Nutrition and GI: Rumen Acidosis Flashcards
What causes rumen acidosis?
- Excessive concentrates- rapid digestion
- Insufficient saliva- reduced saliva flow
Decreased pH rumen
D lactic acid builds up- cannot be metabolised
- What should the rumen pH be?
- What is the problem with low pH?
- 6-7
- Problems with Low pH
* Kills fermentation bacteria
* Encourages- lactobacilli
* Efficiency of digestion falls
* Undigested particles pass through- hind gut fermentation, osmotic diarrhoea
What factors affect rumen pH?
- VFAs produced
- Type of acid- lactic
- Rate of fermentation
- Rate of acid remova- rumen papillae
- Buffering by saliva
Why is saliva so important?
Produced when chewing long fibre- cudding
Contains sodium bicarbonate
70% cows should be cudding at any time
What does long fibre do?
Encourages cuffing- bicarb buffer
Forms a rumen mat
* Keeps food particles in rumen to be digested
* Home to bugs- biofilms
What are risk factors for SARA?
- Insufficient SARA
- Inaccurate fodder DM estimation- insufficient fodder provided
- Overmixing of TMR
- Excessive feeding of sugars and starches
- Poor dry cow managment
- Slug feeding of concentrates in the parlour
- Food deprivation and irregular feeding
- Poor cow comfort
What is SARA?
Sub-acute rumen acidosis
Effect of large concentrate feeds
What are the signs of SARA?
- Herd problem
- pH < 5.5
- Most common nutritional disorder
- Energy deficit
- Overall poor health
- Faces- loose and soft, swishing tails, undigested grains, long fibre present
- Lower cleanliness score
Score faeces 1-5- 3 ideal
What are the effects of SARA?
- Reduced DMI
- Reduced digestability- reduced energy intake, NEB
- Immunosuppression- disease susceptibility
What are the production effects of SARA?
Poor yields
* poor peak yields
* Decline in yields
Milk quality- sometimes
What are the health effects of SARA?
- Displaced abomasum- VFAs enter abomasum- atony
- Digestive upsets
- Ketosis- NEB
- Lameness- sub clinical laminities (ulcers, WLL)
- Mastitis- dirty cows
- Poor resistance and health
- Infections- endocarditis
- Fertility- not seen bulling
How is SARA diagnosed?
Clinical signs
* Fertility
* Lameness
* Ketosis
* LDA
* Faeces
* ‘Odd sick cows’
Observe group
* Cudding
* rumen fill
* tail swishing
* dirt score
Faeces- score 1-5, sieve
History- nutritional managment
Measure rumen pH
What is the maximum length of fibre in faeces?
No longer then 1/2 inch long
No or little undigested grain
What causes mucus casts with SARA?
- When undigested particles pass through rumen causes hindgut fermentation
- Leads to colonic acidosis- damage to colon wall
- Fibrin casts in faeces
How should cows be selected for sampling of rumen pH?
When should the cows be sampled?
Cows calved 14-21 days-
* still adapting to the tation
* DMI is not yet maximal
* Assess transition and early managment
Cows calved 60-80 days
* Should have adapted to ration
* Maximal DMI
* Assess overall diet quality
Sample both groups 2-4 hours after feeding
Record parlour cake fed
DIAGNOSIS- confirmted when 2 cows from either group below threshold
pH < 5.7
