Energy Required for the Avian Patient

Calculation of Energy Required for the Avian Patient

The generally recognized formula for calculation of metabolic rate is:

MR (kcal) = K(Wkg0.75)**

Active metabolic rate is somewhat greater than that of a resting bird. For simplicity we will use the value 1.5.

Active MR (kcal) = 1.5 X MR (kcal)***

An adjustment factor for growth, trauma and disease as expressed as multiple of MR. 1

Condition Adjustment
starvation 0.5-0.7
hypometabolism 0.5-0.9
elective surgery 1.0-1.2
mild trauma 1.0-1.2
severe trauma 1.1-2.0
growth 1.5-3.0
sepsis 1.2-1.5
burn 1.2-2.0
head injury 1.0-2.0

Energy requirement (kcal) = Adjustment factor X Active MR (kcal)

Volume of feeding formula (mL) = Energy requirement (kcal) ¸ caloric density of the feeding formula (kcal/mL)


* Modified from Quesenbery KE, Mauldin G, Hillyer E. Nutritional support of the Avian Patient Proc Assoc Avian Vet, Seattle, 1989, pp. 11-19.

** Resting or maintenance metabolic rate (MR), W is the animals body weight in kg, K is a theoretical constant (for calculation of MR in kcals). Passerine birds K = 129 Nonpasserine birds K = 78. 0.75 is the slope of the metabolic regression line that has been shown to correlate size and MR.

*** The difference between resting (inactive) and active birds has been reported to be 1.24 to 1.23 2 to 1.1 to 1.4.

1. Whittow GC: Regulation of body temperature, in Sturkie PD (ed): Avian Physiology (ed 4). New York, NY, Springer-Verlag, 1986, pp. 222-246.

2. Knut Schmidt-Nielsen, Scaling: Why is animal size so important? Cambridge University Press, 1984.



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