Rumenal acidosis

Clinical acidosis is relatively easy to spot and correct:

  • Decreased rumen movement
  • Erratic appetite
  • Loss of body weight
  • Scouring
  • Lameness

Sub-clinical acidosis is much more of a problem – less clear cut, drain on productivity:

  • Reduced rumination (cud chewing)
  • Great daily variation in feed intake of individual animals
  • Faeces in the same feeding group varies from firm to diarrhea (feed sorting)
  • Faeces foamy, contains gas bubbles
  • Appearance of mucous/fibrin casts in faeces
  • Increase in fiber particle size (> 0.5 inch) in faeces
  • Appearance of undigested fiber/feed in faeces
  • Appearance of undigested, ground (≤ 1/4 inch) grain in faeces
  • Decreased milk production
  • Reduced fat test
  • Poor body condition – despite adequate energy intake
  • High culling rate
  • Unexplained scouring
  • Lameness

Dairy farmers with high yielding cows walk a fine line between maximising milk production/profits and having sick lame cows. Here are some tips to reducing acidosis problems in your herd:

  • Retain the services of a good nutritionist and take his/her advice
  • Meet or exceed dietary fibre minimums of 18-21% acid detergent fibre (DM basis) and 27-30% NDF (DM basis)
  • Meet or exceed dietary NDF from forage minimums of 18-21% (DM basis) for grass silage based diets and 21-23% (DM basis) for maize silage based diets
  • Do not exceed 35-40% NFC (DM basis)
  • Provide TMR with 8-10% of as-fed particles on the top screen of Penn state/Nasco shaker box
  • Monitor and prevent over-mixing or over-processing of the TMR
  • Monitor and minimize separation during feed mixing and delivery
  • Monitor and minimize sorting in the feed bins
  • Periodically calibrate TMR scales
  • Monitor and control daily variation in amounts of individual feed ingredients added to the TMR
  • Routinely check moisture content of wet feeds and adjust rations accordingly to ensure correct DM ratio of forage to concentrate
  • Limit maize silage as a percent of forage DM to 75% or less for lactating cow diets and 50% or less for dry cow diets
  • Feed close-up dry cows 35-40% NFC diets (DM basis) to adapt the rumen microbial population and develop the rumen papillae prior introducing the high-group diet
  • Do not feed less than 50% forage (DM basis) in the close-up dry cow diet; this diet may benefit from addition of baled haylidge
  • Feed a post-fresh transition diet that contains more total NDF and NDF from forage than the high-group diet; this diet may benefit from addition of baled haylidge
  • Feed buffers
  • In component feeding situations, increase concentrate feeding to peak amounts gradually over the first six weeks of lactation and feed grain 3 to 4 times daily
  • In component feeding or partial TMR situations, monitor and control selective consumption of concentrate vs. forage or maize silage vs. grass silage
  • Minimize effects of heat stress on selective consumption of grain vs. forage

Key: Non fibre carbohydrate (NFC)
Neutral detergent fiber (NDF)
Dry matter – intake (DM – DMI)