TMR - Type 1: carbohydrate pool digestion rates
• CB1 Kd 18-20%/hr
• CB3 Kd 5-6%/hr
• Ideal ‘fast pool’ and ‘slow pool’ rates
Observations
• Good manure consistency
• High dry matter intake (DMI)
• Excellent milk yields
• Exceptional feed conversion
Actions to Consider
• Watch for (prevent) sudden changes in feed delivery or consistency.
• Ensure adequate peptide and degradable crude protein to feed rumen microbes.
Corn Silage - Type 1
• Rapid fibre digestion.
• Rapid starch digestion.
• DMI will be good.
TMR - Type 2: carbohydrate pool digestion rates
• Small pool of CB1 that disappears quickly
• CB3 Kd: 5-6%/hr
• A small ‘fast pool’ but ideal ‘slow pool’ rate, resulting in insufficient energy supply
Observations
• Grain in manure
• Low milk protein
• Milk yield lower than expected
• Rough hair coats
• Poor reproduction
Actions to Consider
• Increase supply of rumen-available starch and sugar (CB1 Kd of 20-22%/hr)
• Grind grains finer
• Ensure adequate supply of peptide and NPN protein
Corn Silage - Type 2
• Fibre digestion is slow and not extensive.
• Rapid starch digestion over a short period.
• Potential Acidosis
TMR - Type 3: carbohydrate pool digestion rates
• CB1 Kd: >25%/hr
• A fast ‘fast pool’ and a slow ‘slow pool’, resulting in a high acidosis potential
Observations
• High acidosis potential
• Sore feet, reproductive problems, poor DMI
• Ketosis in early lactation cows
• Fibre in the manure - low rumen pH
• Variability in body condition
• Fat/Protein inversion in >10% of the herd
Actions to Consider
• Increase NDFD by adding non-forage fibre sources
• Slow CB1 Kd to <5%/hr
Corn Silage - Type 3
• Good fibre digestion over a long time period.
• Slow Starch digestion.
3.4
TMR - Type 4: carbohydrate pool digestion rates
• CB1 Kd: <15%/hr
• CB3 Kd: <5%/hr
• A slow ‘fast pool’ and a slow ‘slow pool’
Observations
• Cows look “ok”
• Poor milk production
• Early peak / Poor peak milk
• Average milk components
• Stiff manure despite adequate dietary CP
• Reproduction - delayed, but not too bad
Actions to Consider
• Increasing rumen available starch and sugar
• Grinding grains finer
• Increase NDFD by adding more non-forage fibre (beet pulp, brewers, soyhulls, etc), and/or more digestible forages.
Corn Silage - Type 4
• Fibre digestion is neither rapid nor extensive.
• Starch digestion is neither rapid nor extensive.
• DMI may suffer.
