Assessment of the minimum protein requirement of adult ponies.

The aim of the present study was to determine the minimum protein requirement in adult ponies. Literature data from nitrogen-balance trials in adult ponies were used. In addition, nitrogen balance was measured in three mature ponies that were fed a low- and a high-protein diet according to a cross-over design. On the low-protein ration, which provided 1.1 g digestible crude protein (DCP)/kg(0.75) day, plasma albumin and total protein concentrations were non-significantly decreased by about 6% and group-mean nitrogen balance was negative. Using data from the present experiment and from six other studies, the sum of endogenous faecal and urinary nitrogen losses was calculated to be 166 +/- 37 mg/kg(0.75) day (mean +/- SE, n = 13). Subsequently, a minimum protein requirement of 1.7 g DCP/kg(0.75) day was calculated. The value for minimum protein requirement has low precision, which should be taken into account when setting the protein allowance of adult ponies.