Ruminal Metabolism Flashcards
Acidosis two types
SARA pH
What causes rumen pH to fall
Excess starch hence shift towards amylolytic flora
Process of acidosis
Increase of starch causes incr in VFA and decr in pH
Increase in lactate producing bacteria S.Bovis so incr in lactate
pH
Which VFA supports gluconeogenesis
Proprionate
How can you control pH
Yeast supplements - scavenge O2 giving anaerobic environment for bacterial growth
Which is main VFA produced
Acetate
Solutions to lack of glucose eg at lactation
Utilise oxaloacetate from KA
Burn fat releasing acetyl CoA
BUT
Reduced efficiency of KCA if less oxaloacetate Nx too much acetyl CoA
Acetyl CoA metabolised to ketone bodies in liver and supplies tissues instead of glucose and builds up toxic level
Signs of ketosis
Pear drops
Lethargic
Loss in body weight
Treatment of ketosis
Dextrose (500ml 50%) IV
propylene glycol and glycerol drench
Glucocorticoids
Prevention of ketosis
Balanced ration
Maintain BCS
Cause of hepatic lipidosis
Excess energy intake during dry period
Negative energy balance at calving
Body fat mobilised faster than it is used up
NEFA in blood and stored by liver
What does fatty liver occur with
Metritis
Mastitis
DA
Hypocalcaemia
Prevention of fatty liver
Monitor BCS in dry period, don’t let >3.5
minimise NEB so less fat mobilisation
Minimise stress
DA causes
Hypo motility of abomasum
Incr concentrates and decr roughage
Signs of LDA
Decr milk Gas production Decr appetite/anorexia Alkalosis and hypokalaemia Secondary ketosis common
Signs of RDA
LDA PLUS
ischaemia
Blood supply to GIT compromised
Necrosis
DA treatment
Surgical
Manipulation
Roll
Prevention of DA
promote DMI and rumen fill immediately after calving Feed TMR avoid rapid dietary changes Feed enough roughage Treat ketosis
Causes of retained placenta
Dystocia Twins Stillbirth Abortion Low Se Hypocalcaemia Old age Previous history
Treatment of retained placenta
Trimming of excess tissue don’t manually remove
Prevention of retained placenta
Se supplementation
Cull repeat offenders
Hypocalcemia/ mikl fever causes
Too much calcium in dry period
Not enough vit D or Mg in dry period
Ca:P ratio too low (excess P)
Jersey cow is prone
Milk fever signs
Three stages
1
How do vit D and Mg prevent milk fever
Regulate calcium reabsorptiom
Milk fever prevention
Low calcium diet in dry period
DCAD diet- low pH improves calcium absorption
- promotes parathyroid gland to use bone calcium
-use low K diet S it blocks Mg
Vit D in feed
Cause of twin lamb disease
Poor rationing in pregnancy
Sheep outdoors in poor weather
Ketosis
Signs of twin lamb disease
Don’t want to move
Ketone bodies
Disturbed vision
Treatment of twin lamb disease
Dextrose IV bonus (500mg 50%)
Propylene glycol and glycerol drench
Glucocorticoids
Prevention of twin lamb disease
Good nutrition in last 8w pregnancy
Concentrate supplementation
Cause of hypo magnesaemia
Pasture low in Mg
Fertiliser use reduces pasture uptake of Mg
Signs of hypo magnesaemia
Frothing at mouth
Muscle twitching and teeth grinding
Dead stock at pasture
Treatment of hypo magnesaemia
Mg sulphate (200ml 50%) SC Hay treated 60g Mg oxide daily
Prevention of hypo magnesaemia
Her age dusted with Mg oxide (500g a cow)
Herbage sprayed with 2% Mg sulphate
Mineral licks
Boluses
Causes of cerebrocortical necrosis
Vit b1 deficiency /thiamine deficiency
Carb rich and roughage poor ration causes SUBCLINICAL lactic acidosis
Destruction of thiamine in GI tract
Signs of CCN
circle collapse leg-kicking
Treatment of CCN
early thiamine may cure but not if lesion advanced
Prevention of CCN
Diet ensuring no SARA
Prophylactic vitamins
Causes of swayback
Low Cu causes underdevelopment of myelin sheaths in lambs
Poor absorption of Cu due to copper thhiomolybdate formation
Prevention of swayback
CoSeCure boluses
Supplement copper but with CARE as sheep accumulate copper in liver and toxicity occurs at 25mg/kg
Cause of pine
Lack of Co
Inability to make vit B12 in rumen
Signs of pine
Unthrifty
Dull fleece
No appetite
Treatment of pine
IM injection of vit B12
Drenching up to 1ml/kg cobalt sulphide
Prevention of pine
CoSeCure boluses
Cause of white muscle disease
Se and vit E deficiency
Low bioavailability of inorganic Se
Se incorporated into organic form on pasture
What does Se do
Cofactor for reduction of antioxidant enzymes
Cofactor for thyroid hormone deiodinases
Removes reactive oxygen species
Controls metabolic rate
Signs of white muscle disease
Acute and rapid wasting of skeletal muscle
Unable to stand
Treatment of white muscle disease
IM or SC injection of young lambs with 0.75-1.5mg Se as potassium selenate
Injection of 34-68mg vit E
