DIGESTIVE AND ENERGY-UTILIZATION OF 2 DIETS BY PONIES AND HORSES

Six adult castrated ponies and five standardbred geldings were fed at near maintenance a natural grassland hay (H) and a mixed diet (HM) com posed of 70% of the same hay and 30% of pelleted maize. Faeces were co llected over 6-day periods after adaptation to the diets. Organic matt er, energy and cell wall component digestibility was not significantly different between ponies and horses. Methane production, energy expen diture and energy balances of ponies were determined by indirect calor imetry over 4-day periods. The results were compared with those obtain ed using the same conditions with six sport horses fed similar diets ( H3 and H3M1) one year before. Methane energy losses related to energy intake were 33 and 47% higher in ponies than in horses for the hay and the mixed diet, respectively (P < 0.05). Maintenance energy requireme nts (MEm) of ponies were 16% lower than those of horses (P < 0.05). Ho wever, differences in MEm between the two diets were greater in ponies than in sport horses, which could be related to differences in the en ergy cost of eating. (C) 1997 Elsevier Science B.V.