Comportement alimentaire et état de réplétion du réticulo-rumen chez le mouton nourri à volonté de foin de prairie ou de luzerne, avec accès continu ou limité : incidences sur le contrôle physique de l'ingestion

Abstract

1) The effects of limiting time of access to forage (twice 1 hr 30 min vs continuous access) on feeding behavior and reticulo-ruminal fill were studied with two hays: a late cut grass hay and an early second cut lucerne hay. 2) With continuous access to forage, voluntary intake of lucerne hay was higher (1,693 g dry matter (DM) per day) than that of grass hay (974 g DM per day). Lucerne hay was eaten more rapidly and needed less mastication per g DM. With limited time of access, eating rates were increased, but voluntary intake was maintained only with the grass hay. 3) With continuous access to forage, rumen pool sizes (RPS) of fresh matter, DM, organic matter (OM), and fibre were higher after the evening main meal than after the morning main meal. RPS were always lower with lucerne hay, except after the evening meal. With limited time of access, RPS after the morning meal were higher than those reached by continuous access, but this was not true after evening meal. 4) The net removal of DM and OM, but not of fibre were increased during the main meal, and turnover rates of DM, OM and fibre were higher for lucerne hay. 5) These results confirm that the maximum degree of rumen fill is involved in the control of voluntary intake. However, rumen fill does not seem to control intake during the whole day and other factors may be involved, specially with rapidly digestible hays.