Introduction

Maintenance energy expenditure (EE) and requirements of the cat refer mainly to body weight, sexual status and activity. A recent study did not show any effect of age or season on EE when expressed as a proportion of lean mass.

Objective

The aim of this study was to assess the effect of age on EE assessed using doubly labeled water (DLW) in cats in a wider range of age, from 1.2 to 16.6 y.

Methods

EE was determined in young (1–8 y; 7 females, 11 males, neutered) free-living cats. The space available in the indoor facilities allowed similar social activity. Animals were fed with dry foods (similar food quotient). Cats received DLW intravenously (0.170 g/kg BW of both ²H₂O and H₂¹⁸O). Blood samples were collected over a 12-d period. The free-fat mass (FFM) was assessed from body water pool (¹⁸O dilution), VCO₂ from elimination rates of ¹⁸O and ²H, and EE from VCO₂ and Weir formula.

Results

EE varied among the age groups (but not between genders) when corrected for BW, BW^0.75, FFM or FFM^0.75. The lower EE in aged cats was especially confirmed in 12 animals in which EE was assessed twice, when they were 1.2 y then 12.7 y old (78 ± 2 vs. 66 ± 3 kcal/kg BW^0.75; 102 ± 2 vs. 85 ± 3 kcal/kg FFM^0.75).

Conclusions

These results confirm the decreasing effect of age on EE corrected for BW or FFM (approximately 15% less from 1.2 to 12.7 y).