Subacute Rumenal Acidosis Flashcards
What is the normal rumen pH?
6-7
What’s the pathogenesis of rumenal acidosis?
- High FME in diet leads to an increase in volatile fatty acids in the rumen
- Rumenal pH drops
- This kills of the normal rumen all flora and allows lactobacillus to proliferate, these create lactic acid which further reduces pH
- The efficiency of fermentation is reduced
- Undirected food passed through to the colon
= Colonic fermentation and acidosis - Osmotic diarrhoea, colonic damage and fibrin casts in faeces
What helps to buffer rumen pH?
Rumination with buffer containing saliva
What are the functions of long fibre in the diet?
Fibre mat - keeps feed in the rumen longer
Encourages rumination = buffering with saliva
How does SARA present?
Herd presentation Reduced fertility Increased lameness Abomasal displacements Variable faecal consistency Swishing tails Weight loss - creates an energy deficit Increased incidence of disease - immunosuppression Undigested grains and fibrin casts in the faces Reduced milk yield Reduced dry matter intake Low butterfat and milk protein
What diseases does SARA predispose cows to?
Displaced abomasums Diarrhoea Ketosis Lameness - white line lesions and solar ulcers Mastitis
What production losses does SARA cause?
Poor fertility
Reduced milk yield
Increased incidence of disease
Increased lameness
How can you diagnose SARA?
Faecal sieving Measuring rumen pH Diet analysis - forage : concentrate ratio (ideally 60:40) History Cleanliness scoring
What will you find on faecal sieving in a case of SARA?
Undirected fibre over half an inch long
Mucous casts
Undigested grains
How should you select cows form rumen pH sampling?
Select 6 cows per group
Group 1 - cows that calved 14-21 days ago
Group 2 - cows that calved 60-80 days ago
Where should you sample the rumen and what result is diagnostic of SARA?
Through the left flank, from the lower quadrant
When 2 cows from each group have a rumen pH of 5.7 or below SARA is diagnosed
What is the landmark for rumen sampling and how should the sample be obtained?
6 to 8 inches behind the last rib, on the left hand side, in the lower quadrant of the rumen
Use a 16g or 18g needle, quickly stab in, withdraw contents and analyse immediately
What factors contribute to silage quality?
Grass type First or second cut Time of day cut - higher sugar in the afternoon Moisture content Chop length Compaction in clamp Fermentation
How can you recommend the farmer adds fibre to the diet?
Long fibre 1-4 inches long - not too long otherwise they select
Add 1-2kg of straw or hay
Hay is more palatable
