Abstract
The aim of this study was to investigate the effects of feeding oats alone before or after feeding chopped alfalfa or, in admixture with the alfalfa on the glycaemic and insulinaemic responses of horses as well as post-prandial breath hydrogen and methane excretion. Horses were fed in a randomized order, chopped alfalfa as a source of dietary fibre and unprocessed oats as a source of starch. Chopped alfalfa intake was adjusted to a crude fibre intake of 0.5 g/kg bodyweight (BW) per meal and the oats intake was adjusted to a starch intake of 2 g/kg BW per meal. The feeds were offered in three different ways: (i) alfalfa followed by oats (A/O), (ii) oats followed by alfalfa (O/A) or (iii) a mixture of alfalfa and oats (A + O). Oats alone were used as a control. Blood and breath were collected after the test meal was fed at the end of a 11.5-h overnight fast following a 10-day acclimatization period. The highest glycaemic and insulinaemic responses were measured when the A/O and O/A diets orders were fed, whereas most hydrogen was produced after feeding oats alone. It was concluded that adding alfalfa chaff to a meal of oats prolonged the pre-caecal digestion of starch, but there was no evidence for any effect on pre-caecal starch digestibility.