Faecal dry matter excretion per se affects faecal calcium and phosphorus losses in dogs

The study aimed to investigate the effect of faecal dry matter (DM) excretion on faecal losses of calcium (Ca) and phosphorus (P) without potentially confounding factors. Dogs were fed two levels of the same basal diet (cooked pork, rice, gelatine; 8.5 +/- 0.7 and 12.6 +/- L2 g DM/kg BW). Mineral supplements were added separately for identical Ca and P supply independent of DM intake (Ca 226 and P similar to 170 mg/kg BW). Digestion trials (10 days adaptation, 5 days quantitative faecal collection) were carried out. Digestibility of DM averaged 87% in both trials. Faecal DM and mineral excretion increased highly significant (DM 1.1 +/- 0.3 to 1.7 +/- 0.2 g/kg BW, p = 0.00005; Ca 185 +/- 34 and 233 +/- 22 mg/kg BW, p = 0.00119; P 99 +/- 23 to 127 +/- 12 mg/kg BW, p= 0.00212), revealing a highly significant correlation. Apparent digestibility of Ca was positive in the first trial and negative in the second leading to a slightly negative Ca retention in the latter one. The results suggest that in dogs (i) factors influencing Ca and P absorption can only be compared if faecal DM excretion is identical arid (ii) Ca requirements may be affected by DM intake arid digestibility.

Automated summary

This study aimed to investigate the impact of faecal dry matter excretion on the faecal losses of calcium and phosphorus in dogs. The results showed a significant increase in faecal dry matter and mineral excretion, with a highly significant correlation. Additionally, the apparent digestibility of calcium varied between the two trials, potentially due to differences in faecal dry matter intake and digestibility.