Week 8

Beef: Cow-Calf

Supplementation

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• Goal - Promote the maximum utilization of the feed
• Supplementation should be used to complement or enhance forage utilization
• Protein supplements
  • DIP: SBM, CSM, Urea
  • UIP: blood meal, fish meal, feather meal
• Energy supplements
  • Corn, barley, beet pulp

What do you want to supplement with, protein or energy?

• Protein is usually the “first-limiting” nutrient in grazing production systems

Supplementing Protein

• First Priority
  • DIP or UIP?
• DIP – microbes use DIP to produce Bacterial CP
  • Bacterial CP is a high quality CP source 80% CP and 80% Digestible
• DIP is often less expensive than UIP
• UIP supplementation of LQF may not elicit the same + response as DIP, or the same level of a + response
• DIP sources are also often fairly energy dense, similar to grains
• Added benefit of having additional energy in the diet

Forage Quality

• Alfalfa vs Winter Range
• Lactating two-year old Heifer, 972 lb BW, 12.3 lbs milk/d, 21.6 lbs DMI
• TDN = 13.8 lb/d or 64%
  • Alfalfa = 66.0% TDN
    • 13.8/0.66 = 21.0 lb DMI required
  • Winter Range = 50.5% TDN
    • 13.8/0.505 = 27.0 lb DMI required
• 2.25 lb of CP or 10.4% of diet DM
  • Alfalfa = 18.0%
    • 2.25/.18 = 12.5 lb DM intake required
  • Winter Range = 4.7%
    • 2.25/.047 = 47.9 lb DM intake required
• What is “first-limiting” in this example?????

Effects of Supplementation

• Protein supplementation (DIP)
  • Provides nitrogen for microbial growth
  • Promotes improved fiber digestibility
  • Animal is willing to accommodate increased fill, plus rates of digestion and passage rate are increased
  • Promotes increased intake of poor quality forage
  • Positive Associative Effects
    • Increase in forage intake due to DIP supplementation – Often +25%!
• Energy supplementation
  • Reduce microbial population
    • Microbial shift away from cellulolytic bacteria
    • Microbial preference for starch
  • Depress fiber digestion
  • Decrease forage intake
  • (Negative Associative Effects)

Rules of Thumb for Supplementation

• Optimum % CP in the supplement is in the range of 25-35%
• If use nonstructural carbohydrates with low quality forages, keep level of use under 10%
• Structural carbohydrates are neutral in terms of associative effects

Rules of Thumb for Urea

• Remember: 100% DIP
• See toxic effects with urea at >3% of DM
• When combined in supplement, 30% urea and 70% natural protein

Delivery Methods of Supplement

• Daily or infrequent supplementation
• Liquid tubs
  • Intake controlled by palatability
• Lick blocks
  • Intake controlled by block hardness
• Free choice mineral/salt blocks
  • Should always have out