Bovine GIT Flashcards
The bacteria in the rumen are mostly gram what?
Gram positive
How long does it take rumen microbes to adapt to a new diet?
3 weeks
Out of fibre and FME (fermentable metabolisable energy), which has the highest rate of fermentation?
FME (fast)
Give some examples of FMEs
Starches
Sugars
What is glucose metabolise into in the rumen?
What is this then metabolised into?
Pyruvate
- > Acetic acid (absorbed)
- > Propionic acid (absorbed)
- > Butyric acid (absorbed)
- > CO2 (vented)
- > Methane (vented)
What should rumen pH be?
6-7
How does a low rumen pH lead to ruminal acidosis?
Low pH -> kills microbes, encourages growth of lactobacilli (produce D-lactic acid which can’t be metabolised)
Efficiency of digestion falls if pH falls (destroys papillae)
Undigested particles pass through to hindgut -> osmotic diarrhoea (loose faeces), colonic acidosis (damage to colon wall -> fibrin casts in faeces)
Low pH also destroys rumen papillae -> rumenitis
Give some factors that affect rumen pH
Amount of VFAs being produced
Type of acid produced (lactic acid= strong)
Rate of fermentation (fibre-slow, concentrates (FME)-fast)
Rate of acid removal (absorption across rumen wall-papillae)
Buffering by saliva (chewing the cud)
What % of cows should be chewing the cud at any one time?
70%
What does saliva contain that is so important for a healthy rumen?
Sodium bicarbonate (buffers the acid in the rumen)
Why should dairy cows have plenty of long fibre?
Encourages cudding (bicarbonate in saliva buffers acid in rumen) Forms a rumen mat (home to microbes; keeps food particles in rumen to be digested)
A rumen pH of what value is indicative of SARA (sub-acute ruminal acidosis)?
<5.5
What does swishing tails indicate?
Sore bums (due to acidic faeces)
How might the faeces of a SARA infected cow appear?
Loose and soft
Long fibre present
Undigested grains present
May see fibrin casts (from inflamed colon)
Give some effects of SARA
Reduced DMI
Reduced digestibility (reduced energy intake, negative energy balance)
Immunosuppression (susceptible to disease)
Poor milk yields
Milk butterfat may be low (not always)
Give some health effects of SARA
Displaced abomasum (VFAs enter abomasum -> atony) Digestive upsets Ketosis (negative energy balance) Lameness (ulcers, white line lesions) Mastitis Immunosuppression Infections eg endocarditis
Give some fertility effects of SARA
Cows not seen bulling
Poor conception rates
How can you diagnose SARA?
Measure rumen pH 2-4 hours after feeding (gold standard) (<5.5)
Sieve faeces (undigested grain, long fibres over 1/2 inch, mucus casts)
History (nutritional management)
Condition score (>0.5 loss in CS from dry-peak lactation)
Observe the group (eg tail swishing, cudding)
Clues (eg fertility, lameness, LDA, ketosis)
When should you measure rumen pH?
2-4 hours after feeding
How would you sample rumen pH in a herd?
Sample 2 groups: cows calved 14-21 days ago, and cows calved 60-80 days ago.
First group are still adapting to ration, second group have adapted so have maximal DMI
Sample 6 cows from each group
Diagnosis confirmed when 2 cows from either group are below threshold pH (ie <5.7)
How do you sample rumen pH?
Restrain cow Obtain sample at level of stifle, 6-8" behind last rib Clip and scrub LA 3-5" needle, 16-18G Read sample on pH meter immediately
What is included in a ‘far off diet’?
Grass silage and straw
Give the following values for grass silage:
Energy
Protein
Dry matter
Energy: 10.5-12MJ ME/kg DM
Protein: 14-16%
Dry matter: 20-35%
Give the following values for maize silage:
Energy
Protein
Energy: 11-11.5 ME
Protein: 8-9%
Why is it better to add hay rather than straw to a diet when adding fibre?
Hay is more palatable
When does acute ruminal acidosis occur?
When overeating grain
What clinical signs would you see with acute ruminal acidosis?
Distended rumen Ataxia Diarrhoea (profuse and smelly) Depression Recumbency and shock Anorexia Dilated pupils
What would you see with peracute ruminal acidosis?
Severe ataxia or recumbency, apparently blind, severe dehydration
How would you treat mild acute, subacute and peracute ruminal acidosis?
Mild: give hay and observe
Subacute: oral antacids (magnesium hydroxide/carbonate), hay
Peracute: rumenotomy (empty rumen contents), sodium bicarbonate iv, balanced fluids, calcium borogluconate (source of calcium)
NSAIDs
Antibiotics eg oral penicillin
Animal may be severely dehydrated so give water
How can you prevent ruminal acidosis?
Take care when introducing grain to fattening animals
Good fibre source
Correct mixing of diets
Which part of the rumen acts as a home for microbes?
