NE for Growing/Finishing Beef Cattle
• California Net Energy System
• Lofgreen & Garrett, 1968
• Net Energy for maintenance – NEm
• Net Energy for gain – NEg
• More useful than TDN
• Allows more accurate prediction of
energy
NE for Growing/Finishing Beef Cattle
• NEm – ability of feed to meet energy
reqmt for maintenance
• NEg – ability of feed to meet energy
reqmt for gain
• Maintenance energy must be met first
• Then any additional energy can be
used for gain
NE for Growing/Finishing Beef Cattle
• NE values of feeds + feed intake can be
used to:
• Predict gain on particular diet
• Predict amount of feed required for
particular gain (programmed
feeding)
NE for Growing/Finishing Beef Cattle
• Two NE values for feeds
• Feed energy is used more efficiently
for maintenance than for gain
• NEm values always higher than NEg
Example – NE System
• 715 lb yearling steers (1,300 lb finished)
• From feed records, consuming 16 lb
(7.26 kg) of diet which contains:
• 2.09 Mcal/kg NEm
• 1.42 Mcal/kg NEg
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Example – NE System
• NEm required per day is based only on
body weight (Table 9) = 5.89 Mcal/day
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Example – NE System
requirement
Energy in feed
• 5.89 Mcal NEm/2.09 Mcal NEm/kg =
2.82 kg of diet needed for maintenance
• Total intake is 7.26 kg
• 7.26 kg – 2.82 kg = 4.44 kg remaining
for gain Energy in feed
• 4.44 kg x 1.42 Mcal/kg NEg = 6.30 Mcal
available for gain
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Example – NE System
• 6.30 Mcal available for gain
• From Table 9 – need 6.94 Mcal to gain
3.99 lb/day
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Example – NE System
• From Table 9 – need 6.94 Mcal to gain
What we have
3.99 lb/day
available for
gain
• Extrapolate:
• 3.99 lb/6.94 Mcal = x lb/6.30 Mcal
• x = 3.62 lb/day Predicted ADG
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Example – NE System
• Feed efficiency
• Expressed 2 ways:
• lb feed/lb gain
• 16 lb/3.62 lb = 4.4 or
• lb gain/100 lb feed
• 3.62 lb/0.16 lb = 22.6
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