Felinine excretion in domestic cat breeds: a preliminary investigation.

The aim of this study was to determine possible differences in felinine excretion between domesticated cat breeds. For this purpose, urine was collected from a total of 83 privately owned entire male cats from eight different breeds in the Netherlands during the period of November 2010 till November 2011. In the collected samples, free felinine and creatinine concentrations were measured. Free felinine concentrations were expressed relative to the urinary creatinine concentration to compensate for possible variations in renal output. The mean (±SD) felinine:creatinine (Fel:Cr) ratio as measured over all cats was 0.702 (±0.265). Both the Abyssinian and Sphynx breeds showed the highest Fel:Cr ratio (0.878 ± 0.162 and 0.878 ± 0.341 respectively) which significantly differed from the ratios of the British Shorthairs (0.584 ± 0.220), Birmans (0.614 ± 0.266), Norwegian Forest cats (0.566 ± 0.296) and Siberian cats (0.627 ± 0.124). The Fel:Cr ratios of the Persians (0.792 ± 0.284) and Ragdolls (0.673 ± 0.256) showed no statistical difference with either of the other breeds. A significant proportion of the observed variation between the different feline breeds could be explained by hair growth, as both hair growth and felinine production compete for available cysteine. Shorthaired and hairless cat breeds generally showed a higher Fel:Cr ratio compared to longhaired cat breeds, with the exception of Persian cats. Further research is warranted to more closely study the effect of hair growth on felinine production.