Although its use in zoo medicine has been limited, this approach may have
advantages over the previously described methods. Application of this method
requires acquisition of species-specific pharmacokinetic data, such as clearance
(Cl) and volume of distribution (Vd) from multiple species and plotting them against
body weight. The form of the allometric equation used in scaling pharmacokinetic
parameters across species is
Y¼aðWÞb;Table 1Observed vs. predicted clearance from mammalian data to avian speciesa
Drug Body
weight (kg)Observed
CL (mL/min)Predicted
Cl (mL/min)% errorEnrofloxacin
Turkey 5.1 37 104 181
Ostrich 44 3,268 576 82
Chicken 0.66 18 68 278
Rhea 3 179 68 62
Red-tailed hawk 1.3 5 34 580
Salicylic acid
Pigeon 0.45 0.52 0.09 83
Duck 3 8 1.89 76
Turkey 8 61 8.8 86
Ostrich 19 60 34.3 43
Chicken 2.2 7.7 1.14 85
Meloxicam
Pigeon 0.45 0.29 0.35 21
Duck 3 3.05 2.85 7
Turkey 8 7.3 8.4 15
Ostrich 19 228 21.8 90
Chicken 2.2 0.48 2 317
Flunixin
Pigeon 0.45 0.48 2.22 363
Duck 3 7 5.7 19
Ostrich 19 158 14.3 91
Chicken 2.2 0.33 4.9 1,385
Gentamicin
Red-tailed hawk 1.3 3.1 5.5 77
Owl 1.5 1.8 4.9 172
Golden eagle 3.6 5 12.3 146
Chicken 4.7 1.6 6.7 319
Turkey 11 5 13.9 178
Chloramphenicol
Pigeon 0.45 11.7 1.84 84
Duck 0.98 40 14.6 64
Turkey 11 132 32.4 75
Sulphadimidine
Japanese qual 0.13 0.077 0.064 17
Pheasant 1.2 0.11 0.64 482
Chicken 1.6 0.18 0.85 372
aData from Hunter et al. ( 2008 )Interspecies Allometric Scaling 147