Urinary Energy Loss in Cattle

Correct Answer: 4–5% of GEi

Urinary energy loss in cattle (ruminants) is 4–5% of GEi. Ruminants excrete more energy in urine compared to pigs because ruminants excrete allantoin and hippuric acid (in addition to urea), which carry more energy than urea alone.

Urinary Energy Loss by Species

• Pig: 2–3% of GEi (lowest)
• Ruminants (cattle): 4–5% of GEi

Why Higher in Ruminants?

Ruminants have higher protein turnover and more complex nitrogen metabolism. The main nitrogenous excretory product is urea, but they also excrete allantoin (purine metabolite from microbial nucleic acids), hippuric acid, and creatinine — collectively contributing more urinary energy.

Energy Partitioning in Cattle

GE → (−FE 40–50%) → DE → (−UE 4–5%, −CH₄ 7%) → ME → (−HI) → NE