8. Diet formulation and data analysis

Diet Formulation

• Energy is a limiting nutrient
• Maintenance energy requirements must be met daily
• To avoid ruminal acidosis, maximize energy at 12.5 MJ ME/kg DM

Protein in Diet Formulation

• The minimum crude protein (CP) for optimum Microbial Crude Protein (MCP) yield = 13% (Orskov) which is equivalent to approximately 11% Rumen Degradable Protein (RDP)
• For higher production and lower body weight, use 16 to 18% CP with 20% Undegradable Dietary Protein (UDP)
• Trade cattle diets should be 16% CP for the starter phase and 14% for the finisher phase
• Bullock diets should be 13% CP throughout

Other Diet Formulation Considerations

• Fat content should be ≤ 6% for beef/lambs and ≤ 5% for dairy cattle
• Dairy Neutral Detergent Fiber (NDF) should be 32%
• Beef NDF is generally undefined, but should be ≥ 20% to 23%
• Lamb NDF is also undefined

Water Quality and Requirements

• Water is essential for physiological functions in mammals
• Water is critical for microbial ecosystem function in the rumen; approximately 30% of bacteria exist in the liquid phase
• Water is also essential for mixing and ingesta passage

Water Quality Targets

• Salinity (Electrical Conductivity) target is < 1600
• pH level target is 6.5 to 8.5
• Chloride should be < 1mg/L
• Nitrate should be < 44 mg/L
• Sulphate should be < 500 mg/L
• Bacterial contamination (Faecal Coliforms) should be < 1 Colony Forming Unit/100 ml
• There should be zero tolerance for algae in water sources
• There should be zero tolerance for mouldy/septic odours, combined with elevated total digestible solids, nitrogen and phosphorus levels

Other Diet Formulation Considerations

• ADI for beef has dropped to approximately 2.3 to 2.5% of body weight
• ADI for lambs is up to approximately 3.9% of body weight

Grain Inclusion

• Starter grain should be < 50%
• Make inclusion increments of ≤ 10%
• Run an additional intermediate diet if necessary
• Each diet lasts approximately 5 days, depends on intake and faecal scores
• Recent nutritional history along with initial fibre requirement should be considered.

Initial Allocation

• Consider recent nutritional history with initial fibre allocation
• On the first day, most cattle will approximately eat 1 to 1.3% of body weight as dry matter
• The MMEF can be used as a guide with NEm limitations from book values

Balanced Calcium: Phosphorus Levels

• The calcium to phosphorus ratio should be 1.5 to 2:1, the NRC is defined as too low

Macrominerals Required Dietary Concentration (g/kg DM)

• Calcium: 2.4
• Phosphorus: 1.3
• Magnesium: 1.9 (6 max)
• Potassium: 6 to 8 (30 max tolerable)
• Sodium: 0.8
• Sulphur: 1.5
• Nitrogen: Sulphur: 14:1

Trace Elements Required Dietary Concentration (mg/kg DM)

• Copper: 10
• Zinc: 30 (75 to 100 adaptation)
• Cobalt: 0.11 (upper limit 1 mg/kg BW/d)
• Iron: 30 to 40
• Manganese: 20 to 40
• Selenium: 0.05
• Iodine: 0.5

Vitamins Required Dietary Concentration (IU/kg DM)

• Vitamin A: 11500
• Vitamin E: 15 to 60
• Vitamin D: 200 (only for southern Australia during winter)
• Vitamin B1: 5 to 10 (with PEM problem)
• Vitamin E and A are expensive and should be factored in to off-the-shelf products

Feedlot Data to Measure and Utilize

• Average Daily Intake (kg/hd/d, DM, plots)
• Average Daily Gain (kg/hd/d)
• Feed Conversion Ratio (kg feed/kg LWG)
• Cost of Gain ($/kg LWG)

Performance Targets for Data Management

• Trade cattle (supermarket): Average Daily Gain (ADG) of 1.7, Feed Conversion Ratio (FCR) in the 5's
• Short-fed Jap ox (100 to 120 DOF): Average Daily Gain (ADG) of 2, Feed Conversion Ratio (FCR) in the 6's
• Mid-fed ox (c. 150 DOF): Average Daily Gain (ADG) of 1.7 to 2, Feed Conversion Ratio (FCR) high 6's
• Long fed (c. 400 DOF): Average Daily Gain (ADG) of approximately 1 to 1.4, Feed Conversion Ratio (FCR) 7's

sample Morbidity and Mortality Rates from 2007

• Mean Feedlot Occupancy ytd: 7348
• Treatments as % Turnover ytd (sales): 30.54
• Mean Treatment Rate ytd (% occupancy): 8.78
• Treatments as % Turnover ytd (inductions): 28.76
• Mortalities as % Turnover ytd (sales): 2.75
• Mean Mortality Rate ytd (% occupancy): 0.79
• Monthly Mortalities as % Turnover (inductions, <1%): 2.6
• Pen Deaths as Percentage of all Mortalities (<25%): 17.2
• Pen Deaths as Percentage of Occupancy (<0.15%): 0.14
• Percentage of BRD Treatment Mortalities (CFR, <10%): 7.3