Prevention of white muscle disease
Supplement dams ration in late gestation
Injection of newborn lambs with Se and vit E prep
CoSeCure bolus
SelPlex
Aphosphorosis cause
Phosphorus deficiency due to poor diet or grazing soil low in P
Signs of aphosphorosis
Rickets Stiff joints Poor fertility Decr milk Chew strange things
Treatment of a phosphorosis
Oral P supplementation (won’t work on vomiting or diarrhoea)
Sodium phosphate salts
Prevention of aphosphorosis
P fertiliser on depleted soil
0.42% DM P conc for high yielders
Signs of vit a deficiency
Night blindness Infertility Rough coat Impaired immunity Weak/dead lambs Xerophthalmia (dry conjunctiva)
Treatment of vit a deficiency
Retinol injection and vit a supplement in feed
Goitre causes
Iodine deficiency causing decr thyroxine
Goitrogens reduce T3 and or T4 production and release
Signs of goitre
Enlarged thyroid gland
Weak or hailess young
Treatment of goitre
Potassium iodide oral dosing
Intra ruminal boluses provide slow release of iodine
Prevention of goitre
Add iodine to conc rations
Rapeseed treated to eliminate goitrogens
Clover disease causes
Phytoestrogens produced in clover gives infertility as cysts form in uterus and cervix and uterus doesn’t contract normally
What conditions In Rumen support microbial growth
Temp/moisture /pH
Supply of nutrients
Removal of products of digestion and fermentation
How are VFA produced
From pyruvate by fermentation
What are the three VFAs
Acetate butyrate propionate
Why drive towards propionate production
So less methane produced as acts as hydrogen sink
What diet produces acetate
High fibre
What is the fate of acetate
Converted to acetyl CoA in liver, used in kerbs
Milk fat precursor
What diet favours propionate
High concentrate
What is fate of propionate
20% to lactate during absorption across rumen wall, enters gluconeogenic pathway via PEP
80% to glucose VIA OXALOACETATE
What favours butyrate
High fibre
What is destiny of butyrate
B hydroxybutyrate in absorption, passed to liver and converted to acetyl CoA , or used as energy source
How is methane formed
Reduction of co2, h2 from acetate and butyrate production
What should be pH of rumen
6.7+/- 0.5
What provides buffer
Saliva- 180L a day produced
What is dietary protein made up of
Microbial protein DMTP (from non-protein N)
dietary Undegraded protein RUP
What uses amino acids as energy
Low energy FME diets, form branched VFAs
What is the fate of urea
Converted to ammonia by bacterial urease in the rumen, excreted in urine
What causes low ammonia levels
Low dietary protein
What causes high ammonia levels
More protein degraded than microbial protein formed
What is optimal rumen ammonia conc
8mM
Efficiency of dietary N utilisation and reason
20% retention in rumen
Different rates of degradation of carbs and protein gives low efficiency of microbial protein syn
BALANCE OF RDP AND FME IMPROVES EFFICIENCY
Glycerol base lipids
Neutral triacylglycerol
Structural glycolipids and phospholipids
Non glycerol base lipids
Steroids
Vitamins
PGs
Waxes
How much energy per mole lipid
409 mole ATP
PUFA:SUFA
> 0.45 for healthy cell function and membrane fluidity
Lipid recommendations
Omega 6: omega 3
Where does most of lipid in diet come from
Chloroplast of plants- thylakoids has membrane lipid (omega 3 mainly)
Fatty acids in beef
MUFA»SUFA>PUFA
Process of bio hydrogenation
Protozoa act on cells causing lipolysis to FFAs (incr by red clover)
FFAs undergo bio hydrogenation, PUFA (92% omega 3 and 86% omega 6) lost
Fish oil decr sat fat 18:0 and incr trans Fat 18:1
Role of PPO in red clover
Oxidises phenols to quinones in presence of oxygen which bind to proteins
What causes milk fat depression (fat lowered up to 50%)
Highly polyunsaturated fats- plant oils, oil seeds
Low roughage and high conc
High 18:1 trans fat
What does SREBP1 do
Up regulates de novo synthesis, esterification and desaturation
What drives metabolic disorders
Losing control of rumen pH
Unsustainability of the Holstein
Yield requires energy and protein beyond levels available from pasture
Consumes more than body weight of cereals per lactation- using human resources
Producing cereals uses polluting fertiliser
Ill equipped to digest a grain rich diet- SARA, DA
Proposed solutions to global food security
International network of ‘model farms
Global network of ‘farm platforms’
Critical zone observations
How do PUFAS affect butterfat
Toxic to rumen bacteria, have to be converted from 18:2 and 18:3 to 18:0 by biohydrogenation
A low rumen pH will cause 18:2 or 18:3 to create intermediate c10-t12 TFA which causes milk fat depression as down regulates SREBP1 reducing de novo synthesis of c4-c14 FAs
