Rumen fermentation Flashcards
Describe the chain of carbohydrate digestion in ruminants
Where are VFAs absorbed and where are they transported in ruminants?
rapidly absorbed in rumen-reticulum and transported to liver for processing
Explain fat digestion in the rumen
Limited
High fat diets depress microbial activity
Long chain fatty acids not absorbed
Explain protein digestion in the rumen
protein is digested into rumen undegradable protein (moved into abomasum and SI) and rumen degradable protein
Rumen degradable protein is broken down into amino acids which is either converted to microbial protein (this uses energy) or ammonia (if no energy available)
Explain the process of urea cycling in protein digestion in the rumen
Protein degraded into ammonia when no energy present to convert it to microbial proteins
Ammonia transported to liver where it is converted to urea
Some is excreted in urine
Some is recycled back into saliva where it returns to the rumen to be converted back to ammonia
this ammonia can be converted into microbial protein (uses energy) or be recycled again
What occurs if more proten is available than energy in rumen digestion?
Amount of MCP (microbial crude protein) produced is limited by energy
Increased ammonia => elevated blood urea
What occurs if there is more energy than protein in rumen protein digestion?
Amount of microbial crude protein produced is limited by protein availability
Energy wasted to methane production
What can causes acidosis in the rumen?
too much concentrate or not enough fibre can lead to increased levels of lactic acid
what are the consequences of decreased rumen pH?
Balance of rumen microflora changes
Decreased rate of digestion due to decreased number of viable microorganisms
Changes proportion of different VFAs produced
What are the clinical signs of chronic acidosis and where is it most common?
High producing animals fed diets high in concentrate
- sub-optimal rumen function
- reduced food intake
- pain
- indigestion
- loose faeces
- low milk fat levels
What typically causes acute acidosis in ruminants?
result of grain engorgement
What are the by-products of carb fermentation in ruminants?
Methane and CO2
What is bloat in ruminants?
gases produced by carb fermentation not eructated so accumulate in rumen
What are the 2 forms of bloat?
gas bloat
frothy bloat
What is gas bloat
Something blocks or hinders normal eructation
- physical obstruction
- cessation of normal rumination
- gas being unable to reach oesophagus