Fibre mat
Give some conditions that may occur in the dairy cow after calving
Milk fever (hypocalcaemia) RFM/metritis/endometritis Mastitis Displaced abomasum Ketosis Fertility issues Lameness
Why does milk fever occur?
Hypocalcaemia +/- hypophosphataemia
Drain on Ca2+ due to colostrum/milk demands from calf
What is the role of parathyroid hormone?
Mobilisation of calcium from bone stores
Increased absorption from gut (requires Mg2+)
What is the role of calcitonin?
Reduces calcium absorption and availability
What is the role of vitamin D?
Increased calcium absorption from gut
Ca2+ is present in the blood in which 2 ways?
Bound (chiefly to albumin)
Ionised (active Ca2+)
How does pH affect binding of Ca2+ in blood?
Reduced binding with reduced pH
What are the roles of Ca2+ in the body?
Muscle function (every muscle and gland requires Ca2+ to function)
Nerve impulses
Immune response
What are the clinical signs of acute milk fever?
At/after calving:
Initial hyper-excitement, tremor
Recumbent (muscles stop working)
Guts/gland stop working: no faeces/ urination, dry nose, bloat, slow pulse/HR
Give a common clinical sign of hypophosphataemia
Peri-parturient haemoglobinuria (red urine)
How can you treat hypocalcaemia?
IV calium borogluconate 40% (don’t administer too fast -> arrhythmias)
Hypocalcaemia is often complicated by hypophosphataemia so give foston (organic phosphorus) IV
Sub-clinical hypocalcaemia is a risk factor for which other diseases?
Immune function depression
Coliform mastitis
Metritis/endometritis
‘Post-partum depression’
How can you prevent hypocalcaemia?
Aim to tone up the parathyroids Feed low calcium diet pre-calving Feed high magnesium diet pre-calving Boluses at calving? Maximise DMI pre-calving DCAD diets: aim for a negative DCAD before calving -> induces a compensated metabolic acidosis (causes mobilisation of calcium)
When does hypocalcaemia occur in sheep?
Pre-lambing; stress
How do you treat hypocalcaemia in sheep?
20ml Ca2+ borogluconate IV
or get farmer to give 80ml SC at many sites
What is ‘grass staggers’?
Hypomagnaesmia
Give some clinical signs of hypomagnaesaemia
Peracute/acute-often found dead
Early-twitching, hypersensitive, occasionally aggressive
Recumbent and convulsive- EMERGENCY
Sheep usually found dead
Give some trigger factors for hypomagnaesaemia
Lush pastures (Spring)
High milk output
Stress-weather, movement, handling (noradrenaline binds Mg)
How do you treat hypomagnaesemia?
Be quiet- risk of setting off convulsions
Control convulsions with xylazine iv
Give Ca2+ 40% IV, then slowly give up to 200ml MgSO4 IV
How can you prevent hypomagnaesaemia?
Move off affected pasture
Give additional Mg (dairy cows-high Mg cake; beef cows-mineral supplements, boluses, give straw to slow gut transit time and give Mg more chance to be absorbed)
Where does the reticulum lie?
Opposite 6-8th rib on LHS Lies ventrally (is in contact with the ventral body wall)
Give the clinical signs of traumatic reticulitis
SUDDEN milk drop (eg 20l to 5l) Hunched up appearance Stiff gait Inappetence, dull, depressed Often fed a TMR May grunt spontaneously (pain) Increased temp 39.5 Reduced rumen contractions
How often do rumen contractions occur?
3 rumen/reticular contractions in 2 mins
What are the 2 types of rumen contractions?
Primary (starts in reticulum, works backwards to rumen. Biphasic. Mixing)
Secondary (moves gas to the cardia. Starts in caudal rumen and moves forwards. Belches afterwards)
(2 primary for every 1 secondary)
How can you diagnose traumatic reticulitis?
Eric Williams Test- gold standard. Listen over trachea, feel rumen contractions in left flank (hands on L sub-lumbar fossa) (will slow with reticulitis, pain on reticular contraction)
Withers pinch-abdominal pain
Pole test-abdominal pain
Faeces-stiffer with long fibre
What 3 scenarios may you encounter when doing the Eric Williams test on a cow with traumatic reticulitis?
Reduction in primary cycles
Grunt (pain) immediately prior to primary cycle
Breath holding prior to primary cycle
What are the problems with swallowing a wire and it penetrating the medial reticulum?
Damage to vagus
Abscess in medial wall
No pain receptors
What clinical signs would you have with traumatic pericarditis?
Increased pulse Increased temp Very ill Heart sounds: -Initially: pericardial rub ('grating') -Later: very quiet/absent -Later: 'washing machine sounds' Can be fatal
How would you identify whether traumatic pericarditis had developed into heart failure?
What is the prognosis?
Distended jugular veins
Visible jugular pulse
Sub-mandibular oedema
Euthanasia
Give some consequences of traumatic reticuloperitonitis
Vagus nerve injury (penetration in medial wall of reticulum)
Reticular adhesions