acid (HCl); possible acidosis if has progressed to circulatory failure
      • Liptak test: Insert 4.5-inch spinal needle transabdominally just ventral to ping and aspirate; if acidic then = abomasal fluid
    • Tx:
      • Medical: only indicated in LDA, often unrewarding but can include:
        • IV or oral calcium supplementation, transfaunation, gastric stimulants
      • Surgical:
        • Roll and toggle/blind stitch
        • Abomasopexy
        • Omentopexy
    • Pearls:
      • LDA or uncomplicated RDA: prognosis excellent for life and return to productivity
      • RDA with volvulus: more guarded prognosis depending on duration of disease
      • LDAs NOT emergencies vs. RDA +/- volvulus ARE emergencies
      • Intervene in herd if prevalence of DAs is over 1%
      • Ketosis, subclinical hypocalcemia, uterine disease all predispose to DA
      • Good pre-partum feeding practices that limit prolonged negative energy balance prevent most DAs

Images courtesy of Dr. Lisle George (listeriosis, placenta, bloat, LDA), USDA, APHIS (prolapsed uterus), D'Arcy Norman (intro cow), and DerHexer (kissing cow and dog).

Top Topic Category
Ruminants