Blood Sampling in birds

avian veins

-veins generally superficial

-veins fragile and prone to haematomas

• critical to them, small blood vol, haematoma and haemorrhage,

-approach veins directly not laterally

where can we sample blood from in bird

• jugular

• basilic/ ulnar v

• medial metatarsal

how to avoid avian haematomas and post sampling haemorrhage

-ensure plunger moves smooth

-use small syringe

CAN BE LIFE THREATENING

safe volume to take bloods from birds

-circulating blood is 6-12% of BW

-can collect 10%

-if in poor health take much less

EDTA in birds?

haemolyse RBCs→ so not really used

what is the tube of choice in avian and reptiles

lith hep

lithium heparin in birds for?

haematology and biochem

always take when doing blood samples in bird and reptiles

2 blood smears

haematology of birds

manually done since automated techniques difficult as nucleated RBCs

why dont hold birds around the middle

• lack diaphragm → cant breath

inadequate restraint of birds can cause what

-injury to patient

-injury to handler

-possibly fatal haemorrhage

prolonged restraint of birds cause

-stress

-hyperthermia

why use sedation or GA with gas for birds blood sampling

-less risk in sick or fractious birds

-reduce haematoma formation by relieving stress and lowering blood pressure

how to hold bird for blood sampling

around head and neck, do not push on rest of chest

jugular vein for birds blood sampling

-large accessible vein

-right jugular vein used as often larger

-don't have to pluck feathers

-can palpate and blind technique

issue with jugular vein on birds

-difficult to prevent or stop haematoma

how to access jugular in bird

-bevel down

-access in caudal direction: less likely to come in contact with other structures if move

ulnar/basilic in bird and its issues

-small samples in larger birds

-potential to fracture wing if performed conscious

-haematomas common and can be severe

how to take ulnar/basilic vein in bird

-bird in dorsal recumbency

-extend wing

-wing stabilised with thumb and forefinger

-syringe rested on thumb and advanced into vein

-not in conscious patient→ usually ga or sed

medial metatarsal vein in birds blood sampling

-very useful in waterfowl and chickens

-heavy scaling may be problem

-hyperkeratosis not good for this

how to get blood sample in bird from medial metatarsal vein

-lateral recumbencu with lower lumb extended caudally

-easy to restrain in towel with feed out

-limb held by assistant similar to dog or cat

-medial aspect, above or below joint

-light pressure bandage easily placed to prevent haematoma

primary lymphoid organs of birds

-bursa of Fabricius→ mature b cells

-thymus→ mature t cells

secondary lymphoid organs of birds

-spleen

-interstitial lymphoid tissue

-bone marrow

thymus of bird location

-located in neck and consists of 3-8 flattened, pale pink lobes lying along neck, close to jugular vein

t lymphocyte precursors of birds

produced by stem cells in embryonic yolk sac and bone marrow and develop into t lymphocytes in thymus

thymus in birds at sexual maturity

decreases

bursa of fabricius

-unique to birds

-dorsal diverticulum in proctodeum

-consists of folds of lymphoid tissue

-stem cells in yolk sac produce b lymphocyte precursors which then develop in bursa

-subsequently seeds other lymphoid organs with b cells

spleen of birds

-situated on right side of coelom between proventriculus and ventriculus

-shape varies

-not blood reservoir so relatively small→ so dont really get a splenic contraction etc

-aged erythrocytes are phagocytosed

-aids in lymphopoeisis and production of antibody

avian erythrocytes formed where

bone marrow

difference in avian rbc, and what is function

-nucleated

-similar function to mammals

PCV of birds

35-55%

lifespan of bird erythrocytes

25-45 days

-blood loss replenished in days

how erythrocytes differ between bird species

-cell size

-normal to find mild immature RBC→ bc turnover so quick

avian thrombocyte

-like mammalian platelets

-originate from stem cell not megakaryocyte

-nucleated

thrombocyte function in birds

-phagocytic function

-clotting function weaker compared to mammals

-despite higher blood pressure, clotting still works

avian heterophils

-function like mammals neutrophil

-most abundant

-round cell with lobed basophilic nucleus

-prominent needle shape, oval red cytoplasmic granules

-cytoplasm colourless

role of heterophils

-phagocytosis, bactericidal, roles in inflam

heterophilia in bird

-stress

-infection

heteropaenia in birds

-acute or severe inflam

-sepsis

-viruses

avian eosinophils

-normally low numbers

-round cells, lobed basophilic nucleus

-cytoplasm stains clear blue

-granules bright and tend to be round

when might eosinophils be elevated

-may be elevated with tissue damage and parasitic disease and poss some viral infections

avian basophils

-smaller than heterophils

-clear cytoplasm, darker granules

-nucleus, non lobed round to oval and often obscured by cytoplasmic granules

function of basophils

-function unknown, poss involved in acute inflam and hypersensitivity reactions

avian lymphocytes

-similar to mammals

-large round nucleus with pale blue cytoplasm

-variation in size and shape

lymphocytosis in birds

excitement, leukaemia

lymphopeania in birds

chronic stress

avian monocytes

-rare in healthy birds

-similar to mammals

-largest leukocyte

-little consistency in appearance

monocytosis in birds

-chronic inflam/infectious conditions e.g. psittacosis, TB, aspergillosis, egg coelomitis